Hydraulic and Pneumatic Systems Lecture Notes

Vocabulary flashcards covering the definitions, classifications, and fundamental principles of hydraulic and pneumatic systems as presented in the lecture.

Fluid (hydraulic) machine

A device in which energy is transferred from the fluid flowing through the machine to its operating member (runner, impeller, piston and others), or from the operating member of the machine to the fluid flowing through it.

Working fluid

The fluid (liquid or gas) flowing through a fluid machine.

Turbine

A fluid machine that extracts and converts flow energy from the working fluid directly to mechanical energy of its rotating member.

Pump

A fluid machine where the operating member adds flow energy to the working fluid, specifically when the working fluid is a liquid such as water or oil.

Compressor

A fluid machine where the primary objective is to increase the pressure of air or gas, giving a substantial rise in pressure to the flowing medium.

Fan (or blower)

A fluid machine whose primary objective is to cause the movement of a gas with only a small change in static pressure, where the fluid may be regarded as incompressible.

Density ratio boundary

The criteria used to distinguish fans from compressors, often taken as $1.05$ for fans but much higher for compressors.

Power producing machines

Hydraulic machines in which work is done by the fluid flow.

Power absorbing machines

Hydraulic machines in which work is done on the fluid to raise its potential energy.

Positive-displacement machines

Machines whose functioning is derived essentially from changes of the volume occupied by the fluid within the machine, depending on mechanical and hydrostatic principles.

Rotodynamic machines

Machines involving fluid flow through rotating blades or rotors that extract or add flow energy to the fluid without any intermittent sealing.

Centrifugal pump

A common radial-flow rotodynamic machine where fluid enters axially in the center and is discharged radially along the outer radius of the pump casing.

Scroll

The snail-shaped casing of a centrifugal pump or blower.

Pascal’s Law

The principle stating that pressure applied at any point in a confined fluid is transmitted undiminished in all directions.

Bernoulli’s Principle

The principle stating that in a flowing fluid, the sum of pressure energy, kinetic energy, and potential energy is constant.

Impulse Turbines

A type of hydraulic turbine, such as the Pelton wheel, that converts the kinetic energy of a high-velocity fluid into mechanical energy by directing a high-speed jet onto blades.

Reaction turbine

A turbine that generates power or torque by utilizing both the pressure and velocity of a fluid, operating according to Newton’s third law of motion.

Francis turbine

A mixed flow turbine where water enters the runner blades radially and exits axially, commonly used in hydropower plants.

Kaplan Turbine

An axial flow turbine where water enters and exits in a direction parallel to the runner’s axis of rotation.

Pneumatics

The science that uses compressed air to transmit energy, derived from the Greek word 'Pneuma' meaning wind or breath.