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.

传统的多孔蓄冷器的高流动阻力已经成为限制斯特林发动机整体性能的重要因素。在本文中，开发了一种基于构造概念的新型构造分叉蓄热器，以减小斯特林蓄热器中的流阻。首先，通过CFD方法研究了流经结构分叉蓄热器的各种几何参数的压降和瞬态共轭传热特性。结果表明，加速和减速阶段之间的流体流动和热传递以及排气和吸入阶段之间的流体流和传热都发生了显着变化。这些差异应归因于局部加速效应，在加速阶段形成涡流，蓄热体矩阵在排出和吸入阶段对流体产生不同的迎风面。此外，比较了振荡流和稳定流之间的流动特性，并证明了局部加速效应是两者之间差异的主要原因。然后建立了每种结构的摩擦系数和努塞尔数的三参数相关方程和四个几何参数相关的主相关方程，以预测再生器的性能。此后，将构造的分叉蓄热器转换为等效的多孔介质，从而在接下来的研究中获得了用于斯特林发动机全过程仿真的主要多孔参数。最后，将结构分叉式蓄热器的摩擦系数和努塞尔数与其他常用蓄热器进行比较。结果表明，该结构分叉再生器具有低的流阻和适度的热传递，因此具有较高的综合性能。蓄热室出色的综合性能使改善斯特林发动机的性能成为可能。