离心泵设计计算

项目,,公式,结果,单位,备注,,,

基本参数,流量,Q,0.30,m3/s,,,,

,扬程,H,20.00,m,,,,

,转速,n,1450,r/min,,,,

,装置气蚀余量,NPSHa,4.0,m,,,,

"泵

进

出

口

直

径",泵进口直径,Ds,250,(mm),选vs=3.5m/s,,,

,泵出口直径,Dd,200,(mm),选Dd=0.8Ds,,,

,泵进口速度,Vd,6.11,(m/s),,,,

,泵出口速度,Vs,9.55,(m/s),,,,

气蚀计算,泵安装高度,hg=10.33-0.5-0.24-[NPSH]a,5.59,(m),"常温清水

pv/ρg=0.24m

hc=0.5m",,,

,泵气蚀余量,NPSHr=NPSHa/1.3,3.08,(m),,,,

,泵气蚀转数,C=5.62n√Q/NPSHr3/4,1921.2,,,,,

"比

转

数",比转数,ns=3.65n√Q/H3/4,306.5,,,,,

"确

定

效

率",水力效率,ηh=1+0.0835lg(Q/n)1/3,0.90,,,,,

,容积效率,ηv=1/(1+0.68ns-2/3),0.99,,,,,

,圆盘损失效率,ηm'=1-0.07/(ns/100)7/6,0.98,,,,,

,机械效率,,0.98,,"假定轴承、填

料损失为2％",,,

,总效率,η=ηmηvηh,0.85,,,,,

"确

定

功

率",轴功率,P=ρgQH/1000η,69.24,(kW),,,,

,计算配套功率,P'=KP,90.01,(kW),取K=1.3,,,

,扭矩,Mn=9.55×103P'/n,592.81,(N.m),,,,

,最小轴径,d=(Mn/0.2[τ])1/3,43.91,(mm),"选[τ]=350

×105（N/m2）",,,

,,,,,,,,,

"初

步

确

定

叶

轮

主

要

尺

寸",轮毂直径,,40.00,(mm),,,,

,进口当量直径,D0=K0(Q/n)1/3,236.6,(mm),选K0=4,,,

,叶轮进口直径,Dj=√(D02+dh2),239.9,,,,,

,叶轮出口宽度,"Kb2=0.64(ns/100)5/6

b2=Kb2(Q/n)1/3",97.77,(mm),,,,

,叶轮外径,"KD2=9.35(ns/100)-1/2

D2=KD2(Q/n)1/3",315.9,(mm),,,,

,叶片出口角,β2,22.50,度,,,,

,叶片数,"Z=6.5(D2+D1)*

sin[(β1+β2)/2]/(D2-D1)",6,,"取D1=0.93Dj=60mm

设β1=30。",,,

"精

算

叶

轮

外

径

第

一

次",理论扬程,Ht=H/ηh,22.3,(m),,,,

,修正系数P,P=ψR22/ZS,0.32,,"(0.3-0.45)

5-70.3-0.36

3-50.36-0.4

1-20.4-0.45",,,

,出口叶片厚度,,3.50,(mm),,,,

,无穷叶片数理论扬程,Ht∞=(1+P)×Ht,29.42,,,,,

,"叶片出口排

挤系数","ψ2=1-√(1+(ctgβ2/sinλ2)2

×Zδ2/πD2",0.94,,"取δ2=3.5mm

λ2=90。",,,

,出口轴面速度,vm2=Q/πD2b2ψ2ηv,3.32,(m/s),,,,

,出口圆周速度,"u2=vm2/2tgβ2+

√(vm2/2tgβ2)2+gHt∞",21.5,(m/s),,,,

,出口直径,D2=60u2/πn,282.66,(mm),"与假定不符进

行第二次计算

取D2=173mm",,,

"精

算

叶轮外径第二次","叶片出口

排挤系数","ψ2=1-√(1+(ctgβ2/sinλ2)2

×Zδ2/πD2",0.90,,,,,

,出口轴面速度,vm2=Q/πD2b2ψ2ηv,6.37,(m/s),,,,

,出口圆周速度,"u2=vm2/2tgβ2+

√(vm2/2tgβ2)2+gHt∞",26.34,(m/s),假定P不变,,,

,叶轮外径,D2=60u2/πn,346.88,(mm),"与假定值接近

不在重新计算",,,

"叶

轮

出

口

速

度",出口排挤系数,,0.90,,,,,

,出口轴面速度,"ψ2=1-√(1+(ctgβ2/sinλ2)2

×Zδ2/πD2

vm2=Q/πD2b2ψ2ηv",3.18,(m/s),由上述计算得,,,

,出口圆周速度,u2=πD2n/60,26.34,(m/s),,,,

,"出口圆周分

速度",vu2=gHt/u2,8.30,(m/s),,,,

,"无穷叶片数

出口圆周分速度",vu2=gHt∞/u2,10.96,(m/s),,,,

"叶

轮

进

口

","叶轮进口

圆周速度",90,6.83,(m/s),,,,

,,85,6.45,(m/s),,,,

,,80,6.07,(m/s),,,,

,"叶片进口轴

面流速",a流线,59.82,(m/s),,,,

,,b流线,66.67,(m/s),,,,

,,c流线,73.95,(m/s),冲角=3,,,

项目,,公式,结果,单位,备注,,,

"速

度","流线叶片

进口液流角",a流线,83.5,°,,,安放角,83.5

,,b流线,84.5,°,,,安放角,84.5

,,c流线,85.3,°,,,安放角,85.3

,进口叶片厚度,,2.0,mm,,,,

,校核ψ1c,a流