In: Physics
A horizontal pipe carries a smoothly flowing liquid with density 1.39 × 103 kg/m3. At locations 1 and 2 along the pipe the diameters are 5.23 cm and 2.19 cm, respectively. The flow speed at location 1 is 1.79 m/s. What is the pressure difference between location 2 and location 1 (including its sign)? Ignore viscosity.
Gravitational acceleration = g = 9.81 m/s2
Density of the fluid =
= 1390
kg/m3
Diameter of pipe at location 1 = D1 = 5.23 cm = 0.0523 m
Diameter of pipe at location 2 = D2 = 2.19 cm = 0.0219 m
Area of pipe at location 1 = A1
A1 =
D12/4
Area of pipe at location 2 = A2
A2 =
D22/4
Flow speed of fluid at location 1 = V1 = 1.79 m/s
Flow speed of fluid at location 2 = V2
By continuity equation,
A1V1 = A2V2
(
D12/4)V1
= (
D22/4)V2
D12V1 = D22V2
(0.0523)2(1.79) = (0.0219)2V2
V2 = 10.208 m/s
Pressure of fluid at location 1 = P1
Pressure of fluid at location 2 = P2
The pipe is horizontal, therefore the height of the pipe at location 1 and 2 is same.
Pressure difference between location 2 and location 1 =
P = P2
- P1
By Bernoulli's Equation,




P = -70194.42
Pa
Pressure difference between location 2 and location 1 = -70194.42 Pa