Fluid mechanics considerations are applied in many fields, especially in engineering. Below a list is provided which clearly indicates the far-reaching applications of fluid-mechanics knowledge and their importance in various fields of engineering. Whereas it was usual in the past to carry out special fluid mechanics considerations for each of the areas listed below, today one strives increasingly at the development and introduction of generalized approaches that are applicable without restrictions to all of these fields. This makes it necessary to derive the basic equations of fluid mechanics so generally that they fulfill the requirements for the broadest applicability in areas of science and engineering, i.e. in those areas indicated in the list below. The objective of the derivations in this section is to formulate the conservation laws for mass, momentum, energy, chemical species, etc., in such a way that they can be applied to all the flow problems that occur in the following areas:
- Heat exchanger, cooling and drying technology
- Reaction technology and reactor layout
- Aerodynamics of vehicles and aeroplanes
- Semiconductor-crystal production, thin-film technology, vapor-phase deposition processes
- Layout and optimization of pumps, valves and nozzles
- Use of flow equipment parts such as pipes and junctions
- Development of measuring instruments and production of sensors
- Ventilation, heating and air-conditioning techniques, layout and tests, laboratory vents
- Problem solutions for roof ventilation and flows around buildings
- Production of electronic components, micro-systems analysis engineering
- Layout of stirrer systems, propellers and turbines
- Sub-domains of biomedicine and medical engineering
- Layout of baking ovens, melting furnaces and other combustion units
- Development of engines, catalyzers and exhaust systems
- Combustion and explosion processes, energy generation, environmental engineering
- Sprays, atomizing and coating technologies
Flow often referred as an ideal fluid. We presume that such a fluid has no viscosity. However, this is an idealized situation that does not exist.
 |
| Example (a) Ideal fluid |
Real fluid, the effects
of viscosity are
introduced into the
problem .
Classification type of flow :
Incompressible fluid flow assumes the fluid has constant density (p = constant), though liquids are slightly compressible we usually assume them to be incompressible
Steady flow means steady with respect t time. Thus all properties of the flow at every point remain constant with respect to time.
Uniform flow happened when the cross section ( shape and area) through which the flow occurs remains constant
Path line is the trace made by a single particle over a period of time. The path line shows the direction of the velocity.
Stream line shows the mean direction of a
number of particles at the same instant time
Stream line shows the mean direction of a
number of particles at the same instant time.
Flowrate is known as quantity of fluid flowing
per unit time across any section. The flowrate
can be expressed in terms of
i) Volume flow rate ( discharges)
BG – cfs (cubic per second), gpm ( gallon
per minute, mgd ( million gallon per day)
SI – m3/d
ii) mass flow rate
BG – slugs per second
SI – kg/s
iii) weight flow rate
BG – pounds per second
SI – kN/s
Incompressible fluid – volume flow rate
Compressible fluid – weight & mass flowrat
