Soft heat pipes have many potential applications in the thermal management of the human body and flexible electronic devices. However, the flexibility and heat transfer capability of the current soft heat pipes are limited, which cannot meet the requirements for engineering applications. In this work, according to the working principle of a pulsating heat pipe, a soft multi-branch heat pipe was fabricated by Teflon tubes, where acetone was used as the working fluid. As each heat transfer branch could deform independently, the proposed heat pipe exhibited excellent flexibility. Meanwhile, the proposed heat pipe also has high heat transfer performance with the apparent thermal conductivity being up to 4333 W·m⁻¹·K⁻¹. Therefore, the proposed soft heat pipe can contribute to the development of thermal management garments, cooling of electronic devices, low-grade waste heat recovery.

Sugar alcohols are gaining attention as highly promising medium-temperature phase change materials (PCMs) due to their superior overall performance. Currently, the evaluation of the comprehensive performance of sugar alcohol composite PCMs optimized for a single objective remains incomplete. In this study, erythritol (Ery) was used as a PCM, combined with expanded graphite (EG) and Al₂O₃ as additives. A ternary composite PCM was prepared using the melt blending method, and its comprehensive performance was assessed. The results showed that the components of the ternary composite PCM exhibited excellent physical compatibility. Among them, the ternary composite PCM with 0.5%(wt) Al₂O₃ / 1.5%(wt) EG/Ery demonstrated the best overall performance. This ternary composite PCM maintained a high melting enthalpy of 312.9 kJ/kg and, compared to Ery, achieved a thermal conductivity of 1.083 W/(m·K), an increase of 54%. In the isothermal cooling test, its supercooling degree was reduced by 9.3°C, in the non-isothermal cooling process, its supercooling degree was reduced by 16.7°C. The pyrolysis temperature increased by 20°C, and the maximum pyrolysis rate temperature increased by 8.3°C, significantly enhancing thermal stability. Additionally, after 40 isothermal cycling tests, its supercooling degree and melting enthalpy remained essentially unchanged, demonstrating excellent cycling stability.

Frosting usually has a negative impact on device, when ultrasound is used for frost retardation/defrosting, can realize no downtime defrosting, cooling and heating without interruption during defrosting time. But due to its mechanism is not clear, technical difficulties to pragmatize, failed to get popularization and application. This paper reviews the research progress of ultrasound in the field of frost retardation and defrosting from two aspects of its mechanism and pragmatization. Firstly, the ultrasound characteristics is introduced, including commonly used ultrasound wave types and their propagation, ultrasound effects on frost retardation and defrosting, distribution of equivalent force on the cold surface; then, the growth of frost is inhibited by delaying the generation of liquid droplets, delaying the freezing of droplets, crushing the frozen droplets and suppressing the frost branch growing; based on the frost crystal fracture breaking, defrosting effecting factors and defrosting enhancement methods, ultrasonic defrosting mechanism is summarized; and, from the equipment frost retardation/defrosting effects and its energy consumption comparison, practical difficulties and problems, the ultrasound frost retardation/defrosting practical applications is sorted; Finally, a outlook of the ultrasound used for frost retardation/defrosting in the future is given to provide reference.

The photovoltaic-thermoelectric hybrid power generation system is a promising solar energy technology. However, traditional series-connected photovoltaic-thermoelectric system faces challenges such as mismatched device operating temperature and high thermal resistance. In this study, a bifacial type photovoltaic-thermoelectric hybrid power generation system with a sandwichlike configuration is proposed. An experimental setup is constructed to investigate the effects of different irradiance levels and cooling water flow rates on the performance of the new system under steady-state indoor conditions. Experimental data shows that the output power of photovoltaic module and thermoelectric device in bifacial type system is superior to that of traditional series system. Moreover, increasing irradiance levels can enhance the system’s power generation capacity but may reduce the photovoltaic power generation efficiency. Additionally, increasing the cooling water flow rate can further enhance the system’s output performance.

Thermal conductivity is an important parameter reflecting the thermal properties of materials, whether it is used for heat dissipation or insulation. It is of great significance to accurately measure the thermal conductivity of materials. This paper reviews a thermal conductivity measuring method with strong adaptability, convenient testing, simple sample preparation, and low-cost— the 3ω method. Firstly, the basic principle of 3ω method was introduced. Then the analytical solutions for temperature of heat conduction mathematical models under different sample structures are provided, including semi-infinite substrates, thin film systems, multi-layer structures, and fine rod or filament-like sample. Various improved 3ω methods are introduced, including the anisotropy of thin film thermal conductivity, differential 3ω method that can reduce the influence of irrelevant factors, and the method of fitting thermal conductivity using impedance models through thermal penetration depth equivalence. At the same time, the application of 3ω in sensors are introduced. Finally, the possible errors in the experiment process and the methods to improve the accuracy are analyzed. This paper will help researchers to study the thermal conductivity measurement and provide guidance for the design and analysis of 3ω method.

