This pos-doctoral research proposal is related to several projects about micro-scale convective boiling currently running in the Heat and Mass Transfer Group from the Department of Mechanical Engineering at Escola de Engenharia de São Carlos - USP. Recent results from microchannel literature have showed a disagreement between experimental data from distinct authors. In the specific case of liquid film flows (slug, churn and annular), the most recent literature shows that this difference can be related to intermittent film characteristics near the surface and entrainement in the gas core. These characteristics are related to the physical mechanisms which explain the heat transfer, pressure drop and critical heat flux. In this context, the present research proposal has the aim of studying the instabilities in michochannles during convective boiling. Firstly, a vast bibliographic review about the types of two-phase flow instabilities will be performed. Experimental data from the present group will be analyzed for quantitative information about instabilities in convective boiling inside microchannels. With these results a classification of observed instabilities will be performed and a effort to identify the main physical mechanisms necessary for the development of new predictive models for instabilities and their respective characteristics, like wave amplitude, length, shape and speed.
News published in Agência FAPESP Newsletter about the scholarship: