This paper presented discharge coefficients of the expanded holes at inlet and outlet with plane angles of 20°

45°

90°

radial angles of 0°

30°

65° and the ratios of pitch to diameter of 2

3

4.The momentum flux ratios varied in the range from 1 to 8.The results show that discharge coefficients of radial angle =0° increase significantly when the plane angles increase from 20° to 90°.The effect of plane angle becomes weak with the increasing radial angles.Radial angles have weak influence on the discharge coefficients of plane angle=20° and discharges coefficients of plane angle=45°and plane angle=90° decreases when the radial angles increase from 0° to 65°.Discharge coefficients of plane angle=90°increase when the ratios of hole pitch to the diameter increase from 2 to 4.