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clear;
clc;
printf("\t Example 8.3\n");
T1=323; //wall temp.,K
T2=293; //air temp.,K
H=0.3; //height of wall, m
v1=16.45*10^-6; // molecular diffusivity, m^2/s
b=1/T2; // b=1/v*d(R*T/p)/dt=1/To characterisation constant of thermal expansion of solid, K^-1
v2=2.318*10^-5; //molecular diffusivity, m^2/s
Pr=0.71; //prandtl no.
Ral=9.8*b*(T1-T2)*H^3/((1.566*10^-5)*(2.203*10^-5)); // Rayleigh no.
Nu=0.678*Ral^(0.25)*(Pr/(0.952+Pr))^(1/4); // nusselt no.
h=Nu*0.0267/H // average heat transfer coefficient, W/m^2/K
Nu1=0.68+0.67*((Ral)^(1/4)/(1+(0.492/Pr)^(9/16))^(4/9)); //churchill correlation
h1=Nu1*(0.0267/0.3)-.11; //average heat transfer coefficient, W/m^2/K
printf("\t correlation average heat transfer coefficient is :%.2f W/m^2/K\n",h1)
printf("\t the prediction is therefore within 5 percent of corelation .we should use the latter result in preference to the theoritical one, although the difference is slight.")
//end
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