During the energy release phase of the compressed air energy storage (CAES) system, the air pressure in the storage device gradually decreases. When it falls below a certain threshold, the unit cannot maintain the rated total output power. To address this issue, the study proposes the applications of bypass systems in the CAES system expanders. In this paper, three types of bypass systems are designed for the expander unit of a CAES system: single-stage bypass systems (3 configurations), two-stage bypass systems (3 configurations), and three-stage bypass system (1 configuration), with a total of 7 configurations. By adjusting the openings of the main and bypass valves, the total inlet and outlet pressures of certain turbines are modified, thereby changing their mass flow rates and output powers to achieve the rated total output power. The results show that 5 configurations can achieve the desired performance. The three-stage bypass system enables the lowest terminal air pressure in the storage device, expanding the sliding pressure operation range of the unit. The optimal configuration is the two-stage bypass system that independently controls T1 and T2, which achieves the longest power generation duration and the highest energy density, representing a 71.25% improvement compared to the original unit. Therefore, adopting the bypass control methods can extend the power generation duration and increase the energy density of the CAES system.

Ortho-para hydrogen conversion is an indispensable process in hydrogen liquefaction system. This paper summarizes the experimental research progress of ortho-para hydrogen conversion, comprehensively compares the advantages and disadvantages of various ortho-para hydrogen conversion schemes, analyzes the differences between typical ortho-para hydrogen catalysts, such as iron hydroxide and oxide catalysts and supported nickel catalysts, in terms of the activation methods and catalytic efficiencies, and further summarizes various measurement methods for ortho-para hydrogen concentrations as well as their measurement principles. Regarding the selection of catalysts for ortho-para hydrogen conversion, the literature findings indicate that supported nickel-based catalysts have higher catalytic efficiencies, but taking full consideration of catalyst preparation, activation, deactivation, and liquefier operating requirements, iron hydroxide as well as its oxide catalysts are still the mainstream catalysts for application-oriented catalytic choices. Among the measurement methods of ortho-para hydrogen fractions, compared with spectroscopy, acoustic velocity measurement, nuclear magnetic resonance, enthalpy measurement, etc., the ortho-para hydrogen concentration measurement based on thermal conductivity method has comprehensive advantages in terms of accuracy, response speed, economy and operability, which can be used as the preferred solution for the measurement of ortho-para hydrogen concentration. As large-scale hydrogen liquefaction plants are developing towards the direction of higher efficiency, compactness and reliability, continuous conversion is the mainstream solution for ortho-para hydrogen conversion in the future hydrogen liquefaction processes. However, at present, most of the domestic studies on continuous ortho-para hydrogen conversion remain in conceptual analysis and process application, lacking data on hydrogen conversion, flow and heat transfer under cryogenic conditions, as well as relevant high-precision correlation equations. Based on the measured data of continuous catalysis and cooling of orthopara hydrogen, the development of high-precision correlations for heat transfer, pressure drop and catalysis of hydrogen eat exchangers, and the accurate design of heat exchangers for continuous ortho-para hydrogen conversion, will be an urgent task to be carried out in the future.

The International Maritime Organization (IMO) and port States have increasingly stringent requirements for ship energy efficiency, and the improvement of ship energy efficiency based on waste heat recovery is one of the most effective ways to meet this challenge. TEG-ORC combined cycle is a new method to realize the utilization of multiple waste heat steps in ships, but the effect of bottom cycle ratio on the performance of combined cycle system has not been studied in detail. The theoretical model is optimized and the influence of variable bottom cycle ratio on the performance of the main parameters of the combined cycle system is studied experimentally. The experimental results show that under the conditions of ORC bottom cycle working medium R245fa, working medium mass flow rate m = 0.079 kg/s and evaporation pressure P = 0.7 MPa, with the gradual increase of bottom cycle ratio, the system output power and flue gas waste heat utilization rate of the main engine increase, and the cost of combined power generation decreases. When the bottom cycle ratio of TEG/ORC is 0.885, the flue gas waste heat utilization rate of the main engine is 85.07%, the total output power of the system is 688.4 W, the thermal efficiency of the system is 7.07%, and the power generation cost of the combined cycle system is 3.338 CNY/kWh.

Bag breakup is a typical breakup mode of the Supercooled Large Droplet (SLD) in the field of aircraft icing. The deformation and breakage processes of a water droplet in continuous airflow is studied by combining experimental and numerical simulation methods. A regime map is drawn to give the physical boundary of the bag breakup mode. The deformation ratio, velocity of the initial droplet and size distribution of the secondary droplets are analyzed, and the causes of droplet morphology evolution in each stage of the bag breakup mode are explained. The results show that the range of gaseous Reynolds number and Weber number corresponding to the bag breakage mode are 3100∼4250 and 12∼18, respectively. At the disk moment, the horizontal deformation ratio of the droplet is about 0.4, and it varies slightly with the increase of gaseous Weber number. While, the vertical deformation ratio of the droplet increases gently with the increasing gaseous Weber number. When the gaseous Weber number is 13.4, the droplet breaks in the bag breakup mode. The dimensionless size distribution of the secondary droplets ranges from 0 to 0.28, showing a unimodal distribution, and the peak value appears when the dimensionless size of the secondary droplet is 0.024. This study plays a crucial role in improving the physical model of SLD bag breakup and advancing the simulation accuracy of SLD icing.

