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M A Akhavanbehabadi - One of the best experts on this subject based on the ideXlab platform.
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experimental investigation on thermo physical properties and overall performance of mwcnt water nanofluid flow inside horizontal Coiled Wire inserted tubes
Heat and Mass Transfer, 2017Co-Authors: M A Akhavanbehabadi, Mohamad Shahidi, Mohammad Reza Aligoodarz, Mohammad GhazviniAbstract:The present study is aimed to measure and analyze the thermo-physical properties and overall performance of MWCNT–water nanofluid in turbulent flow regimes under constant heat flux conditions inside horizontal Coiled Wire inserted tubes. For this purpose, stable MWCNT–water nanofluids with different particle weight fractions of 0.05, 0.1 and 0.2 % as well as deionized water were utilized as the working fluids. It was found that the existing theoretical models could not predict the thermo-physical property values accurately, especially in case of specific heat capacity. Therefore, new empirical correlations are presented based on the obtained experimental results to predict such properties for the nanofluids. In addition, the overall performance of heat transfer techniques considered in this paper was evaluated based on thermal performance factor. The results revealed that thermal performance factor for all cases are greater than unity which indicate that simultaneous usage of nanofluids and Wire coil inserts enhances the heat transfer without huge penalty in pumping power. Hence, using nanofluids as the working fluid in combination with Coiled Wire inserted tubes can be considered for some practical applications.
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experimental and numerical investigation on turbulent flow of mwcnt water nanofluid inside vertical Coiled Wire inserted tubes
Thermal Science, 2016Co-Authors: Mohamad Shahidi, Saeed Foroutani, Mohammad Reza Aligoodarz, M A Akhavanbehabadi, Alireza RahbariAbstract:In this paper, heat transfer and pressure drop behavior of MWCNT-water nanofluid turbulent flow inside vertical Coiled Wire inserted tubes with constant heat flux boundary condition were investigated experimentally and numerically. In the experimental section, plain and five Wire coil inserted tubes were used as the test section's geometries. In the numerical section, the governing equations associated with the required boundary conditions were solved using finite volume method based on the SIMPLE technique. The standard k-e turbulence model was used in order to simulate the turbulence flow. The great agreement was found between the obtained experimental and numerical data with those predicted by the classical correlations for heat transfer and pressure drop in the plain tube. After validating the achieved data, the effects of various ranges of Reynolds number, particle weight concentration, Wire diameter and coil pitch ratio on heat transfer coefficient and performance evaluation criterion (PEC) were declared. It was concluded that the Nusselt number has been increased up to 102% at the highest Reynolds number inside the coil Wire WC3. Moreover, the maximum enhanced PEC was seen for the Wire coil with lowest coil pitch-to-tube inner diameter ratio (p/d) and highest Wire-to-tube diameter ratio (e/d).
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experimental and numerical invesitgation on turbulent flow of mwcnt water nanofluid inside vertical Coiled Wire inserted tubes
2016Co-Authors: Mohamad Shahidi, Saeed Foroutani, Mohammad Reza Aligoodarz, M A Akhavanbehabadi, Alireza RahbariAbstract:a Department of Mechanical Engineering, Shahid Rajaee Teacher Training University, Tehran, Iran b School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, Iran c Department of Mechanical Engineering, Tehran Science and Research Branch, Islamic Azad University, Damavand, Iran d Research School of Engineering, The Australian National University, Canberra, ACT 2601, Australia
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an experimental study on heat transfer and pressure drop of mwcnt water nano fluid inside horizontal Coiled Wire inserted tube
International Communications in Heat and Mass Transfer, 2015Co-Authors: M A Akhavanbehabadi, Mohamad Shahidi, Mohammad Reza AligoodarzAbstract:Abstract An experimental investigation has been carried out to study the heat transfer and pressure drop characteristics of Nanofluid turbulent flow inside horizontal copper tube with different Wire coil inserts under constant heat flux. The plain and coil inserted tubes were used as the test section's geometries and were heated by an electrical coil heater to produce constant heat fluxes. Nanofluids with different particle weight concentrations of 0.05%, 0.1%, and 0.2% were prepared by dispersion of functionalized multi-walled carbon nanotubes (MWCNTs) in distilled water and stabilized by means of an ultrasonic device. The effect of different parameters such as Reynolds number, nano-particle concentration, Wire diameter and coil pitch on heat transfer coefficient and pressure drop are studied. Observations clearly show that for a specific nanoparticle concentration, increase in both heat transfer and pressure drop is obtained by inserting coil Wires. In average, 85% increase in heat transfer coefficient and 475% penalty in pressure drop was observed at the highest Reynolds number inside the Wire coil inserted tube with the highest Wire diameter. Finally, two new correlations are introduced using the results of the experiments for predicting the Nusselt number and friction factor of the nanofluid flow inside Coiled Wires inserted tubes.
