Abstract

Nowadays, cooling high thermal flows in compact volumes continues to be one of the crucial problems in the industry. With the advent of advanced technologies, much more attention has been paid to how to improve the performance of cooling systems in the area of micro-technologies. Rectangular mini-channels are typical representatives which commonly used for cooling applications. However, micro-technologies still face the problem of low performance due to the low productivity of cooling related to unbefitting physical parameter values. Here, this work studies the applicability of the heat transfer scheme of convective flow and flow boiling in a rectangular mini-channel for satisfying the cooling requirement of industrial micro-technologies, through a simulation model governed by the coupled mechanism from Navier-Stokes (N-S) equation and heat transfer equations with phase change effect. In this work, various hydraulic diameters and different inlet fluid speed are used to calculate the different velocity profiles, pressure drops, coefficients of friction and finally, the distribution of the temperatures and dissipated heat flux. The simulation results show the applicability of the rectangular mini-channel in diverse applications such as engine cooling, electronic components, automotive on-board electronics and aerospace engineering. Flow boiling simulation results reveal that the obtained patterns were smooth mixture flow and discrete flow. The dissipated heat flux can reach 1.02–5.34 MW/m2 for a hydraulic diameter of 0.5 mm. We show that the system with the gradient temperature that evolves increasingly along the top and bottom walls of the channels presents the highest heat flux dissipated in flow boiling. Additionally, the fin efficiency of the system is 0.88 and the coefficient value of convective heat transfer is in the range between 5000 < h < 100,000, which indicates the flow boiling heat transfer is effective in the mini-channel when the Reynolds number is less than 400. It provides a significant heat exchange for cooling in these application areas.

Highlights

  • Microfluidics is the science and innovation of frameworks that manage the exact control of fluids with small amounts of tiny scales in microchannels

  • Flow boiling heat transfer in an array with a hydraulic diameter varying from 0.1 to 0.54 mm was investigated and it was found that the heat transfer coefficient was almost independent with heat flux at high heat flux [29].In the previous work, it has not been specified how to determine the exact area of application of the rectangular mini-channels by setting or adjusting the values of the parameters of velocity, pressure drop, coefficient of friction and phase transition and heat transfer flux

  • 2Dnumerical numericalstudy study conducted the finite. This the from conducted byby the finite element method to characterize the water flows in a rectangular mini-channel

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Summary

Introduction

Microfluidics is the science and innovation of frameworks that manage the exact control of fluids with small amounts of tiny scales in microchannels. Flow boiling heat transfer in an array with a hydraulic diameter varying from 0.1 to 0.54 mm was investigated and it was found that the heat transfer coefficient was almost independent with heat flux at high heat flux [29].In the previous work, it has not been specified how to determine the exact area of application of the rectangular mini-channels by setting or adjusting the values of the parameters of velocity, pressure drop, coefficient of friction and phase transition and heat transfer flux. This study chooses a representative mini-channel with a rectangular cross-section as the basic elemental geometry for cooling structures and simulate the velocities profiles, drop pressures and friction factor and steady and transient heat transfers in the simplified singe-phase flow and more accurate two-phase (liquid and vapor) flow models of the fluidic flow through the mini-channel in different application areas. 1.02–5.34 MW/m2 for a hydraulic diameter of 0.5 mm and length 150 mm

Materials and Methods
Governing
Laminar Flow
Numerical Method
Simulation Parameters
Boundary Conditions
Results and Discussions
Velocities Profiles
Friction Factor
Heat Transfer of Fluids
80 C TWall
Considering
Conclusions
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