Yan Jia, Shu Yuetong, Wang Chen
School of Civil Engineering and Architecture, Southwest University of Science and Technology, Mianyang 621010, China.
School of Control Science and Engineering, Shandong University, Jinan 250061, China.
Entropy (Basel). 2022 Dec 18;24(12):1847. doi: 10.3390/e24121847.
In this paper, for a highly coupled two-stage ejector-based cooling cycle, the optimization of primary nozzle length and angle of the second-stage ejector under varied primary nozzle diameters of the second stage was conducted first. Next, the evaluation for the influence of variable back pressure on ER of the two-stage ejector was performed. Last, the identification of the effect of the variable back pressure on the key geometries of the two-stage ejector was carried out. The results revealed that: (1) with the increase of the nozzle diameter at the second stage, the ER of both stages decreased with the increases of the length and angle of the converging section of the second-stage primary nozzle; (2) the pressure lift ratio range of the second-stage ejector in the critical mode gradually increased with the increase of the nozzle diameter of the second-stage; (3) when the pressure lift ratio increased from 102% to 106%, the peak ER of the second-stage decreased, and the influence of the area ratio and nozzle exit position of the second-stage ejector on its ER was reduced; (4) with the increase of nozzle diameter of the second-stage, the influence of area ratio and nozzle exit position of the second-stage on the second-stage performance decreased; and (5) the optimal AR of the second stage decreased but the optimal nozzle exit position of the second stage kept constant with the pressure lift ratio of the two-stage ejector.
在本文中，针对基于两级喷射器的高度耦合冷却循环，首先在第二级主喷嘴直径变化的情况下，对第二级喷射器的主喷嘴长度和角度进行了优化。接下来，对可变背压对两级喷射器引射系数（ER）的影响进行了评估。最后，对可变背压对两级喷射器关键几何参数的影响进行了识别。结果表明：（1）随着第二级喷嘴直径的增加，两级的引射系数均随着第二级主喷嘴收敛段长度和角度的增加而降低；（2）临界模式下第二级喷射器的压力升比范围随着第二级喷嘴直径的增加而逐渐增大；（3）当压力升比从102%增加到106%时，第二级的峰值引射系数降低，且第二级喷射器的面积比和喷嘴出口位置对其引射系数的影响减小；（4）随着第二级喷嘴直径的增加，第二级的面积比和喷嘴出口位置对第二级性能的影响减小；（5）随着两级喷射器压力升比的增加，第二级的最佳面积比减小，但第二级的最佳喷嘴出口位置保持不变。
