Studies on the effects of varying secondary gas properties in a low entrainment ratio supersonic ejector

Rao, Srisha M. V.; Jagadeesh, G.

doi:10.1016/j.applthermaleng.2014.12.053

Cited by 14 publications

(7 citation statements)

References 22 publications

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“…Moreover, the viscosity, the thermal conductivity and the other properties that influence the heat transfer should be favorable. A high molecular mass is desirable to increase ω and η ejector [37]; however, this requires smaller ejectors (for the same output), introducing design difficulties and performance issues related to small-scale components. Low environmental impact, as defined by the global warming potential, GWP, and the ozone depletion potential, ODP, is also an important factor for consideration.…”

Section: Criteria For Working Fluid Selectionmentioning

confidence: 99%

“…Supersonic ejectors are used when there is a need to generate a high pressure difference: in the supersonic regime, the primary flow can entrain a high quantity of suction fluid because of the lower-pressure at the nozzle exit and high momentum transfer. Main energy applications are fuel cell recirculation systems [37], i.e., molten carbonate fuel cells [38,39] and solid oxide fuel cells [40,41], ejector metal topping power plants [42,43], ejector organic Rankine cycles [44] and ejector refrigeration systems (ERS), which are the topic of this review.…”

Section: Nozzle Designmentioning

confidence: 99%

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Ejector refrigeration: A comprehensive review

Besagni

Mereu

Inzoli

2016

Renewable and Sustainable Energy Reviews

407

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a b s t r a c tThe increasing need for thermal comfort has led to a rapid increase in the use of cooling systems and, consequently, electricity demand for air-conditioning systems in buildings. Heat-driven ejector refrigeration systems appear to be a promising alternative to the traditional compressor-based refrigeration technologies for energy consumption reduction. This paper presents a comprehensive literature review on ejector refrigeration systems and working fluids. It deeply analyzes ejector technology and behavior, refrigerant properties and their influence over ejector performance and all of the ejector refrigeration technologies, with a focus on past, present and future trends. The review is structured in four parts. In the first part, ejector technology is described. In the second part, a detailed description of the refrigerant properties and their influence over ejector performance is presented. In the third part, a review focused on the main jet refrigeration cycles is proposed, and the ejector refrigeration systems are reported and categorized. Finally, an overview over all ejector technologies, the relationship among the working fluids and the ejector performance, with a focus on past, present and future trends, is presented.

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Section: Criteria For Working Fluid Selectionmentioning

confidence: 99%

Section: Nozzle Designmentioning

confidence: 99%

Ejector refrigeration: A comprehensive review

Besagni

Mereu

Inzoli

2016

Renewable and Sustainable Energy Reviews

407

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“…A sensitivity analysis was carried out on the ejector secondary inlet temperature (T 2 ) and pressure (p 2 ), considering variations related to off-design operations of SOFC systems [25] (the importance of the property variation at the inlet of secondary duct is also shown in [34]). Moreover, also the effect of pressure rise increase (as generated by SOFC degradation) was taken into account.…”

Section: Resultsmentioning

confidence: 99%

Validated ejector model for hybrid system applications

Ferrari

Pascenti

Massardo

2018

Energy

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The aim of this work is the presentation of a new model for ejector performance calculation using a commercial tool. Due to the critical issues in recirculation performance, special attention is devoted to applications in hybrid systems based on high temperature fuel cells. The theoretical activity is supported by an experimental rig able to operate tests on ejectors at different operative conditions, with a layout similar to the fuel cell anodic recirculation. The model validation, operated considering experimental data obtained with this rig, is essential to evaluate the tool performance for design and off-design calculations. This aspect is particularly critical due to important limitations in the recirculation ratio (especially for the anodic side), to avoid unacceptable operative conditions in the fuel cells.The results presented in this work were obtained with this validated model for an ejector applied on the anodic side of a Solid Oxide Fuel Cell (SOFC). A parametric analysis was carried out to show the effects of several parameters on the recirculation performance. The fully independent analysis of the influence of different properties (carried out with a specifically validated model) is an important innovative result for the application of such ejectors on high temperature fuel cells.

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“…A way of achieving this objective at a reasonable cost is through Computational Fluid Dynamics (CFD) [13]. For instance, Rao and Jagadeesh [22] conduct a numerical investigation using CFD to supplement the experimental results and understand the details of the flow features within the ejector.…”

Section: Introductionmentioning

confidence: 99%

“…In aerospace engineering, they are used to mixed exhaust gases with fresh air in order to reduce the thermal signature [5]. In fuel cell technology their use have been studied [22] in the recirculation and in the purge systems. Obviously, the design performances are different for each application.…”

Section: Introductionmentioning

confidence: 99%