Convection in a horizontal fluid layer having a shear-free upper surface and uniform volumetric energy sources

Experiments were performed to obtain interferograms of the temperature profiles and measurements of the heat transfer in a horizontal fluid layer with a uniformly-distributed interior heat source and a rigid lower boundary. Copper plates coated with mylar served as the rigid upper and lower boundaries of the fluid container. The plate temperatures were controlled by a circulating field, and a Mach-Zehnder interferometer visualized the temperature fields. Helium formed a gas layer between the upper surface and the lower solution, an electrolyte. Maintaining a free upper surface for the electrolyte, i.e., not letting it come into contact with the upper plate, produced a high rate of heat transfer at the upper surface and a lower transfer coefficient at the lower surface, in addition to a decrease in the maximum temperature of the layer.