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experimental study on heat transfer and pressure drop of nanofluid flow in a horizontal Coiled Wire inserted tube under constant heat flux
Experimental Thermal and Fluid Science, 2012Co-Authors: M Saeedinia, M A Akhavanbehabadi, M NasrAbstract:Abstract In this work, an extensive experimental study has been carried out to investigate the heat transfer and pressure drop characteristics of CuO/Base oil nanofluid laminar flow in a smooth tube with different Wire coil inserts under constant heat flux. The nanofluid is prepared by dispersion of CuO nanoparticles in base oil and stabilized by means of an ultrasonic device. Particles volume fraction is ranging from 0.07% to 0.3%. Five Coiled Wires having pitches of 25–35 mm and Wire diameters of 0.9–1.5 mm were put one by one in the test section. The effect of different parameters such as Reynolds number, Wire diameter, coil pitch, nanofluid particles concentration and heat flux on heat transfer and friction factor are studied. The experimental results clearly indicate that for a specific nanoparticle concentration, increase in both heat transfer and pressure drop is obtained by inserting coil Wires. In average, 45% increase in heat transfer coefficient and 63% penalty in pressure drop was observed at the highest Reynolds number inside the Wire coil inserted tube with the highest Wire diameter. Since the applied heat transfer enhancement techniques are accompanied by increase in flow pressure drop, the overall performance of these techniques is evaluated at different Reynolds number. Finally, two empirical correlations are developed for predicting the Nusselt number and friction factor of the nanofluid flow insideCoiled Wires inserted tubes. These correlations predict the experimental data in an error band of (±20%).
Veysel Ozceyhan - One of the best experts on this subject based on the ideXlab platform.
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Second law analysis of a mixture of ethylene glycol/water flow in modified heat exchanger tube by passive heat transfer enhancement technique
Journal of Thermal Analysis and Calorimetry, 2020Co-Authors: Orhan Keklikcioglu, Toygun Dagdevir, Veysel OzceyhanAbstract:This experimental study presents the entropy generation analysis of diverging, converging–diverging and converging conically Coiled Wire inserts in a heat exchanger tube using ethylene glycol and water mixtures as a working fluid. The experiments are performed with three different volumetric ratios of ethylene glycol and water mixtures and two different pitch ratios of diverging, converging–diverging and converging conically Coiled Wire inserts. The effects of conically Coiled Wire inserts on the dimensionless entropy generation number and Bejan number are discussed for the Reynolds number ranging from 4627 to 25,099. The results indicated that the converging conically Coiled Wire inserts generate higher entropy rates than the other insert types. It is pointed out that the entropy generation numbers for the diverging conically Coiled Wire inserts used tube reach the lowest value for each fluid type. The experimental results revealed that because the friction forces increase with the use of ethylene glycol, the Bejan number is lower for the fluids with 20 and 40% ethylene glycol than pure water. The highest Bejan number of 0.968 is determined for the smooth tube with pure water at the lowest Reynolds number. The lowest Entropy generation number of 0.42 is obtained for a pure water as a working fluid and diverging conically Coiled Wire insert with pitch ratio of 2 at the Reynolds number 6882, and the highest entropy generation number of 0.94 is observed while the converging conically Coiled Wire insert with pitch ratio of 3 is used in tube flow at Reynolds number of 22,230 for fluid type with 60% water and 40% ethylene glycol.
