User talk:Piedmonting

I'd like to get some information about the range of convection coefficient in air and hydroge. Some said in air h is from 10~100, but no hydrogen's. Some said the h can be calculated from Nusselt number and nusselt nubmer from reynolds number easily. Actually it is not. For example in order to get Reynolds number, you need to know flow speed while there is no wind for free convection. If based v=0, Re=0 too, and then Nu<1. This mean convection coefficient is less than air conduction coefficient. This result seams not right? My question is someone published a chart that indicates h with related common condition, such as for a 1mX1m vertical steel plate h = ??? under such such condition, and indicates how h will vary with plate area, temperature, pressure, space size. I do not expect the accurate numbe but I need to know how to influence. I think this should be obtained by some test easily. If there is no a common solution for common use, the theory is nothing but beautiful and strange equations. And from the form of equation, same are just emperical formula for certain case and cannot be used in other case. That is just junk.