Empirical Correlations(Contd ong Horizontal Cylinder Very common geometry(pipes, wires) For isothermal cylinder surface, use general Plume form equation for computing nusselt E hD 9.33 =CRa k Boundary Constants for general lay Nusselt number equation Rap 10-10-10 2 0.6750.058 Table9.110-2-10 02 0.148 102-10 0.8500.188 0.4800.250 0 0.1250.333 Heat Transfer Su Yongkang School of Mechanical EngineeringHeat Transfer Su Yongkang School of Mechanical Engineering # 7 Empirical Correlations (Cont’d) Long Horizontal Cylinder • Very common geometry (pipes, wires) • For isothermal cylinder surface, use general form equation for computing Nusselt # • Constants for general Nusselt number equation RaD C n 10 -10 0.125 0.333 10 -10 0.480 0.250 10 -10 0.850 0.188 10 -10 1.02 0.148 10 -10 0.675 0.058 7 12 4 7 2 4 2 2 10 2 − + − − Table 9.1 Eq 9.33 n D CRaD k hD Nu = =