College】 【weak basic parameters of the pump.

<br> <BR> characterization of the basic parameters of the pump main properties are the following: <BR> First, the pump flow rate Q <BR> traffic is transported out of the unit time of liquid (volume or mass). .<BR> Volume flow with Q, the unit is: m3 / s, m3 / h, l / s and so on. .<BR> Mass flow with Qm, the unit is: t / h, kg / s and so on. .<BR> Mass flow and volume flow relationship: <BR> Qm = ρQ <BR> where ρ - liquid density (kg/m3, t/m3), room temperature water ρ = 1000kg/m3. .<BR> II, head of the pump head H <BR> pumping unit weight of the liquid from the pump inlet (pump suction flange) to the pump outlet (pump outlet flange) energy value. .Is a Newtonian fluid through the pump to obtain the effective energy. .The unit is N · m / N = m, ie the pump pumping the liquid column height of liquid, used for short meters. .<BR> Third, speed is the shaft speed n <BR> number of revolutions per unit time, with the symbol n, the unit is r / min. .<BR> IV NPSH NPSH NPSH <BR> also known as net positive suction head, cavitation performance is that the main parameters. .NPSH said China had used Δh. .<BR> V. <BR> pump power and efficiency of power usually refers to the input power, the former motive power on the mass support shaft, it is also known as shaft power, with P expressed; <BR> effective power and pump .said output power, with Pe said. .It is the unit of time away from the liquid transfer pump in the pump to get the effective energy. .<BR> Because the head is the output of the unit weight of the pump liquid from the pump effective energy obtained, so the head and the quality of the product flow and the acceleration of gravity is the unit time of liquid from the pump output effective energy obtained - .- that is, the effective pump power: <BR> Pe = ρgQH (W) = γQH (W) <BR> where ρ - density of the liquid pumping (kg/m3); <BR> γ - pumping liquids .severe (N/m3); <BR> Q - the pump flow (m3 / s); <BR> H - pump head (m); <BR> g - acceleration due to gravity (m/s2). .<BR> Shaft power P and the effective power Pe is the difference between the loss of pump power, its size is measured by the efficiency of the pump. .Efficiency of the pump power and shaft power for the effective ratio, with η said. .<BR>.