Basics of Hydraulics

Chapter: 3

Basics of Hydraulics

"Water is fluid, soft, and yielding. But water will wear away rock, which is rigid and cannot yield. As a rule, whatever is fluid, soft, and yielding will- overcome whatever is rigid and hard. This another paradox: what is soft is strong.

– Lao-Tzu (600 B.C.)

"If A is a success in life, then A equals x plus y plus z. Work is x; y is play; and z is keeping your mouth shut."

- Albert Einstein

"It's being proven in the lab that the positive hormones ciate you within your own system with positive feelings do more for your regenera- tion than you might know. 

- Doc Childre

Learning Objectives

While reading and after studying this chapter, you will be able to:

• Understand the meaning of force, pressure and pressure head.

• Explain the different forms of pressure measure- ment and their relationship.

• Define the Pascal's law and appreciate its applica- tions.

• Discuss the operation of hydraulic jack and an air-to-hydraulic pressure booster.

• Distinguish between laminar and turbulent flow. 

• Appreciate the significance of Reynold's number. 

• Apply the continuity equation, Bernoulli's equation, and energy equation to completely analyse a fluid power system.

• Apply the Darcy's equation to determine the head loss in a flow through pipes.

• Determine the functional losses in valves and fittings.

1. INTRODUCTION

In Chapter 2, we have discussed the various properties desired of a hydraulic fluid and their significance. In order to understand and design a hydraulic system, the basic principles associated with the science of hydraulics are to be understood thoroughly. The basic principles of hydraulics include the concepts of force, pressure and head; concept and applications of Pascal's law; difference between laminar and turbulent flow; definition and significance of Reynolds number; and the concept and applications of Darcy's equation. It is essential for a fluid power designer or engineer to have the above basic principles of hydraulics so that to design, analyse, and apply the hydraulic systems. In this chapter, we . shall review such basic principles of hydraulics.