Work for a CV Energy transfers can occur by heat and work dE。=Q-w Control volume dt 2 + 2 + Exit e -Dashed line defines the control volume boundary Net rate of work across the boundary (1)Fluid pressure as mass flow (2)All other work “+” (peAe)Ve-（pA)V; We (p--pressure,A--area,V-velocity) AV riw Specific volume W=Wev+m(p)-m,D四 Mass flow rate Flow work 上游气通大粤 Mar/20,Mon,2017 3 SHANGHAI JLAO TONG UNIVERSITYMar/20, Mon, 2017 3 Work for a CV Net rate of work across the boundary (1) Fluid pressure as mass flow (2) All other work Wcv (p--pressure, A--area, V– velocity) “+” “-” Mass flow rate Specific volume Flow work