新型回热器结构设计及换热特性研究

回热器作为斯特林热机的关键部件,对于太阳能斯特林热机整机性能有着重要影响。为克服传统金属丝网回热器结构存在的填料单一,制造成本较高,工艺复杂问题,采用实用等温分析法,以回热器的长径比、通流面积、填料种类以及孔隙率各项回热器参数为基础,设计了一种新型斯特林热机回热器,该回热器具有轴向压降小,换热性能高,结构稳定,加工制造简单的特点。开展了新型回热器和传统金属丝网回热器的换热性能对比研究,采用振荡条件下的局部热平衡方法研究回热器的传热过程,对比传统金属丝网回热器和新型回热器的温度变化,速度变化以及压力变化。结果表明:在整体孔隙率相同的条件下,新型回热器和传统金属丝网回热器相比,整体启动速率相似,但新型回热器压降减少0.04 MPa,速度出现分段式变化,有利于回热器的换热和结构稳定。因此,新型回热器不但在结构上优于传统金属丝网回热器,在换热特性上也优于传统金属丝网回热器。

A structure design and heat transfer characteristics research of the new type regenerator

As the key component of Stirling engine, the regenerator has an important influence on the performance of solar Stirling engine.Therefore, it is necessary to study its structure and heat transfer characteristics.In order to overcome the problems of the structure of traditional wire regenerator is single, high cost and complex process,a new type of Stirling heat engine regenerator has been designed based on the long diameter ratio of the regenerator, the flow area and the type of packing and the parameters of the porosity of the regenerator.The regenerator has a low axial pressure drop, high heat transfer performance, stable structure, and simple processing and manufacturing characteristics.This paper carried out a new type of regenerator and traditional wire mesh comparative study on the heat transfer performance of the regenerator, the oscillation under the condition of local thermal equilibrium method to study the heat transfer process of the regenerator, compared to traditional metal screen regenerator and new regenerator temperature, speed and pressure changes, the results show that under the condition of the same porosity, the new regenerator compared to traditional metal screen regenerator, new regenerator reduced the pressure drop of 0.04 MPa.Therefore, the new type regenerator is superior to the traditional metal mesh regenerator in structure, and is superior to the traditional wire regenerator in heat transfer.