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experimental investigation on heat transfer enhancement in a circular tube with equilateral triangle cross sectioned Coiled Wire inserts
Applied Thermal Engineering, 2018Co-Authors: Orhan Keklikcioglu, Veysel OzceyhanAbstract:Abstract The thermo-hydraulic performance of Coiled-Wire inserted in a tube was experimentally investigated. The Wire inserts have equilateral triangular cross-sections; they were Coiled in a specific way to ensure that a vertex of the triangle was oriented to face the incoming air flow. The Coiled-Wires were installed with a 1 mm separation from the inner tube wall so that the heat transfer enhancement due to the viscous sublayer disturbance could be investigated. In total, six different Coiled-Wire configurations (three different pitch-to-diameter ratios: P/D = 1, P/D = 2 and P/D = 3 and two different ratios of triangle side-length to tube diameter: e/D = 0.0714 and e/D = 0.0892) were chosen for the experiment. To determine the effect of triangle position on thermal performance, the results of present study were compared with a previous study results. The maximum thermal performance is approximately 1.67 times that for a smooth tube was observed for a Wire with ratios of e/D = 0.0892, P/D = 1 and 11–18% more heat transfer enhancement was achieved than the previous work results. In conclusion, to enhance heat transfer, a Coiled-Wire that a vertex of the triangle is oriented to face the flow can be widely applied wherever heat exchangers with tubes are used.
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entropy generation analysis for a circular tube with equilateral triangle cross sectioned Coiled Wire inserts
Energy, 2017Co-Authors: Orhan Keklikcioglu, Veysel OzceyhanAbstract:This experimental study addresses the entropy generation in a circular tube with Coiled-Wire inserts. The Wire inserts were manufactured with an equilateral triangular cross-section and were Coiled using a method so that an edge of the triangle was oriented to face the flow direction. The triangle side length of 4, 5 and 6 mm were chosen for the experiment. The Coiled-Wire inserts were installed with 1, 1.5 and 2 mm separations from the inner tube wall and Coiled with three different pitch-to-diameter ratios: P/D = 1, P/D = 2 and P/D = 3. A uniform heat flux was applied to the outer surface of the tube. Experiments were performed for a range of Reynolds numbers from 2731 to 27,732. The effect of several conditions on entropy generation were studied. The experimental results revealed that entropy generation number increases with increasing of Reynolds number and decreases with increasing pitch ratio. The thinner Wire configuration's entropy generation numbers were lower than the other models. The entropy generation number was quite closer to each other in terms of separation between inner wall of the tube and the Wire inserts. The minimum entropy generation was obtained for the tube-and-insert combination with s = 2 mm, e = 4 mm and P/D = 3.
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Experimental investigation on heat transfer enhancement of a tube with Coiled-Wire inserts installed with a separation from the tube wall
International Communications in Heat and Mass Transfer, 2016Co-Authors: Orhan Keklikcioglu, Veysel OzceyhanAbstract:Abstract An experimental investigation was conducted for the thermo-hydraulic performance of a circular tube with Coiled-Wire inserts which were installed with a small separation from the inner wall of the tube. The Wire inserts had an equilateral triangular cross-sections with a constant side length of e = 6 mm and they were Coiled with three different pitch-to-diameter ratios: P/D = 1, P/D = 2, P/D = 3. A specific method was employed to coil the Wires so that an edge of the triangle was oriented to face the incoming air flow. The Coiled-Wire inserts were installed with 1 and 2 mm separation from the inner tube wall so that the heat transfer enhancement due to the laminar boundary layer disturbance could be investigated. Experiments were performed for Reynolds numbers from 3429 to 26,663. The Coiled-Wire inserts led to a significant increase in both the heat transfer rate and friction factor over the smooth tube based on coil pitches and clearance. The maximum thermal performance was observed around 1.82 for the P/D = 1, s = 1 type at a Reynolds number of 3429. In conclusion, the laminar boundary layer disturbance can be effectively enhanced by using these types of Coiled-Wire inserts.
