conservation of mass principle min=50 kg Dashed line defines the control volume mi boundary One-inlet,one-exit control volume system mev(t) > me Inlet i mcv(t+△t)-mev(t) mi me Exit e △t △t △t At time t time rate of change of time rate of flow time rate of flow mass contained within of mass in across of mass out across the control volume at time t inlet i at time t exit e at time t Multi-streams dmev At time t: dt mi me → L Mass flow rate (SI units:kg/s) 上游充通大 Mar/15,Wed,2017 4 SHANGHAI JIAO TONG UNIVERSITYMar/15, Wed, 2017 4 conservation of mass principle At time t mcv(t) mi me At time t: Mass flow rate (SI units: kg/s) Multi-streams One-inlet, one-exit control volume system