Download - 第二章 液压传动 流体力学基础
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1(1) () =m/V kg/m3 2020C () =G/V= g N/m3m(kg)() V(m3)g (m/s2)
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(2) ()2-1 F=Adu/dy =F/A =du/dy
2-1
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A( ) =F/A*du/dy N s/m2Pa.sB = / m 2/s St(cm 2/s) cSt St(mm 2/s) 1 m 2/s=104 St=106 cSt=106m m2/s 40CcSt N3250C
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C t t=t1/t2 (t1t220C) E=[1E1+2E2-c(E1-E2)]/100 12c 1.35E3.2 =(8E-8.64/E)10-6 E>3.2 =(7.6E-4/E) 10-6
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2 p= 1+0.003PpP101.33kPa, ,3: 2-2:
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2-2 2-2
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VIVIVI901.
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2. 3. ,,,
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()
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4.
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5. : GB/T14039-93NAS1638
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1. p=F/A : qvPaKPaMPa2.
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1 p=po +ghpogh 2-3
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22-4
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1. =+ =
2. Pa
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:2-6
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1. : F=pA=pD2/4 2. 2-7
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1()2-8
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2(qv) qv=V/t : m3/s , L/min(v)v=qv/A : m/s , m/min,,(qm):3
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1. 1v1A1= 2v2A22. q 1=q2 v 1A 1=v 2A 2 2-9
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1.
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2. 12
1212hw
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2-10
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1. ::
m=Vq=V/t
FFxFy
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2. F,X
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/ =64/Re, Re
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=p1/pp=(pp-p)/pp=1-p/pp
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1. l/d 0.5;D>>d, 1-1 v10; 2-2 2=1;,
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2. :
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=64/Re=64/(dv)v=4q/d2 ::
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KK=d2/32lm 0.51
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