Experimental investigation on mixed refrigerant Joule–Thomson cryocooler with flammable and non-flammable refrigerant mixtures

Walimbe, N. S.; Narayankhedkar, K.G.; Atrey, M. D.

doi:10.1016/j.cryogenics.2010.06.002

Cited by 59 publications

(14 citation statements)

References 9 publications

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“…Based on the studies carried out on the MR J-T cryocooler development at IIT Bombay [1], it has been found that heat exchanger plays a very crucial role in determining the performance of cryocooler. Experiments are being carried out to study the heat exchanger performance with respect to mixture composition and operating parameters.…”

Section: Advances In Cryogenic Engineeringmentioning

confidence: 99%

“…Experiments are being carried out to study the heat exchanger performance with respect to mixture composition and operating parameters. Many experimental/numerical studies that have been carried out by various workers on MR J-T cryocooler are mainly related to the optimization of mixtures used and the thermodynamic performance of overall refrigeration system [1][2][3]. The gas mixture in such a system undergoes boiling and condensation heat transfer in the heat exchanger, which is responsible for the high efficiency of J-T coolers.…”

Section: Advances In Cryogenic Engineeringmentioning

confidence: 99%

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Investigations on two-phase heat exchanger for mixed refrigerant Joule-Thomson cryocooler

Ardhapurkar¹,

Sridharan²,

Atrey³

2012

AIP Conference Proceedings

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The design of the recuperative heat exchanger used to pre-cool the refrigerant mixture prior to J-T expansion is crucial for the efficient operation of the mixed refrigerant JouleThomson (MR J-T) cryocooler. The multi-component non-azeotropic refrigerant mixture undergoes boiling and condensation heat transfer simultaneously in the heat exchanger. Therefore, it is important to analyze the performance of the heat exchanger in terms of temperature distribution with respect to the mixture of gases used.In the present work, temperature measurements are carried out at the ends of the heat exchanger for high pressure stream, while eight sensors are installed at equal distance along the length of heat exchanger to measure temperature of low pressure stream. The paper reports variation in heat transfer coefficient along the length of the heat exchanger. The variation is discussed with respect to temperature distribution across the length and changes in thermo-physical properties of the gas mixture.

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Section: Advances In Cryogenic Engineeringmentioning

confidence: 99%

Section: Advances In Cryogenic Engineeringmentioning

confidence: 99%

Investigations on two-phase heat exchanger for mixed refrigerant Joule-Thomson cryocooler

Ardhapurkar¹,

Sridharan²,

Atrey³

2012

AIP Conference Proceedings

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“…For example, Nayak and Venkatarathnam [1] have reported exergy efficiencies of about 30% for cooling to 90 K with ARC system. Single stage cryocoolers, without phase separation, are much less complicated with the expense of having much lower exergy efficiency of a few percentage only [2][3][4][5][6][7]. Increasing the efficiency is also possible by adding a pre-cooling stage for the refrigerant [8][9][10][11] which complicates the whole cooling system.…”

Section: Introductionmentioning

confidence: 99%

Mixed-refrigerant Joule-Thomson (MR JT) mini-cryocoolers

Tzabar¹

2014

AIP Conference Proceedings

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Abstract. This paper presents the progress in our ongoing research on Mixed-Refrigerant (MR) Joule-Thomson (JT) cryocoolers. The research begun by exploring different MRs and testing various compressors: oil-lubricated and oil-free, reciprocating and linear, custom-made and commercial. Closed-cycle JT cryocoolers benefit from the fact that the compressor might be located far from the cold-end and thus there are no moving parts, no vibrations, and no heat emission near the cold-end. As a consequence, the compressor may be located where there are no severe size limitations, its heat can be conveniently removed, and it can be easily maintained. However, in some applications there is still a demand for a small compressor to drive a JT cryocooler although it is located far from the cooled device. Recently, we have developed a miniature oil-free compressor for MR JT cryocoolers that weighs about 700 g and its volume equals about 300 cc. The cryocooler operates with a MR that contains Ne, N 2 , and Hydrocarbons. This MR has been widely investigated with different compressors and varying operating conditions and proved to be stable. The current research investigates the performances of MR JT mini-cryocooler operating with the MR mentioned above, driven with our miniature compressor, and a cold-finger prototype. A Dewar with heat load of about 230 mW is cooled to about 80 K at ambient temperatures between 0°C and 40 °C. The experimental results obtained are stable and demonstrate the ability to control the cooling temperature by changing the rotation speed of the compressor.

