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clear;
clc;
printf("\t Example 7.3\n");
m=21.5; //mass flow rate, kg/s
e=260*10^-6; //wall roughness,m
D=0.12; //diameter of pipe, m
T1=363; //pipe temperature,K
T2=323; //bulk temp. of fluid,K
a=977; //density, kg/m^3
u=m/(a*3.14*(D/2)^2); //average velocity,m/s
Re=u*D/(4.07*10^-7); //reynolds no.
Uw=3.1*10^-4; // wall side viscosity,N*s/m^2
Ub=5.38*10^-4; //bulk viscosity, N*s/m^2
Pr=2.47; //prandtl no.
f=1/(1.8/2.303*log(6.9/Re+(e/D/3.7)^1.11))^2; //friction factor from haaland equation.
Re1=Re*e/D*(f/8)^0.5; //roughness reynols no.
Nu=(f/8)*Re*Pr/(1+(f/8)^0.5*(4.5*Re1^(0.2)*Pr^(0.5)-8.48)); //correlation for local nusselt no.
h=Nu*0.661/D/1000; //convection heat transfer coefficient, kW/(m^2*K)
printf("\t correlation friction factor is :%.5f\n",f);
printf("\t convection heat transfer coefficient is :%.1f kw/(m^2*K)\n",h);
printf("\t in this case wall roughness causes a factor of 1.8 increase in h and a factor of 2 increase in f and the pumping power.we have omitted the variable properties hre as they were developed for smooth walled pipes.")
//end
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