Answer:
modify temperature is lower than by the 0.196 %
Explanation:
given data
D = 250 mm
d = 0.1 mm
v = 0.5 m/s
V = 50 m/s
D = 150 mm
d = 0.1 mm
v = 0.3 m/s
V = 25 m/s
solution
first we get here initial coating condition for temperature change ΔT is
ΔT = A \times D^{1/4} \times d^{3/4}\times \frac{V}{v}^{1/2} ...............1
put here value for both condition
ΔT = A \times 250^{1/4} \times 0.1^{3/4}\times \frac{50}{0.5}^{1/2}
ΔT = 7.07 A ......................2
and
ΔT = A \times 150^{1/4} \times 0.1^{3/4}\times \frac{25}{0.3}^{1/2}
ΔT = 5.68 A .......................3
so here percentage change is
percentage change =
percentage change = - 0.196
so that modify temperature is lower than by the 0.196 %