低温差斯特林发动机热力学分析

Thermodynamic Analysis of Low Temperature Differential Stirling Engine

在低温差斯特林发动机的功率预测和参数优化分析中,传统的分析方法并不实用。为了快速准确地预估低温差斯特林发动机的输出功率,文中研究二阶Simple模型在低温差斯特林发动机的热力学循环分析中的应用。描述了低温差斯特林发动机的简化结构模型与内部工质的温度特性,基于Simple模型推导低温差斯特林发动机中非理想换热器的实际换热方程式,分析发动机的回热损失、泵送损失和换热器实际换热量。通过实例计算说明低温差斯特林发动机系统内部工质的温度、压力和能量随曲柄转角的变化,分析低温差斯特林发动机的理论输出功率。将低温差斯特林发动机在不同加热温度下的实际输出功率与Simple模型的计算功率对比,对比结果显示,Simple模型计算的输出功率与实际输出功率之间的误差较小,表明Simple模型与低温差斯特林发动机的实际循环吻合较好。为了研究低温差斯特林发动机中回热器对发动机性能的影响,文中优化了低温差斯特林发动机的回热器结构,将回热器优化后的实际输出功率和Simple模型计算功率,与回热器优化前的实际输出功率和Simple模型计算功率对比。对比结果显示,优化回热器后的低温差斯特林发动机的实际输出功率与Simple模型计算功率均提高20%,表明优化回热器结构是提高低温差斯特林发动机性能的切实有效的方法。

The traditional analysis method is not practical in the power prediction and parameter optimization analysis of low temperature differential Stirling engine. In order to predict the output power of low temperature differential Stirling engine quickly, this paper studied the application of the second order Simple model in the thermodynamic cycle analysis of low temperature differential Stirling engine. It described the simplified structural model of low temperature differential Stirling engine and the temperature characteristics of internal working medium. Based on Simple model, this study derived the actual heat transfer equation of non-ideal heat exchanger in low-temperature differential Stirling engine, and analyzed the heat return loss, pumping loss and actual heat transfer of heat exchanger. The variation of the temperature, pressure and energy of the working medium in the lowtemperature differential Stirling engine system with the crank Angle was illustrated by examples, and the theoretical output power of the low-temperature differential Stirling engine was analyzed. The actual output power of low temperature differential Stirling engine at different heating temperatures was compared with the calculated power of Simple model. The comparison results show that the error between the output power calculated by the Simple model and the actual output power is small, indicating that the Simple model is in good agreement with the actual cycle of the low-temperature differential Stirling engine. In order to study the influence of regenerator on engine performance of low temperature difference Stirling engine, the paper optimized the structure of regenerator of low temperature difference Stirling engine. The output power of the regenerator after optimization was compared with that before optimization. The comparison results show that after optimizing the regenerator, the actual output power of the lowtemperature differential Stirling engine and the calculated power of the Simple model are both increased by 20%. It is shown that optimizing the structure of regenerator is an effective method to improve the performance of low temperature differential Stirling engine.