wiz-icon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

Air flows over a heated plate at a velocity of 50 m/s. The local skin friction coefficient at a point on a plate is 0.004. The following properties for air are, density=0.88 kg/m3,viscosity=2.286×105kgm/s, specific heat=1.001 kJ/kg K, thermal conductivity of air = 0.035 W/mK and use St.Pr1/3=Cfx/2.

The local heat transfer coefficient is

A
58.45W/m2K
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
116.9W/m2K
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
11.69W/m2K
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
29.225W/m2K
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
Open in App
Solution

The correct option is D 29.225W/m2K

u=50m/s
cfx=0.004
ρ=0.88kg/m3
μ=2.286×105Pas
cp=1001 J/kg.K
kair=0.035 W/mK

According to correlation
St×Pr2/3=cfx2

NuxRe.Pr.Pr2/3=cfx2

Nux=cfx2×Re.PrPr2/3

Nux=cfx2×Re.Pr1/3

hx.Lk=cfx2×ρ.u×Lu×Pr1/3

Pr=μcpk=2.286×105×10010.035=0.653796

hx=cfx2×ρ×uμ×Pr1/3×k

=0.0042×0.88×502.286×105×(0.6537)1/3×0.035

hx=116.89 W/m2K

flag
Suggest Corrections
thumbs-up
0
similar_icon
Similar questions
View More
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Atmospheric Pressure
PHYSICS
Watch in App
Join BYJU'S Learning Program
CrossIcon