A capillary viscometer measures the time required for a specified volume of liquid to flow through a small-bore glass tube, as in Fig. P6.17. This transit time is then correlated with fluid viscosity. For the system shown,
(a) derive an approximate formula for the time required, assuming laminar flow with no entrance and exit losses.
(b) If L= 12 cm, =2 cm, 8= cm3 , and the fluid is water at 20°C, what capillary diameter D will result in a transit time t of 6 seconds?
