By adopting Newton’s Cooling Law

heat transfers between fluid and surfaces of metal tube(heat transfer oil and internal metal tube surface

cold air and external surface of metal tube)are illustrated respectively.Then based on Fourier Experiment Law

heat transfer inside inner metal tube is introduced

and boundary condition is presented.At last

dynamic relationship between hot air temperature

flux and temperature of heat transfer oil

flux of air is summarized.Simulation and experiment show that dynamic and static characters between model and real plant are coincident.Static data show that mean and standard deviation are all less than 5%

which means model is exact enough for practice application.Moreover

cause of error is analyzed.