A CFD Analysis of the Flow Structure Inside an R141b Ejector to Identify the Internal Flow Variations in its Design and Off-Design Working Modes

International Journal of Mechanical Engineering

© 2024 by SSRG - IJME Journal

Volume 11 Issue 6

Year of Publication : 2024

Authors : Devendra Kumar Patel, M. Anoop Kumar

10.14445/23488360/IJME-V11I6P102

How to Cite?

Devendra Kumar Patel, M. Anoop Kumar, "A CFD Analysis of the Flow Structure Inside an R141b Ejector to Identify the Internal Flow Variations in its Design and Off-Design Working Modes," SSRG International Journal of Mechanical Engineering, vol. 11,  no. 6, pp. 7-18, 2024. Crossref, https://doi.org/10.14445/23488360/IJME-V11I6P102

Abstract:

A CFD analysis on an R141b ejector is performed to understand the flow variations at the selected internal sections in its design and off-design modes of operation. The flow inside an ejector with given conditions is numerically simulated, and its correctness is verified with experimental results. Further, the verified numerical model is used to simulate the varying modes of working of the ejector by changing its back pressure (Pb). Seven vertical sections were considered in the flow domain to study the variations in flow parameters. Contours of Mach number and streamlines of the flow were analyzed to understand the varying modes of working of the ejector. A study of the variations in velocity, pressure, temperature, and density along the ejector axis showed that the flow patterns are similar in all modes until the entry of the constant area missing section. After that, in critical mode, the variations are abrupt due to a shock wave, while in other modes, the variations are smooth. Secondary flow velocity at the inlet vertical section decreased from 6.04m/s for Pb=0.05MPa to -3.44 m/s for Pb=0.09MPa. This variation at a vertical section at the primary nozzle outlet is 5.6m/s and 0.07m/s, respectively. In different vertical sections in a constant area mixing chamber, the variations in velocity revealed the momentum exchange happening in the entrainment process.

Keywords:

Ejector refrigeration, Critical and subcritical modes, Entrainment ratio, CFD, R141b refrigerant, Design and off-design operation, Internal study, Mach number, Streamlines, Velocity variations.

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