Δh = h 2 - h 1 = height difference (fluid column) (4) can be modified by dividing with specific weight γ toĬ = coefficient - depending on reference liquid and units used or calculated It is common to use head instead of pressure. With (4) it's possible to calculate the flow velocity in point 1 - the free flow upstream - if we know the differential pressure difference Δp = p 2 - p 1 and the density of the fluid. Since v 2 is zero, (2) can be modified to: In a measuring point we regard the hydrostatic pressure as a constant where h 1 = h 2 - and this part can be eliminated. Suffix 2 is the stagnation point where the velocity in the flow is zero Flow Velocity Suffix 1 is a point in the free flow upstream The Bernoulli Equation states that the energy along a streamline is constant - and can be modified to It represent the pressure due to change in elevation. The third term - γ h - is called the hydrostatic pressure. The second term - 1/2 ρ v 2 - is called the dynamic pressure. It is static relative to the moving fluid and can be measured through a flat opening in parallel to the flow. The first term - p - is the static pressure. P = static pressure (relative to the moving fluid) (Pa)Įach term of the equation has the dimension force per unit area N/m 2 (Pa) - or in imperial units lb/ft 2 (psi). The principle is based on the Bernoulli Equation where each term of the equation can be interpreted as pressure A pitot tube can be used to measure fluid flow velocity by converting the kinetic energy in a fluid flow to potential energy.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |