Experimental study of the operation characteristics of an air-driven free-piston linear expander
Experimental study of the operation characteristics of an air-driven free-piston linear expander
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DOI：
10.1016/j.apenergy.2017.03.032
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发表时间：
2017-06
期刊：
影响因子：
11.2
通讯作者：
Yaodong Wang;Lin Chen;Boru Jia;A. Roskilly
中科院分区：
文献类型：
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作者：
Yaodong Wang;Lin Chen;Boru Jia;A. Roskilly
自由活塞发动机是一种线性内燃机，具有机械结构简单、摩擦损失小、热效率高、操作灵活等优点。本研究利用气动自由活塞式直线膨胀机的概念，建立了一套双活塞气动自由活塞式直线膨胀机的实验装置。线性发电机用于在膨胀过程中将活塞的机械功转换为电力。活塞动力学，发电机的输出电压，和膨胀机的操作频率，以及系统的能量转换效率被识别。观察到活塞位移曲线类似于正弦波。发现活塞在中间冲程期间以相对高的速度运行，并且峰值速度通常在活塞接近中间冲程时达到。发电机的输出电压对活塞速度敏感。驱动压力越高，膨胀机频率越高。能量转换效率随着驱动压力的增加而增加，并且在3.75 bar的驱动压力下可以达到55%。本研究提出了一个FPLE原型的基本分析，这可以作为指导未来的设计这种FPLE类型。
Free-piston engine is a kind of linear internal combustion engine, and shows advantages on simple mechanical structure, low frictional losses, high thermal efficiency and operational flexibility. In this research, an experimental test rig of a dual-piston air-driven free-piston linear expander (FPLE) is established using the FPE concept. A linear generator is used to convert the mechanical work of the pistons into electricity during the expansion process. The piston dynamics, the output voltage of the generator, and the expander operation frequency, as well as the system energy conversion efficiency are identified. It is observed that the piston displacement profile is similar with a sinusoidal wave. The piston is found to run at relative high speed during the middle stroke, and peak velocity is usually achieved when the piston approaches the middle stroke. The output voltage of the generator is sensitive with the piston velocity. With higher driven pressure, the expander frequency is higher. The energy conversion efficiency increases with higher driven pressure and can reach up to 55% with a driven pressure of 3.75 bar. This research presents a fundamental analysis of a FPLE prototype, which can be used as a guidance for the future design of this FPLE type.