Fundamentals of Heat and Mass Transfer – Problem 1.18

The temperature distribution across a wall 0.3 m thick at a certain instant of time is T(x) = a + bx + cx2, where T is in degrees Celsius and x is in meters, a = 200 °C, b = -200 °C /m, and c = 30 °C /m2, The wall has a thermal conductivity…

A spherical interplanetary probe of 0.5-m diameter contains electronics that dissipate 150 W. If the probe surface has an emissivity of 0.8 and it does not receive radiation from other surfaces, such as the sun, what is its surface temperature of the probe? All sample problems and notes are based on the following textbook: Fundamentals…

A transmission case measures W = 0.30 m on a side and receives a power input of Pi= 150 hp from the engine. If the transmission efficiency is η=0.93 and air flow over the case corresponds T =30 degree C and h=200 W/m2-K. What is the surface temperature of the transmission? All sample problems and notes…

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?…

The heat flux through a wood slab 50 mm thick, whose inner and outer surface temperatures are 40 and 20 degree C. respectively, has been determined to be 40 W/m2. What is the thermal conductivity of the wood? All sample problems and notes are based on the following textbook: Fundamentals of Heat and Mass Transfer…

What is the thickness required of a masonry wall having thermal conductivity 0.75 W/m K if the heat rate is to be 80% of the heat rate through a composite structural wall having a thermal conductivity of 0.25 W/m K and a thickness of 100 mm? Both walls are subjected to the same surface temperature…