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A Taguchi approach for optimization of design parameters in a tube with Coiled Wire inserts
Applied Thermal Engineering, 2011Co-Authors: Sibel Gunes, Eyuphan Manay, Ercan Senyigit, Veysel OzceyhanAbstract:Abstract This study presents the determination of the optimum values of the design parameters in a tube with equilateral triangular cross-sectioned Coiled Wire inserts. The effects of the design parameters such as the ratio of the distance between the Coiled Wire and test tube wall to tube diameter (s/D), pitch ratio (P/D), ratio of the side length of equilateral triangle to tube diameter (a/D) and Reynolds number (Re) on heat transfer and pressure drop were investigated by using Taguchi method. The Nusselt number and friction factor were considered as performance parameters. An L9(34) orthogonal array was chosen as experimental plan. The goal of this study is to reach maximum heat transfer (i.e. Nusselt number) and minimum pressure drop (i.e. friction factor). First of all, each goal was optimized, separately. Then, all the goals were optimized together, considering the priority of the goals. Contribution ratios for each parameter on the heat transfer and pressure drop were determined. Consequently, the optimum results were found to be s/D = 0.0357, P/D = 1, a/D = 0.0714 and Re = 19800.
Mohammad Reza Aligoodarz - One of the best experts on this subject based on the ideXlab platform.
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Experimental and numerical invesitgation on turbulent flow of multiwall carbon nanotube-water nanofluid inside vertical Coiled Wire inserted tubes
Thermal Science, 2018Co-Authors: Mohamad Shahidi, Saeed Foroutani, Mohammad A. Akhavan-behabadi, Mohammad Reza Aligoodarz, Alireza RahbariAbstract:In this paper, heat transfer and pressure drop behavior of MWCNT-water nanofluid turbulent flow inside vertical Coiled Wire inserted tubes with constant heat flux boundary condition were investigated experimentally and numerically. In the experimental section, plain and five Wire coil inserted tubes were used as the test section's geometries. In the numerical section, the governing equations associated with the required boundary conditions were solved using finite volume method based on the SIMPLE technique. The standard k-e turbulence model was used in order to simulate the turbulence flow. The great agreement was found between the obtained experimental and numerical data with those predicted by the classical correlations for heat transfer and pressure drop in the plain tube. After validating the achieved data, the effects of various ranges of Reynolds number, particle weight concentration, Wire diameter and coil pitch ratio on heat transfer coefficient and performance evaluation criterion (PEC) were declared. It was concluded that the Nusselt number has been increased up to 102% at the highest Reynolds number inside the coil Wire WC3. Moreover, the maximum enhanced PEC was seen for the Wire coil with lowest coil pitch-to-tube inner diameter ratio (p/d) and highest Wire-to-tube diameter ratio (e/d).
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experimental investigation on thermo physical properties and overall performance of mwcnt water nanofluid flow inside horizontal Coiled Wire inserted tubes
Heat and Mass Transfer, 2017Co-Authors: M A Akhavanbehabadi, Mohamad Shahidi, Mohammad Reza Aligoodarz, Mohammad GhazviniAbstract:The present study is aimed to measure and analyze the thermo-physical properties and overall performance of MWCNT–water nanofluid in turbulent flow regimes under constant heat flux conditions inside horizontal Coiled Wire inserted tubes. For this purpose, stable MWCNT–water nanofluids with different particle weight fractions of 0.05, 0.1 and 0.2 % as well as deionized water were utilized as the working fluids. It was found that the existing theoretical models could not predict the thermo-physical property values accurately, especially in case of specific heat capacity. Therefore, new empirical correlations are presented based on the obtained experimental results to predict such properties for the nanofluids. In addition, the overall performance of heat transfer techniques considered in this paper was evaluated based on thermal performance factor. The results revealed that thermal performance factor for all cases are greater than unity which indicate that simultaneous usage of nanofluids and Wire coil inserts enhances the heat transfer without huge penalty in pumping power. Hence, using nanofluids as the working fluid in combination with Coiled Wire inserted tubes can be considered for some practical applications.
