离心式逆布雷顿循环中双U型旋转圆形通道的流动损失分析

Analysis of Flow Loss in Double U-Shaped Rotating Circular Channel in a Centrifugal Reverse Brayton Cycle

摘要: 离心式逆布雷顿循环(CRBC)是一种利用离心力势能–压能转换的新型制冷循环，以工质在旋转通道内的离心和向心流动实现高效压缩和膨胀过程，为提升传统气体制冷循环的制冷效率提供了潜在可能性。本文在前期研究基础上，通过对双U型旋转圆形通道进行模拟仿真，研究通道内部流动损失机理与不同旋转数下的流动损失规律，为系统的评估及改进提供理论依据和数据支持。模拟计算结果经过实验验证，取得了良好的一致性。研究发现，离心力影响着整段管道的流动损失，科式力在径向段主要通过改变流场结构，而在轴向段通过改变流体流速来影响流动损失。随着旋转数的增加，双U型旋转圆形通道的流动损失系数呈现总体下降的趋势。当Ro > 1时，双U型旋转圆形通道的平均流动效率达到95%以上，符合离心式逆布雷顿循环对压缩/膨胀效率的要求。

Abstract: The Centrifugal Reverse Brayton Cycle (CRBC) is a novel refrigeration cycle that harnesses the con-version of inertial potential energy to pressure energy, enabling efficient compression and expan-sion processes through the centrifugal and centripetal flow of the working fluid within a rotating tube. This offers a promising potential for improving the refrigeration efficiency of conventional gas refrigeration cycles. On the basis of previous studies, this work simulated double U-shaped rotating circular channel to investigate the flow loss mechanisms and flow loss laws at different rotation speeds, in order to provide theoretical support and data for system evaluation and improvement. The simulation results showed good agreement when validated experimentally. It was found that centrifugal forces influenced the flow losses throughout the channel, while Coriolis forces impacted the flow losses in the radial section primarily by altering the flow structure, and in the axial section by changing the fluid velocity. As the rotation speed increased, the flow loss coefficient of the double U-shaped rotating circular channel generally decreased. When Ro > 1, the average flow efficiency of the double U-shaped rotating circular channel exceeded 95%, meeting the efficiency requirements for compression/expansion in the centrifugal reverse Brayton cycle.