A study of oscillatory thermocapillary convection in circular containers with carbon dioxide laser heating
Oscillatory thermocapillary convection in small circular containers heated at the center of the free surface with CO2 laser is studied by investigating the various onset conditions. The effect of container dimensions, aspect ratios and heating zone ratios as well as the effect of viscosity are investigated. The onset of unsteady state is determined by observing the flow structures with flow visualization and the temperature distributions with a thermocouple probe and an I.R. imager. It is observed that when the input heat flux is increased beyond a certain limit, a distinctive unsteady flow pattern appears. This unsteady phenomenon is identified as oscillatory thermocapillary and is similar in flow structure to the constant temperature case studied earlier where the fluid was heated by a Nichrome wire along the container axis. The factors involved in the cause of the oscillations are presented. Silicone oils with 2cSt and 5cSt kinematic viscosity are used as the test fluids. To supplement the experimental work a numerical analysis of steady thermocapillary flow is also conducted.
School:Case Western Reserve University
School Location:USA - Ohio
Source Type:Master's Thesis
Keywords:oscillatory thermocapillary convection circular containers carbon dioxide laser heating
Date of Publication:01/01/1994