Pressure and flow:Fluid types

Fluid types

Fluids may be classified as follows:

• Ideal fluid

• Real fluid

• Newtonian fluid

• Non-Newtonian fluid.

Ideal fluid

An ideal fluid is one, which is incompressible and has no viscosity. Such a fluid is only imaginary, as all existing fluids possess some viscosity.

Real fluid

Simply speaking, a fluid which possesses viscosity is known as a real fluid. All fluids, in actual practice are real fluids.

Newtonian fluid

During the course of our discussion on viscosity, we have seen that shear stress is proportional to the velocity gradient i.e. ra dv/dy. A real fluid in which the shear stress is proportional to the velocity gradient is known as a Newtonian fluid.

Non-Newtonian fluid

A real fluid in which the shear stress is not proportional to the velocity gradient is known as a non-Newtonian fluid.

Comments

Post a Comment

Popular posts from this blog

BASIC DIAGRAMS AND SYSTEMS:Automatic Venting at End of Cycle.

Image
Automatic Venting at End of Cycle In systems where it is not necessary to hold pressure at the end of a cycle, it is possi­ble to unload the pump by automatically venting the relief valve. Figure 9-10 shows such a system using a cam-operated pilot valve to vent the relief valve. Midstroke Extending In view A of Figure 9-10, the machine cycle begins when the solenoid of the spring off­ set directional valve is energized. Pump output is to the cap end of the cylinder. The vent line from the directional control valve is blocked at the cam-operated pilot valve. Midstroke Retracting In view B of Figure 9-10, the limit switch has contracted the cam at the end of the extension stroke. This contact breaks the circuit of the solenoid. The directional control valve has shifted to retract the cylinder. The relief valve vent connection is still blocked. Automatic Stop View C of Figure 9-10 illustrates the circuit at the end of the retraction stroke. The cam on the cyl...
Read more

First approximation design methods:Methods presented

Image
First approximation design methods Introduction Pneumatic conveying system design is generally carried out either by using published mathematical models, or by using reliable conveying data that may be available. Mathematical models are often used when some confidence has been established in their suitability for a particular application, such as the conveying of a specified mater- ial over a given range of conveying conditions. They are, however, generally restricted to dilute phase suspension flow. Conveying data is used extensively in situations where previous experience is avail- able, or from the results of tests specifically carried out for the purpose of system design. In cases where no previous experience of the material, or the range of convey- ing conditions required is available, then conveying trials are usually carried out in order to obtain the necessary data for system design. This is particularly so if dense phase conveying is required. In many cases a quick appro...
Read more

Design procedures:The use of equations in system design and Logic diagram for system design.

Image
Design procedures Introduction It is essential however that the available data relates to the same grade of material for which the new plant design is required. It is also essential that the data is available to slightly higher values of solids loading ratio and to slightly lower values of conveying line inlet air velocity, than are contemplated for the new design. Existing data should never be scaled beyond known conveying boundaries. In cases where no previous experience of the material or the range of conveying conditions required is available, then conveying trials are usually carried out in order to obtain the necessary test data for system design purposes. A set of logic diagrams are presented and these can be used for the purpose of both designing a new conveying system and for checking the capability of an existing system, using both mathematical models and test data. The use of equations in system design The design of pneumatic conveying systems using mathematical models ...
Read more