Apparatus and method for characterizing two phase fluid flow

An apparatus for determining at least one fluid property of a two phase fluid, the apparatus comprising:

• a conduit providing a fluid pathway for the two phase fluid;
• a restriction element operably disposed inside said conduit for restricting flow of the two phase fluid therethrough:
• means for measuring pressure of the two phase fluid downstream of the restriction element;
• means for measuring temperature of the two phase fluid flowing through said conduit downstream of the restriction element;
• means for measuring time of flight of sonic pulses within the two phase fluid flowing through said conduit downstream of the restriction element:
• means for calculating the speed of sound within the two phase fluid flowing through said conduit from the measured time of flight;
• and
• means for calculating at least one fluid property of the two phase fluid from the measured pressure, the measured temperature, and the calculated speed of sound.