Fundamentals of Heat and Mass Transfer – Problem 1.26

A heat sink also spelled heatsink, is a passive heat exchanger that moves heat generated by an electronic or mechanical device to a fluid medium, typically air or a liquid coolant. This process helps dissipate the heat away from the device, allowing for temperature regulation. Heat sinks are commonly used in computers to cool CPUs,…

To determine the effect of the temperature dependence of the thermal conductivity on the temperature distribution in a solid, consider a material for which this dependence may be represented as k = ko + aT where ko is a positive constant and a is a coefficient that may be positive or negative. Sketch the steady-state…

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…

Radioactive wastes are packed in a long, thin-walled cylindrical container. The wastes generate thermal energy nonuniformly according to the relation q = qo [1 – (r/ro)2], where q is the local rate of energy generation per unit volume, qo is a constant, and ro is the radius of the container. Steady-state conditions are maintained by…

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…

The free convection heat transfer coefficient on a thin hot vertical plate suspended in still air can be determined from observations of the change in plate temperature with time as it cools. Assuming the plate is isothermal and radiation exchange with its surroundings is negligible, evaluate the convection coefficient at the instant of time when…