Basic concepts-thermal considerations 1. The mean temperature viscid flow regio Boundary layer region l Hydrodynamic entrance region Fully developed region fd力 For the internal energy puc,l4.andE,≡ mc T So SJ puc TdA puc,TdA C nc pumAc For incompressible flow in a circular tube 2 Heat Transfer Su Yongkang School of Mechanical EngineeringHeat Transfer Su Yongkang School of Mechanical Engineering # 4 Basic concepts—thermal considerations • 1. The mean temperature • For the internal energy • So • For incompressible flow in a circular tube,   ro  = Ac t v TdAc E uc  t v Tm E m  c and   m c v A v c v A v c m u A c uc TdA mc uc TdA T c c      = =   = 0 0 2 0 2 r m m uTrdr u r T