residence time (hydraulic retention time), \(t_{\text{r}}\)

in biotechnology
https://doi.org/10.1351/goldbook.R05310
The average time a particle or volume element of the culture resides in a @B00662@ (or other device) through which a liquid medium continously flows. @R05309@ of the liquid is the reciprocal of @D01740@.
Source:
PAC, 1992, 64, 143. (Glossary for chemists of terms used in biotechnology (IUPAC Recommendations 1992)) on page 164 [Terms] [Paper]