Multi-User Equipment approved in grant 16/09509-1: high speed video camera phantom V2012

Abstract

It is a fact that the analyzes of flow images is necessary to study quantitatively and qualitatively two-phase flows. In this context, the general objective of the present proposal is the acquisition of a high-speed camera to study fundamentals and applications involving two-phase flows, focusing on processes involving liquid-vapor phase change. The specific objectives are the following: (1) Provide, through the combination of images from an infrared camera and a high-speed camera, simultaneous results of two-phase hydrodynamic and temperature distribution on the heated surface. These results would provide a better understanding of the physical phenomenon, providing data for the modeling of heat transfer mechanisms during convective boiling in microchannels; (2) Analyze mal distribution effects associated to thermal instabilities in heat spreaders based on flow boiling inside microchannels. Such results would provide new insights to minimize such effects and improve the cooling performance of these devices; (3) Perform studies of two-phase flow hydrodynamics in pulsed heat pipes. The knowledge of the hydrodynamic in these devices is fundamental to the development of mechanistic models; (4) Theoretical and experimental study of convective boiling and critical heat flux; (5) Evaluation of the flow pattern and the liquid film thickness for annular flow patterns. The knowledge of the film thickness and of its behavior is fundamental to the development of models for the heat transfer coefficient, pressure drop and critical heat flux for condensation / evaporation inside tubes; (6) Experimental and theoretical evaluation of the velocities flow field for external flows across tube banks through spatial filtering velocimetry. (AU)