理想液體：既無(wú)粘性又不可壓縮的液體 恒定流動(dòng)（穩(wěn)定流動(dòng)、定常流動(dòng)）：流動(dòng)液體中的任一點(diǎn)p，u和ρ流不會(huì)隨時(shí)間而變化流動(dòng). 流線—某一瞬時(shí)液流中各處質(zhì)點(diǎn)運(yùn)動(dòng)狀態(tài)的一 條條曲線 流束—通過(guò)某截面上所有各點(diǎn)作出的流線集合構(gòu)成流束 有與流線正交的截面(垂直于液體流動(dòng)方向的截面) 流量—單位時(shí)間內(nèi)流過(guò)某通流截面液體體積qdq=v/t=udA 整個(gè)過(guò)流段流量：q=∫AudA 平均流速—通流截面上各點(diǎn)均勻分布假想流速 q=vA=∫AudA v=q/A液壓缸的運(yùn)動(dòng)速度取決于進(jìn)入液壓缸的流量，并且隨著流量的變化而變化。
連續(xù)性原理-當(dāng)理想液體在管道中恒定流動(dòng)時(shí)，根據(jù)質(zhì)量守恒定律，管道中的液體既不能增加也不能減少因此，在單位時(shí)間內(nèi)流入液體的質(zhì)量應(yīng)與流出液體的質(zhì)量相等 結(jié)論：當(dāng)液體在管道中流動(dòng)時(shí)，流過(guò)各段的流量相等，因此流量與流過(guò)段成反比。
能量守恒定律：當(dāng)理想液體在管道中穩(wěn)定流動(dòng)時(shí)，根據(jù)能量守恒定律，同一管道任何一段的總能量應(yīng)相等 或者：外力對(duì)物體的作用應(yīng)等于物體機(jī)械能的變化 理想液體伯努利方程 1外力對(duì)液體所做的功 W=p1A1v1dt-p2A2v2dt=(p1-p2)?V2機(jī)械能的變化量位能的變化量：?Ep=mg?h=ρg?V(z2-z1) 動(dòng)能的變化量：?Ek=m?v2/2=ρ?V(v22-v21)/2 根據(jù)能量守恒定律，有：W=?Ep+?Ek (p1-p2)?V=ρg?V(z2-z1)+ρ?V(v22-v21)/2 整理后得單位重量理想液體伯努利方程為：p1+ρgZ1+ρv12/2=p2+ρgZ2+ρv22/2 或p/ρg+Z+v2/2g=C（c為常數(shù))理想液體伯努利方程的物理意義:在封閉管道中恒定流動(dòng)的理想液體有壓力能、位能和動(dòng)能三種形式。
在流動(dòng)過(guò)程中，三種能量可以相互轉(zhuǎn)化，但三種能量之和恒定在每個(gè)過(guò)流截面上 實(shí)際液體伯努利方程 ∵實(shí)際液體具有粘性 ∴液體流動(dòng)時(shí)會(huì)產(chǎn)生內(nèi)摩擦力，從而損耗能量 故應(yīng)考慮能量損失hw，并考慮動(dòng)能修正系數(shù) ,則實(shí)際液體伯努利方程為： p1/ρg+Z1+α1v12/2g=p2/ρg+Z2+α2v22/2g+hw層流α=2 紊流α=1 p1-p2=△p=ρghw應(yīng)用伯努利方程時(shí)必須注意的問(wèn)題 （1）斷面1、2需順流向選?。ǚ駝thw為負(fù) 值），且應(yīng)選在緩變的過(guò)流斷面上。
（2）斷面中心在基準(zhǔn)面以上時(shí)，z取正值；反之取負(fù)值通常選取特殊位置的水 平面作為基準(zhǔn)面動(dòng)量定理：作用在物體上的外力等于物體單位時(shí) 間內(nèi)動(dòng)量的變化量即∑F=d（mv）/dt X向動(dòng)量方程：∑Fx=ρq(β2v2x-β1v1x) X向穩(wěn)態(tài)液動(dòng)力：F'x=-∑Fx=ρq(β1v1x-β2v2x) 結(jié)論：作用于滑閥閥芯的穩(wěn)態(tài)液動(dòng)力總是試圖關(guān)閉閥口。
90-L-055-HS-1-AB-60-P-4-S1-C-03-GBA-32-14-30 90L055HS1AB60P4S1C03GBA321430 90-L-055-HS-1-BC-60-P-3-S1-C-03-GBA-17-17-24 90L055HS1BC60P3S1C03GBA171724 90-L-055-HS-1-BC-60-P-4-S1-C-03-GBA-35-35-24 90L055HS1BC60P4S1C03GBA353524 90-L-055-HS-1-BC-60-R-3-S1-D-03-GBA-42-42-30 90L055HS1BC60R3S1D03GBA424230 90-L-055-HS-1-BC-60-R-4-S1-C-03-GBA-42-42-24 90L055HS1BC60R4S1C03GBA424224 