水平光滑管内R245fa轴向均匀沸腾传热特性实验研究

R245fa是有机朗肯循环系统（Organic Rankine Cycle，ORC）最常用的工质之一，研究其传热流动特性对于指导R245fa的ORC设计和运行有重要价值。搭建了有机工质单管传热流动测试台并开展了水平光滑管内R245fa在90℃下的沸腾传热实验研究。实验获得了平均干度、质量流率对平均流动沸腾传热系数和壁温沿管程分布的影响规律，并分析了原因。将实验结果与3个经典传热关联式预测结果进行了对比，结果显示平均偏差分别为38%、39%、20%。R245fa高温蒸发实验结果可为进一步修正传热关联式提供基础数据库，并用于指导热力循环工程实践。

An Experimental Study of Axial Uniform Boiling Heat Transfer Characteristics of R245fa in Horizontal Smooth Tube

R245fa is one of the most commonly working fluids used in organic Rankine cycle (ORC) system. Investigating its heat transfer flow characteristics is of great importance in guiding the design and operation of ORC system. An experimental test rig is established for the test of the in-tube heat transfer and flowing of the organic working fluids. The experimental research for the boiling heat transfer of R245fa in a horizontally smooth tube is conducted. Firstly, the influence of mean quality and mass velocity on the average flow boiling heat transfer coefficient and wall temperature distribution along the tube are obtained and analyzed; then, experimental results are compared with three classical heat transfer correlations prediction results, with an average deviation of 38%, 39%, and 20%. The high temperature evaporation experimental results provide a basic database for the correction of heat transfer correlation and guidance for the engineering design practices.