Question

Mercury at 25°c flows over a 3-m-long and 2-m-wide flat plate maintained at 75°c with a velocity of 0. 01 m/s. Determine the rate of heat transfer from the entire plate?

Answer 1

The rate of heat transfer from the entire plate is 710.8 kW

The properties of mercury at the film temperature of (75+25)/2= 50°C

k = 8.83632 W/m °C

v = 1.056 × $10^-^7$ m²/s

Pr = 0.0223

The local Nusselt number relation for liquid metals is given by

 $N_u =\frac{h_sx}{k} = 0.565 9Re_x Pr)^\frac{1}{2}$

The average heat transfer coefficient for the entire surface can be determined from

$h = \frac{1}{L} \int\limits^1_0 {h_x} \, dx$

Substituting the local Nusselt number relation into the above equation and performing the integration we obtain

$N_u = 1.13 (Re_s Pr)^\frac{1}{2}$

The Reynolds number is

$Re_L = \frac{VL}{v} = \frac{(0.01)(3m)}{1.056 * 10^-^7 m^2/s} = 0.028 * 10^7$

Using the relation for the Nusselt number, the average heat transfer coefficient and the heat transfer rate are determined to be

                       Q = 710.8 kW

Therefore, the rate of heat transfer from the entire plate is 710.8 kW

Learn more about heat transfer here:

https://brainly.com/question/16055406

#SPJ4