Selected studies of flow maldistribution in a minichannel plate heat exchanger

Dąbrowski, Paweł; Klugmann, Michał; Mikielewicz, Dariusz

doi:10.1515/aoter-2017-0020

Cited by 26 publications

(10 citation statements)

References 43 publications

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“…A pumping power requires for circular shape and rectangular shape of minichannel is maximum and minimum, respectively. Hydrodynamic studies were made by [16] on the topic of flow maldistribution in multiple minichannels heat exchanger. The pressure drops were measured in plate heat exchanger which contains 51 parallel minichannels with a rectangular cross section of four hydraulic diameters is 461 μm, 574 μm, 667 μm, and 750 μm connected by trapezoidal inlet and outlet manifold.…”

Section: Introductionmentioning

confidence: 99%

A Loop Thermosyphon for Liquid Cooled Minichannels Heat Sink With Pulsate Surface Heat Flux

Al-Tae'y

Jaddoa

Abd

2021

Journal of Thermal Engineering

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The period operation of power electronic acts as switching element, where the power dissipated consists of pulses at certain duty cycle, the semiconductor temperature oscillates and varies as a waveform. In the present study, an experimental investigation was carried out for a loop thermosyphon order to evaluate the effect of pulsate surface heat flux on the single-phase buoyancy driven convection of ethylene glycol flow through a minichannels heat sink with hydraulic diameter 1.5 mm. An electric heater block is used to supply the heat flux to minichannels heat sink in a rectangle waveform. The study is done at different heat flux frequencies of 2.777×10-3 Hz, 8.333×10-4 Hz, 5.555×10-4 Hz and 4.166×10-4 Hz, while the heat flux amplitude (2 watt), Rayleigh number (1864) and duty cycle (50 %) are kept constant. The results revealed that for a range of the measured frequency for the complete power cycle and due to unsteady state operation conditions, the pulse heat flux pattern is close to a rectangle-wave, this generates the fluid outlet temperature pattern close to a triangle-wave. The fluid outlet temperature increases with the decreases of heat flux frequency and tends to reach to the fluid outlet temperature for a constant and continuous heat flux case. Due to closed-loop of thermosyphon, the fluid inlet temperature is changed in pattern like that the fluid outlet temperature change.

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Section: Introductionmentioning

confidence: 99%

A Loop Thermosyphon for Liquid Cooled Minichannels Heat Sink With Pulsate Surface Heat Flux

Al-Tae'y

Jaddoa

Abd

2021

Journal of Thermal Engineering

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“…The maldistribution is not examined well enough and there are inconsistencies in reports about reasons, predictions and methods of reduction. Moreover, there are a lot of works that are dealing with a maldistribution phenomenon in parallel minichannels (Dąbrowski et al 2019;García-Cascales et al 2017;Najim & Feddaoui, 2018;Dąbrowski et al 2017;Sakamatapan & Wongwises, 2014;Yang et al 2017;Zhou et al 2014) but few that mentioned about flow non-uniformity and non-uniform temperature field in minigaps (Alam et al 2013;Mathew et al 2019;Tamanna & Lee, 2015).…”

Section: Introductionmentioning

confidence: 99%

Mitigation of Flow Maldistribution in Minichannel and Minigap Heat Exchangers by Introducing Threshold in Manifolds

Dąbrowski

2020

JAFM

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In the present paper, a detailed numerical investigation has been carried out to analyze the flow maldistribution in 50 parallel rectangular cross-section (1 mm depth and 1 mm width) minichannels and minigap section (1 mm depth and 99 mm width) with rectangular/trapezoidal manifolds in Z-type flow configuration. The author carried out numerical investigation with various mass flow rates, namely 0.05 kg/s, 0.1 kg/s and 0.2 kg/s which results in Reynolds number of 1532, 3064, 6128 respectively. A novel approach for the mitigation of non-uniform flow has been proposed introducing threshold at the entrance of the minigeometry section. The conventional case without threshold (as reference) and 1 mm, 3 mm and 7 mm threshold were introduced. The threshold has been employed by making a manifolds' depth bigger than section's depth. The maldistribution coefficient can be reduced twice in minigap section or three times in the minichannel section already with the 1 mm threshold as compared to the arrangement without threshold. It is found that rectangular manifold gives lower maldistribution coefficient than trapezoidal manifold which corresponds with actual state of the art. The distribution is more uniform in minichannel section than in minigap section for the same inlet parameters. To obtain uniform distribution of fluid flow should be stabilized already at the inlet manifold, at the entrance to the minichannel or minigap section. That was done by introducing the threshold in the manifolds, which is novelty of this study.

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“…Dąbrowski et al [33] accomplished hydrodynamic studies in a minichannel plate heat exchanger which contained 51 parallel minichannels. The channels' cross-section was rectangular with a constant width and various depths, which resulted in various hydraulic diameter of channels (461, 574, 667, and 750 µm).…”

Section: Introductionmentioning

confidence: 99%

Flow Boiling in Minigap in the Reversed Two-Phase Thermosiphon Loop

2019

Self Cite

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The paper presents the results of experimental investigations of a model of a heat exchanger featuring a minigap, which is perceived as an evaporator for an inverted thermosiphon. The system works with a single component test fluid. The tested evaporator generates pumping power in the test loop in a way similar to the mammoth pump. The tests regarded a module of the heat exchanger, consisting of a hot leg and a cold leg with the width by the length of 0.1 × 0.2 m, heated by a uniform heat flux. In the tests, the minigaps of 1, 2 and 3 mm were formed. Two fluids, namely, distilled water and ethanol, were tested in the facility. Two-phase flow structures for both working fluids and various operational parameters, together with comprehensive visualization material, are presented. The specifics of pressure changes and its influence on operating parameters and flow structure are discussed.

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Selected studies of flow maldistribution in a minichannel plate heat exchanger

Cited by 26 publications

References 43 publications

A Loop Thermosyphon for Liquid Cooled Minichannels Heat Sink With Pulsate Surface Heat Flux

A Loop Thermosyphon for Liquid Cooled Minichannels Heat Sink With Pulsate Surface Heat Flux

Mitigation of Flow Maldistribution in Minichannel and Minigap Heat Exchangers by Introducing Threshold in Manifolds

Flow Boiling in Minigap in the Reversed Two-Phase Thermosiphon Loop

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