Pre-chamber jet combustion technology is a crucial pathway for achieving breakthroughs in the thermal efficiency of spark-ignition engines. However, there are still many research gaps regarding the combustion mechanisms of pre-chamber engines. This paper reviews the development of pre-chamber engine jet combustion technology and reports recent advancements in laser diagnostics and numerical simulations of pre-chamber engine jet combustion. Research indicates that the ignition modes of pre-chamber engines can be categorized into “flame ignition” and “jet ignition”. In the flame ignition mode, flame quenching does not occur at the pre-chamber nozzle, resulting in good combustion stability and improved engine thermal efficiency. Due to the large flame quenching distance of ammonia fuel, pre-chamber ignition tends to exhibit the jet ignition mode, which can lead to reduced combustion stability and thermal efficiency of the engines.

Detonation engines, compared with traditional aviation engines that adopt the Brayton cycle, have higher unit thrust and lower fuel consumption rate, and thus have broad application prospects. Rotating detonation engines have attracted significant attention in the global aerospace field in recent years due to their advantages such as high operating frequency, single ignition and low start Mach number. The funding intensity and engineering application progress of various countries in this research field are all in a state of rapid development. In view of this, this paper conducts a comprehensive review of the research progress of rotating detonation in the international community. It analyzes the current research status of multiple key technical problems in turbine-based rotating detonation engines, and elaborately describes the breakthrough progress made by our research team in these fields. Finally, it looks forward to the future development of turbine-based rotating detonation engines and puts forward development suggestions for each research direction. The subsequent research work on turbine-based rotating detonation engines will focus on three application directions: internal/external afterburning detonation and turbine-ramjet rotating detonation combined engines. Key technical challenges such as reliable initiation of combustor over a wide range, modulation and propagation stabilization of detonation wave modes, optimization of combustor and injection structures, suppression of pressure feedback, efficient thermal protection of combustor, and stable matching of engine will be overcome to accelerate the engineering application of rotating detonation engines.

As a natural refrigerant, CO₂ exhibits excellent environmental performance and low production costs, making it an ideal replacement for high-GWP refrigerants. To enhance system efficiency, vapor injection technology, characterized by its simple structure and reliable operation, has been widely employed in CO₂ heat pump systems. However, these systems still face significant challenges in practical applications due to inherent issues such as high operating pressures and substantial throttling losses. To address these challenges, this study incorporates three low-pressure refrigerants into the CO₂ heat pump system to improve operational efficiency and reduce system pressure. The research findings demonstrate that the CO₂/R161 system surpasses traditional CO₂ heat pump systems in terms of energy efficiency. The CO₂/R161 system achieves up to a 17.6% increase in efficiency under various thermal demand conditions and a maximum pressure reduction of 33.7% at an outlet water temperature of 85°C, compared to conventional CO₂ heat pump systems.

The efficiency of the supercritical carbon dioxide (SCO₂) Brayton cycle is closely related to the parameters of the components in the cycle system. Based on the MATLAB/Simulink platform, a modularized calculation procedure for the SCO₂ Brayton cycle was established. The design and analysis of a large capacity coal-fired power generation system were carried out using split flow recompression and secondary reheating schemes, and the influence of relevant parameters of components was investigated, such as turbines, compressors, and flue gas coolers. The results showed that the optimal split ratio of the recompressor decreased with the increase of turbine inlet pressure; The power distributions of the heater exchangers in boiler were significantly affected by the split ratio of the flue gas cooler; The circulation efficiency of the system reached its highest level at 35 MPa and 600°C , when the primary reheat pressure and secondary reheat pressure were 25 MPa and 16 MPa, respectively, and the split ratio of the recompressor and the flue gas cooler is 0.3 and 0.05, respectively; As the inlet temperature and pressure of the compressor increased, the circulation efficiency gradually decreased. The research results of this article have important reference value for the establishment and optimization of the large-scale coal-fired SCO₂ power generation systems.

