ME 353 Heat Transfer 1

M.M. Yovanovich

FCTURB1.MWS

Turbulent forced convection in a circular pipe.

______________________________________________

Water flows in an isothermal circular pipe of diameter D

and length L. The tube wall is isothermal.

The flow is turbulent, i.e., ReD > 2300.

Determine the Reynolds number, the friction factor, the mass

flow rate, the Nusselt number and the heat transfer coefficient

for water at temperature T = 340 K.

Tube diameter is 30 mm.

_______________________________________________

> restart:

> waterprops:=
(rho = 979.43, cp = 4.188, mu = 420e-6, kf = .660,
Pr = 2.66, nu = 0.4288e-6);

System parameters.

> syspar:= (D = 30/1000, Um = 1.5, Tw = 380, Tinlet = 310);

Correlation equations for turbulent flow.

Nusselt number and friction factor.

Use the correlation of Petukov, Eq. (8.62), and the

friction factor given by Eq. (8.21).

> h:= kf*NuD/D;

> NuD:= (f/8)*ReD*Pr/(1.07 + 12.7*(f/8)^(1/2)*(Pr^(2/3) - 1));
#For 0.5 < Pr < 2000 and 10^4 < ReD < 10^6

> f:= (0.790*ln(ReD) - 1.64)^(-2);
#For 3000 < ReD < 5e6

> ReD:= Um*D/nu;

Calculate the Reynolds number, friction factor, mass flow rate,

Nusselt number and the heat transfer coefficient.

> ReD1:= evalf(subs(waterprops, syspar, ReD), 5);

> f1:= evalf(subs(ReD = ReD1, f), 5);

> mdot1:= evalf(subs(waterprops, syspar, rho*Um*Pi/4*D^2), 5);

> NuD1:= evalf(subs(ReD = ReD1, syspar, waterprops, NuD), 5);

> h1:= evalf(subs(waterprops, syspar, h), 5);

>