ME 2305 - APPLIED HYDRAULICS AND PNEUMATICS

TWO MARK QUESTION AND ANSWER

UNIT - I

1. Define Fluid Powers? (Anna, Nov-2005)

Fluid power technology is a means to convert, transmit, control and apply fluid energy to perform

useful work.

2. What are the four primary functions of a hydraulic fluid?

The four primary functions are

i) To transmit power

ii) To lubricate moving parts

iii) To seal clearances between mating parts

iv) To dissipate heat

3. Define Pascal's -Law

A pressure applied to a confined fluid at rest is transmitted with equal intensity throughout the fluid.

4. What is the function of hydraulic actuator?

Hydraulic actuators convert the pressure energy of fluid into mechanical output to perform

useful work.

5. Define back Pressure.

The pressure encountered on the return side of a fluid system.

6. Define Bulk modulus? ( Anna, June-2006)

Hydraulic fluids are relatively incompressible. They are not however, completely incompressible.

The bulk modulus of a liquid is a measure of its incompressible, or “stiffness”.

7. Define Pump.

A device, which causes a liquid to flow against a pressure. It converts mechanical energy into

fluid energy.

8. Define Motor Anna, Nov-2005

A device that converts fluid power into mechanical power. It usually delivers Torque and rotary

motion to a shaft.

9. Define Viscosity. (Anna, June-2006)

A measure of the internal friction or the resistance to fluid flow.

10. Differentiate between liquid pressure and liquid flow rate?

The liquid pressure is responsible for the force developed at hydraulic actuator while the liquid

flow rate is responsible for the speed of the hydraulic actuator.

11. How velocity of the hydraulic actuator is calculated?

Velocity of the hydraulic actuator = Input flow rate

Area of piston

12. State the Bernoulli’s principle?

If the flow rate in the system is constant, then the total energy in the system will also be constant

irrespective of the variation in the cross section of the fluid passages.

13. Name the three basic types of control systems.

The three basic types of fluid power control systems are

i) Electrical

ii) Fluid logic

iii) Programmable

14. What device creates a force that can pull or push a load?

A hydraulic cylinder produces a force that can pull or push a load.

15. What device creates a torque that can rotate a shaft?

A hydraulic motor produces a torque that can rotate a shaft.

16. Why can’t air be used for all fluid power applications?

Pneumatic systems exhibit spongy characteristics due to the compressibility of air. So, air is not

used for all fluid power applications.