Inverse heat transfer problems involve the estimation of the internal characteristics or thermal boundary conditions by using the internal or surface temperature measurements in the heat transfer system. Inverse heat transfer problems widely exist in scientific and technological fields such as energy and power engineering, metallurgical engineering, intelligent mechanical manufacturing, biomedical engineering, and aerospace. In the past half century, research on the calculation methods and applications of inverse heat transfer problems have been very active. In this article, the research progress on the application of inverse heat transfer problems is surveyed and the research progress of calculation methods for inverse heat transfer problems is systematically elaborated; the current challenges and future development directions of the calculation methods and application research of inverse heat transfer problems have been laid out to promote the development of numerical calculation technology and applications for inverse heat transfer problems, empower production practice with research of heat transfer inverse problems, contribute to the construction of industrial digital twins, and contribute to the implementation of China’s digital transformation national strategy. 

To address the challenges of carbon dioxide capture in hydrogen production and electricity generation from fossil fuels, as well as the supply-demand mismatch in the utilization of intermittent and unstable solar energy, this paper proposes a solar-driven hydrogen and electricity cogeneration system with source decarbonization. The system employs an iron-nickel mixed oxygen carrier, which reduces the reduction reaction temperature while achieving efficient carbon dioxide capture. The results indicate that under a solar irradiance of 750 W/m², the system achieves a solar energy input ratio of 30.80%, with energy utilization rates of 67.23% and 59.47% for hydrogen production and electricity generation under design conditions, respectively. In addition, by regulating the sensible heat of the inlet oxygen carrier and its oxidation degree during the reaction process, the system can operate stably under varying irradiation conditions and flexibly adjust hydrogen and electricity outputs. When the solar irradiation intensity is 750 W/m², the adjustable hydrogen-toelectricity ratio ranges from 0.17 to 0.59 m³/kWh, demonstrating excellent adaptability to varying operating conditions. This study offers a novel technological pathway for highly efficient hydrogen and electricity co-production and source decarbonization through the complementary use of solar energy and natural gas.

Hydrogen production is considered to be a promising new hydrogen production method in the future. However, there are high overpotential and slow kinetic process of oxygen evolution reaction (OER), and corrosion of the electrode caused by chlorine evolution reaction (CER), which make the hydrogen production technology of seawater electrolysis face great challenges. In recent years, relevant studies have shown that coupling the anodic oxidation reaction of hydrazine, urea, sulfide, sugars, microplastics and other substances into the seawater electrolysis hydrogen production system can replace OER, avoid problems such as chlorine corrosion and achieve higher economic benefits. This paper systematically reviews the principle, challenges and the research status of related catalysts, focuses on the progress of the oxidation reaction of electrolytic seawater with lowenergy consumption in recent years, and finally discusses the problems that need to be breakthrough and the future research direction.

With the increasing integration of renewable energy, the inherent uncertainty of energy sources and loads, coupled with the nonlinear coupling characteristics of multi-energy systems, poses significant challenges to the operation and management of distributed energy systems. This paper accounts for the nonlinear characteristics of electricity-heat transmission and conversion processes by incorporating a heat current model and a column-and-constraint generation algorithm, proposing a two-stage robust optimization model and a bilevel iterative optimization algorithm. Compared to a simplified robust optimization model that neglects nonlinear characteristics, the proposed approach reduces operating costs by 3.2%. Furthermore, the results demonstrate that in actual system operation, the proposed algorithm effectively mitigates the infeasibility risk of robust scheduling strategies caused by model simplifications, thereby verifying its economic efficiency and robustness. 

Multi-energy co-generation systems are crucial for improving energy efficiency, enhancing system flexibility, and integrating various energy sources for end users. This paper proposes a largescale, cross-seasonal, and cross-regional CO₂-based combined cooling, heating, power and fuel system. A thermodynamic model of the system is developed to investigate the effects of parameters such as CO₂ mass flow coefficient, internal waste heat, compression/expansion stages, and intercooler outlet temperature on system performance. The results show that as the ratio of CO₂ mass flow rate within the CO₂ energy storage module to that captured by the direct air capture module increases from 200 to 600, the system energy utilization factor improves from 75% to 85%. When the expansion stage number is 3, 4, 5, 6, 8, 10, 11, 13 and 15, the system begins to generate cooling energy at higher compression stages. When the compression and expansion stages are 14 and 5, the system energy utilization factor reaches its maximum value of 105%. The optimal electrical roundtrip efficiency and system energy utilization factor are 70% and 105%, respectively.

In order to solve the problem of mismatch between heat source temperature and evaporation pressure in low-pressure stage, a double gas-liquid separator (DS-DPORC) system was proposed based on the basic dual-pressure organic Rankine cycle (DPORC) system. The thermal performance of DPORC and DS-DPORC system is compared and analyzed. Both traditional and advanced exergy analysis methods were used to study the improvement potential and interaction relationship of the optimized DS-DPORC system and its components. It is shown that there is an optimal evaporation pressure at high and low-pressure stages, respectively, which enables the thermal performance of both systems to reach the optimal level. At that time, DS-DPORC had a 10.02% increase in net output compared to DPORC, while the exergy efficiency increase was 10.4%. There are differences between traditional and advanced exergy analysis methods. The former thinks that the preheater with the highest exergy destruction has the greatest potential for improvement, while the latter thinks that the high-pressure turbines has the highest priority for improvement considering both the exergy destruction rate and the exergy destruction. In addition, exergy destruction of various components in the DS-DPORC system mostly belongs to internal exergy destruction, and the exergy destruction of components is relatively poor in inter dependency.