90-L-055-HS-1-BC-60-R-4-S1-D-03-GBA-26-26-24 90L055HS1BC60R4S1D03GBA262624 90-L-055-HS-1-BC-80-P-4-S1-C-03-GBA-35-35-24 90L055HS1BC80P4S1C03GBA353524 90-L-055-HS-1-BC-80-P-4-S1-C-09-GBA-35-35-24 90L055HS1BC80P4S1C09GBA353524 90-L-055-HS-1-BC-80-P-4-S1-D-09-GBA-35-35-30 90L055HS1BC80P4S1D09GBA353530 90-L-055-HS-1-BC-80-R-4-S1-C-03-GBA-35-35-24 90L055HS1BC80R4S1C03GBA353524 90-L-055-HS-1-BC-80-S-4-S1-C-03-GBA-26-26-24 90L055HS1BC80S4S1C03GBA262624 90-L-055-HS-1-CD-60-L-3-S1-D-02-GBA-42-42-24 90L055HS1CD60L3S1D02GBA424224 90-L-055-HS-1-CD-60-P-3-S1-C-03-GBA-23-23-24 90L055HS1CD60P3S1C03GBA232324 90-L-055-HS-1-CD-60-P-3-S1-C-03-GBA-32-32-24 90L055HS1CD60P3S1C03GBA323224 90-L-055-HS-1-CD-80-L-3-S1-C-02-GBA-42-42-24 90L055HS1CD80L3S1C02GBA424224 90-L-055-HS-1-CD-80-L-3-S1-D-02-GBA-42-42-24 90L055HS1CD80L3S1D02GBA424224 90-L-055-HS-1-CD-80-P-3-C6-D-02-GBA-29-29-24 90L055HS1CD80P3C6D02GBA292924 90-L-055-HS-1-CD-80-P-4-S1-C-02-GBA-42-42-20 90L055HS1CD80P4S1C02GBA424220 90-L-055-HS-1-CD-80-S-4-S1-C-00-GBA-32-32-24 90L055HS1CD80S4S1C00GBA323224 90-L-055-HS-1-NN-60-L-3-S1-D-03-GBA-32-32-24 90L055HS1NN60L3S1D03GBA323224 90-L-055-HS-1-NN-60-P-3-S1-C-03-GBA-20-20-24 90L055HS1NN60P3S1C03GBA202024 90-L-055-HS-1-NN-60-P-3-S1-C-03-GBA-23-23-24 90L055HS1NN60P3S1C03GBA232324 90-L-055-HS-1-NN-60-P-3-S1-C-03-GBA-32-14-24 90L055HS1NN60P3S1C03GBA321424 90-L-055-HS-1-NN-60-P-4-S1-C-03-GBA-32-14-30 90L055HS1NN60P4S1C03GBA321430 90-L-055-HS-1-NN-60-P-4-S1-C-03-GBA-32-17-30 90L055HS1NN60P4S1C03GBA321730 90-L-055-HS-1-NN-60-S-4-S1-C-03-GBA-35-35-24 90L055HS1NN60S4S1C03GBA353524 90-L-055-HS-1-NN-80-P-3-C6-C-03-GBA-38-38-24 90L055HS1NN80P3C6C03GBA383824 90-L-055-HS-1-NN-80-P-3-S1-D-03-GBA-26-26-24 90L055HS1NN80P3S1D03GBA262624 90-L-055-HS-1-NN-80-P-4-S1-C-03-GBA-35-35-24 90L055HS1NN80P4S1C03GBA353524 90-L-055-HS-1-NN-80-P-4-S1-D-03-GBA-35-35-24 90L055HS1NN80P4S1D03GBA353524 90-L-055-HS-1-NN-80-R-3-S1-C-03-GBA-26-26-24 90L055HS1NN80R3S1C03GBA262624 90-L-055-HS-1-NN-80-R-3-S1-C-03-GBA-38-38-24 90L055HS1NN80R3S1C03GBA383824 