Weekly Tutorial Assignment Wk6 Solution
3
AMME2261 Weekly Tutorial Assignment Due at the start of your tutorial class in Wk 6 The nozzle on a large fire hose is connected to the hose by a flange fitting. The geometry is indicated in the figure below. The gauge pressure and velocity in the hose at a location just upstream of the nozzle are 1 bar (i.e. 100 kPa) and 5m/s, respectively. The velocity may be assumed to be uniform across the diameter of the hose and nozzle. a) Use the integral form of the equation for conservation of mass to find the flow speed at the nozzle exit. b) Use the integral form of the equation for conservation of momentum to find the force on the flange bolts.
-
Upload
william-deng -
Category
Documents
-
view
225 -
download
3
description
Weekly Tutorial Assignment for Fluid Dynamics
Transcript of Weekly Tutorial Assignment Wk6 Solution
AMME2261 Weekly Tutorial Assignment
Due at the start of your tutorial class in Wk 6
The nozzle on a large fire hose is connected to the hose by a flange fitting. The geometry is indicated in the figure below. The gauge pressure and velocity in the hose at a location just upstream of the nozzle are 1 bar (i.e. 100 kPa) and 5m/s, respectively. The velocity may be assumed to be uniform across the diameter of the hose and nozzle.
a) Use the integral form of the equation for conservation of mass to find the flow speed at the nozzle exit.b) Use the integral form of the equation for conservation of momentum to find the force on the flange bolts.
Solution:
Why is the force negative?My assumption in the FBD was that the force would be to the left, but the negative answer indicates that force is in fact to the right. The flow is accelerated through the nozzle imparting a momentum on the fluid to the right which must be balanced by the external forces acting on the control volume. In this example, the pressure force is not sufficient and so an additional force must be applied at the flange to hold the nozzle stationary.
