膨胀比对活塞式膨胀机工作特性影响的研究

Study on Influence of Expansion Ratio on Operating Characteristics of Piston Expander

活塞式膨胀机在压缩空气储能领域具有广泛的应用,但是效率低,很大程度上限制了其发展。为改善活塞式膨胀机的工作性能,通过MATLAB建立活塞式膨胀机的仿真模型,通过实验方法验证仿真模型的准确性,以输出功率和效率作为性能指标对活塞式膨胀机进行研究,分析了进气压力、间隙容积、进气持续角对膨胀机输出特性的影响。结果表明:在恒定工况下,随着进气压力的增大,膨胀机的输出功率增大,但效率降低;在稳定的进气压力下,膨胀机存在最优间隙容积与进气持续角;活塞式膨胀机的效率随进气持续角的增大而降低,进气持续角越大膨胀机输出功率随转速的升高下降斜率增大;3 MPa的进气压力下,膨胀比为2.18时膨胀机的效率最佳,进气持续角为90°时膨胀机输出功率最优,在转速为570 r/min时输出功率达最大4.29 kW、效率达到19.6%。为可变膨胀比活塞式膨胀机的设计提供了理论依据。

Piston expander has been widely used in compressed air energy storage field,but the low efficiency of piston expander greatly restricts its development.In order to improve the performance of the piston expander,a simulation model of the piston expander was established by MATLAB,and the accuracy of the simulation model was verified by experiment.Research on piston expander with output power and efficiency as performance indicators.Simulation studies impact on the output characteristics of the expander by intake pressure,clearance volume and intake duration angle.The results show that under constant working conditions,the power of expander increases continuously with the increase of inlet pressure,but the efficiency decreases gradually with the increase of inlet pressure.Under the sTab.intake pressure,the expander has the optimal clearance volume and intake duration angle.The efficiency of piston expander decreases with the increase of inlet duration angle.The larger the intake persistence angle,the larger the decline slope of the expander output power with the increase of the speed.At the intake pressure is 3 MPa,the efficiency of the expander is the best when the expansion ratio is 2.18,the output power of the expander was the best when the inlet continuous angle is 90°.And the maximum output power is 4.29 kW and the efficiency is 19.6%when the rotational speed is 570 r/min.The research provides a theoretical basis for the design of piston expander with variable expansion ratio.