Research Of Tube Material Thermal Resistance On The Performance Of Gas Wave Refrigeration

Double opening air wave refrigerator is a new type of expansion refrigeration equipment which uses pressure wave motion to realize the separation of cold and hot gas.One of the core component of gas wave refrigerator is the pressure oscillation tubes.For double opening gas wave refrigeration equipment,the pulsating heat transfer behavior between oscillating tube and fluid in tube will cause the loss of air wave refrigeration efficiency.The experimental platform of air wave refrigeration with multi-point temperature measurement system was built.The refrigeration performance of pressure oscillation tubes with different thermal resistance materials was compared and the performance changes of air wave under different parameters were studied.The main work and research results are as follows:(1)Two dimensional and three-dimensional numerical models were established to analyze the pulsation coupled heat transfer behavior of pressure oscillation tube.It was found that the temperature distribution on the outer wall of the oscillating tube is uniform along the circumferential direction and varies along the axial direction under the effect of fluid solid heat transfer,and the performance of gas wave refrigeration was reduced.The heat release mainly occurred in the high temperature exhaust stage,and the heat absorption mainly occurred in the low temperature exhaust stage.It was found that the fluid solid heat transfer weakened the pressure wave in the tube.(2)Considering the effect of fluid solid heat transfer,the effects of different parameters on the performance of gas wave refrigeration were studied by experiments and numerical analysis.An oscillating tube static gas wave refrigeration experimental platform with multi-point temperature measurement system was built.It was found that increasing the pressure ratio,reducing the gap and double cycle refrigeration can effectively improve the refrigeration depth.There was an optimal rotation speed and deflection angle to maximize the depth of gas wave refrigeration.At the design speed,the deflection angle of high pressure and high temperature changed from 12.5° to 14.5° and 16.5°,It was found that the wall temperature of the oscillating tube on the high temperature side increased by 7.6K and 40.4K respectively because the high temperature gas cannot be discharged,the temperature of the oscillating tube on the high pressure side increases by 6.6k and 16.2k respectively under the action of axial heat conduction,the convective heat transfer on the low temperature side was enhanced,and The refrigeration depth decreased by 3.0k and 4.1K respectively.(3)The effect of axial heat conduction on the performance of gas wave refrigeration was studied by changing the axial heat conduction area of the oscillating tube and weakening the temperature transfer at the high temperature side.The experimental results showed that the wall thickness of the oscillating tube decreases,the axial heat conduction area decreases and the axial heat conduction behavior weakens,under the expansion ratio of 1.6,1.8 and 2.0,the maximum refrigeration depth increased by 1.7%,2.9% and 1.9% respectively.It was found that the forced heat transfer first decreased and then increased.Under the effect of forced cooling,the maximum cooling depth increased by 12.4%,18.6% and 19.8%,respectively.(4)The effect of high thermal barrier pressure oscillation tube on the performance of gas wave refrigeration was studied.By comparing the mechanical properties of different high thermal resistance nonmetallic materials,the material selection of pressure oscillation tube was determined,and the pressure oscillation tube was manufactured by 3D printing.Through numerical analysis,the influence of wall roughness on the refrigeration performance was studied to determine the 3D printing accuracy.It was found that with the increase of roughness,the heat absorption of fluid increased sharply and then tended to be flat.The printing accuracy was determined to be 0.2mm finally.The experimental platform of gas wave refrigeration with high thermal resistance oscillating tube was built.The results showed that the axial heat transfer rate of the oscillating tube decreased significantly,and the maximum refrigeration depth increased by 10.2%,6.3% and 8.5%,respectively.