To boil water how many watts per square centimeter does it take.?

Question

I would like to know; What is the relationship between watts/square centimeter, and the boiling point of water for system pressures between 0 and 40 psi. Also, I'd like to know what the relationship of water flow past the heating element would be for energy densitys above the boiling energy density. Specifically, if I use a heating element that has a watt density above the boiling poine (at 0 pressure), how much flow (past the heating element surface) do I need for various energy densities to not have boiling?

Thank you

I'm new at this, and underestimated the caliber of intelect available here, and may have some trouble phrasing my problem. I understand that there is a relationship between the rate of energy input and the heat disipation capabilities for a given "system". I am simply looking for maximum amount of energy that can be applied to water passing through a closed loop system expressed in watts/sq.cm. Spicifically for a aluminum V8 engine and amuminum radiator. The total weight of the engine is 450lbs. and volume of water is 2.5 gal., circulating at 3 gpm, measured through a flow meter. Initially the syatem (water) is cold and at 0 pressure. As the system ubsorbs the energy from a heat source the pressure raises. I know from experience that the tendency for the heating element to boilthe water increases as the temperature increases, say around 230 degrees F at about 20 psi. So, is ther any reasonable approxmation for this set of conditions?

Answer 1

YOur answer is not possible, because you wil need the depth of the water.

Answer 2

There is no relationship like the one you describe. A Watt is a unit of power, which is a RATE of energy transfer. If your water was suffciently insulated, it would take only a tiny value of wattage to make it boil.
Flowing water: For a given level of input watts, a higher mass flow of water by the heater will yield a lower temperature increase. Watt density cannot be equated to boiling temperature.