Question

12. A fluid is flowing through a pipe with a radius of 5.1 x 10-3 m. The viscosity of the fluid is 1.0 x 10-3 Pa-s. A flow rate of 2.8 x 10-4 m3/s is required, and it is found that a pressure difference of 1.8 × 103 Pa is needed to drive this flow. With this information, calculate the length of the pipe. Hint: assume the flow is viscous flow (a) 1.7 m (b) 5.9 m (c) 3.2 cm (d) 45.2 m (e) 0.035 cm

Answer 1

Q ( flow rate) = $\frac{\Delta p\pi R^4}{8\eta L}$

2.8 x 10^-4 = 1.8 x 10^ 3 x 3.14 x 5.1^4 x 10^-12 / 8(1x 10^-3 x L)

2.8 = 3823 .69 x 10^ -2 / ( 8L)

L = 1.7 m apprx