Heat transfer from a transistor may be enhanced by inserting it in an aluminum sleeve (k =

Question:

Heat transfer from a transistor may be enhanced by inserting it in an aluminum sleeve (k = 200 W/ m. K ) having 12 integrally machined longitudinal fins on its outer surface. The transistor radius and height are r1 = 2.5 mm and = 4 mm, respectively, while the fins are of length = r3 - r2 = 8 mm and uniform thickness t = 0.8 mm. The thickness of the sleeve base is r2 - r1 = 1 mm, and the contact resistance of the sleeve-transistor interface is R"t.c = 0.6 × 10-3 m2. K/W. Air at T = 20°C flows over the fin surface, providing an approximately uniform convection coefficient of h = 30 W/m2. K

  (a) When the transistor case temperature is 80°C, what is the rate of heat transfer from the sleeve?

  (6) Identify all of the measures that could be taken to improve design and/or operating conditions, such that heat dissipation may be increased while still maintaining a case temperature of 80°C. In words, assess the relative merits of each measure. Choose what you believe to be the three most promising measures, and numerically assess the effect of corresponding changes in design and/or operating conditions on thermal performance. 

Fantastic news! We've Found the answer you've been seeking!

Step by Step Answer:

Related Book For  book-img-for-question

Fundamentals of Heat and Mass Transfer

ISBN: 978-0471457282

6th Edition

Authors: Incropera, Dewitt, Bergman, Lavine

Question Posted: