Concept explainers
The viscosity of some fluids changes when a strong electric ?eld is applied on them. This phenomenon is known as the electrorheolegical (ER) effect, and fluids that exhibit such behavior are known as ER fluids. The Bingham plastic model for shear stress, which is expressed as
Answer: (b)
(a)
The relationship for the torque generated by a clutch when the output shaft is stationary.
Answer to Problem 128P
The torque generated by a clutch when the output shaft is stationary is
Explanation of Solution
Given information:
The thickness of the fluid is
Write the expression for the shear stress for Bingham plastic.
Here, the shear stress is
Write the expression for the velocity gradient.
Here, the thickness of the film is
Write the expression for the velocity of shaft.
Here, the angular velocity is
Write the expression for the force.
Here, the force is
Write the expression for the torque generated by the shaft.
Here, the torque generated by the shaft is
Write the expression for the area of the plate.
Calculation:
Substitute
Substitute
Substitute
Substitute
Integerating both side taking lower limit
The torque generated by the both surface of the plate.
For
Conclusion:
The torque generated by a clutch when the output shaft is stationary is
(b)
The torque for an ER clutch.
Answer to Problem 128P
The torque for an ER clutch is
Explanation of Solution
Given information:
The number of clutch plate is
Write the expression for the angular speed of the shaft.
Here, the angular speed is
Calculation:
Substitute
Substitute
Conclusion:
The torque for an ER clutch is
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Chapter 2 Solutions
Fluid Mechanics: Fundamentals and Applications
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