实际热声微热力学循环的特性研究

对热声热机微热力学循环的研究有助于了解热声热机的热力学特性。根据热声非等熵振荡特性，建立实际热声发动机中微热力学循环的理论模型，该模型在p-V图上表现为一个椭圆，椭圆的偏转角度主要取决于压力和体积之间的相位差。得到循环中吸热过程和放热过程的分界点，在考虑热漏和不可逆程度因子的情况下推导循环的量纲一输出声功和热效率。数值计算表明输出功与热效率之间的关系曲线是一条回原点的柳叶形，与经典卡诺热机循环的输出功和热效率之间的关系曲线形状相同。输出功和热效率都有一极大值，两极值点之间的曲线是热声发动机运行的最佳工况。此外，压力和体积之间的相位差以及不可逆因素对输出功和热效率的影响较大。研究结果有助于热声发动机的优化设计。

Performance of Actual Thermoacoustic Engine Micro-cycle

The research on a thermoacoustic engine micro-cycle is of great importance to understand the thermodynamic performance of thermoacoustic engine. An actual thermoacoustic engine micro-cycle ideal model which expressed as an ellipse in pressure-volume diagram is established in terms of the feature of thermoacoustic non-constant entropy oscillation. And the deflection angle of the ellipse depends mainly on the phase displacement between pressure oscillation and volume oscillation. The demarcation points of endothermic processes and exothermic processes in the micro-cycle are found. The expressions of the dimensionless acoustic work output and the thermal efficiency are derived with considering the influence of heat leakage and factor of irreversible degree. The relationship between the work output and the thermal efficiency are investigated by numerical calculation. It is a willow-shaped curve, which is identical with that of a classical Carnot cycle, and in which there are a maximum work output and a maximum thermal efficiency. The region between the maximum work output and the maximum thermal efficiency is the optimal operation conditions of a thermoacoustic engine. In addition, the phase displacement and the irreversible factor have a significant effect on the work output and the thermal efficiency. The results obtained will be helpful for optimal design of thermoacoustic engine.