ABSTRACT
Fortunately, we may only need to know how the system of interest affects a transport operation and so can treat the system as a black box, operating on a fluid passing through. Such an approach is often used to analyze piping systems where a fluid is being pushed along by pumps or compressors and all this equipment is lumped together. In other circumstances, a transport process may occur along a predominant direction and we may only need detailed information in that direction. Examples include knowing the temperature distribution along the length of a heat exchanger, or the composition along the axis of a chemical reactor or piece of separations equipment. We can modify the microscopic balance equations to apply to these systems by integrating over nonessential coordinate directions. This partial integration leads to macroscopic, engineering, or lumped analysis balances. In this chapter, we derive these balances and apply them to several physical systems involving momentum, energy, mass, and charge transport.
