Engine oil at 60degreeC flows over a 5 m long flat plate who

Engine oil at 60degreeC flows over a 5 m long flat plate whose temperature is 20degreeC with a velocity of 2 m/s. Determine the the rate of heat transfer per unit width of the entire plate.

Solution

Solution

The rate of heat transfer is then determined from Newton\'s law of cooling to be

dQ/dt = hAs (T Ts )

        h = k Nu / L

       Nu = 0.6664 Re^0.5 Pr^1/2

            = 0.664(1.46 * 10⁵)^0.5 (1505)^1/3

              = 2908

               h = 2908 (0.141W / mC) / 6 = 68.3W / m² C

          The rate of heat tranfer would be

              dQ / dt = hAs (Tinfity - Ts)

                (dQ /dt) / dx         = (68.3)(6m) (60-20)

                                           = 16392 W / m = 16.3 KW / m