This equation is based on the law of conservation of
mass. For a fluid flowing through the pipe having
single inlet and single outlet, the flow rate of
fluid at all the cross sections is constant.
i.e. mass flow rate at inlet = mass flow rate at
outlet
(ρ A V)_{inlet} = (ρ A V)_{outlet}
If
the fluid is incompressible then
(A
V)_{inlet} = (A V)_{outlet}
Where ‘A’ is Area of cross section, ‘V’ is Velocity of
fluid and ‘ρ’ is density of fluid.