Global warming is one of the major challenges for the mankind. In order to reduce CO₂ emissions, it is necessary to build a new low-carbon/carbon-free and sustainable energy system. Ammonia, with its excellent fuel properties and carbon-free characteristics, as well as its ease of liquefaction and storage, shows great potential for development in the energy transition. However, there are challenges in the ammonia combustion process, including flame instability and high NO_x emissions. This paper reviews options to improve the flame stability and reduce NO_x emissions of ammonia through the addition of reactive small molecules, hydrogen-ammonia co-combustion, oxygen-enriched combustion technology, plasma-assisted combustion, and mild combustion. When hydrogen-ammonia fuel is used in combustion engine oriented, the ammonia combustion flame is more stable at high pressure, and the rich and lean combustion blowout equivalence ratio can be slightly prolonged by increasing the pressure due to the enhanced combustion intensity and denser flame at high pressure. Liquid ammonia has energy consumption and cost issues for combustion engine applications, but the stability of its spray flame can be improved by preheating the air and co-firing small molecule fuels.

Carnot battery is an emerging energy storage technology characterized by low cost and independence from geographical constraints. The use of latent heat thermal energy storage in Carnot battery results in high energy density, offering broad application prospects. This paper constructs a Carnot battery system based on a packed bed latent heat storage and establishes its dynamic model. The analysis includes the impact of heat transfer fluid flow rate and organic working fluid mass flow rate on system performance. A functional relationship for the mass flow rates of the heat transfer fluid and organic working fluid has been established at a design power of 1000 kW. Subsequently, using the NSGA-II algorithm for multi-objective optimization with roundtrip efficiency and energy density as optimization objectives. After balancing using the LINMAP method, the roundtrip efficiency and energy density obtained were 62.74% and 12.96 kWh/m³.

Membrane electrode assembly (MEA) is a key part of electrocatalytic carbon dioxide reduction (eCO₂RR), which converts carbon dioxide into valuable chemicals and fuels. This paper proposes a structural design of a CO₂ reduction electrolyser based on a membrane electrode assembly to simultaneously achieve the diffusion of CO₂ and the timely discharge of the product carbon monoxide (CO). The experiment investigated the effects of different flow channel configurations on the catalytic activity, product distribution and current density of the reaction system. The results showed that the vein-shaped bionic flow channel achieved a CO Faraday efficiency of up to 96.72 % at a cell voltage of 2.5 V and a current density of 115 mA·cm⁻². Combined with numerical simulation, the coupling relationship between CO₂ mass transfer and electrochemical reaction was established. 

To deeply investigate the distribution of liquid water in the proton exchange membrane fuel cell, a two-dimensional model of non-isothermal two-phase flow including gas-water-heatelectricity-force multi-physical fields was developed in this paper to simulate the cell performance and liquid water distribution of two different types of gas diffusion layer (GDL) materials at the operating conditions of 80°C, 200 kPa abs, and 80% RH. Performance tests and neutron radiograph experiments were also conducted and compared with the simulation results. The results show that the cell with Freudenberg GDL have a better performance compared to the cell with Toray GDL, especially at high current density. The peak liquid water saturation using Toray GDL occurs in catalyst layer under the ribs, and it can reach to 0.4. The peak liquid water saturation using Freudenberg GDL occurs in the gas diffusion layer under the ribs, and it can reach to 0.25.

It remains an open question in thermophysics to understand and model inelastic phonon scattering in heat transport at solid/solid interface. In this work, we develop a theoretical model to compute and spectrally decompose the energy exchange at the interface based on anharmonic phonon non-equilibrium Green’s function method, to study the interfacial heat transport at Si/Ge interface. For high-frequency phonons, local anharmonic scattering dominates the interfacial energy exchange, while both local and non-local scattering are important for moderate- and low-frequency phonons. The anharmonic decay of interfacial phonon modes plays a crucial role in bridging the bulk phonon modes at both sides of the interface. This work will promote the understanding of interfacial heat transport mechanism and future development of theoretical models.

With the development of electric vehicles and electronic devices, the two-phase immersion cooling technology using dielectric coolants has gradually attracted attention due to its significant advantages in temperature control performance and integration. The demand for the application of this technology in low-temperature conditions is also increasing. However, there is currently limited research on the boiling heat transfer of dielectric coolants, especially at low temperatures. This study investigates the effect of liquid static pressure on the boiling heat transfer characteristics of Novec 7100 on a smooth copper surface under low saturation pressure conditions using an airtight experimental system with controllable saturation pressure (temperature). The experiment reveals a unique trend of critical heat flux decreasing first and then increasing with decreasing saturation pressure. After the saturation pressure drops below 8.34 kPa, the pool boiling process exhibits “intermittent boiling” and “self-induced subcooled boiling” as two distinct heat transfer modes, and the critical heat flux increases with the liquid height. When the saturation pressure is 0.741 kPa, the critical heat flux values at liquid levels of 23 mm and 35 mm show the greatest difference, approximately 39 kW/m².

