1995 Volume 79 Issue 2 Pages 116-121
Solutions for the temperature rise and heat flow within a heated plate are determined by computer analysis of a simulated electrical resistance-capacitance network equivalent to the given thermal system Water evaporation at surfaces of the substance is simulated by a resistor, r.
This analysis assumes that only the surface of the substance is radiation-heated and that the substrate is heated only by thermal conduction. It also assumes that irradiated heat flow input of each surface, q0is constant (though it actually decreases a little as heated surface temperature rises) and that the heated substance behaves like pure water.
Some important conclusions are that when both sides of the plate are heated the steady state temperature rise at a constant evaporation rate is given by rq0, that this steady state is reached faster when r is smalle, and that equal heating throughout the substance is obtained as heating proceeds and approaches the steady state.
When only one side of the plate is irradiated and no evaporation takes place at the other side, the same equal heating characteristic is also obtained, when evaporation takes place at both surfaces, however, the heated surface temperature rise becomes greater than that of the other surface. That is, unequal heating within the substance occurs. The difference between surfaces temperatures depends on the ratio of r to water thermal resistance.
