螺旋式气波制冷机结构参数匹配数值研究

Numerical study of structural parameter matching of helical gas wave refrigerator

结合理论分析和数值计算,对螺旋式气波制冷机中的核心结构——波转子,进行了结构敏感性分析.首先,根据波转子内激波与膨胀波等波系的流动,建立螺旋式波转子的理想波图,由此揭示波转子内能量传递与气体流动规律.在此基础上给出一维螺旋式波转子结构设计方法,该方法具有一定精度,可以用于指导螺旋式气波制冷机设计.接下来建立螺旋式压力振荡管的数值模型,研究波转子垂直长度、螺旋长度以及螺旋导程对其效率的影响,并提出最优螺旋导程的拟合方程.最后,建立螺旋式气波制冷机整机模型,对比不同螺旋导程下的等熵制冷效率.结果表明,对一定垂直长度的波转子来说,随着螺旋导程的增大,等熵制冷效率先增大后减小,与拟合方程结果相符.经过螺旋最优化的波转子等熵制冷效率高于同垂直长度的均直型波转子,提高值可达13%.

The sensitivity of wave rotor structure in helical gas wave refrigerator is analyzed by combining theoretical analysis and numerical simulation. Firstly, according to the flow of shock wave and expansion wave in wave rotor, the ideal wave diagram of helical wave rotor is established, then the law of gas flow and energy transfer in the wave rotor is revealed. On this basis, the structural design method of 1D helical wave rotor is given. The method has certain accuracy and can be used to guide the design of helical gas wave refrigerator. Next, the numerical model of helical pressure oscillation tube is established to study the effects of wave rotor vertical length, helical length and helical lead on its efficiency, then the fitting equation of optimal helical lead is proposed. Finally, the whole model of helical gas wave refrigerator is established to compare the isentropic refrigeration efficiency under different helical leads. The results show that for a wave rotor with a certain vertical length, with the increase of helical lead, the isentropic refrigeration efficiency increases first and then decreases, which is in line with the results of the fitting equation. The isentropic refrigeration efficiency of the helical optimized wave rotor is higher than that of the straight wave rotor with the same vertical length, and the improvement value can be up to 13%.