φ-mβ=dm/dm=1 ∑(nA1)m=∑(P,A1)m∑(m)m=(m)om Conservation of mass(质量守恒)( Continuity Equation) φ-mVβ=d(mV/dm=Ⅴ Fx= ri(v2x-vix) ∑ am m(out-v dt 2 2-out 1-in The Linear Momentum Equation(动量方程) Newton's Second Law Coordinate Control Volumef=m =dm/dm=1 ( ) ( ) out in i i i i i i i i    AV V =  A ( ) ( ) i in i out i i   m m = Conservation of mass (质量守恒) (Continuity Equation) f=mV =d(mV)/dm=V ) ( ) ( s out in d mV F m V V dt  = = − 2－out, 1－ in F m V V x x x = − ( ) 2 1 F m V V y y y = − ( ) 2 1 F m V V z z z = − ( ) 2 1  o x y z The Linear Momentum Equation (动量方程) （ Newton’s Second Law ） * Coordinate , Control Volume