// Display mode mode(0); // Display warning for floating point exception ieee(1); clc; disp("Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 4 Example # 4.4 ") // Length of the crankcase in m is given as L = 0.6; // Width of the crankcase in m is given as b = 0.2; // Depth of the crankcase in m is given as d = 0.1; // Surface temperature in K is given as Ts = 350; // Air temperature in K is given as Tinfinity = 276; // Air velocity in m/sec is given as Uinfinity = 30; // It is stated that boundary layer is turbulent over the entire surface //Average air temperature in degree K is T = (Ts+Tinfinity)/2; // At this average temperature, we get the following for air rho = 1.092;//density in kg/m^3 mu = 0.000019123;//viscosity in SI units Pr = 0.71;//Prandtl number k = 0.0265;//Thermal conductivity in W/m-K // Reynold''s number is therefore given as ReL = ((rho*Uinfinity)*L)/mu; //From eq. 4.82, average nusselt number could be given as Nu = (0.036*(Pr^(1/3)))*(ReL^0.8); //We can write from the basic expression, Nu=hc*L/k, that //Heat transfer coefficient in W/m^2-K hc = (Nu*k)/L; // The surface area that dissipates heat is 0.28 m2 disp("Total heat loss from the surface in W is therefore") //Heat loss from the surface in W q = (hc*0.28)*(Ts-Tinfinity)