Chips of width L_15 mm on a side are mounted to a substrate that is installed in an enclosure whose walls and air are maintained at a temperature of Tsur-T=25°C. The chips have an emissivity of ɛ=0.60 and a maximum allowable temperature of T=85°C. (a) If heat is rejected from the chips by radiation and natural convection, what is the maximum operating power of each chip? The convection coefficient may be approximated as h=11.7 W/m?K. (b) If a fan is used to maintain airflow through the enclosure and heat transfer is by only forced convection, with h=250 W/m?K, what is the maximum operating power?

Chips of width L_15 mm on a side are mounted to a substrate that is installed in an enclosure whose walls and air are maintained at a temperature of Tsur-T=25°C. The chips have an emissivity of ɛ=0.60 and a maximum allowable temperature of T=85°C. (a) If heat is rejected from the chips by radiation and natural convection, what is the maximum operating power of each chip? The convection coefficient may be approximated as h=11.7 W/m?K. (b) If a fan is used to maintain airflow through the enclosure and heat transfer is by only forced convection, with h=250 W/m?K, what is the maximum operating power?

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter8: Natural Convection

Section: Chapter Questions

Problem 8.18P

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