temperature of each chip may not exceed 80°C, what is the maximum allowable power per chip? What is the maximum allowable power if a turbulence promoter is used to trip the boundary layer at the leading edge?

A square isothermal chip is of width w = 5 mm on a side and is mounted in a substrate such that its side and back surfaces are well insulated, while the front surface is exposed to the flow of a coolant at T_infinity = I5 °C. From reliability considerations, the chip temperature must not…

The thermal conductivity of a sheet of rigid, extruded insulation is reported to be k = 0.029 W/m·K, the measured temperature difference across a 20mm-thick sheet of the material is T1-T2 =10°C. (a) What is the heat flux through a 2m x 2m sheet of insulation? (b) What is the rate of heat transfer through…

The 5-mm-thick bottom of a 200-mm-diameter pan may be made from aluminum (k = 240 W/m·K.) or copper (k = 390 W/m·K.). When used to boil water, the surface of the bottom exposed to the water is nominally at 110 °C. If heat is transferred from the stove to the pan at a rate of…

An electric resistance heater is embedded in a long cylinder of diameter 30mm. When water with a temperature of 25degree C and velocity of 1 m/s flows crosswise over the cylinder, the power per unit length required to maintain the surface at a uniform temperature of 90degreeC is 28kW/m. When air is also at 25…

A one-dimensional plane wall of thickness 2L=100mm experiences uniform thermal energy generation of q dot=1000 W/m3 and is convectively cooled at x=+/-50mm by an ambient fluid characterized by T infinity=20°C. If the steady-state temperature distribution within the wall is T(x)=a(L2-x2)+b where a=10 °C /m2 and b=30 °C, what is the thermal conductivity of the wall?…

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=25C. The chips have an emissivity of ε = 0.60 and a max allowable temperature of Ts = 85 C. (a) If heat…