A combined cooling, heating and power(CCHP) system with solid oxide fuel cell (SOFC) coupled with chemical chain combustion (CLC) carbon capture is proposed. After methanol reforming, H₂ is separated by membrane separation technology to drive SOFC to generate electricity, and the remaining syngas is burned into the chemical chain to achieve carbon capture, and supercritical carbon dioxide (SCO₂) Brayton cycle, absorption refrigeration system (ARS) and heating system are integrated to realize cascade utilization of energy. The performance analysis models of key components and the whole CCHP system are constructed, and the effects of key parameters such as reforming reactor temperature, water-carbon ratio, SOFC operating pressure and temperature on the system performance are studied. A combination of energy analysis and analysis was used to comprehensively evaluate the performance of the system. The energy efficiency and exergy efficiency of the new system reach 66.29% and 57.70%. Compared with the reference system of traditional CCHP system with SOFC without integrated with chemical chain combustion, after achieving a CO₂ capture rate of more than 99%, the power generation efficiency of new system is about 1.95% higher than that of the reference system and the exergy efficiency of new system has an increase of 0.75%.

Open microchannels have advantages such as promoting vapor-liquid separation, stabilizing two-phase flow, and improving heat transfer performance. However, with the increasing demands for thermal management of electronic devices, enhancing the flow boiling heat transfer capacity of open microchannels has become a research focus. In this study, low-surface-tension fluid SF-33 is used as the working fluid to experimentally compare the flow boiling characteristics in smooth surface open microchannels (SSOMC) and multi-stage enhanced open microchannels (MEOMC). High-speed visualization is employed to observe bubble behavior and flow regime transitions in both types of microchannels, analyzing the effect of micro/nano structures on flow boiling heat transfer mechanisms. The results show that under high heat flux, a plug-stratified flow is observed in SSOMC, while a new flow regime, termed plug-dispersed flow, is observed in MEOMC. The multi-stage enhanced structures significantly improve the flow boiling heat transfer performance of open microchannels, with a more pronounced improvement during subcooled flow boiling. Additionally, due to the strong capillary wicking effect of the micro/nano structures, the two-phase pressure drop in MEOMC is consistently lower than that in SSOMC.

Heat dissipation with high heat flux has always attracted much attention. In this paper, a heat dissipation scheme of liquid metal jet impinging cooling is proposed in order to achieve efficient heat dissipation on the surface with high heat flux density. Using Ga₆₈ln₂₀Sn₁₂ and Na₂₂K₇₈ as working fluids, the numerical simulation of impinging heat transfer of liquid metal jet was carried out, and compared with water jet. In addition, the firing distance and inlet velocity were changed to explore their effects on the heat transfer performance of liquid metal jet. The results show that under the same working conditions, the average heat transfer coefficient of Na₂₂K₇₈ jet and Ga₆₈ln₂₀Sn₁₂ jet is 3.7 and 6 times higher than that of water jet, respectively. And the heat transfer performance is the best when the firing distance is less than 2 times the jet aperture. Changing the firing distance in the jet core area has little effect on the heat transfer performance. While continuously increasing the firing distance beyond the core area will not be conducive to heat transfer. The inlet flow rate has a significant effect on the heat transfer performance. So increasing the flow rate can enhance the heat transfer, but the enhancement effect will gradually weaken. The research results of this paper are of reference value for the study of heat dissipation with high heat flux.

In order to eliminate the influence of the discontinuous curvature on the performance of the compressor airfoil and improve the optimal design capability of compressor cascade, a parameterization method with a continuous-curvature surface was proposed. The curvature continuity condition of the two Bezier curves at the connection point can be achieved, by using the connection of the endpoint guide vector and the control point of the Bezier curve to make the corresponding control point satisfy a specific relationship. Based on this property of the Bezier curve, the leading edges and trailing edges of the compressor blade are reconfigured. In order to remove discontinuous curvature at the connection point between the leading edge and the airfoil，the least squares method was used to fit the suction section and pressure section of compressor airfoil in the parameterization process. The numerical simulation method is used to calculate the flow field, and the aerodynamic performance of the parameterization airfoil and the original airfoil are compared. The results show that the parameterization method can obtain a continuous-curvature surface, which can effectively improve the flow condition of the leading edge and improve the aerodynamic performance of the compressor airfoil.

