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Inventions 2018, 3(3), 50;

Heat Transfer Enhancement by Detached S-Ribs for Twin-Pass Parallelogram Channel

Department of System and Naval Mechatronic Engineering, National Cheng Kung University, No. 1, University Road, Tainan City 701, Taiwan
Department of Materials and Mineral Resources Engineering, National Taipei University of Technology, 1, Sec. 3, Zhongxiao E. Rd., Taipei 10608, Taiwan
Author to whom correspondence should be addressed.
Received: 29 May 2018 / Revised: 10 July 2018 / Accepted: 11 July 2018 / Published: 23 July 2018
(This article belongs to the Special Issue Heat Transfer and Its Innovative Applications)
PDF [4793 KB, uploaded 23 July 2018]


Detached S-ribs are proposed to arrange in the stagger manner along two parallelogram straight channels interconnecting with a 180° smooth-walled sharp bend for heat transfer enhancements. The detailed Nusselt number distributions over the two opposite channel endwalls at Reynolds numbers of 5000, 7500, 10,000, 12,500, 15,000 and 20,000 are measured using the steady-state infrared thermography method. The accompanying Fanning friction factors are evaluated from the measured pressure drops across the entire test channel. Having acquired the averaged heat transfer properties and Fanning friction factors, the thermal performance factors are determined under the criterion of constant pumping power consumptions. With the regional accelerated flows between the detached S-ribs and the channel endwall, the considerable heat transfer elevations from the Dittus–Boelter correlation levels are achieved. The comparative thermal performances between the two similar twin-pass parallelogram channels with detached 90° and S-ribs disclose the higher regional heat transfer rates over the turning region and the larger Fanning frictions factors, leading to the lower thermal performance factors, for present test channel with the detached S-ribs. To assist design applications, two sets of empirical correlations evaluating the regionally averaged Nusselt numbers and Fanning friction factors are devised for present twin-pass parallelogram channel with the detached S-ribs. View Full-Text
Keywords: heat transfer enhancement; detached S-rib; parallelogram twin-pass channel heat transfer enhancement; detached S-rib; parallelogram twin-pass channel

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Chang, S.W.; Cai, W.-L.; Wu, R.-J. Heat Transfer Enhancement by Detached S-Ribs for Twin-Pass Parallelogram Channel. Inventions 2018, 3, 50.

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