Flow over a blunt body

Numerical on OTTO and Diesel Cycle. and Animations of V.C.R.S. and VARS

Numerical on Air standar Cycle

http://nptel.ac.in/courses/101101001/downloads/lec20-problem-solution.pdf

Vapour Absorption Cycle

http://www.youtube.com/watch?v=34K61ECbGD4
Vapour Compression cycle

http://www.youtube.com/watch?v=-Wj_MO4BqtA

Fundamental Equation which holds the basics of fluid mechanics

Basic Fundamental Equation

Pitot Static Probe also Known as Prandlt tube

This page shows a schematic drawing of a pitot-static tube. Pitot-Static tubes, which are also called Prandtl tubes, are used on aircraft as speedometers. The actual tube on the aircraft is around 10 inches (25 centimeters) long with a 1/2 inch (1 centimeter) diameter. Several small holes are drilled around the outside of the tube and a center hole is drilled down the axis of the tube. The outside holes are connected to one side of a device called a pressure transducer. The center hole in the tube is kept separate from the outside holes and is connected to the other side of the transducer. The transducer measures the difference in pressure in the two groups of tubes by measuring the strain in a thin element using an electronic strain gauge. The pitot-static tube is mounted on the aircraft, or in a wind tunnel , so that the center tube is always pointed in the direction of the flow and the outside holes are perpendicular to the center tube. On some airplanes the pitot-static tube is put on a longer boom sticking out of the nose of the plane or the wing.

Difference in Static and Total Pressure

Since the outside holes are perpendicular to the direction of flow, these tubes are pressurized by the local random component of the air velocity. The pressure in these tubes is the static pressure (ps) discussed in Bernoulli's equation. The center tube, however, is pointed in the direction of travel and is pressurized by both the random and the ordered air velocity. The pressure in this tube is the total pressure (pt) discussed in Bernoulli's equation. The pressure transducer measures the difference in total and static pressure which is the dynamic pressure q.

measurement = q = pt - ps

Solve for Velocity

With the difference in pressures measured and knowing the local value of air density from pressure and temperature measurements, we can use Bernoulli's equation to give us the velocity. On the graphic, the Greek symbol rho is used for the dair density. In this text, we will use the letter r. Bernoulli's equation states that the static pressure plus one half the density times the velocity V squared is equal to the total pressure.

ps + .5 * r * V ^2 = pt

Solving for V:

V ^2 = 2 * {pt - ps} / r

V = sqrt [2 * {pt - ps} / r ]

where sqrt denotes the square root function.

There are some practical limitations to the use of a pitot-static tube:

If the velocity is low, the difference in pressures is very small and hard to accurately measure with the transducer. Errors in the instrument could be greater than the measurement! So pitot-static tubes don't work very well for very low velocities.

If the velocity is very high (supersonic), we've violated the assumptions of Bernoulli's equation and the measurement is wrong again. At the front of the tube, a shock wave appears that will change the total pressure. There are corrections for the shock wave that can be applied to allow us to use pitot-static tubes for high speed aircraft.

If the tubes become clogged or pinched, the resulting pressures at the transducer are not the total and static pressures of the external flow. The transducer output is then used to calculate a velocity that is not the actual velocity of the flow. Several years ago, there were reports of icing problems occuring on airliner pitot-static probes. Output from the probes was used as part of the auto-pilot and flight control system. The solution to the icing problem was to install heaters on the probes to insure that the probe was not clogged by ice build-up.

Loss coefficient for different pipe fittings

Minor head loss in pipe and tube systems can be expressed as

h_{minor_loss} = ξ v²/ 2 g         (1)

where

h_{minor_loss} = minor head loss (m, ft)

ξ = minor loss coefficient

v = flow velocity (m/s, ft/s)

g = acceleration of gravity (m/s², ft/s²)

Minor loss coefficients for some of the most common used components in pipe and tube systems

Type of Component or Fitting	Minor Loss Coefficient - ξ -
Tee, Flanged, Line Flow	0.2
Tee, Threaded, Line Flow	0.9
Tee, Flanged, Branched Flow	1.0
Tee, Threaded , Branch Flow	2.0
Union, Threaded	0.08
Elbow, Flanged Regular 90o	0.3
Elbow, Threaded Regular 90o	1.5
Elbow, Threaded Regular 45o	0.4
Elbow, Flanged Long Radius 90o	0.2
Elbow, Threaded Long Radius 90o	0.7
Elbow, Flanged Long Radius 45o	0.2
Return Bend, Flanged 180o	0.2
Return Bend, Threaded 180o	1.5
Globe Valve, Fully Open	10
Angle Valve, Fully Open	2
Gate Valve, Fully Open	0.15
Gate Valve, 1/4 Closed	0.26
Gate Valve, 1/2 Closed	2.1
Gate Valve, 3/4 Closed	17
Swing Check Valve, Forward Flow	2
Ball Valve, Fully Open	0.05
Ball Valve, 1/3 Closed	5.5
Ball Valve, 2/3 Closed	200
Diaphragm Valve, Open	2.3
Diaphragm Valve, Half Open	4.3
Diaphragm Valve, 1/4 Open	21
Water meter	7

Fluid statics

Fluid statics (also called hydrostatics) is the science of fluids at rest, and is a sub-field within fluid mechanics. The term usually refers to the mathematical treatment of the subject. It embraces the study of the conditions under which fluids are at rest in stable equilibrium