We have one electric process heater ( this is similar to tube-shell exchanger, only output constant heat flux by tube),fluid is air, which is pumped into heater at constant temp and presure, Heater wattage is from 0-100% adjust, example full wattage is 100Kw, I want to simluate watt increase by steps (such as 5KW), If the maximum temp of tube is up to 200C, the simulation is finished, I want to know how to input dependency between max tube temp and wattage by flow simulation?