Maybe this one will help you: http://www.enggtutorial.com/2015/06/analysis-of-critical-thickness-of.html

Mr.Jeeva, there is a design modeller file called pipe Insulation.agdb.. In that file database the inside radius represents the outside radius of the pipe..For ex., if you set the outside radius to be 50 mm it represents 25 mm of insulation ..BC's consists of temperature specified on inner surface and convection on outer ...Courtesy Fereydoon dhadkhah jack zecher P E SDC publications book on ANSYS WB software tutorial with CD .. This is just to help you and you have to check and see the option ..