Flow Boiling of Low-Pressure Water in Microchannels of Large Aspect Ratio

Liang Chen,Xingchen Li,Runfeng Xiao,Xue Yang,Kunpeng Lv,Yu Hou

doi:10.3390/en13112689

Abstract

Flow boiling heat transfer in microchannels can provide a high cooling rate, while maintaining a uniform wall temperature, which has been extensively studied as an attractive solution for the thermal management of high-power electronics. The depth-to-width ratio of the microchannel is an important parameter, which not only determines the heat transfer area but also has dominant effect on the heat transfer mechanisms. In the present study, numerical simulations based on the volume of fraction models are performed on the flow boiling in very deep microchannels. The effects of the depth-to-width ratio on the heat transfer coefficient and pressure drop are discussed. The bubble behavior and heat transfer characteristics are analyzed to explain the mechanism of heat transfer enhancement. The results show the very deep microchannels can effectively enhance the heat transfer, lower the temperature rise and show promising applications in the thermal management of high-power electronics.

Highlights

With the rapid development of the microelectronic technology, the size of electronic devices has been downscaled intensively and integrated with billions of transistors, and the resulting high-power dissipation and the excessive temperature can cause a rapid deterioration in reliability.Microchannel heat sinks offer several prospective advantages, including compact size, low weight, and high cooling performance. [1] The flow boiling in microchannels shows a promising heat transfer capacity for the thermal management of high-power electronic devices [2]
The effects of channel height and width with depth-to-width ratio up to 10 on two-phase flow heat transfer characteristics are discussed. These results demonstrate the advantages of very deep microchannel heat sinks for applications of the thermal management of high-power electronics
Different from conventional macro-scale channels, the flow boiling in the microchannel has a strong dependence on the surface tension, the inertial force, the viscous force and gravity

Summary

Introduction

With the rapid development of the microelectronic technology, the size of electronic devices has been downscaled intensively and integrated with billions of transistors, and the resulting high-power dissipation and the excessive temperature can cause a rapid deterioration in reliability.Microchannel heat sinks offer several prospective advantages, including compact size, low weight, and high cooling performance. [1] The flow boiling in microchannels shows a promising heat transfer capacity for the thermal management of high-power electronic devices [2]. Microchannel heat sinks offer several prospective advantages, including compact size, low weight, and high cooling performance. [1] The flow boiling in microchannels shows a promising heat transfer capacity for the thermal management of high-power electronic devices [2]. Microchannel heat sinks still need to be optimized for improved heat transfer performance. A number of numerical and experimental studies have been reported on the heat transfer characteristics of microchannel heat sinks. Salimpour et al [3] performed the geometric optimization of microchannel heat sinks with rectangular, elliptic, and isosceles triangular cross-sections. Lorenzini and Joshi [5] simulated the two-phase flow boiling in microchannels with non-uniform heat flux using water as working fluid

Methods

Results

Discussion

Conclusion