Conference Year

2016

Keywords

Ejector, Swirl, Entrainment Ratio, COP, VJRS

Abstract

Among the various heat powered refrigerated systems, vapour jet refrigeration system (VJRS) is attractive because of its simple and rugged nature. Ejector is a key component in VJRS and the performance of the whole system depends on the effective performance of the ejector. Ejector can be operated with low grade energy by utilizing the heat from solar energy, waste heat from industrial exhaust, automobile exhaust, etc, at minimum temperature of about 60°C[1]. Besides that, this system requires relatively less maintenance as it has no moving parts and it consumes negligible electrical energy for refrigerant recirculation pump used in the system. Ejector could be used in versatile applications  ranging from desalination, refrigeration, textile, petrochemical, metallurgy, aerospace and it can also be used as a device for safe dilation and purging of unspent fuel or gasses, fuel recirculation in fuel cells, etc.[2].  Ejector performance could be improved by enhancing the mixing of the primary and secondary streams by using swirler in the primary nozzle [3,4].  This paper focuses on numerical and experimental studies of air ejector to analyse the influence of swirl on the performance of the system. Three-dimensional numerical analysis has been carried out for the ejector with and with- out swirl and the same has been verified with experimetal studies using flow visualisation technique, particle image velocimetry (PIV). Swirl is generated in the primary stream by incorporating fixed vane swirler of camber angle of 10°, just upstream of the convergent portion of the primary nozzle which is a convergent-divergent (CD) nozzle Velocity vectors obtained from PIV and CFD were compared and found that the results fall with in an acceptable range. The studies have been carried out for an ejector under various priamry stream pressures and secondary and discharge pressure being open to atmosphere. By incorporating swirl generator in the primary nozzle, it has been observed that, entrainment ratio of ejector has been relatively enhanced compared to ejector with no-swirl.  References:  Selvaraju, A., Mani, A., 2006, Experimental investigations on R134a vapour ejector refrigeration system, Int. J.Refrig., vol. 29, p. 1160-1166. Parveen Banu. J., Mani.A., 2014, Review on ejector of vapour jet refrigeration system, Int. J. Air-Cond. Ref. 22, 1430003, [30 pages] DOI: 10.1142/S2010132514300031 Park, I.S., 2009, Enhancement of entraining performance on thermal vapor compressor for multi-effect desalination plants by swirl effects of motive steam, Numerical Heat Transfer, Part A, vol. 56 , p. 406-421. Parveen Banu JIAUTHEEN, Shaligram TIWARI, Mani ANNAMALAI, Three-dimensional Numerical  Investigations on Ejector of Vapour Jet Refrigeration System, 2291, Page 1, 15th International Refrigeration and Air Conditioning Conference at Purdue, July 14-17, 2014. Â

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