Test Method For Thermal Performance Of Compact Heat Transfer Structure Based On Impulse Function Transient Method

Compact heat exchanger is a type of advanced heat exchange equipment with small size,light weight,and high efficiency.Compared with traditional heat exchangers,compact heat exchangers have higher heat transfer area per unit of volume,less occupying space and better pressure resistance which will significantly improve the thermal energy efficiency,reduce energy consumption and extend service life.Due to these advantages,it has wide application prospects in engineering.However,due to the highly compact structure,it is difficult to measure the wall temperature of heat transfer surface by traditional test methods.Therefore,it is urgent to develop a new method used for measuring the heat transfer and resistance performance of compact heat exchanger with small flow passages.To the above issues,an impulse function transient test method,which do not need to measure the wall temperature,is proposed based on the heat transfer experiments of foam metal structures in the present study.Then the heat transfer and resistance performance of a practical compact heat exchanger has been studied by this proposed method.The major research works are summarized as follows:1)The existing test system is improved in order to meet the test requirements of the impulse function transient test method.Data acquisition and automatic control program are written and optimized.The response characteristics and test errors of the system are analyzed through the tests of standard samples.Based on the above,the stability and accuracy of the test system is improved.2)The optimum impulse width is obtained for four kinds of foam metal structures with different parameters through transient impulse tests.Then the heat transfer and resistance performance of these four foam metal structures are tested and studied under this optimum impulse width.Finally,the impulse function transient test method for compact heat exchangers is established based on these results.3)The heat transfer and resistance performance of the compact heat exchanger used in engineering are tested and analyzed by using the impulse function transient test method.The feasibility of this proposed test method is further studied and verified.