Heat transfer figures of merit for mapping passive regenerator performance to active regenerator cooling power

Liang, Jierong; Nielsen, Kaspar Kirstein; Engelbrecht, Kurt; Bahl, Christian

doi:10.1016/j.applthermaleng.2020.115993

Cited by 12 publications

(3 citation statements)

References 67 publications

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“…6 (b). When the utilization is fixed, the effectiveness is generally lower at smaller porosities due to the higher fluid penetration [50]. Although the porosity of the Gd regenerator is higher than for the microchannel regenerator (0.45 to 0.38), the effectiveness in the microchannel regenerator is not significantly lower than in the Gd regenerator.…”

Section: Heat Transfermentioning

confidence: 96%

Performance assessment of a triangular microchannel active magnetic regenerator

Liang

Engelbrecht

Nielsen

et al. 2021

Applied Thermal Engineering

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Section: Heat Transfermentioning

confidence: 96%

Performance assessment of a triangular microchannel active magnetic regenerator

Liang

Engelbrecht

Nielsen

et al. 2021

Applied Thermal Engineering

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“…By increasing the inclination angle (α) from 15 to 25 at Re = 12,000 with the same diameter ratio (d/b = 0.25), the thermal performance is increased by approximately 17.6 percent. Doubleperforated inclined elliptic (DPIE) ortex generators with d/ b = 0.25 and = 25 achieve the highest thermal performance parameter (η) of 1.849 at Re = 16,000.They have several advantages over active methods, including relative simplicity, lower manufacturing costs, and lower maintenance and repair costs (Gokulnathan, 2021;Wu, 2011;Liang et al, 2020).In passive techniques, increasing flow turbulence is the key to improving heat transfer, while pressure drop or friction factor is typically kept as low as possible. The most commonly used turbulators to improve thermal efficiency are baffles, ribs, winglets, perforated turbulators, louvered strips, inclined elliptical strips, twisted tapes , and different helical inserts, rectangular turbulators (Mahani, 2021), ring inserts, and springs (Kareem, 2015;Liu, 2013).…”

Section: Literature Reviewmentioning

confidence: 99%

Improvement of Heat Transfer Through Use of Twisted Tape Inserts: A Review

2024

EPPM-Journal

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The objective of this review paper is to identify the gap in finding out the direction toward the enhancement of heat transfer and the performance of heat exchangers. Heat exchangers can be found in many applications ranging from engineering devices to household consumer appliances. Heat exchangers must offer a good heat transfer performance apart from saving energy. Heat transfer enhancement techniques help to save energy and cool hot components in the design of electronic and mechanical circuits. However, enhancement in heat transfer takes place at the cost of a bearable increase in friction losses and pressure drop. Therefore, miniature heat exchanger systems and the cost of energy, motivate industries to use energy-saving methods in their design. With aging, the most common problem in heat exchangers is the reduction in heat transfer rate. Numerous studies have proved that placing a disturbance occurs in the fluid flow path and it can help to increase the heat transfer rate in the case of worn-out heat exchangers. For decades, researchers are numerically investigating the effects of various kinds of insert tape to improve the heat transfer operation in the heat exchangers. As heat exchangers form the backbone of many industrial processes, the idea of saving energy with the design of a cost-effective tape insert motivated us to work on this area of research. The paper proposes the new model of heat exchanger with an insert having a trapezoidal cut on both sides of an insert and using the different ratios of twist experimentation that will perform and compare the output with the previous studies by using different fluid or phase change materials as a fluid to maximize the performance of heat transfer rate. Also, it aims to find out the impact on friction factor as well pressure drop in the heat exchanger when there is a change in ratios of twist. This research aims to review the findings of earlier researchers in this area and to utilize the knowledge for improving the heat transfer rate of conventional tubes in our future work.

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“…They have many advantages compared to active methods such as their relative simplicity, lower manufacturing costs and lower maintenance and repair costs [1][2][3]. In passive techniques increasing turbulence in the flow is the key aspect of heat transfer improvements, while the pressure drop or friction factor usually retains at a lower possible level.…”

Section: Introductionmentioning

confidence: 99%