The effect of lateral thermal coupling between parallel microchannels on two-phase flow distribution

Oevelen, Tijs Van; Weibel, Justin A.; Garimella, Suresh V.

doi:10.1016/j.ijheatmasstransfer.2018.03.073

Cited by 28 publications

(4 citation statements)

References 45 publications

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“…Parallel micro-channels, functioning as fluid distributors to segregate a singular inlet stream into multiple branches, are ubiquitously employed across a vast array of industrial apparatus, including reactors [1], mixers [2], and heat exchangers [3], among others. Notably, the fluidic properties undergo significant alterations when the system dimensions are scaled down to the micro-scale, defined by a diameter range of 1 µm to 1000 µm [4].…”

Section: Introductionmentioning

confidence: 99%

Phase Distribution of Gas–Liquid Slug–Annular Flow in Horizontal Parallel Micro-Channels

Liu,

Jiang,

Wang

2024

Energies

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As a transitional flow pattern, slug–annular flow occurs over a wide range of operating conditions in micro-channels while its distribution in parallel micro-channels has not been well characterized. Herein, we conducted an experiment to study the phase distribution of slug–annular flow in parallel micro-channels. The test section consists of a header with a diameter of 0.48 mm and six branch channels with a diameter of 0.40 mm. Nitrogen and 0.03 wt% sodium dodecyl sulfate (SDS) solution were used as the test fluids. It was found that the phase distribution of the slug–annular flow was unstable and the duration of the varying process showed regularity with different inlet conditions. Increasing the liquid superficial velocity facilitated the liquid phase to flow into channels at the fore part of the header, while the channels at the rear part of the header were more supplied with liquid as the gas superficial velocity, volume fraction of gas, and volume flow rate increased. Furthermore, the results indicated that the channels located at the rear part of the header experienced a pronounced enhancement in the supply of both the liquid and gas phases, with the spacing between the branches increasing. A predictive correlation was formulated to ascertain the distribution of the liquid phase within slug–annular flow across parallel micro-channels.

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Section: Introductionmentioning

confidence: 99%

Phase Distribution of Gas–Liquid Slug–Annular Flow in Horizontal Parallel Micro-Channels

Liu,

Jiang,

Wang

2024

Energies

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“…It can also maintain a more uniform wall temperature and requires less pumping power compared to a single-phase coolant for equivalent performance [6]. Despite the benefits of dissipating higher heat flux, two-phase flow boiling in microspaces encounters some critical problems like flow instability, premature dry out, lower heat transfer coefficient, and pressure drop during boiling [7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Two-Dimensional Flow Boiling Characteristics With Wettability Surface in Microgap Heat Sink and Heat Transfer Prediction Using Artificial Neural Network

Karim

Kim

2021

Journal of Heat Transfer

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As technology becomes increasingly miniaturized, thermal management becomes challenging to keep devices away from overheating due to extremely localized heat dissipation. Two-phase cooling or flow-boiling in micro-spaces utilizes the highly efficient thermal energy transport of phase change from liquid to vapor. However, the excessive consumption of liquid-phase by highly localized heat source causes the two-phase flow maldistribution, leading to a significantly reduced heat transfer coefficient, high-pressure loss, and limited flow rate. In this study, flow-boiling in a two-dimensional microgap heat sink with a hydrophilic coating is investigated with bubble morphology, heat transfer, and pressure drop for conventional (non-hydrophilic) and hydrophilic heat sinks. The experiments are carried out on a stainless steel plate, having a micro gap depth of 170 µm using deionized water at room temperature. Two different hydrophilic surfaces (partial and full channel shape) are fabricated on the heated surface to compare the thermal performance with the conventional surface. Vapor films and slugs are flushed quickly on the hydrophilic surfaces, resulting in heat transfer enhancement on the hydrophilic heat sink compared to the conventional heat sink. The channel hydrophilic heat sink shows better cooling performance and pressure stability as it provides a smooth route for the incoming water to cool the hot spot. Moreover, the artificial neural network prediction of heat transfer coefficient shows a good agreement with the experimental results as data fits within ±5% average error.

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“…The temperature difference between the channels was relatively small due to redistribution of heat through the conductive substrate. The effect of thermal coupling between parallel channels on the flow distribution was theoretically investigated by Van Oevelen et al [22] by additionally accounting for heat conduction in their previous model [13]. By quantifying the flow maldistribution in parallel-channel systems having varying strengths of inter-channel thermal coupling, it was shown that increasing thermal coupling damped the severity of the flow maldistribution.…”

mentioning

confidence: 99%

Ledinegg instability-induced temperature excursion between thermally isolated, heated parallel microchannels

Kingston

Weibel

Garimella

2019

International Journal of Heat and Mass Transfer

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Two-phase flow through heated parallel channels is commonly encountered in thermal systems used for power generation, air conditioning, and electronics cooling. Flow boiling is susceptible to instabilities that can lead to maldistribution between the channels and thereby heat transfer performance reductions. In this study, the Ledinegg instability that occurs during flow boiling in two thermally isolated parallel microchannels is studied experimentally. A dielectric liquid (HFE-7100) is delivered to the parallel channels using a constant pressure source. Both channels are uniformly subjected to the same power, which is in increased in steps. Flow visualization is conducted simultaneously with pressure drop, mass flux, and wall temperature measurements to characterize the thermal-fluidic effects of the Ledinegg instability. When the flow in both channels is in the single-phase regime, they have equal wall temperatures due to evenly distributed mass flux delivered to each channel. Boiling incipience in one of the channels triggers the Ledinegg instability which induces a temperature difference between the two channels due to flow maldistribution. The temperature difference between the two channels

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The effect of lateral thermal coupling between parallel microchannels on two-phase flow distribution

Cited by 28 publications

References 45 publications

Phase Distribution of Gas–Liquid Slug–Annular Flow in Horizontal Parallel Micro-Channels

Phase Distribution of Gas–Liquid Slug–Annular Flow in Horizontal Parallel Micro-Channels

Two-Dimensional Flow Boiling Characteristics With Wettability Surface in Microgap Heat Sink and Heat Transfer Prediction Using Artificial Neural Network

Ledinegg instability-induced temperature excursion between thermally isolated, heated parallel microchannels

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