HYDRAULICS 11

HYDRAULICS 11: ORIFICE PREPARED BY: ENGR. BILLY I. REJUSO ORIFICE - Is an opening with a closed perimeter through which fluid flows. - Orifice can be in circular, square or rectangular in cross-section.

Sample Problem: 1. A 75 mm Ø orifice discharges 0.023 m3/s of liquid under a head of 2.9m. The diameter of a jet at vena contracta is found to be 66.5m. Determine the following: A. Coefficient of Discharge B. Coefficient of Contraction C. Coefficient of Velocity

2. An orifice having an area of 0.00785m2 is attached to a vertical side of a cylindrical tank having a diameter of 4m. The weight of water discharged in 1 min and 40 sec is 22563N under a constant head of 1.2m. The jet strikes at a point 1.92m horizontally from the vena contracta and 0.8m vertically below the orifice. Compute for the following: A. CV B. C C. Cc

3. Water flows through an orifice at the vertical side of a large tank under a constant head of 2.4m. How far horizontally from the vena contracta will the jet strikes the ground 1.5m below the orifice?

4. A 50-mm diameter circular sharp-edged orifice at the side of a tank discharges water under a head of 3m. If the coefficient of contraction CC=0.63 and the head lost is 240mm, compute for the discharge and the coefficients of velocity CV and discharge C.

5. A calibration test of a 12.5-mm diameter circular sharp-edged orifice in a vertical side of a large tank showed a discharge of 590N of water in 81 seconds at a constant head of 4.70m. Measurement of the jet showed that it traveled 2.35m horizontally while dropping 300mm. Compute the three orifice coefficients.