Calculation method for the residence time.

The time spent by a material which is flowing through a volume   is known as residence volume. The fluids in a chemical reactor is an example of it. There are three time constants which are used for representing the resident time distribution. They are turn over time,mean  age, and mean transit time. The turn over time is the ratio of the material which passes through the volume. The length of time material in the reservoir is Mean age ,while the transit