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experimental and numerical investigation on turbulent flow of mwcnt water nanofluid inside vertical Coiled Wire inserted tubes
Thermal Science, 2016Co-Authors: Mohamad Shahidi, Saeed Foroutani, Mohammad Reza Aligoodarz, M A Akhavanbehabadi, Alireza RahbariAbstract:In this paper, heat transfer and pressure drop behavior of MWCNT-water nanofluid turbulent flow inside vertical Coiled Wire inserted tubes with constant heat flux boundary condition were investigated experimentally and numerically. In the experimental section, plain and five Wire coil inserted tubes were used as the test section's geometries. In the numerical section, the governing equations associated with the required boundary conditions were solved using finite volume method based on the SIMPLE technique. The standard k-e turbulence model was used in order to simulate the turbulence flow. The great agreement was found between the obtained experimental and numerical data with those predicted by the classical correlations for heat transfer and pressure drop in the plain tube. After validating the achieved data, the effects of various ranges of Reynolds number, particle weight concentration, Wire diameter and coil pitch ratio on heat transfer coefficient and performance evaluation criterion (PEC) were declared. It was concluded that the Nusselt number has been increased up to 102% at the highest Reynolds number inside the coil Wire WC3. Moreover, the maximum enhanced PEC was seen for the Wire coil with lowest coil pitch-to-tube inner diameter ratio (p/d) and highest Wire-to-tube diameter ratio (e/d).
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experimental and numerical invesitgation on turbulent flow of mwcnt water nanofluid inside vertical Coiled Wire inserted tubes
2016Co-Authors: Mohamad Shahidi, Saeed Foroutani, Mohammad Reza Aligoodarz, M A Akhavanbehabadi, Alireza RahbariAbstract:a Department of Mechanical Engineering, Shahid Rajaee Teacher Training University, Tehran, Iran b School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, Iran c Department of Mechanical Engineering, Tehran Science and Research Branch, Islamic Azad University, Damavand, Iran d Research School of Engineering, The Australian National University, Canberra, ACT 2601, Australia
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an experimental study on heat transfer and pressure drop of mwcnt water nano fluid inside horizontal Coiled Wire inserted tube
International Communications in Heat and Mass Transfer, 2015Co-Authors: M A Akhavanbehabadi, Mohamad Shahidi, Mohammad Reza AligoodarzAbstract:Abstract An experimental investigation has been carried out to study the heat transfer and pressure drop characteristics of Nanofluid turbulent flow inside horizontal copper tube with different Wire coil inserts under constant heat flux. The plain and coil inserted tubes were used as the test section's geometries and were heated by an electrical coil heater to produce constant heat fluxes. Nanofluids with different particle weight concentrations of 0.05%, 0.1%, and 0.2% were prepared by dispersion of functionalized multi-walled carbon nanotubes (MWCNTs) in distilled water and stabilized by means of an ultrasonic device. The effect of different parameters such as Reynolds number, nano-particle concentration, Wire diameter and coil pitch on heat transfer coefficient and pressure drop are studied. Observations clearly show that for a specific nanoparticle concentration, increase in both heat transfer and pressure drop is obtained by inserting coil Wires. In average, 85% increase in heat transfer coefficient and 475% penalty in pressure drop was observed at the highest Reynolds number inside the Wire coil inserted tube with the highest Wire diameter. Finally, two new correlations are introduced using the results of the experiments for predicting the Nusselt number and friction factor of the nanofluid flow inside Coiled Wires inserted tubes.
S Harish S Kruthiventi - One of the best experts on this subject based on the ideXlab platform.
