Basic concepts-thermal considerations In the thermally fully developed flow of a fluid with constant properties, the local convection coefficient is a constant, independent ofx h≠f(x) For the special case of uniform surface heat flux aT d Axial t Independent of gradient fa, t dx radial location fa, t cons tan t For the case of constant surface temperature Depends on the aT (T-T)dmn radial coordinate Ox\d, (T。-Tn)ax T=cons tan t Heat Transfer Su Yongkang School of Mechanical EngineeringHeat Transfer Su Yongkang School of Mechanical Engineering # 6 Basic concepts—thermal considerations • In the thermally fully developed flow of a fluid with constant properties, the local convection coefficient is a constant, independent of x. • For the special case of uniform surface heat flux • For the case of constant surface temperature h  f (x) fd t m fd t dx dT x T , , =   q cons t s  = tan Axial T gradient Independent of radial location f d t m s m s f d t dx dT T T T T x T , , ( ) ( ) − − =   T cons t s = tan Depends on the radial coordinate