Research On Heat Transfer Enhancement Of Perforated Heat Exchanger

With the continuous progress and development of science and technology,the heat generation problem of equipment in the engineering field is becoming more and more serious,so the heat dissipation problem of high-temperature structures has become an urgent problem to be solved.An important direction of current heat exchange technology development.Plate-fin heat exchangers have been more and more widely researched and applied due to the advantages of large heat exchange area per unit volume and higher efficiency.On the basis of plate-fin heat exchangers,further strengthening heat transfer has become an important research direction.Based on this,this paper designed a new type of fin-perforated heat exchanger using enhanced heat transfer technology,and compared the performance of the traditional parallel plate heat exchanger and the new perforated heat exchanger through numerical simulation and experiment.It is confirmed that this new type of perforated heat exchanger has better heat exchange performance.The main research work is as follows:(1)A heat transfer enhancement method based on a new type of heat exchanger based on perforated fins is constructed.By analyzing the flow characteristics of the traditional parallel plate heat exchanger flow channel,it was found that the fluid flow was mainly laminar flow,and the flow channel boundary layer was thick,resulting in poor heat transfer performance of the heat exchanger;The perforated design destroys the fluid flow boundary layer and increases fluid mixing,forming a strong convection environment and greatly improving the heat exchange capacity of the heat exchanger.(2)The influence of the parameters of the perforated heat exchanger on the heat exchange performance of the heat exchanger is analyzed.Regardless of whether it is a constant heat flow boundary condition or a constant temperature boundary condition,the perforated heat exchanger can improve the heat transfer capacity while almost not increasing the inlet and outlet pressure drop.Numerical studies have shown that under constant heat flow conditions,the way of inlet and outlet,the width of the channel,the size and number of holes have a greater impact on the heat transfer performance of the heat exchanger,and the layout and shape of the holes have little effect.(3)The PIV test of the flow characteristics of the perforated heat exchanger was carried out.Through the PIV experiment,it was found that compared with the flow field diagram of the unperforated heat exchanger,the flow state of the fluid is more chaotic and disordered,and vortices will also form in the flow channel,destroying the original boundary layer.The thickness of the original boundary layer is reduced,and the heat transfer performance is higher.The difference between the heat transfer performance and the streamline diagram of the perforated heat exchanger and the traditional fin heat exchanger are compared from the numerical simulation and the experiment.Through numerical simulation,it is found that the maximum temperature and average temperature of the bottom surface of the perforated channel heat exchanger are lower than those of the non-perforated heat exchanger,and the inlet and outlet pressure drop has not increased significantly.