19P505 APPLIED HYDRAULICS AND PNEUMATICS
Unit 1: ELEMENTS OF FLUID POWER SYSTEM
Lecture 02- Properties of fluid
,Learning Objectives
Upon completion of this chapter, the student should be able to:
• Define three states of matter: Solid, liquid and gas.
• Define mass density, specific weight and weight density. Understand the meaning of the term pressure.
•
• Explain the difference between gauge and absolute pressures.
• Understand the difference between kinematic and absolute viscosities.
• Differentiate between the ideal and real fluids.
• Define bulk modulus Explain the dependence of viscosity on temperature.
, Fluids, both liquids and gases, are characterized by their continuous deformation when a shear force, how
small, is applied.
Liquids and gases may be distinguished by their relative incompressibilities and the fact that liquid may have
surface while a gas expands to fill its confining container.
Because the liquid is the medium of transmission of power in hydraulic system, knowledge of its characterist
essential. The purpose of this chapter is to define certain fundamental properties of fluids which will be usefu
the basic principles of fluid mechanics to the solution of practical problems on fluid power.
, Solid, Liquid and Gas
The molecules of a solid are usually closer to each other than those of a fluid. The attractive forces between t
of a solid are so large that a solid tends to retain its shape. This is not the case with a fluid where the attr
between the molecules are smaller. An ideal elastic solid deforms under load, and once the load is removed
its original state.
A fluid may be either a gas or a liquid. The molecules of a gas are much farther apart than those of a liquid. He
very compressible, and when all external pressure is removed, it tends to expand indefinitely. A liquid
incompressible, and if all pressure, except its own vapor pressure, is removed, the cohesion between mole
them together, so that the liquid does not expand indefinitely. Therefore, a liquid may have a free surfac
surface from which all pressure is removed, except its own vapor pressure.
Unit 1: ELEMENTS OF FLUID POWER SYSTEM
Lecture 02- Properties of fluid
,Learning Objectives
Upon completion of this chapter, the student should be able to:
• Define three states of matter: Solid, liquid and gas.
• Define mass density, specific weight and weight density. Understand the meaning of the term pressure.
•
• Explain the difference between gauge and absolute pressures.
• Understand the difference between kinematic and absolute viscosities.
• Differentiate between the ideal and real fluids.
• Define bulk modulus Explain the dependence of viscosity on temperature.
, Fluids, both liquids and gases, are characterized by their continuous deformation when a shear force, how
small, is applied.
Liquids and gases may be distinguished by their relative incompressibilities and the fact that liquid may have
surface while a gas expands to fill its confining container.
Because the liquid is the medium of transmission of power in hydraulic system, knowledge of its characterist
essential. The purpose of this chapter is to define certain fundamental properties of fluids which will be usefu
the basic principles of fluid mechanics to the solution of practical problems on fluid power.
, Solid, Liquid and Gas
The molecules of a solid are usually closer to each other than those of a fluid. The attractive forces between t
of a solid are so large that a solid tends to retain its shape. This is not the case with a fluid where the attr
between the molecules are smaller. An ideal elastic solid deforms under load, and once the load is removed
its original state.
A fluid may be either a gas or a liquid. The molecules of a gas are much farther apart than those of a liquid. He
very compressible, and when all external pressure is removed, it tends to expand indefinitely. A liquid
incompressible, and if all pressure, except its own vapor pressure, is removed, the cohesion between mole
them together, so that the liquid does not expand indefinitely. Therefore, a liquid may have a free surfac
surface from which all pressure is removed, except its own vapor pressure.
