Abo Bibliothek: Guest

ISSN Online: 2377-424X

ISBN Print: 0-89116-909-1

International Heat Transfer Conference 9
August, 19-24, 1990 , Jerusalem, Israel

CHARACTERISTICS OF PLUMES IN TURBULENT THERMAL CONVECTION IN A HORIZONTAL FLUID LAYER

Get access (open in a dialog) DOI: 10.1615/IHTC9.3270
pages 537-542

Abstrakt

An experimental study has been conducted to investigate the characteristics of heat transfer of turbulent thermal convection in a horizontal layer of water or silicone oils for several Prandtl numbers ( 7−1000 ). The overall dimensions of fluid layer were 200×210mm, and thickness of the layer were varied from 10 to 100mm.
Heat transfer correlation had dependency on Prandtl number at mediate Rayleigh number (106 −107), where Nusselt number became larger as Prandtl number increased.
Thermal boundary layer near the upper or the lower surface renewed periodically and released into bulk core region toward opposite boundary as thermal plume. Periods of plume generation were correlated with Rayleigh numbers and they had little dependency on thickness of fluid layer.
Temperature and flow fields were visualized by using liquid crystal tracer which changed its color with temperature. Thermal plumes formed polygonal pattern near the boundary in horizontal cross section's view. The sizes and lengths of these polygons in unit area had dependency on thickness of fluid layer.