Water at 288.7 k flows through a 15.24-cm. diameter horizontal pipe into a 190-l drum. determine the minimum time it will take to fill the drum if the flow remains laminar.

The flow will be laminar if Reynold's number is less than 2000.

Use the Reynold's formula and rearrange to calculate velocity of water in the pipe.

Where, is velocity of the fluid, is the diameter of pipe, and is the kinematic viscosity i.e. for water at 288.7 K from Appendix.

So, velocity is:

The flow rate Q:

" alt=" t = \frac{V}{\frac{N_R \nu \pi D}{4}} = \frac{4V}{N_R \nu \pi D} =\frac{4 \times 190 L\frac{10^{-3} m^3}{L}}{2000 \times 1.12\times 10^{-6} m^2/s \pi 15.24 cm\frac{1 m}{100 cm}} = 2226.3 s \frac{1 min}{60 s}= 37.1 min" /> " />

Where A is the area of cross section of pipe.

The time taken to fill is:

Where V is the capacity of the tank.