1—1解:1)基本计算吸入管过流断面面积:32210854.71.044-⨯=⨯==ππD A吸入管内平均流速:s m A Q /203.110854.73600343=⨯⨯==-υ, 吸入管的沿程损失:m g d L h 266.08.92203.11.01802.0222=⨯⨯⨯=⨯⨯=υλ 2)求泵入口处的压强设吸水池液面为1—1断面,泵入口处为2-2断面。
根据伯努里方程,有:h gg p H g p g +++=222211υρρ Pah g Hg g p p 5552522112105485.0104645.010013.1266.08.92203.14.48.9100010013.12⨯=⨯-⨯=⎪⎪⎭⎫ ⎝⎛+⨯+⨯⨯-⨯=⎪⎪⎭⎫ ⎝⎛++-=υρ mmHg H 46.34854.41176028.133105485.07605=-=⨯-=真O mmH O mH p H 22525597597.59800105485.09800==⨯==1—2解:设泵入口处为1-1断面,泵出口处为2-2断面。
根据伯努里方程,有:gg p z H g g p z 2222222111υρυρ++=+++入口和排出管径相同,有21υυ=。
gp g p z z H ρρ1212-+-= Pa p 613168.9136003.010013.151=⨯⨯-⨯=Pa p 24840014710010013.152=+⨯=m H 95.258.9750613162484005.0=⨯-+=1-3解:吸水管内平均流速:s m d Q/183.31.04025.042211=⨯==ππυ排出管内平均流速:s m d Q/659.5075.04025.042222=⨯==ππυ设泵入口处为1—1断面,泵出口处为2—2断面。
根据伯努里方程,有:gg p z H g g p z 2222222111υρυρ++=+++泵的扬程为:()mgg p p z z H 955.388.92183.3659.58.91000103924.0102373.38.02225521221212=⨯-+⨯⨯--⨯+=-+-+-=υυρ 泵的有效功率:kW gQH N e 544.91000955.38025.08.910001000=⨯⨯⨯==ρ泵的轴功率:kW N N 625.115.1293.0=⨯==电电轴η泵的效率:82.0625.11544.9===轴泵N N e η 1-4解:设吸水罐液面为1—1断面,排水罐液面为2-2断面。
根据伯努里方程,有:hw gg p H H H H g g p z m ++++=++++222223212111υρυρ由于吸水罐液面和排水罐液面稳定,021==υυ。
吸入和排出管路总水力损失为:m g p h h h d s w 818.1908.98501372930251=⨯++=∆++=ρ因此,泵的扬程为:hw gp p H H H H m +-+-+=ρ12132 m813.198818.1908.910001961337.1764798414=+⨯-+-+= 1—5解:1)当泵流量h m Q T /2.73=时s m n D u /82.136********.06022=⨯⨯==ππs m B D Q c T r /555.036009.0007.0182.02.72222=⨯⨯⨯⨯==πτπs m ctg ctg c u c A r u /856.1230555.082.1302222=⨯-=-=∞βm c u g H u T 13.18856.1282.138.91122=⨯⨯==∞∞ 2)当泵流量h m Q T /8.283=时s m B D Q c T r /221.236009.0007.0182.08.282222=⨯⨯⨯⨯=='πτπs m ctg ctg c u c A r u /975.93022.282.1302222=⨯-=-='∞β m c u g H u T067.14975.982.138.91122=⨯⨯=='∞∞ 3)画出两种流量时叶轮出口的速度三角形(略)随流量T Q 的增大,r c 2增加,u c 2减小,∞T H 下降。
1-6解:sm nD u /406.3360290022.06022=⨯⨯==ππs m B D Q c T r /617.301.022.0025.0222=⨯⨯==∞ππs m c w A r /655.922sin 617.3sin 0222===∞∞βs m c u c A r u /454.2422cot 617.3406.33cot 02222=⨯-=-=∞∞β0222413.8454.24617.3arctan arctan===∞∞∞u r c c α ()()s m c c c r u /72.24617.3454.242222222=+=+=∞m c u g H r T 357.83454.24406.338.91122=⨯⨯==∞∞ 1—7解:1)求圆周速度和堵塞系数s m nD u /295.2460145032.06022=⨯⨯==ππ938.029sin 32.0005.061sin 102222=⨯⨯⨯-=-=πβπδτA D z s m nD u /3.12601450162.06011=⨯⨯==ππ809.018sin 162.0005.061sin 101111=⨯⨯⨯-=-=πβπδτA D z2)求理论流量由于进口无旋,液体沿径向进入叶片流道,0190=α。
