Consider the electronic elements that are cooled by forced convection in Problem 6.26. The cooling system is designed and tested at sea level (P = I atm), but the circuit board is sold to a customer in Mexico City with an elevation of 2250 m and atmospheric pressure of 76.5 kPa.

(a) Estimate the surface temperature of the chip located 120 mm from the leading edge of the board when the board is operated in Mexico City. The dependence of various thermo physical properties upon pressure is noted in Problem 6.17.

(b) It is highly desirable for the chip operating temperature to be independent of the location of the customer. What air velocity is required for operation in Mexico City if the chip temperature is to be the same as at sea level?