Abstract
AbstractEjectors have some advantages such as being simple, reliable and no moving parts. They can be used in air-conditioning and refrigeration applications. This paper presents a comparison of ejector performance, primary pressure (Pp), back pressure (Pb) and area ratios of ejectors (A2/At) predictions by an analytical model and a computational fluid dynamics model for different operating conditions. Six different area ratios of ejector using air as working fluid in this study were proposed and tested experimentally. The variable area ratios of ejectors (A2/At) were used with a range from 10.68 to 30.62. Two sets of ejectors (A and C) are studied and examined depend on the kind of nozzle. The aim of this study was to investigate these ejectors under variation of primary pressure (Pp) (1.5–6.0 bar) and adjustable spindle position (0 to −25 mm). Two groups of ejectors (A and C) were categorized based on the type of nozzle. The experimental results validate the solutions of the main parameters of ejectors using air as working fluid. The results show that group A is more appropriate for higher values of back pressure, while group C is more suitable for high performance of the ejector. Finally, the main parameters were carried out on six different ejectors to find the best combination based on various nozzles and constant area sections.
Highlights
Ejectors have been used in cooling systems since the 1900s [1]
The results showed primary flow rate was in good agreement between computational fluid dynamics (CFD) and experiment under all operating conditions and spindle positions
The results show that the variable area ejector increases the pressure lift ratio up to 40% by eliminating a shock wave from the ejector
Summary
Ejectors have been used in cooling systems since the 1900s [1] They were not preferred in refrigeration systems because of their low coefficient of performance (COP). Waste heat, solar energy, geothermal energy and biomass products applied to drive a refrigeration system or to generate electricity. They reduce pollution in comparison with fossil fuel power plants. Varga et al [2] and Chandra and Ahmed [3] studied water as a working fluid. R236fa, R152a and R600a were studied by Varga et al [4], Zhang et al [5] and Zhang et al [6]. Kumar et al [12], Hemidi et al [13, 14] and Mazzelli et al [15] have used air in a supersonic ejector
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