Question:-
For flow over a flat plate the hydrodynamic boundary layer thickness is 0.5 mm. the dynamic viscosity is 25 x 10-6 pas, specific heat is 2.0 kJ/(Kg K) and thermal conductivity is 0.05 W/(m-K). The thermal boundary layer thickness would be
Option (A)
0.1 mm
Option (B)
0.5 mm
Option(C)
1 mm
Option(D)
2 mm
Correct Option:
(B)
Question Solution:
dt/d = (1/(Pr1/3))
Where d = boundary layer thickness
Pr = mcp/K = ((25 x 10-6 x 2 x 102) / 0.05)
= ((50 x 10-3 x 102) / 5)= 1
dt = d = 0.5 mm
question-answer-faq-6093