work in the fluid system - augusta county public schoolswork in the fluid system 12. example –a...
TRANSCRIPT
Work in the
Fluid System
Notes
Work in the Fluid System
1. What is the prime mover in the fluid
system?
• pressure difference
2. In the fluid system, what does work?
• pressure difference
3. Why does pressure difference
accomplish work?
• it can cause a fluid to move
Work in the Fluid System
4. Example – What causes wind to
blow?
• air moves from high pressure regions to low
pressure regions
Work in the Fluid System
5. What are the two structural types of
fluid systems?
• open systems
• closed system
Work in the Fluid System
6. What is a closed fluid system?• the fluid is contained in the
system
• it is retained and recirculatedthrough the system
7. Examples of closed systems• blood circulating in body, brake
system in car, hydraulic jacks or lifts, hydraulic motors
Work in the Fluid System
8. What is an open fluid system?• fluid flows through system
one time only
• it is not retained and recirculated
9. Examples of open fluid systems• city water systems,
gasoline pump, paint sprayers, fire/garden hose
Work in the Fluid System
10. How do we calculate the work done by a
fluid?
• Work = Pressure Difference x Volume of Fluid
• W = P x V
• W = ∆P x V (ex. Town water system)
• W = P x ∆V (ex. Hydraulic cylinder)
10a. What are the units?
• lbs/ft2 x ft3 giving…
• lbs-ft
Example of Town Water Supply
Example of Hydraulic Cylinders
Work in the Fluid System
12. Example – A hydraulic cylinder moves
a piston 10 cm horizontally while pushing
on a mechanical load. The fluid pressure
on the piston face is 80,000 N/m2. The
area of the piston face is 12 cm2.
• What is the total work done on the piston?
Solution – next page
Work in the Fluid System
Solve: W = P x ∆V
• you know the pressure is 80,000 N/m2
• you do not know the volume of the fluid
moved – you must find it from the area (A) of
the piston head and the length (L) of the
cylinder
• V = A x L
• V = 12 cm2 x 10 cm = 120 cm3
Work in the Fluid System
• convert 120 cm3 into 0.00012 m3 by dividing
by 1,000,000 (1m3 = 1,000,000 cm3)
• Now, find work from volume and pressure
Solve W = P x ∆V
• W = (80,000 N/m2)(0.00012 m3)
• W = 9.6 N-m