Theoretical approach to predict frequency of density wave oscillation in large length to diameter microchannel heat sink

Abstract

The mechanistic model using theoretical approach is suggested to predict the frequency of density wave oscillation(DWO) and intermittent dryout in large length to diameter microchannel heat sink. Repeating generation and disappearance of liquid slug by the bubble expansion is the main idea of the model. The initial location of the bubble is determined by onset of nucleation boiling and bubble expands along the control volume analysis. After bubble pushes liquid slugs into the channel, liquid slug enters the channel again by pressure difference between inlet plenum and inlet channel. The velocity of surged liquid is determined by mass flux and density of fluid. In the results, the MAE of predicted frequency is 14.76% and increases as high heat flux and mass flux. The predicted frequency shows same tendency with experimental results but the value is overpredicted for all cases. The intermittent dryout is predicted from steady state liquid film thickness of annular flow and predicted frequency. The convective heat transfer coefficient from experimental results decreases after passing dryout location obtained by DWO frequency.