In steady-state operation, the accumulation term in the general balance equation is what?

In steady-state operation, the accumulation term in the general balance equation is what?

• A. It is positive
• B. It is negative
• C. It depends on the system
• D. It is zero

Answer: (D)

In steady-state operation, there is no net change in the amount stored within the control volume over time. The accumulation term represents the rate at which quantity (mass or energy) is being stored inside the system. If nothing is accumulating, that rate is zero, so the accumulation term vanishes. This is why, in steady state, the balance reduces to inflows minus outflows (plus any generation or consumption) balancing without a changing storage term.

In steady-state operation, there is no net change in the amount stored within the control volume over time. The accumulation term represents the rate at which quantity (mass or energy) is being stored inside the system. If nothing is accumulating, that rate is zero, so the accumulation term vanishes. This is why, in steady state, the balance reduces to inflows minus outflows (plus any generation or consumption) balancing without a changing storage term.