Study of oscillating flows through a novel constructal bifurcation Stirling regenerator
Study of oscillating flows through a novel constructal bifurcation Stirling regenerator
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新型结构分叉斯特林再生器振荡流研究
DOI：
10.1016/j.applthermaleng.2020.116413
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发表时间：
2021-02
影响因子：
6.4
通讯作者：
Liu Wei
中科院分区：
文献类型：
--
作者：
Yu Minjie;Xin Feng;Lai Xiaotian;Xiao Hui;Liu Zhichun;Liu Wei
传统的多孔回热器中的高流动阻力一直是限制斯特林发动机整体性能的重要因素。为了降低斯特林回热器的流动阻力，提出了一种基于结构概念的新型结构分叉回热器。首先，采用CFD方法研究了不同几何参数的分叉回热器内振荡流动的压降和瞬态共轭换热特性。结果表明，在加速段和减速段之间，以及在排出段和吸入段之间，流体的流动和传热发生了显著的变化。这些差异是由于局部加速效应、加速阶段涡流的形成以及回热器基体在排气和吸气阶段对流体产生不同的迎风面所致。此外，还比较了振荡流和定常流的流动特性，证明了局部加速效应是造成两者差异的主要原因。建立了各结构的摩擦系数和努塞尔数的三参数关联方程和四个几何参数相关的主关联方程，预测回热器性能。然后，将结构分叉回热器等效为多孔介质，得到了斯特林发动机全过程模拟所需的主要多孔介质参数。最后，将结构分叉再生器的摩擦系数和努塞尔数与其他常用再生器的摩擦系数和努塞尔数进行了比较。结果表明，结构分叉回热器流动阻力小，传热适中，具有较高的综合性能。回热器的上级综合性能使斯特林发动机性能的提高成为可能。
High flow resistance in conventional porous regenerators has been an important factor for limiting the overall performance of Stirling engines. Herein, a novel constructal bifurcation regenerator based on constructal concept was developed to reduce the flow resistance in the Stirling regenerator. First, the pressure drop and transient conjugate heat transfer characteristics of oscillating flows through the constructal bifurcation regenerator with various geometrical parameters were investigated by the CFD approach. The results showed that the fluid flow and heat transfer between the acceleration and deceleration phases, as well as the discharge and suction phases, were varied significantly. These differences should be resulted from the local acceleration effect, the formation of eddies in the acceleration phase, and different windward surfaces generated by the regenerator matrix to the fluid in the discharge and suction phases. Additionally, the flow characteristics between the oscillating and steady flows were compared and the local acceleration effect was proven to be the main cause of the difference between them. Then the three-parameters correlation equations of friction factor and Nusselt number for each structure and four master correlation equations with geometrical parameter dependence were built to predict the regenerator performance. Thereafter, the constructal bifurcation regenerators were converted to equivalent porous media, and thus the main porous parameters were obtained for the full Stirling engine simulation in the next studies. Finally, the friction factor and Nusselt number of the constructal bifurcation regenerator were compared with those of other commonly used regenerators. It showed that the constructal bifurcation regenerator had a low flow resistance and moderate heat transfer, thus obtaining a high comprehensive performance. The superior comprehensive performance of the regenerator makes it possible to improve the performance of Stirling engines.
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DOI：
10.1016/j.ijheatmasstransfer.2016.11.096
发表时间：
2017-05
影响因子：
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