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These are called the pump curves. They are determined by studies, whose methodology is standardized. These curves are specified when water is pumped with a density of 1000 kg/m3 and kinematic viscosity of 1 mm2/s. When the circulating pump is used for liquids of different density and viscosity, the pump curves have to be recalculated.
The forced recirculation head from the recirculation pumps is very useful in controlling power, however, and allows achieving higher power levels that would not otherwise be possible. The thermal power level is easily varied by simply increasing or decreasing the forced recirculation flow through the recirculation pumps.
Turbulent flow is defined as the flow in which the system's inertial forces are dominant over the viscous forces. This phenomenon is described by Reynolds number, a unit-less number used to determine when turbulent flow will occur. Conceptually, the Reynolds number is the ratio between inertial forces and viscous forces. [6]
The pump must be beneath the steam drum to take advantage of the pressure due to the height of the water. If the pump was not there; when it reaches the steam separator and water returns to the pump, the pressure may become low enough in the eye of the impeller to cause cavitation and subsequent damage.
A flow that is not a function of time is called steady flow. Steady-state flow refers to the condition where the fluid properties at a point in the system do not change over time. Time dependent flow is known as unsteady (also called transient [8]). Whether a particular flow is steady or unsteady, can depend on the chosen frame of reference.
Water reservoir - it is not a part of reciprocating pump, however, it is the main source where from the reciprocating pump takes the water. It may be a source of other fluid as well. Strainer - It removes all impurities from the liquid to avert chocking the pump. Suction Pipe - It is a pipe by which pump takes the water from the reservoir.
Vertical recirculating-type steam generator (typical of Westinghouse and Combustion Engineering-designed reactors) and components. In commercial power plants, there are two to four steam generators per reactor; each steam generator can measure up to 70 feet (21 m) in height and weigh as much as 800 tons.
These pumps employ rollers to squeeze the tube. Except for a 360° eccentric pump design, these pumps have a minimum of 2 rollers 180° apart and may have as many as 8, or even 12 rollers. Increasing the number of rollers increases the pressure pulse frequency of the pumped fluid at the outlet, thereby decreasing the amplitude of pulsing.