To address the core challenge of low salt resource utilization in solar desalination, this study designs a biomimetic ion-channel graphene oxide/polyamide (GO/PA) interfacial evaporator. By tuning the charge characteristics of the PA layer, a dual-negative GO/PIP membrane and a heterogeneously charged GO/PEI membrane were developed. The GO/PIP membrane achieves selective separation of Cl−/SO²⁻₄ through the Donnan effect and size sieving effect while inducing NaCl crystallization at the membrane edge via lateral ion channels. In contrast, the GO/PEI membrane forms a vertical electric field within the membrane, driving the directional migration of anions and cations, thereby effectively inhibiting salt deposition in the short term. Experimental results show that the evaporation rate of the GO/PA membrane is more than 2.6 times higher than that of pure water, with the GO/PIP membrane exhibiting the highest evaporation rate of 1.94 kg·h⁻¹·m⁻². The crystallization rate of the GO/PIP membrane reaches 280 g·m⁻²·h⁻¹, and after three cycles, the NaCl purity reaches 96.13% (separation factor 3.5). The anti-salt crystallization dynamic equilibrium strategy proposed in this study provides an engineering-ready solution for achieving zero-liquid discharge treatment of high-salinity wastewater. 

When Reynolds number decreases to near the critical value (approximately 2×10⁵), the separation-transition process on the surface of compressor blade/endwall induces strong turbulent fluctuations, leading to a sharp degradation in efficiency and stability margin. However, the transition mechanisms and the spatio-temporal evolution of multi-scale vortex structures under different Reynolds numbers remain unclear, making it difficult to accurately identify the core factors responsible for the performance degradation of compressors. In this study, a high-subsonic compressor cascade is selected to explore the instability of separated shear layers and vortex dynamics under various Reynolds numbers, thereby clarifying the mechanism of performance variation. The results indicate that disturbances in the separated shear layer initially exhibit exponential growth, followed by nonlinear effects that trigger the onset of transition. As the Reynolds number decreases from 4.5×10⁵ to 1.5×10⁵, the disturbance growth rate in the shear layer declines, nonlinear effects are delayed, and the transition onset and end locations shift significantly downstream, with the separation bubble length increasing by 122%. Concurrently, the vortex shedding frequency in the shear layer decreases, while the roll-up and breakdown intensity of three-dimensional hairpin vortices at the late transition stage intensify, leading to a rapid expansion of high-level Reynolds shear stress regions and a 241% increase in loss. A rapid increase in the pressure gradient at the separation point under low Reynolds numbers is identified. Then, a correlation model between the pressure gradient at the separation point and the separation scale/boundary layer growth rate under different Reynolds numbers is established, which accurately pinpoints the key sensitive parameters responsible for performance degradation. This provides direct theoretical support for compressor blade design and flow control strategies under low Reynolds number conditions。

The optimization of centrifugal compressors steps into data-driven pattern with the introduction of the surrogate model, while the optimization is still based on the quasi-three design method. However, the input parameters completely rely on experience of designer. It is necessary for centrifugal impeller design to establish data-driven optimized design method. Based on the quasithree design method, adopted all-over-controlled vortex method and combined k-fold cross validation method, the swirl distribution provided by the designer is optimized in full operation range. The numerical results indicate that the efficiency at design condition increases by 0.61%. Finally, the parameters sensitivity is analyzed by Sobol global sensitivity analysis method. The results show that the efficiency at design condition is more sensitive to the leading edge loading, while the trailing edge loading has more effects on the stall margin. This research is driven by data, and has a certain reference value to the design of a large flow coefficient centrifugal compressor. 

In view of the randomness of the initial population diversity and limited local optimal ability of the snake optimization algorithm, an Improved Particles Transmit Information Snake Optimization (IPTISO) algorithm is proposed. By using a strategy to update the worst individual in different stages of egg laying, the global search ability and local search ability of the algorithm are balanced, and Circle chaotic mapping is introduced in the initial stage to improve the diversity of the population. At the same time, a pheromone induction method was introduced to change individual characteristics during the fighting and mating stages. By using the above improved method and introducing the green certificate-carbon trading mechanism, the power system of 1 concentrated solar power station and 10 thermal power units is solved, and various scheduling scenarios are analyzed and compared with other classical algorithms. The results show that compared with other algorithms, IPTISO algorithm can obtain the optimal economic and environmental scheduling scheme, which provides a new way to solve the optimal scheduling problem of power system.

A 520 mm diameter constant volume bomb model was constructed using the CONVERGE software to investigate the effects of the ammonia/diesel injector angle, ammonia/diesel injector injection angle and ammonia injection timing on mixing and pilot diesel ignition characteristics of high pressure liquid ammonia spray. The results show that optimal contact positions and diesel flame development area can elevate the peak of heat release rate. Smaller angle between ammonia/diesel injector is beneficial for the intersection of ammonia spray with the flame, enhancing the ignition effect. Larger injector injection angle will accelerate the ignition timing of ammonia spray. The impact location of ammonia spray on the flame is influenced by the ammonia injection timing, and collision position has an impact on ammonia ignition and emissions. Proper control of the injection timing helps optimize the contact between ammonia spray and the diesel flame. 

