Experimental results for heat transfer over a flat plate with an extremely rough surface were found to be correlated by an expression of the form Nux=0.04 Rex0.9 Pr1/3 where Nux is the local value of the Nusselt number at a position x measured from the leading edge of the plate. Obtain an expression for the ratio of the average heat transfer coefficient hˉx to the local coefficient hx

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…

A glass window of width W= 1 m and height H = 2 m is 5 mm thick and has a thermal conductivity of kg 1.4 W/m·K. If the inner and outer surface temperatures of the glass are 15°C and -20°C, respectively, on a cold winter day, what is the rate of heat loss through…

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…

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…

Abstract The purpose of this lab was to determine the thermal conductivity k of the disk material by measuring the temperature distribution for transient and steady-state heat conduction in a cylindrical wall. To conduct this experiment cooling water was pumped though the HT10X Heat Transfer service Unit at approximately 1.5 liters/min. Initially the heating power…

A blood warmer is to be used during the transfusion of blood to a patient. This device is to heat blood taken from the Blood Bank at 10°C to 37°C at a flow rate of 200 mL/min. The blood passes through tubing of length 2 m, with a rectangular cross-section of 6.4 mm x 1.6…