Problem 15.61 Unfiltered olive oil must flow at a minimum speed of 3.0 m/s to pr
ID: 1792997 • Letter: P
Question
Problem 15.61
Unfiltered olive oil must flow at a minimum speed of 3.0 m/s to prevent settling of debris in a pipe. The oil leaves a pump at a pressure of 86 kPa through a pipe of radius 9.3 mm. It then enters a horizontal pipe at atmospheric pressure. Ignore the effects of viscosity.
Part A What is the speed of the oil as it leaves the pump if it flows at 3.0 m/s in the horizontal pipe? Express your answer to two significant figures and include appropriate units.
Part B What is the radius of the horizontal pipe? Express your answer to two significant figures and include appropriate units.
Explanation / Answer
Given that,
v2 = 3 m/s
P1 = 86000 Pa
P2 = 101325 Pa
r1 = 9.3*10^(-3) m
(A)
Apply bernaolli's equation,
(1/2)P1v1^2 = (1/2)P2v2^2
86000 * v1^2 = 101325 * 3^2
v1 = 3.25 m/s
speed of the oil as it leaves the pump = 3.25 m/s
(B)
From equation of continuity,
A1*v1 = A2*v2
pi*r1^2 * v1 = pi*r2^2 * v2
(9.3*10^(-3))^2 * (3.25)^2 = r2^2 * 3^2
r2 = 10.09 mm
radius of the horizontal pipe = 10.09 mm