An experimental study on the effect of the valve angle of counter-flow Ranque–Hilsch vortex tubes on thermal energy separation

A vortex tube is a Thermo-fluidic device, which generates cold and hot streams from a single injection of pressurized gas. Without any moving parts or chemical reaction within the tube, the interesting phenomenon of energy separation results only from fluid dynamic effects.The main part of a typical counter-flow vortex tube is a straight tube with a tangential injection, through which compressed gas is injected into the tube. There are two exits, located at different ends of a counter-flow vortex tube, or at the same end for a uni-flow vortex tube. A control plug is positioned inside the tube away from the injection point, which has a smaller dimension than the inner diameter of the tube, and this allows the gas to escape from the small gap between the control plug and the tube. The cold exit is located in the central part of the tube at the same end of the injection, while the hot exit is the gap between the plug and the tube.When the compressed gas is injected into the tube tangentially at a high velocity, two streams with different temperatures will be generated and exhausted from the two exits of the tube. This phenomenon of temperature separation in a vortex tube is known as the Ranque effect.Several explanations for the energy separation in a vortex tube have been proposed since its invention. However, due to the complex internal flow, the nature of the energy separation in the vortex tube, is still unclear. The proposed hypotheses can only be used to explain part of the phenomenon and they do not cover all the aspects of the temperature separation in the vortex tube. Therefore, to date, there has not been a well-accepted explanation for the thermal separation, and the flow behaviour inside the vortex tube remains unclear.This thesis presents fundamental investigations on the Ranque-Hilsch Vortex Exergy density analysis in the air-operated vortex tube was performed in this study and offered solid support for the proposed hypothesis. The analysis from this study, as well as the data from other studies, show a slightly decreased peripheral iii exergy density in the rear part of the tube, which defines the dominant contribution to the temperature rise from the stagnation and mixture due to multi-circulation.The dramatically reduced exergy density in the front part of the tube, together with an estimation of the temperature drop based on the forced vortex assumption, indicate that the pressure gradient in the front part of the tube is the primary factor contributing to the temperature drop.Based on the proposed hypothesis, discussion of various geometrical effects, such as cold mass flow ratio, tube length, tube diameter and inlet nozzle, on the tube performance has been undertaken. A good agreement between the theoretical and experimental results demonstrates the validity of the proposed hypothesis for the temperature separation occurring within a vortex tube.As a result of the study presented, a novel explanation for the temperature separation phenomenon inside a vortex tube can be forwarded, and can...

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Section: Motivation and Significancementioning

confidence: 99%

“…The vortex tube has also been used to dehumidify air or generate water from air. Liew et al [20] reported that the concentration of liquid increases with increasing humidity of the injected gas.Therefore, it is reasonable to conclude that when factors such as compactness, energy resources, reliability and equipment cost are to be considered, the RHVT …”

mentioning

confidence: 99%

Prospects of using vortex devices in cryogenics

Бондаренко¹,

Тишко²,

Симоненко³

2017

EJSI

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“…Singh et al reported that, change in L/D ratio does not affect energy separation (Singh, Tathgir, Gangacharyulu, & Grewal, 2004). Markal et al noticed (Markal, Aydin, & Avci, 2010) that smaller L/D ratio deteriorate performance because of mixing of the cold and hot streams.…”

Section: Effect Of L/d Ratiomentioning

confidence: 99%

“…Dincer et al used conical valves (Dincer, Baskaya, Uysal, & Ucgul, 2009) and reported that maximum temperature difference occurs at 30 and 60 0 valve angle. Markal et al examined (Markal, Aydin, & Avci, 2010) the valve angles effect and reported that at higher valve angles, flow becomes more unstable because of sudden change in direction of hot streams. Dincer et al (Dincer, Yilmaz, Berber, & Baskaya, 2011) investigated the cascading effect on hot end, and the results state that cascading improves efficiency of the system.…”

Section: Effect Of Hot End Valves/plug/cones (θ)mentioning

confidence: 99%

“…Figure 10 shows the various valve angles researchers used during analysis. Many researchers during their experimental studies (Marshall, 1977;Dyskin, 1989;Aydin & Baki, 2006;Dincer, Baskaya, Uysal, & Ucgul, 2009;Markal, Aydin, & Avci, 2010;Dincer, Yilmaz, Berber, & Baskaya, 2011;Devade & Pise, 2012;Im & Yu, 2012;Avci, 2013;Devade & Pise, 2014) have used different valves Bovand, Rashidi, & Esfahani, 2016) and shapes. Dyskin (Dyskin, 1989) used detwister on hot end and observed that the heating effect increase by 3 to5 0 .…”

Section: Effect Of Hot End Valves/plug/cones (θ)mentioning

confidence: 99%

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Parametric Review of Ranque-Hilsch Vortex Tube

Devade¹,

Pise²

2017

AJHMT

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Vortex tube is the device that separates pressurized fluid into hot and cold fluid streams simultaneously. The scientific community has done extensive experimental and theoretical studies since invention of vortex tube to augment the performance of the tube by varying geometrical and operational parameters; the paper deals with parametric review of all such work. The review takes into account effect of almost 14 parameters on performance of vortex tube. It includes developments in tube geometry like L/D ratio, number of nozzles; hot end valve angle and cold orifice diameter etc. are discussed along with different fluids and operational parameters like CMF and stagnation point etc. The focus of most of the theoretical and experimental studies was to investigate mechanism of thermal separation and geometry optimization. The main objective of this review is to discuss efforts made in order to enhance the refrigeration effect so that, missing links could help for future research.

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Detailed thermodynamics for analysis and design of Ranque‐Hilsch vortex tubes

O’Connell

2017

AIChE Journal

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The Ranque‐Hilsch vortex tube is a device for continuously separating an inlet pressurized fluid stream into two outlet streams of warmer and cooler temperatures at lower pressures, with no moving parts and without any heat or work effects. It has been applied to cool or heat small systems where refrigeration is impractical. Studies of the fluid mechanics inside the tube have not fully established the flow structure that provides the separation. Thermodynamic energy and entropy balances giving relations among properties and the relative amounts of the three fluid streams have been examined to determine consistency among measured data along with sensitivity of the phenomena to tube configuration, measurement error, and properties. The strong response of the temperature separation to small variations in entropy generation is shown to limit the possibilities for generalized prediction of vortex tube behavior. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1067–1074, 2018

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An experimental study on the effect of the valve angle of counter-flow Ranque–Hilsch vortex tubes on thermal energy separation

Cited by 73 publications

References 8 publications

Prospects of using vortex devices in cryogenics

Prospects of using vortex devices in cryogenics

Parametric Review of Ranque-Hilsch Vortex Tube

Detailed thermodynamics for analysis and design of Ranque‐Hilsch vortex tubes

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