The Experiment Investigations Of A Two Phase Flow Modulation Heat Exchanger With 3 Inner Tubes

Shell and tube heat exchanger has been widely applied in the field of condensing, In order to seek the excellent performance of a heat exchanger in modern industry, the heat transfer enhancement of heat exchangers has been extensively studied. Meanwhile R245fa is a new type of HFC compounds, It has a broad application prospect in the field of low-grade energy utilization, such as refrigeration, power generation and so on. Therefore, In this paper, the condensation law of R245fa in a 3-tubes two-phase flow modulation heat exchanger was studied through the experiment in the Beijing Key Laboratory of low-grade energy and multiphase flow.In this paper, the 3-tubes two-phase flow modulation heat exchanger is a shell and tube heat exchanger, it has three tubes, which has the inner diameter of 14.7 mm and the length of 1600mm. In each tube, it has four concentric hollow mesh cylinders in series, a piece of the cylinders has the length of 370mm, it uses 900 PPI (15 um filtering accuracy)stainless steel mesh. The study describes how to build a reliable experimental system and how to do the experiment study, the experiment runs as follows:R245fa mass flow rate of 200～500 kg/m2s, inlet vapor mass quality of 0.1 to 0.7, the test section inlet saturation temperature is 62.8℃ (corresponding to the saturation pressure of 0.5 MPa).By analyzing the experimental results, it showed that:the 3-tubes heat exchangers inserted with 4 consecutive hollow mesh cylinders can effectively improve the heat transfer efficiency, the heat transfer enhancement factor EF of all runs is greater than 1; The overall performance of the heat exchanger is good, the integrated evaluation parameter PEC of the vast majority of experiment runs is greater than 1. Meanwhile, Based on three kinds of the experment runs:(1) the outlet is the supercooled state; (2) the outlet is close to saturation; (3) the outlet is still in the two-phase state, this paper proposed some improvement suggestions of the heat exchanger, which laid the foundation for future experimental research and practical application.