Keywords

Flow boiling, microchannel, phase change, simulation, two-phase flow

Presentation Type

Talk

Research Abstract

Thermal management of high-power electronic devices continues to be a critical challenge. Flow boiling in microchannel heat sinks has been demonstrated to be an effective method for removing high heat fluxes from these devices owing to utilization of the latent heat of the fluid and the large surface area enhancement for heat exchange. However, microchannel flow boiling technologies have yet to be broadly implemented due to a lack of experimentally validated prediction and design tools. The goal of this study is to use high-fidelity experimental data to validate a previously developed numerical phase change model, to help enable physics-based prediction of flow boiling heat transfer characteristics and reduce the reliance on empirical-based correlations. A novel experimental facility was used to generate archetypal microchannel slug flow boiling and capture high-speed flow visualizations for a range of heat fluxes and flow rates. Image processing of the flow visualizations was performed to extract time-resolved hydrodynamic and heat transfer parameters, such as vapor bubble length and liquid film thickness. The experimental boundary, initial, and operating conditions are input into the numerical model, implemented via a user-defined function in a commercial finite-volume software package, to predict the vapor bubble growth by phase change and the liquid film thickness. A direct comparison of the model prediction and experimental results is performed and good agreement is obtained.

Session Track

Materials Science

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Aug 2nd, 12:00 AM

Experimental Validation of a Numerical Phase Change Model for Microchannel Slug Flow Boiling

Thermal management of high-power electronic devices continues to be a critical challenge. Flow boiling in microchannel heat sinks has been demonstrated to be an effective method for removing high heat fluxes from these devices owing to utilization of the latent heat of the fluid and the large surface area enhancement for heat exchange. However, microchannel flow boiling technologies have yet to be broadly implemented due to a lack of experimentally validated prediction and design tools. The goal of this study is to use high-fidelity experimental data to validate a previously developed numerical phase change model, to help enable physics-based prediction of flow boiling heat transfer characteristics and reduce the reliance on empirical-based correlations. A novel experimental facility was used to generate archetypal microchannel slug flow boiling and capture high-speed flow visualizations for a range of heat fluxes and flow rates. Image processing of the flow visualizations was performed to extract time-resolved hydrodynamic and heat transfer parameters, such as vapor bubble length and liquid film thickness. The experimental boundary, initial, and operating conditions are input into the numerical model, implemented via a user-defined function in a commercial finite-volume software package, to predict the vapor bubble growth by phase change and the liquid film thickness. A direct comparison of the model prediction and experimental results is performed and good agreement is obtained.