管道的附加部件导致难以使用一维模型准确描述管内流体的瞬态流动换热，本文提出将其等效为温度不同于管道的部件，按照集总参数法处理附加部件与管道的换热。本文进行温度阶跃和余弦变化工况下圆管的瞬态换热特性实验研究，并采用附加热容法仿真计算出口温度响应，结果表明：附加热容法能够显著提升计算精度，各工况下仿真结果与实验数据的平均相对误差均不超过2%。同时，本文定义平均迟滞时间量化固体热容对流体温度变化的影响。

The additional components of the tube make it difficult to accurately describe the transient flow and heat transfer of the internal fluid using a one-dimensional model. Therefore, this paper proposes to equate them to components with different temperatures than the tube, and treat the heat transfer between the additional components and the tube using the lumped parameter method. This paper conducts experimental research on the transient heat transfer characteristics of circular tube under temperature step and cosine change conditions, and calculates the outlet temperature response using the additional heat capacity method. The results show that the additional heat capacity method can significantly improve the calculation accuracy, and the average relative error between the simulation results and experimental data under various conditions does not exceed 2%. Meanwhile, this paper defines the average hysteresis time to quantify the impact of solid heat capacity on fluid temperature changes.