New empirical flow-regime-based model of water boiling in rectangular microchannels

•A new empirical flow-regime-based model of water boiling in rectangular microchannels is proposed.•The present model considers a more comprehensive flow regime map.•Prediction results generally presents a similar trend to experimental results in the literature.•The new model can capture up to 4 different trends of HTC. A new empirical flow-regime-based model of water boiling in rectangular microchannels is proposed and programmed using MATLAB code in the present paper. The prediction model divides the flow regime map into four parts: single-phase convection regime, sub-cooled boiling regime, saturated boiling regime, and partial dry-out boiling regime. Each zone is also divided into several sub-zones according to corresponding criteria. Suitable empirical heat transfer correlations and flow transition criteria are adopted for each flow pattern to reasonably capture the boiling heat transfer mode according to the vapor quality or the efficient heat flux. The prediction results generally present a similar trend to experimental results from the literature. The new model is also compared with the existing empirical flow-regime-based models in the literature. The Lee and Mudawar model and the Ma model can only capture up to 3 and 2 different trends of HTC, respectively. However, the new model considers a complete flow regime map and can capture up to 4 different trends of HTC.