Answer to Question #241215 in Mechanical Engineering for shaym

Question #241215

A spherical ball of diameter 20 mm is initially maintained at a uniform temperature of 400 °C. It is first subjected to heat (h = 10 * W/(m ^ 2 - K)) treatment first by passing ambient air at 20 °C until the temperature at its center line is lowered down to 335 °C. The spherical ball is next dipped in a liquid pool at 20 °C with a very high heat transfer coefficient (h = 6000 * W/(m ^ 2 - K)) due to boiling until the center of the sphere cools down to 50 °C. What is the overall time required to complete this heat treatment plus quenching process.


Assume the following material properties: rho = 3000 kg / (m ^ 3) , C =


1000 J kg-K' rho = 3000 kg / (m ^ 3) , a = 6.66 x 10-6 m² / sec


1
Expert's answer
2021-09-24T02:12:50-0400

D=20mm,r=10mm=0.01m

h1=10W/m2K

T1=335°C

h2=6000W/m2K

T2=50°C

C=1000J/kgK

=6.66*10-6m2/s

t1=187.6s

t2=3.91s

Overall time,t=t1+t2

=(187.6+3.91)s

=191.51s


Need a fast expert's response?

Submit order

and get a quick answer at the best price

for any assignment or question with DETAILED EXPLANATIONS!

Comments

No comments. Be the first!

Leave a comment

Ask Your question

LATEST TUTORIALS
New on Blog
APPROVED BY CLIENTS