A probe 10,170 is provided that measures the
speed of sound and / or vortical disturbances propagating in a
single phase fluid flow and / or multiphase mixture to determine parameters, such as mixture quality, particle size, vapor /
mass ratio, liquid / vapor ratio,
mass flow rate,
enthalpy and volumetric flow rate of the flow in a
pipe or unconfined space, for example, using acoustic and / or dynamic pressures. The probe includes a spatial array of unsteady pressure sensors 15-18 placed at predetermined axial locations x1-xN disposed axially along a tube 14. For measuring at least one parameter of a saturated vapor / liquid mixture 12, such as steam, flowing in the tube 14. The pressure sensors 15-18 provide acoustic pressure signals P1(t)-PN(t) to a
signal processing unit 30 which determines the
speed of sound amix propagating through of the saturated vapor / liquid mixture 12 in the tube 14 using acoustic spatial array
signal processing techniques. Frequency based sound speed is determined utilizing a dispersion model to determine the parameters of interest.