针束型回热器熵产率的分析

摘要

The stack is the key element of thermoacoustic engines, and pin-array stack has excellent performance compared with other stack geometries. In the case of parameters optimization of pin-array stack, a minimum entropy generation rate optimization model was established to study parametric optimization of stack based on irreversibility. Based on the analysis of the thermodynamic irreversibilities produced by heat transfer and viscous dissipation, the theoretical study and the numerical calculation on entropy generation rate in pin-array stack with the oscillating working gas have been done. Cross-section entropy generation rate distribution and cross-section average entropy generation rate were obtained, the variation law of entropy generation rate in different cross-section of pin-array stack was analyzed, and effect of temperature gradient on cross-section average entropy generation rate was studied. For the fixed characteristic dimension and the minimum cross-section average entropy generation rate, the optimization frequency and the optimization impedance ratio were obtained.%回热器是热声装置的关键部件,在多种具有规则流道的回热器结构中,针束型结构是综合性能最优的结构.针对针束型回热器参数优化问题,建立了以最小熵产率为目标的优化模型,研究基于不可逆性的回热器参数优化方法.通过分析工质在回热器内振荡时由于与固壁的换热和黏性扩散导致的热动力学上不可逆性,对工质在针束型回热器内运动时的熵产率进行了理论分析和数值计算.计算获得了回热器截面分布和截面平均熵产率表达式,分析了针束型回热器中不同位置截面分布熵产率的变化规律,分析了温度梯度对截面平均熵产率的影响,获得了给定特征尺寸截面平均熵产率最小时的最优频率和最优阻抗比.