① Control surface Control volume P A h2 ds Fig 10.5 Finite control volume for quasi-one-dimensional flow 准一维流有限控制体
Fig.10.5 Finite control volume for quasi-one-dimensional flow 准一维流有限控制体 1 1 h 2 2 h
·dS V·dS=0 Controf surface Control volume y =p2242 x Fig 10.5 Finite control volume for quasi-one-dimensional flow 连续方程: pV ds=0 P1141=P22 (10.1)
Fig.10.5 Finite control volume for quasi-one-dimensional flow •连续方程: 1 u1 A1 = 2 u2 A2 (10.1) = S V dS 0 V •dS = 0 1 1 1 1 u A A = − • V d S 2 2 2 2 u A A = • V d S
动量方程 在定常、无粘、忽略体积力作用的假设下,积分 形式的动量方程可以写成: (pv edsy=pds (10.2) 对应方向分量·4M=ad)m0
•动量方程 在定常、无粘、忽略体积力作用的假设下, 积分 形式的动量方程可以写成： • = S V d S V - pd S S ( ) ( ) • = S x S (V d S )u - pd S (10.2) 对应x方向分量： (10.3)
V·dS=0 Controler Control volume y A1 (pv·dSu=pu1(-A1)1 PV·dSm=p2(+A2) A1 2 f11 Fig 10.5 Finite control volume for quasi-one-dimensional flow
Fig.10.5 Finite control volume for quasi-one-dimensional flow 1 2 1 1 1 1 1 ( ) ( ) 1 u A u u A u A = − • = − V d S 2 2 2 2 2 2 2 ( ) ( ) 2 u A u u A u A = • = + V d S ( )u的积分: V •dS = 0 S V •d S
」(pods 」(pos) -(P2)(A2)=-p2A2 (P1)(-A1)=P1A1 Control surface S Control volume y A1 A (pds) (pds)=-pda Fig 10.5 Finite control volume for quasi-one-dimensional flow
Fig.10.5 Finite control volume for quasi-one-dimensional flow ( ) 1 1 1 1 ( p )( A ) p A p x = − − = A1 - d S ( ) 2 2 2 2 ( p )(A ) p A p x = − = − A 2 - d S − = − − = 2 1 2 1 ( ) A A A A A x pdS pdA pdA u l ( pdS) x = −pdA ( ) 的积分: S x - pd S α dA α dS dS