離心泵設(shè)計計算

項目,,公式,結(jié)果,單位,備注,,,

基本參數(shù),流量,Q,0.30,m3/s,,,,

,揚(yáng)程,H,20.00,m,,,,

,轉(zhuǎn)速,n,1450,r/min,,,,

,裝置氣蝕余量,NPSHa,4.0,m,,,,

"泵

進(jìn)

出

口

直

徑",泵進(jìn)口直徑,Ds,250,(mm),選vs=3.5m/s,,,

,泵出口直徑,Dd,200,(mm),選Dd=0.8Ds,,,

,泵進(jìn)口速度,Vd,6.11,(m/s),,,,

,泵出口速度,Vs,9.55,(m/s),,,,

氣蝕計算,泵安裝高度,hg=10.33-0.5-0.24-[NPSH]a,5.59,(m),"常溫清水

pv/ρg=0.24m

hc=0.5m",,,

,泵氣蝕余量,NPSHr=NPSHa/1.3,3.08,(m),,,,

,泵氣蝕轉(zhuǎn)數(shù),C=5.62n√Q/NPSHr3/4,1921.2,,,,,

"比

轉(zhuǎn)

數(shù)",比轉(zhuǎn)數(shù),ns=3.65n√Q/H3/4,306.5,,,,,

"確

定

效

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

,容積效率,ηv=1/(1+0.68ns-2/3),0.99,,,,,

,圓盤損失效率,ηm'=1-0.07/(ns/100)7/6,0.98,,,,,

,機(jī)械效率,,0.98,,"假定軸承、填

料損失為2％",,,

,總效率,η=ηmηvηh,0.85,,,,,

"確

定

功

率",軸功率,P=ρgQH/1000η,69.24,(kW),,,,

,計算配套功率,P'=KP,90.01,(kW),取K=1.3,,,

,扭矩,Mn=9.55×103P'/n,592.81,(N.m),,,,

,最小軸徑,d=(Mn/0.2[τ])1/3,43.91,(mm),"選[τ]=350

×105（N/m2）",,,

,,,,,,,,,

"初

步

確

定

葉

輪

主

要

尺

寸",輪轂直徑,,40.00,(mm),,,,

,進(jìn)口當(dāng)量直徑,D0=K0(Q/n)1/3,236.6,(mm),選K0=4,,,

,葉輪進(jìn)口直徑,Dj=√(D02+dh2),239.9,,,,,

,葉輪出口寬度,"Kb2=0.64(ns/100)5/6

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

,葉輪外徑,"KD2=9.35(ns/100)-1/2

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

,葉片出口角,β2,22.50,度,,,,

,葉片數(shù),"Z=6.5(D2+D1)*

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

設(shè)β1=30。",,,

"精

算

葉

輪

外

徑

第

一

次",理論揚(yáng)程,Ht=H/ηh,22.3,(m),,,,

,修正系數(shù)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",,,

,出口葉片厚度,,3.50,(mm),,,,

,無窮葉片數(shù)理論揚(yáng)程,Ht∞=(1+P)×Ht,29.42,,,,,

,"葉片出口排

擠系數(shù)","ψ2=1-√(1+(ctgβ2/sinλ2)2

×Zδ2/πD2",0.94,,"取δ2=3.5mm

λ2=90。",,,

,出口軸面速度,vm2=Q/πD2b2ψ2ηv,3.32,(m/s),,,,

,出口圓周速度,"u2=vm2/2tgβ2+

√(vm2/2tgβ2)2+gHt∞",21.5,(m/s),,,,

,出口直徑,D2=60u2/πn,282.66,(mm),"與假定不符進(jìn)

行第二次計算

取D2=173mm",,,

"精

算

葉輪外徑第二次","葉片出口

排擠系數(shù)","ψ2=1-√(1+(ctgβ2/sinλ2)2

×Zδ2/πD2",0.90,,,,,

,出口軸面速度,vm2=Q/πD2b2ψ2ηv,6.37,(m/s),,,,

,出口圓周速度,"u2=vm2/2tgβ2+

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

,葉輪外徑,D2=60u2/πn,346.88,(mm),"與假定值接近

不在重新計算",,,

"葉

輪

出

口

速

度",出口排擠系數(shù),,0.90,,,,,

,出口軸面速度,"ψ2=1-√(1+(ctgβ2/sinλ2)2

×Zδ2/πD2

vm2=Q/πD2b2ψ2ηv",3.18,(m/s),由上述計算得,,,

,出口圓周速度,u2=πD2n/60,26.34,(m/s),,,,

,"出口圓周分

速度",vu2=gHt/u2,8.30,(m/s),,,,

,"無窮葉片數(shù)

出口圓周分速度",vu2=gHt∞/u2,10.96,(m/s),,,,

"葉

輪

進(jìn)

口

","葉輪進(jìn)口

圓周速度",90,6.83,(m/s),,,,

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

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

,"葉片進(jìn)口軸

面流速",a流線,59.82,(m/s),,,,

,,b流線,66.67,(m/s),,,,

,,c流線,73.95,(m/s),沖角=3,,,

項目,,公式,結(jié)果,單位,備注,,,

"速

度","流線葉片

進(jìn)口液流角",a流線,83.5,°,,,安放角,83.5

,,b流線,84.5,°,,,安放角,84.5

,,c流線,85.3,°,,,安放角,85.3

,進(jìn)口葉片厚度,,2.0,mm,,,,

,校核ψ1c,a流