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“…The two-phase friction factor f tp, is calculated on the basis of the two-phase Reynolds number, Re tp as expressed in equation (2). …”

Section: 1homogeneous Flow Model (Hfm)mentioning

confidence: 99%

“…However, the overall performance of such mixed refrigerant Joule-Thomson (MR J-T) cryocoolers greatly depends on the refrigerant mixture, heat exchanger and compressor. Numerous experimental and theoretical studies of MR J-T cryocoolers operating in the temperature range of 80-230 K have been reported in the literature [1][2][3][4]. These studies are mainly related to the optimization of mixtures used and the overall performance of the refrigeration systems.…”

mentioning

confidence: 99%

Prediction of two-phase pressure drop in heat exchanger for mixed refrigerant Joule-Thomson cryocooler

Ardhapurkar¹,

Atrey

2015

IOP Conf. Ser.: Mater. Sci. Eng.

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Abstract. The overall efficiency of a mixed refrigerant Joule-Thomson (MR J-T) cryocooler is governed by the performance of the recuperative heat exchanger. In the heat exchanger, the hot stream of the mixed refrigerant undergoes condensation at high pressure while the cold stream gets evaporated at low pressure. The pressure drop in the low pressure stream is crucial since it directly influences the achievable refrigeration temperature. However, experimental and theoretical studies related to two-phase pressure drop in mixtures at cryogenic temperatures, are limited. Therefore, the design of an efficient MR J-T cryocooler is a challenging task due to the lack of predictive tools.In the present work, the existing empirical correlations, which are commonly used for the prediction of pressure drop in the case of pure refrigerants, evaporating at near ambient conditions, are assessed for the mixed refrigerants. Experiments are carried out to measure the overall pressure drop in the evaporating cold stream of the tube-in-tube helically coiled heat exchanger. The predicted frictional pressure drop in the heat exchanger is compared with the experimental data. The suggested empirical correlations can be used to predict the hydraulic performance of the heat exchanger. IntroductionJoule-Thomson (J-T) cryocoolers are known for fast cool-down time, low cost and low vibrations at the cold end because of no moving parts in the cold section. The use of a refrigerant mixture of nitrogen-hydrocarbons as a working medium in these cryocoolers enhances their efficiency. Additionally, pressure requirements drastically get reduced up to 2 MPa in comparison to that of using a pure component as a working fluid, which allow the use of oil-lubricated compressors. However, the overall performance of such mixed refrigerant Joule-Thomson (MR J-T) cryocoolers greatly depends on the refrigerant mixture, heat exchanger and compressor. Numerous experimental and theoretical studies of MR J-T cryocoolers operating in the temperature range of 80-230 K have been reported in the literature [1][2][3][4]. These studies are mainly related to the optimization of mixtures used and the overall performance of the refrigeration systems. However, little work [5][6][7] is done on the performance analysis of the recuperative heat exchanger used in the MR J-T cryocooler, even though it plays a crucial role in its efficient operation. This is mainly due to the lack of the experimental data available, related to flow boiling/condensation heat transfer and pressure drop of mixed refrigerants at cryogenic temperatures. The refrigerant mixture undergoes boiling and condensation heat transfer simultaneously, in the counter-flow heat exchanger. The hydraulic diameter of the heat exchangers is

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Experimental investigation on mixed refrigerant Joule–Thomson cryocooler with flammable and non-flammable refrigerant mixtures

Cited by 59 publications

References 9 publications

Investigations on two-phase heat exchanger for mixed refrigerant Joule-Thomson cryocooler

Investigations on two-phase heat exchanger for mixed refrigerant Joule-Thomson cryocooler

Mixed-refrigerant Joule-Thomson (MR JT) mini-cryocoolers

Prediction of two-phase pressure drop in heat exchanger for mixed refrigerant Joule-Thomson cryocooler

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