Question

Air at T=25°C and pressure P=1 bar flows over a square plate with a velocity V=1 m/s. This plate has a length L= 1 m and it is heated over its entire length; the plate temperature is constant Tp=100°C.

The following data are given. For air:

dynamic viscosity: mu = 1.9*10–5 kg/(m.s);

density: rho = 1.05 kg/m3;

conductivity k = 0.03 W/(m K);

Specific heat Cp = 1.007 kJ/(kg K);

Prandtl number Pr = 0.7

For laminar flow over a flat plate, use the relation

Nux = 0.332 (Rex)1/2 Pr1/3

For Turbulent flow over a flat plate, use the relation

Nux = (0.037 (Rex)4/5-871) Pr1/3

(The boundary layer flow over a flat plate will be laminar if (Rex= rho*U*x / mu < 5*105)

(The boundary layer flow over a flat plate will be turbulent if (Rex= rho*U*x/mu > 5*105)

1- Determine the Reynolds number at x=L, Re,

2- Check if the flow is laminar or turbulent for x=L,

3- Determine the Reynolds number as a function of x, Rex,

4- Determine the Nusselt number as a function of x, Nux,

5- Determine the convection heat transfer coefficient at x=L, h,

6- Determine the convection heat transfer coefficient as a function of x, hx,

7- Determine the convection heat transfer coefficient haverage,

8- Determine the rate of heat transfer flux q” from the plate in (W/m2),

Answer 1