Experimental investigation into the influence of vortex control on transcritical R744 ejector and cycle performance

Abstract Vortex control over a diphasic convergent-divergent nozzle through adjustable nozzle inlet vortex can improve the performance of transcritical R744 ejector cooling cycle due to its potential for flow control with less sacrifice of nozzle efficiency and no requirement of geometry change. In this study, the influence of vortex control on transcritical R744 ejector and cycle performance has been experimentally investigated. Vortex control was applied to ejectors with different geometric parameters. The results with vortex control were compared with those with series expansion valve control and needle control. Design guidelines for ejector with vortex control were provided. It was found that the total work recovery efficiency of ejector with vortex control can be better than series expansion valve control and is close to needle control. Vortex control can be used to improve system performance by adjusting the high-side pressure of the transcritical R744 ejector cycle. Under off-design conditions, system capacity and COP can be improved by 11.0% and 8.1%, respectively, by applying vortex control.

[1]  Armin Hafner,et al.  Performance of fixed geometry ejectors with a swirl motion installed in a multi-ejector module of a CO2 refrigeration system , 2016 .

[2]  Trond Andresen,et al.  Experimental and numerical investigation of the influence of the two-phase ejector geometry on the performance of the R744 heat pump , 2012 .

[3]  Somchai Wongwises,et al.  Experimental investigation on the performance of the refrigeration cycle using a two-phase ejector as an expansion device , 2004 .

[4]  Alan A. Kornhauser,et al.  Performance tests of a two phase ejector , 1995 .

[5]  Armin Hafner,et al.  Performance comparison of fixed-and controllable-geometry ejectors in a CO2 refrigeration system. , 2016 .

[6]  Stefan Elbel,et al.  Experimental investigation of a novel expansion device control mechanism: Vortex control of initially subcooled flashing R134a flow expanded through convergent-divergent nozzles , 2018 .

[7]  Pei-Xue Jiang,et al.  Flow visualization of supersonic two-phase transcritical flow of CO2 in an ejector of a refrigeration system , 2017 .

[8]  Neal Lawrence,et al.  Experimental investigation on control methods and strategies for off-design operation of the transcritical R744 two-phase ejector cycle , 2019, International Journal of Refrigeration.

[9]  Il Seouk Park.  Enhancement of Entraining Performance on Thermal Vapor Compressor for Multi-Effect Desalination Plants by Swirl Effects of Motive Steam , 2009 .

[10]  Jahar Sarkar,et al.  Ejector enhanced vapor compression refrigeration and heat pump systems—A review , 2012 .

[11]  Predrag Stojan Hrnjak,et al.  Experimental validation of a prototype ejector designed to reduce throttling losses encountered in transcritical R744 system operation , 2008 .

[12]  Stefan Elbel,et al.  Influence of Nozzle Divergent Part Length and Throat Diameter on Vortex Control of Initially Subcooled Flashing Flow , 2017 .

[13]  Stefan Elbel,et al.  Measurement of static pressure profiles of vortex flashing R134a flow expanded through convergent–divergent nozzles , 2019 .

[14]  David F. Bagster,et al.  A New Ejector Theory Applied to Steam Jet Refrigeration , 1977 .

[15]  Sven Försterling,et al.  Multi-ejector concept for R-744 supermarket refrigeration , 2014 .

[16]  Mani Annamalai,et al.  REVIEW ON EJECTOR OF VAPOR JET REFRIGERATION SYSTEM , 2014 .

[17]  Neal Lawrence,et al.  Experimental investigation of a two-phase ejector cycle suitable for use with low-pressure refrigerants R134a and R1234yf , 2014 .

[18]  Junye Shi,et al.  Numerical and experimental investigation on nozzle parameters for R410A ejector air conditioning system , 2014 .

[19]  Eckhard A. Groll,et al.  Transcritical CO2 refrigeration cycle with ejector-expansion device , 2005 .

[20]  Eckhard A. Groll,et al.  Investigation on performance of variable geometry ejectors for CO2 refrigeration cycles , 2012 .

[21]  Armin Hafner,et al.  Development and performance mapping of a multi-ejector expansion work recovery pack for R744 vapour compression units. , 2015 .

[22]  Stefan Elbel,et al.  A New Control Mechanism for Two-Phase Ejector in Vapor Compression Cycles for Automotive Applications Using Adjustable Motive Nozzle Inlet Swirl , 2016 .