# Calculation of the pump unit

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initial data liquid water temperature t =5оС; density of water ρ=999,99 kg/m3; kinematic viscosity of water ν=0,0152 cm2/s; Hydraulic calculation of pipelinePipe diameters are determined by the recommended a calculated rate of water movement in them. The calculated velocity is adopted in accordance with the Table
 Pipe diameters, mm Recommended the calculated velocity of water in the pipes, m/s in the suction line in the discharge line ≤ 250 0,7…1,0 0,8…2,0 300…800 0,8…1,5 1,0…3,0 > 800 1,2…2,0 1,5…4,0
Calculated pipe diameter suction line. The average velocity of the fluid V=0,7…1,0 m/s, d1=(4Q)0.5/(π∙V)0.5=(4∙0.061)0.5/(π∙0.7)0.5=0.333 m d1=(4∙0.061)0.5/(π∙1)0.5=0.279 m Estimate the diameter of the pipe, the pressure line V=0,8…2,0 m/s d2=(4∙0.061)0.5/(π∙0.8)0.5 =0.311 m d2=(4∙0.061)0.5/(π∙2)0.5 =0.197 m where Q =0,061m3/s– pump performance (specified flow rate); Rated power at the pump shaft NВ=ρ•g•Q•H•10-3/η=1000•9,81•0,061•53•10-3/0,7= 45,39 kW, where g =9,81m/s2— acceleration of gravity; H = 53 m – pump design head;
η - pump efficiency. Estimated nominal motor power Nm=NВ/(ηc•ηm)=45,39/(0,96•0,92)=51,39 kW, where ηc - Coupling efficiency; ηm - motor efficiency. Rated power of the motor mounting Nmount=β•Nm= 1,2•51,39 = 61,67 kW, where β=1,2 - power factor of safety for the pressure line pipe diameter 0,2 m. Victor Priymak Chief technical designеr.