Mass Flow Rate (m ):
In absence of any mass getting stored system we can write; Mass flow rate at inlet = Mass flow rate at outlet
That is, m_{f1} = m_{f2}
as m_{f} = density X volume flow rate = density X Area X velocity = .A.V
1.A_{1}.V_{1} = 2.A_{2}.V_{2}
or, m_{f} = A_{1}.V_{1}/ 1 = A_{2}.V_{2}/ ν_{2}; Where: ν_{1}, ν_{2} = specific volume
Q. 13: Derive steady flow energy equation
Sol: Since the steady flow process is that in which the condition of fluid flow within a control volume do not vary with time, that is the mass flow rate, volume, pressure, work and rate of heat transfer are not the function of time.
That is, for steady flow
(dm/dt)_{entrance} = (dm/dt)_{exit} ;
that is, dm/dt = constant
dP/dt = dV/dt = d /dt = dE_{chemical} = 0