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performance of j t refrigerators operating with mixtures and Coiled Wire finned heat exchangers
Journal of Thermal Analysis and Calorimetry, 2020Co-Authors: S Harish S Kruthiventi, G VenkatarathnamAbstract:Joule–Thomson refrigerators operating with mixtures require heat exchangers with an effectiveness of over 96% for the system to function. The hot (high pressure) stream enters the heat exchanger in a superheated condition and leaves in a subcooled state. The cold (low pressure) stream, on the other hand, enters the heat exchanger in a two-phase state and leaves in a superheated state. The streams undergo a temperature change of over 200 K in the heat exchanger. The above requirements mandate the use of innovative heat transfer surfaces in the heat exchanger. Coiled Wire-finned heat exchangers have been employed successfully in this work. In this paper, we present the performance of the J–T refrigerator with two different Wire-finned heat exchangers (Wire-fin pitches of 8 mm and 12.7 mm) measured in our test stand. About 20 K lower temperature could be obtained when the Wire-fin pitch was changed from 12.7 to 8 mm. The exergy efficiency of the refrigerator also improved.
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Performance of J–T refrigerators operating with mixtures and Coiled Wire-finned heat exchangers
Journal of Thermal Analysis and Calorimetry, 2020Co-Authors: S Harish S Kruthiventi, G VenkatarathnamAbstract:Joule–Thomson refrigerators operating with mixtures require heat exchangers with an effectiveness of over 96% for the system to function. The hot (high pressure) stream enters the heat exchanger in a superheated condition and leaves in a subcooled state. The cold (low pressure) stream, on the other hand, enters the heat exchanger in a two-phase state and leaves in a superheated state. The streams undergo a temperature change of over 200 K in the heat exchanger. The above requirements mandate the use of innovative heat transfer surfaces in the heat exchanger. Coiled Wire-finned heat exchangers have been employed successfully in this work. In this paper, we present the performance of the J–T refrigerator with two different Wire-finned heat exchangers (Wire-fin pitches of 8 mm and 12.7 mm) measured in our test stand. About 20 K lower temperature could be obtained when the Wire-fin pitch was changed from 12.7 to 8 mm. The exergy efficiency of the refrigerator also improved.
G Venkatarathnam - One of the best experts on this subject based on the ideXlab platform.
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performance of j t refrigerators operating with mixtures and Coiled Wire finned heat exchangers
Journal of Thermal Analysis and Calorimetry, 2020Co-Authors: S Harish S Kruthiventi, G VenkatarathnamAbstract:Joule–Thomson refrigerators operating with mixtures require heat exchangers with an effectiveness of over 96% for the system to function. The hot (high pressure) stream enters the heat exchanger in a superheated condition and leaves in a subcooled state. The cold (low pressure) stream, on the other hand, enters the heat exchanger in a two-phase state and leaves in a superheated state. The streams undergo a temperature change of over 200 K in the heat exchanger. The above requirements mandate the use of innovative heat transfer surfaces in the heat exchanger. Coiled Wire-finned heat exchangers have been employed successfully in this work. In this paper, we present the performance of the J–T refrigerator with two different Wire-finned heat exchangers (Wire-fin pitches of 8 mm and 12.7 mm) measured in our test stand. About 20 K lower temperature could be obtained when the Wire-fin pitch was changed from 12.7 to 8 mm. The exergy efficiency of the refrigerator also improved.
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Performance of J–T refrigerators operating with mixtures and Coiled Wire-finned heat exchangers
Journal of Thermal Analysis and Calorimetry, 2020Co-Authors: S Harish S Kruthiventi, G VenkatarathnamAbstract:Joule–Thomson refrigerators operating with mixtures require heat exchangers with an effectiveness of over 96% for the system to function. The hot (high pressure) stream enters the heat exchanger in a superheated condition and leaves in a subcooled state. The cold (low pressure) stream, on the other hand, enters the heat exchanger in a two-phase state and leaves in a superheated state. The streams undergo a temperature change of over 200 K in the heat exchanger. The above requirements mandate the use of innovative heat transfer surfaces in the heat exchanger. Coiled Wire-finned heat exchangers have been employed successfully in this work. In this paper, we present the performance of the J–T refrigerator with two different Wire-finned heat exchangers (Wire-fin pitches of 8 mm and 12.7 mm) measured in our test stand. About 20 K lower temperature could be obtained when the Wire-fin pitch was changed from 12.7 to 8 mm. The exergy efficiency of the refrigerator also improved.