# Heat Transfer MCQ’s – Von- Karmal Equation

1 - Question

Glycerin at 10 degree Celsius flows past a flat plate at 20 m/s. Workout the velocity components at a point P(x, y) in the fluid flow where x = 2 m from the leading edge of the plate y = 5 cm from the plate surface For glycerin at 10 degree Celsius, kinematic viscosity = 2.79 * 10 -3 m2/s
a) 15.92 m/s and 0.0952 m/s
b) 16.92 m/s and 0.0952 m/s
c) 17.92 m/s and 0.0752 m/s
d) 18.92 m/s and 0.0752 m/s
Explanation: u/U INFINITY = 0L.846 and v/U INFINITY (Re) ½ = 0.57.

2 - Question

A plate 0.3 m long is placed at zero angle of incidence in a stream of 15 degree Celsius water moving at 1 m/s. Find out the stream wise velocity component at the mid-point of the boundary layer. For water at 15 degree Celsius p = 998.9 kg /m3 µ = 415.85 * 10 -2 kg/hr m
a) 0.736 m/s
b) 0.636 m/s
c) 0.536 m/s
d) 0.436 m/s
Explanation: n = y (U INFINITY/v x) ½ = 2.5.

3 - Question

Air at 25 degree Celsius flows over a flat surface with a sharp leading edge at 1.5 m/s. Find the boundary layer thickness at 0.5 from the leading edge. For air at 25 degree Celsius, kinematic viscosity = 15.53* 10n -6 m2/s
a) 4.1376 cm
b) 3.1376 cm
c) 2.1376 cm
d) 1.1376 cm
Explanation: δ = 5 x/ (Re) ½ = 1.1376 m.

4 - Question

Local skin friction coefficient is given by
a) 0.646/ (Re) 1/2
b) 1.646/ (Re) 1/2
c) 2.646/ (Re) 1/2
d) 3.646/ (Re) 1/2
Explanation: It should be 0.646/ (Re) ½.

5 - Question

A plate 0.3 m long is placed at zero angle of incidence in a stream of 15 degree Celsius water moving at 1 m/s. Find out the maximum boundary layer thickness. For water at 15 degree Celsius. For water at 15 degree Celsius p = 998.9 kg /m3 µ = 415.85 * 10 -2 kg/hr m
a) 4.945 m
b) 3.945 m
c) 2.945 m
d) 1.945 m
Explanation: Re = l p U INFINITY/µ.

6 - Question

Shear stress at the middle of the plate is given by
a) T W = 0.964 p U INFINITY 2/2 (Re) 1/2
b) T W = 0.864 p U INFINITY 2/2 (Re) 1/2
c) T W = 0.764 p U INFINITY 2/2 (Re) 1/2
d) T W = 0.664 p U INFINITY 2/2 (Re) 1/2.
Explanation: T W = 3 µ U INFINITY/2 δ = 0.664 p U INFINITY 2/2 (Re) ½.

7 - Question

Boundary layer thickness is given by
a) δ = 5.64 x/ (Re) ½
b) δ = 5.64 x/ (Re) ½
c) δ = 6.64 x/ (Re) ½
d) δ = 7.74 x/ (Re) ½
Explanation: δ/x = (140 * 2/13) ½ (µ/x p U INFINITY) ½.

8 - Question

Air at 25 degree Celsius flows over a flat surface with a sharp leading edge at 1.5 m/s. Find the value of Reynolds number. For air at 25 degree Celsius, kinematic viscosity = 15.53* 10n -6 m2/s
a) 38694
b) 12846
c) 48294
d) 76386
Explanation: Re = x U INFINITY/v = 48294.

9 - Question

A plate 0.3 m long is placed at zero angle of incidence in a stream of 15 degree Celsius water moving at 1 m/s. Find out the maximum value of the normal component of velocity at thr trailing edge of the plate. For water at 15 degree Celsius p = 998.9 kg /m3 µ = 415.85 * 10 -2 kg/hr m
a) 1.6885 * 10 -2 m/s
b) 1.6885 * 10 -3 m/s
c) 1.6885 * 10 -4 m/s
d) 1.6885 * 10 -5 m/s