An Experimental Study of Circulation Patterns in Natural Convection Using PIV

Abstract

The objective of this study is to investigate, experimentally, using Particle Image Velocimeter (PIV), the effect of different heat transfer boundary conditions on natural convection (specifically on flow patterns) inside a storage tank (a rectangular enclosure in this case with an aspect ratio of 0.5.) Purified water is used as the working fluid and it is seeded with 10 micron hollow glass sphere particles. The results of the first set of experiments are used to verify the flow patterns expected for the constant wall temperature boundary condition, the benchmark case. Similar experiments are conducted for the constant heat flux boundary condition. The Rayleigh number for all the cases studied lie between 106 and 107. The time averaged velocity field is determined using standard cross correlation techniques. Streamlines, and velocity contour plots are generated using this velocity field. Finally, the results of both cases are compared to identify the differences in circulation patterns and thermal stratification in the fluid.