Experimental Study On Flow And Heat Transfer Of Truss Structure Heat Exchanger

Heat dissipation of high-temperature structures has always been a common concern in engineering field,especially in aerospace and other high-end fields,heat transfer enhancement has always been a hot issue for relevant experts to explore.The R&D work of high-efficiency heat exchanger equipment suitable for different operating conditions has become the main trend of current heat transfer technology development.Greater heat transfer surface improves the heat transfer effect of heat exchanger obviously.TSHE has many advantages,such as lightweight,compact,high thermal efficiency and low flow resistance,which make it has great research and engineering application value.In order to study the flow and heat transfer of TSHE and verify the feasibility of this new type of heat exchanger,we designed and built a relevant experimental platform based on the given experimental operating conditions.Three TSHE with compactness(798 m~2/m~3,1331m~2/m~3,2427 m~2/m~3)are tested.We control the inlet temperature and flow rate of hot and cold fluids,measure their inlet and outlet temperature,pressure and flow rate,observe the phenomena of the experimental process,and finally summarize some experimental rules and conclude the experimental correlations under different working conditions.and the conclusions are as follows:With the increase of air flow rate,heat transfer increases,and heat transfer increases faster with the increase of compactness;the total heat transfer coefficient of TSHE shows a logarithmic growth trend,while the air side pressure drop shows an exponential growth trend,that is,the flow resistance seriously deteriorates while enhancing the heat transfer effect.With the increase of Reynolds number,the efficiency of TSHE decreases.And with the compactness increase,the efficiency of TSHE goes up,and different compactness heat exchangers have the same changing trend.The total pressure recovery coefficient decreases rapidly with the increase of Reynolds number,and the greater the compactness,the faster the total pressure recovery coefficient decreases.In addition,based on the FloEFD,the numerical simulation of the TSHE model is carried out to study the flow and heat transfer in the TSHE.It is found that the simulation results are in good agreement with the experimental results,and the following conclusions are drawn:From the inlet to the outlet of the TSHE,the temperature and pressure decrease in a stratified manner;A small area of high temperature and pressure appears at the front of the air inlet,and the higher the air inlet velocity,the larger the high temperature and pressure area correspondingly,and the extreme temperature and pressure appears at the position l*=0.28.