CIESC Journal ›› 2024, Vol. 75 ›› Issue (2): 604-615.DOI: 10.11949/0438-1157.20231101

• Surface and interface engineering • Previous Articles     Next Articles

Study on critical chocked characteristics of supercritical carbon dioxide spiral groove dry gas seal under thermal-fluid coupling lubrication

Zhi ZHU1(), Hengjie XU1(), Wei CHEN1,2, Wenyuan MAO1, Qiangguo DENG1, Xuejian SUN1   

  1. 1.Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming 650500, Yunnan, China
    2.Faculty of Mechanical and Electrical Engineering, Kunming University of Science and Technology, Kunming 650500, Yunnan, China
  • Received:2023-10-26 Revised:2024-02-01 Online:2024-04-10 Published:2024-02-25
  • Contact: Hengjie XU

超临界二氧化碳螺旋槽干气密封热流耦合润滑临界阻塞特性研究

朱芝1(), 许恒杰1(), 陈维1,2, 毛文元1, 邓强国1, 孙雪剑1   

  1. 1.昆明理工大学化学工程学院,云南 昆明 650500
    2.昆明理工大学机电工程学院,云南 昆明 650500
  • 通讯作者: 许恒杰
  • 作者简介:朱芝(1999—),女,硕士研究生,3024659512@qq.com
  • 基金资助:
    国家自然科学基金项目(52105189);云南省基础研究专项青年项目(202101AU070019)

Abstract:

Under the premise of stable operation of the seal, promoting the formation of blocked flow at the seal end face outlet to increase the air film opening force and reduce end face leakage is an effective way to optimize dry gas sealing performance. Taking supercritical carbon dioxide (CO2) spiral groove dry gas seal as the object, the finite difference method was used to solve the pressure and temperature governing equations on the basis of the effects of real gas, centrifugal inertia, turbulence and chocked flow. The critical chocked characteristics (e.g. critical chocked inlet pressure po_cir, critical chocked speed N_cir, critical chocked film thickness h0_cir and chocked critical instability film thickness hsc) under thermal-fluid coupling lubrication were qualitatively studied. The results show that there is a chocked interval at the outlet of supercritical CO2 dry gas seal in isothermal and adiabatic model. The intervals corresponding to the inlet pressure, film thickness and rotational speed are po>po_cir,h0_cir<h0<hsc and N<N_cir, respectively. The increase of the rotating speed can continuously enhance the critical chocked inlet pressure and the critical chocked film thickness. The increase of the film thickness will lead to the decrease of the critical chocked pressure and the increase of the critical chocked speed. The high-pressure inlet will make the chocked zero stiffness corresponding to the film thickness (chocked critical instability film thickness hsc) down. Compared with the isothermal flow hypothesis, the influence of gas film thermal effect on the critical chocked characteristic parameters of supercritical CO2 dry gas seal is significant, and the influence rules are different.

Key words: supercritical carbon dioxide, dry gas seal, thermal-fluid coupling, critical choked characteristics, choked occurrence interval

摘要:

在密封稳定运行的前提下,促成密封端面出口形成阻塞流动以提升气膜开启力、降低端面泄漏不失为干气密封性能优化的有效途径。以超临界二氧化碳(CO2)螺旋槽干气密封为研究对象,综合考虑实际气体、离心惯性、湍流和阻塞流效应,采用有限差分法耦合求解压力和温度控制方程,定性研究了热流耦合润滑下的临界阻塞特性(临界阻塞进口压力po_cir、临界阻塞转速N_cir、临界阻塞膜厚h0_cir和阻塞临界失稳膜厚hsc)。结果表明:等温流动和绝热流动模型下超临界CO2干气密封端面间隙出口均存在阻塞发生工况区间,进口压力、膜厚、转速对应的阻塞发生区间分别为po>po_cirh0_cir<h0<hscN<N_cir;转速升高可以对临界阻塞进口压力和临界阻塞膜厚产生持续增强作用,增大膜厚则会导致临界阻塞压力降低、临界阻塞转速上升,高压进口将使阻塞零刚度对应的膜厚(阻塞临界失稳膜厚hsc)下行;相较于等温流动假设,气膜热效应对超临界CO2干气密封临界阻塞特性参数的影响程度较为显著,且影响规律各有不同。

关键词: 超临界二氧化碳, 干气密封, 热流耦合, 临界阻塞特性, 阻塞发生区间

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