Hi, I would like to ask you for advice with a problem, I'm working on. I have a regular shape object (glass cylinder) in which is the 100W heat source. The heat source is ind the middle of cylinder and radiates heat uniformly throughout it’s height. Heat, of course, gradually moving into surrounding area. Thy cylinder is closed on both ends by heat insulating material. I need to know the temperature at which the air in the cylinder stabilizes and there is a temperature balance between inner and outer space. Please help as I should come to a result. Thank you and please pardon my english.