Apparatus and a method of measuring the flow of a fluid

An apparatus for measuring a mass flow rate of a multi-phase fluid flowing through a conduit, the apparatus comprising:

• a differential pressure element located in a conduit;
• a first differential pressure measurement device in communication with said multi-phase fluid between a first position and a second position across said differential pressure element for measuring a first fluid differential pressure;
• a second differential pressure measurement device in communication with said multi-phase fluid between a third position and a fourth position across said differential pressure element for measuring a second fluid differential pressure;
• a processor in communication with said first and second differential pressure measurement devices for receiving said first and second fluid differential pressures, respectively, said processor calculating a Reynolds number and a discharge coefficient using said first and second fluid differential pressures;
• and said processor calculating a mass flow rate by using said calculated Reynolds number and discharge coefficient.