Effects of Mixer Length and Diffuser Angle on Two-Phase CO<sub>2</sub> Ejector

Long Junan; Pan Meina; Shi Junye; Chen Jiangping

doi:10.12465/j.issn.0253-4339.2025.01.132

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Effects of Mixer Length and Diffuser Angle on Two-Phase CO₂ Ejector

更新时间：2025-01-23

- Effects of Mixer Length and Diffuser Angle on Two-Phase CO₂ Ejector
- Journal of Refrigeration Vol. 46, Issue 1, Pages: 132-139(2025)
- 作者机构：
  
  1.上海交通大学制冷与低温工程研究所　上海　 200240
  2.南京航空航天大学能源与动力学院　南京　 210016
  3.上海市高效冷却系统工程技术研究中心　上海　 200240
- 作者简介：
  
  Chen Jiangping, male, Ph. D., professor, Institute of Refrigeration and Cryogenics, Shanghai Jiao Tong University, 86-21-34206775, E-mail: jpchen_sjtu@163.com. Research fields: refrigeration and cryogenics, automotive air conditioning technology.
- 基金信息：
  
  National Natural Science Foundation of China(51776119)
- DOI：10.12465/j.issn.0253-4339.2025.01.132
  CLC： TB61⁺1;TB657.5
- Received：22 November 2023，
  
  Revised：2023-12-10，
  
  Accepted：24 January 2024，
  
  Published：16 February 2025
- 稿件说明：
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Long Junan, Pan Meina, Shi Junye, et al. Effects of Mixer Length and Diffuser Angle on Two-Phase CO₂ Ejector[J]. Journal of Refrigeration, 2025, 46(1): 132-139.
DOI：

Long Junan, Pan Meina, Shi Junye, et al. Effects of Mixer Length and Diffuser Angle on Two-Phase CO₂ Ejector[J]. Journal of Refrigeration, 2025, 46(1): 132-139. DOI： 10.12465/j.issn.0253-4339.2025.01.132.

摘要

利用已验证的CFD模型研究不同工况下混合室长度和扩压室锥半角对喷射器升压性能的影响。结果表明：在给定工况下，存在最优的混合室长度和扩压室角度参数组合使喷射器的升压性能最高。两者对喷射器性能的影响具有强相关性：当混合室足够长时，掺混较为充分，混合流扩压时不易发生流动分离，扩压室锥半角在0.5°~3°变化对喷射器性能的影响相对较小；而混合室较短时，扩压室壁面附近容易产生湍流损失，扩压室角度的影响较大。此外，最优结构参数受到运行工况的影响，随喷嘴入口压力和温度降低，最优混合室长度增加，最优扩压室角度减小。在研究工况和喷嘴配置下，喷射器最优混合室长度约为38 mm，最优扩压室锥半角为1°~1.5°。

Abstract

This study employed a validated computational fluid dynamics (CFD) model to investigate the influences of the mixer length and diffuser angle on the ejector pressure-recovery performance. The results demonstrated that an optimal combination of mixer length and diffuser angle exists at which the ejector has the highest performance. The effects of these two geometrical parameters on the ejector performance were highly consistent. When the mixer length was sufficiently long

the mixing was sufficient

and the mixed flow was not subjected to separation during pressure recovery. Under these circumstances

the effect of the diffuser angle on the ejector performance was relatively trivial

varying between 0.5° and 3°. However

when the mixer length was short

the flow was prone to turbulent losses near the diffuser wall. In this case

the effect of the diffuser angle was significant. In addition

the optimal geometries were affected by the operating conditions. The optimal mixer length increased as the nozzle inlet pressure and temperature decreased

whereas the optimal diffuser angle decreased. Under the conditions and nozzle configuration investigated in this study

the optimal mixer length was approximately 38 mm and the optimal diffuser cone half angle was between 1° and 1.5°.

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references

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Related Institution

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School of Mechanical Engineering, Shanghai Jiao Tong University

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⁰

Effects of Mixer Length and Diffuser Angle on Two-Phase CO2 Ejector

DOI：10.12465/j.issn.0253-4339.2025.01.132

摘要

Abstract

关键词

Keywords

references

Effects of Mixer Length and Diffuser Angle on Two-Phase CO₂ Ejector