90-L-055-HS-1-NN-80-R-4-S1-C-03-GBA-38-38-24 90L055HS1NN80R4S1C03GBA383824 90-L-055-HS-1-NN-80-R-4-S1-D-03-GBA-26-26-24 90L055HS1NN80R4S1D03GBA262624 90-L-055-HS-2-CD-80-P-3-C6-C-03-GBA-38-38-24 90L055HS2CD80P3C6C03GBA383824 90-L-055-HS-2-CD-80-P-3-C6-C-03-GBA-42-42-24 90L055HS2CD80P3C6C03GBA424224 90-L-055-HS-2-CD-80-P-3-S1-C-03-GBA-42-42-24 90L055HS2CD80P3S1C03GBA424224 90-L-055-HS-2-NN-80-P-3-C6-C-03-GBA-38-38-24 90L055HS2NN80P3C6C03GBA383824 90-L-055-HS-2-NN-80-P-3-S1-C-03-GBA-38-38-24 90L055HS2NN80P3S1C03GBA383824 90-L-055-HS-2-NN-80-P-3-S1-C-03-GBA-42-42-24 90L055HS2NN80P3S1C03GBA424224 90-L-055-HS-5-AB-60-P-4-S1-B-03-GBA-42-42-24 90L055HS5AB60P4S1B03GBA424224 90-L-055-HS-5-AB-80-S-3-S1-C-03-GBA-42-17-20 90L055HS5AB80S3S1C03GBA421720 90-L-055-HS-5-AB-80-S-4-S1-C-03-GBA-26-26-24 90L055HS5AB80S4S1C03GBA262624 90-L-055-HS-5-BC-80-R-3-S1-D-02-GBA-42-42-24 90L055HS5BC80R3S1D02GBA424224 90-L-055-HS-5-BC-80-S-4-S1-C-03-GBA-26-26-24 90L055HS5BC80S4S1C03GBA262624 90-L-055-HS-5-CD-80-L-3-S1-C-03-GBA-32-32-28 90L055HS5CD80L3S1C03GBA323228 90-L-055-HS-5-CD-80-L-4-S1-C-04-GBA-35-35-24 90L055HS5CD80L4S1C04GBA353524 90-L-055-HS-5-CD-80-S-3-S1-C-02-GBA-26-26-24 90L055HS5CD80S3S1C02GBA262624 90-L-055-HS-5-CD-80-S-3-S1-C-03-GBA-26-26-24 90L055HS5CD80S3S1C03GBA262624 90-L-055-HS-5-CD-80-S-4-S1-C-03-GBA-26-26-24 90L055HS5CD80S4S1C03GBA262624 90-L-055-HS-5-NN-60-P-4-S1-D-06-GBA-42-42-24 90L055HS5NN60P4S1D06GBA424224 90-L-055-HS-5-NN-60-R-4-S1-C-03-GBA-26-26-24 90L055HS5NN60R4S1C03GBA262624 90-L-055-HS-5-NN-60-R-4-S1-C-03-GBA-38-38-32 90L055HS5NN60R4S1C03GBA383832 90-L-055-HS-5-NN-60-R-4-S1-D-06-GBA-42-42-24 90L055HS5NN60R4S1D06GBA424224 90-L-055-HS-5-NN-80-L-3-S1-C-03-GBA-35-35-24 90L055HS5NN80L3S1C03GBA353524 90-L-055-HS-5-NN-80-R-4-S1-D-03-GBA-35-35-24 90L055HS5NN80R4S1D03GBA353524 90-L-055-HS-5-NN-80-R-4-S1-D-06-GBA-26-26-24 90L055HS5NN80R4S1D06GBA262624 90-L-055-HS-5-NN-80-S-3-S1-C-03-GBA-26-26-24 90L055HS5NN80S3S1C03GBA262624 90-L-055-HS-5-NN-80-S-4-S1-C-03-GBA-26-26-24 90L055HS5NN80S4S1C03GBA262624。
