In
fluid dynamics
In physics and engineering, fluid dynamics is a subdiscipline of fluid mechanics that describes the flow of fluids— liquids and gases. It has several subdisciplines, including ''aerodynamics'' (the study of air and other gases in motion) an ...
, total dynamic head (TDH) is the total equivalent height that a fluid is to be pumped, taking into account friction losses in the pipe.
:
: TDH = Static Height + Static Lift + Friction Loss + Velocity Head
where:
: ''Static height'' is the maximum height reached by the pipe after the pump (also known as the ''discharge head'').
: ''Static lift'' is the height the water will rise before arriving at the pump (also known as the ''suction head'').
: ''Friction loss'' (or ''
head loss
Hydraulic head or piezometric head is a specific measurement of liquid pressure above a vertical datum., 410 pages. See pp. 43–44., 650 pages. See p. 22.
It is usually measured as a liquid surface elevation, expressed in units of length, ...
'').
: ''Velocity head'' represents the energy of the fluid due to its bulk motion.
This equation can be derived from
Bernoulli's Equation
In fluid dynamics, Bernoulli's principle states that an increase in the speed of a fluid occurs simultaneously with a decrease in static pressure or a decrease in the fluid's potential energy. The principle is named after the Swiss mathematici ...
.
For a relatively incompressible fluid such as water, TDH is simply the
pressure head
In fluid mechanics, pressure head is the height of a liquid column that corresponds to a particular pressure exerted by the liquid column on the base of its container. It may also be called static pressure head or simply static head (but not ''sta ...
difference between the inlet and outlet of the pump, if measured at the same elevation and with inlet and outlet of equal diameter.
TDH is also the
work
Work may refer to:
* Work (human activity), intentional activity people perform to support themselves, others, or the community
** Manual labour, physical work done by humans
** House work, housework, or homemaking
** Working animal, an animal tr ...
done by the pump per
unit weight
The specific weight, also known as the unit weight, is the weight per unit volume of a material.
A commonly used value is the specific weight of water on Earth at , which is .National Council of Examiners for Engineering and Surveying (2005). ''Fu ...
, per unit volume of fluid.
See also
*
Hydraulic head
Hydraulic head or piezometric head is a specific measurement of liquid pressure above a vertical datum., 410 pages. See pp. 43–44., 650 pages. See p. 22.
It is usually measured as a liquid surface elevation, expressed in units of length, ...
*
Fluid dynamics
In physics and engineering, fluid dynamics is a subdiscipline of fluid mechanics that describes the flow of fluids— liquids and gases. It has several subdisciplines, including ''aerodynamics'' (the study of air and other gases in motion) an ...
External links
On-line TDH calculator- Pump World
* http://www.wolframalpha.com/input/?i=total+dynamic+head -wolframalpha.com
Fluid mechanics