# Calculation of the pump unit

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Fri, 11/14/2014 - 11:30 - virtuas

initial data
liquid water
temperature t =5

Calculated pipe diameter suction line. The average velocity of the fluid
V=0,7…1,0 m/s,
d

η - pump efficiency. Estimated nominal motor power N

^{о}С; density of water ρ=999,99 kg/m^{3}; kinematic viscosity of water ν=0,0152 cm^{2}/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 TablePipe 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 |

_{1}=(4Q)^{0.5}/(π∙V)^{0.5}=(4∙0.061)^{0.5}/(π∙0.7)^{0.5}=0.333 m d_{1}=(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 d_{2}=(4∙0.061)^{0.5}/(π∙0.8)^{0.5}=0.311 m d_{2}=(4∙0.061)^{0.5}/(π∙2)^{0.5}=0.197 m where Q =0,061m^{3}/s– pump performance (specified flow rate); Rated power at the pump shaft N_{В}=ρ•g•Q•H•10^{-3}/η=1000•9,81•0,061•53•10^{-3}/0,7= 45,39 kW, where g =9,81m/s^{2}— acceleration of gravity; H = 53 m – pump design head;η - pump efficiency. Estimated nominal motor power N

_{m}=N_{В}/(η_{c}•η_{m})=45,39/(0,96•0,92)=51,39 kW, where η_{c}- Coupling efficiency; η_{m}- motor efficiency. Rated power of the motor mounting N_{mount}=β•N_{m}= 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.
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