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In most contexts a mention of rate of fluid flow is likely to refer to the volumetric rate. In hydrometry, the volumetric flow rate is known as discharge. Volumetric flow rate should not be confused with volumetric flux, as defined by Darcy's law and represented by the symbol q, with units of m 3 /(m 2 ·s), that is, m·s −1. The integration ...
is the volumetric flow rate (e.g. CFM, GPM or L/s) is the impeller diameter (e.g. in or mm) is the shaft rotational speed (e.g. rpm) is the total dynamic head developed by the pump (e.g. m or ft) is the shaft power (e.g. W or HP)
A screw turbine at a small hydro power plant in Goryn, Poland. The Archimedean screw is an ancient invention, attributed to Archimedes of Syracuse (287–212 BC.), and commonly used to raise water from a watercourse for irrigation purposes.
For example, a low-head hydro power plant with hydrostatic head of few meters to few tens of meters can be classified either as an SHP or an LHP. [30] The other distinction between SHP and LHP is the degree of the water flow regulation: a typical SHP primarily uses the natural water discharge with very little regulation in comparison to an LHP.
Specific speed N s, is used to characterize turbomachinery speed. [1] Common commercial and industrial practices use dimensioned versions which are of equal utility. Specific speed is most commonly used in pump applications to define the suction specific speed —a quasi non-dimensional number that categorizes pump impellers as to their type and proportions.
By Newton's second and third laws, the force F imposed by the jet on the runner is equal but opposite to the rate of momentum change of the fluid, so F = −m(V f − V i)/t = −ρQ[(−V i + 2u) − V i] = −ρQ(−2V i + 2u) = 2ρQ(V i − u), where ρ is the density, and Q is the volume rate of flow of fluid.
A hydropower resource can be evaluated by its available power. Power is a function of the hydraulic head and volumetric flow rate. The head is the energy per unit weight (or unit mass) of water. [5] The static head is proportional to the difference in height through which the water falls. Dynamic head is related to the velocity of moving water.
For still water, this is the difference in height between the inlet and outlet surfaces. Moving water has an additional component added to account for the kinetic energy of the flow. The total head equals the pressure head plus velocity head. ˙ = flow rate (m 3 /s)