Void diagnostics in liquid-filled pressure sensing lines

Air or gas entrapped in liquid-filled sensing lines can result in false pressure readings, sluggish response, and extraneous noise due to acoustic resonances. This work models the impact on the pressure system transfer function of voids inside sensing lines based on an equivalent pi circuit along with a lumped parameter void representation. Field test data from a fossil power plant are used to validate the simulation results. Two void indicators derived from resonant peak frequencies are also introduced to perform sensing line diagnostics.