由进口速度三角形得;s m u c A r /997.318tan 3.12tan 0111=⨯==βs m c b D Q r T /054.0997.3809.0033.0162.031111=⨯⨯⨯⨯==πτπ3)求理论扬程考虑叶片数和叶片厚度对扬程的影响,确定扬程修正系数ψ和滑移系数μ,即()()89.029sin 16.0sin 16.002=+⨯=+=A βψ715.032016211689.0211112112221=⎪⎭⎫⎝⎛-•⨯+=⎪⎪⎭⎫ ⎝⎛-•+=r r z ψμs m B D Q c T r /031.3938.0019.032.0054.02222=⨯⨯⨯==πτπ()()mc u u g H A r T 37.3329cot 031.3295.24295.24715.08.91cot 102222=⨯-⨯⨯⨯=-=βμ 4)估计泵的流量、扬程和轴功率s m Q Q T v /0513.0054.095.03=⨯==ηmH H T h 034.3037.339.0=⨯==ηkW gQHN e 1.151000034.300513.08.910001000=⨯⨯⨯==ρkW N N e 415.1882.01.15===η1-8解:1)求作出口速度三角形和∞T Hs m n D u /327.3460298022.06022=⨯⨯==ππs m c w A r /091.545sin 6.3sin 0222===∞∞β s m c u c A r u /727.3045cot 6.3327.34cot 02222=⨯-=-=∞∞β()()s m c c c u r /937.30727.306.32222222=+=+=∞∞()()mc u u gH A r T 629.10745cot 6.3327.34327.348.91cot 102222=⨯-⨯⨯=-=∞β 2)求T H考虑叶片数和叶片厚度对扬程的影响,确定扬程修正系数ψ和滑移系数μ,即()()024.145sin 16.0sin 16.002=+⨯=+=A βψ()7455.05.0118024.1211112112221=-•⨯+=⎪⎪⎭⎫⎝⎛-•+=r r z ψμm H H T T 24.80629.1077455.0=⨯==∞μ1—9证明:因dyn pot T H H H +=dyn T pot H H H -=因()gc H u dyn 222=,所以()()()()()()()⎪⎪⎭⎫⎝⎛-=-=-=-=2222222222222221222u gH H u H g H g u c u g H gc H H T T T T u T u T pot又因hT T h HH H H ηη=⇒=,所以()⎪⎪⎭⎫ ⎝⎛-=h h pot u gH H H ηη2221 1—10解:1)求泵的有效率功率e NkW gQH N e 96.759610001367.58.910001000=⨯⨯⨯==ρ2)求泵的总效率η7705.0986096.7596===N N e η 3)求泵的水力效率h η91.092.092.07705.0=⨯==⇒=m v h h m v ηηηηηηηη 1—11解:根据相似理论,有s m nn D D Q Q /68.029*********.0333=⨯⨯='⎪⎭⎫ ⎝⎛'='m n n D D H H 1002900145021002222=⎪⎭⎫ ⎝⎛⨯⨯=⎪⎭⎫ ⎝⎛'⎪⎭⎫ ⎝⎛'='kW n n D D N N 2.7352900145028.1833525=⎪⎭⎫⎝⎛⨯⨯=⎪⎭⎫ ⎝⎛'⎪⎭⎫ ⎝⎛'='1-12解:根据比例定律,有min /2175355.521450r Q Q n n n n Q Q =⨯='='⇒'=' m n n H H 5.139145021756222=⎪⎭⎫ ⎝⎛⨯=⎪⎭⎫ ⎝⎛'='kW n n N N 65.25145021756.732=⎪⎭⎫ ⎝⎛⨯=⎪⎭⎫ ⎝⎛'='1-13解:1)求作转速min /2320r 时泵的性能参数和曲线根据等比定律:⎪⎭⎫ ⎝⎛'='n n Q Q 2⎪⎭⎫ ⎝⎛'='n n H H 3⎪⎭⎫ ⎝⎛'='n n N N将转速min /2900r2)求泵的转速根据相似抛物线得2222203125.04050Q Q Q Q H H ==''=(1)转速min /2900r 时泵的流量—扬程回归方程为:200402.00299.068Q Q H -+=(2)将式(1)代入(2),整理得003527.00299.0682=-+Q Qh m Q /33.4403527.026803527.040299.00299.032=⨯-⨯⨯+--=m Q Q H 424.6133.4400402.033.440299.06800402.00299.06822=⨯-⨯+=-+=m in .261733.44402900r Q Q n n =⨯='='1—14解:根据相似理论,有2623⎪⎭⎫⎝⎛'⎪⎭⎫ ⎝⎛'=⎪⎪⎭⎫ ⎝⎛'⇒'⎪⎭⎫ ⎝⎛'='n n D D Q Q n n D D Q Q (1) 66322⎪⎭⎫⎝⎛'⎪⎭⎫ ⎝⎛'=⎪⎭⎫ ⎝⎛'⇒⎪⎭⎫ ⎝⎛'⎪⎭⎫ ⎝⎛'='n n D D H H n n D D H H (2) 因此,将式(2)/(1),得min /79.10695.938120802900423423423r Q Q H H nn n n Q Q H H =⎪⎭⎫ ⎝⎛⎪⎭⎫ ⎝⎛=⎪⎪⎭⎫ ⎝⎛'⎪⎭⎫ ⎝⎛'='⇒⎪⎭⎫ ⎝⎛'=⎪⎪⎭⎫⎝⎛'⎪⎭⎫⎝⎛'1-15解:1)求泵在min /2900r 时的比转速min /32.584280360064290065.365.34343r i H Q n n s =⎪⎭⎫ ⎝⎛⨯⨯=⎪⎭⎫⎝⎛=泵为低比转速泵2)求泵在min /1450r 时的比转速h m n n Q Q /3229001450643=⨯=⎪⎭⎫⎝⎛'='m n n H H 702900145028022=⎪⎭⎫⎝⎛⨯=⎪⎭⎫ ⎝⎛'='min /32.58470360032145065.365.34343r i H Q n n s =⎪⎭⎫ ⎝⎛⨯⨯=⎪⎭⎫ ⎝⎛''=' 1—16解:由于9.0933.0268250>=='D D ,根据叶轮切割理论,有sL D D Q Q /694.7326825079=⨯='='m D D H H 663.152********2=⎪⎭⎫⎝⎛⨯=⎪⎭⎫ ⎝⎛'='kW D D N N 475.132682506.1633=⎪⎭⎫ ⎝⎛⨯=⎪⎭⎫ ⎝⎛'='转速min /1450r ,效率84.0=η。