scholarly journals Modulation of a R245fa Supersonic Ejector By A Movable Needle: A Numerical Study

2021 ◽  
Author(s):  
Charles P. Rand ◽  
Sergio Croquer ◽  
Michel Poirier ◽  
Sébastien Poncet
Keyword(s):  
Numerical Study ◽  
Supersonic Ejector

scholarly journals Computational fluid dynamic modelling of supersonic ejectors: comparison between 2D and 3D modelling

2021 ◽  
Vol 2116 (1) ◽  
pp. 012091
Author(s):  
Giorgio Besagni ◽  
Lorenzo Croci ◽  
Nicolò Cristiani ◽  
Fabio Inzoli ◽  
Gaël Raymond Guédon
Keyword(s):  
Numerical Study ◽  
Fluid Dynamic ◽  
A Priori ◽  
Dynamic Modelling ◽  
Global Scale ◽  
Entrainment Ratio ◽  
Local Flow ◽  
Supersonic Ejector ◽  
Precise Knowledge ◽  
Flow Phenomena

Abstract It is known that the global performances of ejector-based systems (viz., at the “global-scale”) depend on the local flow properties within the ejector (viz., at the “local-scale”). For this reason, reliable computational fluid-dynamics (CFD) approaches, to obtain a precise and an a-priori knowledge of the local flow phenomena, are of fundamental importance to support the deployment of innovative ejector-based systems. This communication contributes to the existing discussion by presenting a numerical study of the turbulent compressible flow in a supersonic ejector. In particular, this communication focuses on a precise knowledge gap: the comparison between 2D and 3D modelling approaches as well as density-based and pressure-based solvers. The different approaches have been compared and validated against literature data consisting in entrainment ratio and wall static pressure measurements. In conclusion, this paper is intended to provide guidelines for researchers dealing with the numerical simulation of ejectors.

CFD Design Study of a Pressure Probe for Centerline Static Pressure Measurement in Supersonic Ejectors

2019 ◽  
Vol 36 (1) ◽  
pp. 107-112 ◽  
Author(s):  
Ala Bouhanguel ◽  
Philippe Desevaux ◽  
Mohamed Khan
Keyword(s):  
Pressure Measurement ◽  
Test Bench ◽  
Static Pressure ◽  
Capillary Tube ◽  
Numerical Study ◽  
Pressure Probe ◽  
Design Study ◽  
Supersonic Ejector ◽  
Thin Tube ◽  
Flow Pressure

Abstract The measurement of the static pressure of the flow inside a supersonic ejector can be achieved by using a thin tube with a radially drilled hole to capture the flow pressure, and which is inserted along the ejector axis. This paper presents a numerical study by CFD permitting to predict the disturbances generated by the presence of the probe in the ejector. Also this study allows guiding the design of the probe, in particular of the capillary tube diameter for the least disturbed measurement. A probe prototype has been built and tested on an ejector test bench.

Numerical Study of Mixing Enhancement in 2D Supersonic Ejector

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
M. Dandani ◽  
P. Desevaux ◽  
A. Ghezal ◽  
V. Lepiller
Keyword(s):  
Kinetic Energy ◽  
Pressure Loss ◽  
Momentum Flux ◽  
Numerical Study ◽  
Stagnation Pressure ◽  
Mixing Enhancement ◽  
Mixing Process ◽  
Performance Parameters ◽  
Supersonic Ejector ◽  
Mixing Chamber

AbstractThe present study deals with the numerical study of the mixing process in a 2D supersonic ejector. The performance parameters such as momentum flux, degree of mixing and stagnation pressure loss are used to analyse mixing process. The evolution of the kinetic energy of turbulence is also observed. The investigation is carried out on a conventional 2D supersonic ejector and on a 2D supersonic ejector equipped with wall slot injectors along the mixing chamber. The performance parameters show a significant mixing enhancement when transverse micro-jets are used.

scholarly journals Introductory Numerical Study on Supersonic Ejector Working with R32

2019 ◽  
Vol 213 ◽  
pp. 02096
Author(s):  
Lukas Vojta ◽  
Jan Kracik ◽  
Vaclav Dvorak
Keyword(s):  
Numerical Analysis ◽  
Nozzle Exit ◽  
Numerical Study ◽  
Back Pressure ◽  
Working Fluid ◽  
Future Research ◽  
Fixed Boundary ◽  
Supersonic Ejector ◽  
Mixing Chamber ◽  
Increasing Demand

Nowadays, there is an increasing demand for devices which work efficiently with the smallest possible consumption of energy. In this regard, incorporating ejectors seems to be an interesting choice. This paper describes the numerical analysis of the flow in a supersonic ejector working with R32 (difluoromethane) as the working fluid. The ejector geometry under investigation in this paper has already been experimentally analysed, however, air was used as the working fluid. Therefore, this paper deals with a numerical analysis of the same geometry but with a different working fluid. Furthermore, the design of the ejector enabled the adjustment of a particular distance of the motive nozzle from the beginning of the mixing chamber, i.e. the nozzle exit position (NXP). This work examines the ejector numerically for eleven values of back-pressure with the NXP of two millimetres; consequently, the performance line of the ejector with fixed boundary conditions at both inlets was obtained. Finally, the obtained results are discussed and some recommendations for future research have been made.

Numerical study of the low-frequency atomic dynamics in a Lennard-Jones glass

1998 ◽  
Vol 77 (2) ◽  
pp. 473-484 ◽  
Author(s):  
M. Sampoli, P. Benassi, R. Dell'Anna,
Keyword(s):  
Numerical Study ◽  
Low Frequency ◽  
Lennard Jones
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