旋流后置型超声速分离器激波控制方法数值模拟

Numerical simulation of shock wave control method of rear-swirl type supersonic separator

关键词:  超声速流动  激波控制  纯化  旋流后置  数值模拟  跨旋流结构

Key words:  supersonic flow  shock wave control  purification  rear-swirl  numerical simulation  trans-swirl structure

摘要:

目的 超声速分离是一种基于收缩-扩张喷管的新型气体净化与燃料气加工技术。旋流后置型超声速分离器中的旋流器通常设置在扩压段前，易诱发正激波并破坏分离器内部低温环境，同时，激波难以控制。因此，拟通过优化超声速分离器结构的方式削弱激波的影响。方法 ①基于热力学和空气动力学的原理，提出了一种适用于旋流后置型超声速分离器的激波控制理论；②根据该理论设计了一种能够控制激波的跨旋流结构，建立了该结构的普适性设计公式；③通过数值模拟研究，分析了跨旋流结构的倾斜角度、渐扩段长度、旋流器的叶片扭转角度3个重要结构参数对激波控制的影响。结果 当跨旋流结构的倾斜角度为3.3°、渐扩段长度为107 mm、旋流器的叶片扭转角度为120°时，分离器具有最佳性能。结论 相比传统的旋流后置型分离器，添加跨旋流结构可以保证流体流通面积在渐扩段持续增加，从而实现对激波的有效控制，以提高分离器的冷凝和分离效率。

Abstract:

Objective Supersonic separation is a new gas purification and fuel gas processing technology based on contraction-expansion nozzle. The cyclone in the post-swirl supersonic separator is usually set in front of the diffuser section, which is easy to induce the positive shock wave and destroy the low temperature environment inside the separator. Moreover, the shock wave is difficult to control. Therefore, this study intends to reduce the impact of shock waves by optimizing the structure. Methods Firstly, based on the principles of thermodynamics and aerodynamics, a shock wave control theory for a rear-swirl supersonic separator was proposed. Secondly, according to the theory, a trans-swirl structure which could control shock waves was designed, and a universal design formula for the structure was established. Thirdly, through numerical simulation, the effects of three important structural parameters on the shock waves control were analyzed, namely, the dip angle of the trans-swirl structure, the length of the gradually expansion section and the twist angle of the cyclone blade. Results The separator had the best performance when the dip angle of the trans-swirl structure was set to 3.3°, the length of the gradual expansion section was set to 107 mm, and the blade torsion angle of the cyclone was set to 120°. Conclusions Compared with the traditional cyclone post-separator, the addition of the trans-swirl structure can ensure that the fluid flow area continues to increase in the gradual expansion section, thereby achieving effective control of shock waves and improving the condensation and separation efficiency.