Flow Conditioner Location Effects in Orifice Flowmeters

摘要

Tests sponsored by Gas Research Institute were conducted with orifice flowmetersof two nominal sizes: 104 mm (4 in) and 52 mm (2 in). For the 104 mm orifice meter the authors compared discharge coefficients measured in two common piping configurations used by laboratories to establish baseline flow conditions. The discharge coefficients are similar for beta ratios of 0.43, 0.55, and 0.67, but not for the 0.73 beta ratio plate. For other tests with the orifice meter, a 90 degree elbow or a reducer was located upstream of the orifice plate and flow conditioner. Two beta ratios (0.54, 0.67) were tested in the 52 mm orifice meter in baseline configuration and with an elbow at 17D and a flow conditioner at 12D. For many of the tests, differential pressures were measured at more than one flange tap location. Placing the flow conditioner too close to the orifice plate in either meter yields discharge coefficients below baseline values. The location of the flow conditioner with respect to the orifice plate appears to influence meter performance more significantly than the type or location of flow disturbance upstream of it.