Wednesday, 28 November 2018

CONTINUITY EQUATION

Continuity equation
  • The continuity equation is a mathematical expression for the law of conservation of mass.
  • The equation of continuity is useful for calculating the velocity of a fluid flowing through pipes of different diameters.
It states that for a steady flow system, the rate of mass entering the flow system is equal to that leaving as accumulation is either constant or nil in the flow system under steady conditions

  • Rate of mass entering the flow system = ρ1 u1 A1
  • Rate of mass entering the flow system = ρ2 u2 A2
  • According to the law of conservation of mass

Mass entering the tube = Mass leaving the tube
per unit time       per unit time



  • This is the equation of continuity.
  • It is applicable to compressible as well as incompressible fluids.
  • when ρ1 = ρ2

where
Continuity equation