Search results
Results from the WOW.Com Content Network
Specific Fan Power (SFP) is a parameter that quantifies the energy-efficiency of fan air movement systems. It is a measure of the electric power that is needed to drive a fan (or collection of fans), relative to the amount of air that is circulated through the fan(s).
˙ is the shaft power (units of power, or energy/time). [ 3 ] These laws assume that the pump/fan efficiency remains constant i.e. η 1 = η 2 {\displaystyle \eta _{1}=\eta _{2}} , which is rarely exactly true, but can be a good approximation when used over appropriate frequency or diameter ranges.
The output power of a motor is the product of the torque that the motor generates and the angular velocity of its output shaft. Likewise, the power dissipated in an electrical element of a circuit is the product of the current flowing through the element and of the voltage across the element. [1] [2]
In physics, there are equations in every field to relate physical quantities to each other and perform calculations. Entire handbooks of equations can only summarize most of the full subject, else are highly specialized within a certain field. Physics is derived of formulae only.
Kinetic energy per unit mass: 1 / 2 v 2, where v is the speed (giving J/kg when v is in m/s). See also kinetic energy per unit mass of projectiles . Potential energy with respect to gravity, close to Earth, per unit mass: gh , where g is the acceleration due to gravity ( standardized as ≈9.8 m/s 2 ) and h is the height above the ...
In unit systems where force is a derived unit, like in SI units, g c is equal to 1. In unit systems where force is a primary unit, like in imperial and US customary measurement systems , g c may or may not equal 1 depending on the units used, and value other than 1 may be required to obtain correct results. [ 2 ]
It is a measure of the electric power that is needed to operate a pump (or collection of pumps), relative to the volume flow rate. It is not constant for a given pump, but changes with both flow rate and pump pressure. This term 'SPP' is adapted from the established metric Specific fan power (SFP) for fans (blowers). [1]
The specific speed value for a turbine is the speed of a geometrically similar turbine which would produce unit power (one kilowatt) under unit head (one meter). [6] The specific speed of a turbine is given by the manufacturer (along with other ratings) and will always refer to the point of maximum efficiency. This allows accurate calculations ...