In fluid dynamics, total dynamic head (TDH) is the work to be done by a pump, per unit weight, per unit volume of fluid. TDH is expressed as the total equivalent height that a fluid is to be pumped, taking into account friction losses in the pipe. TDH is essential for pump specification.
- TDH = Static Lift + Pressure Head + Velocity Head + Friction Loss
where:
- Static lift is the difference in elevation between the suction point and the discharge point.
- Pressure head is the difference in pressure between the suction point and the discharge point, expressed as an equivalent height of fluid.
- Velocity head represents the kinetic energy of the fluid due to its bulk motion.
- Friction loss (or head loss ) represents energy lost to friction as fluid flows through the pipe.
This equation can be derived from Bernoulli's Equation.
For incompressible liquids such as water, Static lift + Pressure head together equal the difference in fluid surface elevation between the suction basin and the discharge basin.