Synthetic lubricating oil is widely used in various types of refrigeration and heat pump equipment, and its thermophysical properties are the basic data for analyzing thermodynamic energy efficiency, heat transfer performance and pressure drop along the way, which is of great significance for evaluating and optimizing the system structure. In this paper, a set of low-temperature and high-pressure pendant drop surface tension experimental measurement system was developed, and the liquid phase density and surface tension of basic lubricating oils (POE, PVE and PAG) were studied by using vibrating tube density meter and pendant drop surface tension experimental system, and the measured temperature range was 243.15∼363.15 K, and the extended uncertainty of liquid phase density and surface tension measurement was within 0.2% and 0.1 mN·m⁻¹, respectively. The experimental results show that the liquid phase density and surface tension of the base lubricating oil decrease with the increase of temperature, and the absolute average deviation between the calculated value and the experimental value of the correlation equation is less than 0.04% and 0.5%, respectively.

The achievement of distant, directed, and high-speed movement of liquid droplets on solid surfaces holds significant importance in applications such as water collection and energy recovery. Currently, researchers have made substantial progress in magnetic, thermal, and electric fielddriven methods. Among these, the dielectric wetting driving mechanism has garnered widespread attention due to its advantages of fast response, low energy consumption, and simple device setup. However, current electric wetting driving is predominantly conducted on hydrophobic surfaces, imposing certain limitations on speed. In recent years, the excellent performance of superhydrophobic surfaces has been extensively studied. Yet, there is limited literature on the electric wetting-driven motion of liquid droplets on superhydrophobic surfaces. This paper proposes a method for preparing a superhydrophobic surface and further achieves ultra-high-speed electric wetting-driven droplet motion on this surface. Experimental results indicate stable control over saline water, acids, bases, and certain organic reagents. This is of significant importance for the further expansion of electric wetting-based digital microfluidic technologies.

The staggered height layout has a great influence on the overall wake structure of wind farms. In order to study the effect of small wind turbine operation on the wake in a staggered-height wind farm, a wind tunnel was used to study the evolution of the wake in the smooth flow by small wind turbines operating at different location in downstream of the large wind turbine downstream. The results show that the operation of a small wind turbine exacerbates the cleavage of the vortex structure inside the wake and reduces the contribution of the vortex turbulence kinetic energy to the whole field energy to 1/4 of that in the case of no small wind turbine operation, and the extent of the effect in the vertical direction diminishes with the increase of the height, with the maximum extent of the effect being no higher than that of the upper tip position of the large wind turbine. In the horizontal direction, the effect of small wind turbine operation only occurs within two times the turbine diameter downstream of the turbine, but can still be observed farther upstream. 

The operating altitude of the airship is controlled by the large volume change caused by the phase change of ammonia, which is an innovative way to solve the problem of long-term stable airborne stay of the airship. The focus of this method is to strengthen the condensation heat transfer process of ammonia outside the thin-walled wire tube in the stratosphere. In this paper, the condensation heat transfer process of ammonia under 7 different tube row structures at 6.5 kPa was analyzed through numerical simulation. The study found that when the tube bundle arrangement angle is 98◦ and the tube spacing is 2d, the condensation efficiency of ammonia outside the tube is the best under low pressure. Compared with the structure with the tube bundle arrangement angle of 60°, the average condensation heat transfer coefficient around the tube is increased by 49.1%, and the condensation rate is increased by 1.1 times. Compared with the structure with a tube spacing of 1.5d, the average condensation heat transfer coefficient around the tube is increased by 82.9%, and the condensation rate is increased by 89.4%.

Lithium silicate serves as a novel CO₂ absorbent with moderate absorptionregeneration temperature range (500∼700°C) and excellent cycling stability. In this study, Li₂CO₃ was selected as the precursor for the preparation of lithium silicate. Additionally, a eutectic co-doping method with potassium elements was employed to enhance its reactivity. Using extrusion-spheronization, we successfully produced absorbent particles with high mechanical strength and cycling stability. The effects of absorption-regeneration temperature, CO₂ concentration and particle diameter on the performance of absorbent particles have been studied in detail. Furthermore, mixed with NiO oxygen carriers, sorption-enhanced chemical looping reforming (SE-CLR) experiments were conducted at the range of 500∼650°C for hydrogen production and in situ CO₂ capture factors such as reaction temperatures and oxygen carrier to absorbent mass ratios were then investigated The results showcase that at the optimal reaction temperature of 600°C, the SE-CLR process effectively lowered the reaction temperature by 25°C, achieving a 13% increase in methane conversion rate and hydrogen purity and CO₂ capture rate above 90% were attained