If there are several one-D inlets and outlets: dd ∑(月41)m-∑(月pA Steady, 1-D only in inlets and outlets, no matter how the flow is within the Cv 33 Conservation of mass(质量守恒) (Continuity Equation) O=m B=dm/dm ∑(A1om-(OA)m=0 Σ(P,A1)=E(P,A)m∑(m)m=∑(m2) out Mass fluⅹ(质量流量m)If there are several one-D inlets and outlets : ( ) ( ) s out i i i i i i i i in i i d AV AV dt      = −   Steady , 1-D only in inlets and outlets, no matter how the flow is within the CV . 3.3 Conservation of mass (质量守恒) (Continuity Equation) f=m =dm/dm=1 ( ) ( ) 0 s out in i i i i i i i i dm A A V V dt = − =     ( ) ( ) out in i i i i i i i i    AV V =  A ( ) ( ) i in i out i i   m m = Mass flux (质量流量 m )