The experimental investigation of the performance of a vapour ejector refrigeration system is described. The system uses R134a as working fluid and has a rated cooling capacity of 0.5 kW. The influence of generator, evaporator and condenser temperatures on the system performance is studied. This kind of system can be operated with low grade thermal energy such as solar energy, waste heat, etc. The operating conditions are chosen accordingly as, generator temperature between 338 K and 363 K, condenser temperature between 299 K and 310.5 K, and evaporator temperature between 275 K and 285.5 K. Six configurations of ejectors of different geometrical dimensions are selected for the parametric study. The performance of the refrigeration system at different operating temperatures is presented. © 2006 Elsevier Ltd and IIR.

A Mani

Department of Mechanical Engineering

AIR EJECTORS

Condensers (liquefiers)

Cooling systems

FLUIDS

Solar energy

Thermal effects

CONDENSER TEMPERATURE

EVAPORATOR TEMPERATURE

Geometrical dimensions

R134A VAPOR EJECTOR REFRIGERATION SYSTEM

Refrigerators

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It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

International Journal of Refrigeration

This paper presents three-dimensional numerical studies of ejector with swirl generator (SG) using computational fluid dynamics (CFD) software, ANSYS, FLUENT 15.0. Performance analysis is carried out with two different configurations of swirl generators, namely solid vane type and cavity type. As expected, swirl increases the entrainment performance due to better momentum exchange between the motive and secondary streams compared to the ejector without swirl generator. Also, it is confirmed from the studies that, cavity type SG, imparts higher swirl strength to the flow stream than that of the solid vane type, due to the sweep angle in addition to the camber angle. Hence the studies are further extended with cavity type SG, at camber angle of 10° with various sweep angles like 10° 20° and 30° for analyzing the swirl effect over the performance of the ejector. The increase in entrainment ratio observed is about 15% with SG, compared to ejector without SG. © 2018 Elsevier Masson SAS

International Journal of Thermal Sciences

Numerical studies on ejector with swirl generator

Experimental studies have been conducted to depict the flow patterns in a small rectangular ejector by using schlieren flow visualisation technique. A transparent ejector is designed, fabricated, and operated using air as working fluid. Geometry of the ejector is in form of two-dimensional extrusion with two suction inlets: one on top and other at bottom of the convergent-divergent nozzle. Ejector performance has been analysed by measuring the mass flow rates at primary and secondary inlets. The results of flow visualisation studies have been compared with those obtained using numerical computations. Variation of entrainment ratio with change in primary stream pressure has been presented. Moreover, the shock wave patterns in constant area mixing chamber and diffuser for set of inlet and outlet conditions have been visualised and presented. © 2019 Elsevier Masson SAS

Experimental studies on a rectangular ejector with air

The performance and flow structure in a three-dimensional rectangular ejector have been numerically investigated by using air as the working fluid. Commercial software ANSYS Fluent 15.5 has been used for numerical simulation of supersonic, compressible, turbulent flow ejectors. In order to confirm the appropriate turbulence model, the computed results are validated against indigenous experimental data. The study aims to optimize the convergent-divergent (C-D) nozzle position for each operating condition and to bring out the influence of reflected shock waves and boundary layer in the constant area mixing chamber on the performance of the ejector. Also, the variation of entrainment ratio (ER) for a range of primary, secondary and exit pressure has been investigated. Both the on-design and the off-design characteristics and local flow structure of a rectangular ejector have been considered. © 2017

Three-dimensional numerical investigations on rectangular cross-section ejector

When an ejector is operated at choking-mode, it gives a better performance with higher entrainment ratio. To obtain this better performance at different operating conditions, area ratio of the ejector is varied. A computer code based on existing one-dimensional ejector theory is written to analyze performance of the ejector. The code includes effects of friction at the constant-area mixing chamber and change in specific heat of the working fluid besides internal irreversibility of the ejector. The simulated performance is compared with the available experimental data from the literature for validation. The effects of operating parameters on critical ejector area ratio and critical entrainment ratio are studied. Comparison of performance of ejector with environment friendly refrigerants, R134a, R152a, R290, R600a and R717 is made. © 2003 Elsevier Ltd. All rights reserved.

Applied Thermal Engineering

Analysis of an ejector with environment friendly refrigerants

Vapour ejector refrigeration system yields better performance when the ejector operates at choking-mode. A computer code based on existing one dimensional ejector theory has been developed to carry out a study on performance of the system. When operating conditions are changed, the critical performance parameters of the system get shifted to different critical values. The code includes effects of change in specific heat of the working fluid and friction at the constant-area mixing chamber besides internal irreversibility of the ejector. The simulated performance results are compared with the available experimental data from the literature for validation. The effects of operational parameters and ejector configurations of the system on critical performance are studied. Also, comparison of performance of the system with environment friendly refrigerants, R134a, R152a, R290, R600a and R717 is made. © 2004 Elsevier SAS. All rights reserved.

Analysis of a vapour ejector refrigeration system with environment friendly refrigerants

A computer simulation of a vapour jet refrigeration system is carried out using a one-dimensional model based on mass, momentum and energy balances. The simulated performance of the system is in good agreement with the available experimental performance from the literature. A comparison of system performance is carried out for the same ejector geometry using the environmentally friendly working fluids R123, R134a, R152a and R717 (ammonia). The results suggest that, for different boiler temperatures, the entrainment ratio and the system efficiency (COP) depend mainly on the ejector geometry and the compression ratio.

Journal	International Journal of Refrigeration
ISSN	01407007
Open Access	No