On the Prediction of Pressure Fluctuations and Pressure Drop Caused by Confined Bubble Growth During Flow Boiling in a Rectangular Mini/Micro-Channel

Abstract

Heat-sinks based on flow boiling in microchannels have the potential to mitigate temperature rise in high heat flux devices such as electronic equipment. One of the major challenges is the instability associated with pressure fluctuations caused due to the confined bubble growth during boiling in a microchannel. This paper presents a comprehensive model to estimate the dynamic pressure fluctuations in a channel of rectangular cross-section and compares with the experimental results. The time-averaged pressure drop obtained from the transient model has been verified with the experimental results and the steady two-phase flow pressure drop correlations. Effects of various parameters such as heat flux and mass flux on the time-averaged pressure drop and the transient pressure fluctuations are presented. The paper also provides an approximate methodology to estimate the nucleation frequency derived from the waiting period of the bubble. The calculated frequency is validated qualitatively with the experimental observation available in the literature. The current work also demonstrates that the transient pressure drop models, which, with suitable inputs, predict the local pressure fluctuations during confined bubble growth, can also be used to predict the steady- flow pressure drop.

Additional information

Notes on contributors

Shashwat Jain

Shashwat Jain is an MS research scholar at Heat Transfer and Thermal Power Laboratory in the Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai, India. He has a bachelor’s degree in Mechanical Engineering (Design and Manufacturing) from Indian Institute of Information Technology, Design, and Manufacturing, Kancheepuram, Chennai, India. His research interest includes two-phase flow heat transfer, computational fluid dynamics, and cooling of electronic equipment.

Sateesh Gedupudi

Sateesh Gedupudi is an Assistant Professor in the Department of Mechanical Engineering at Indian Institute of Technology (IIT) Madras, Chennai. He obtained his Ph.D. in Heat Transfer from IIT Madras and has done postdoctoral research in flow boiling in mini/micro-channels at Brunel University, UK. His current research interests are two-phase flow heat transfer and heat exchangers.