Mass flow rate measurement device

A method for measuring mass flow rate, in a device comprising:

• a flow tube defining a fluid-flow path;
• a first group of actuators, including at least two actuators placed in a first plane including a first cross section of the tube and perpendicular to the fluid-flow path, the actuators of the first group being configured to move selectively in the first plane;
• at least one sensor for measuring a force or a stress in a direction perpendicular to the flow path, said measuring sensor being placed in proximity to the actuators of the first group on the flow path and furthermore being configured to measure a force in said direction perpendicular to the flow path;
• the measuring method comprising:
• controlling a movement of the first and second actuators of the first group so that the area of the cross section of the flow through the tube in the first plane remains constant, said actuators of the first group being controlled with acceleration setpoints or with setpoints for an amount of movement in the first plane;
• computing the mass flow rate passing through the flow tube depending on the force or the stress measured by said sensor,
• wherein the movement of the first and second actuators of the first group are controlled to selectively form a recess or protrusion with respect to the tube, said recess and said protrusion having an area Aa in the first plane, the flow area in the tube level with the first plane being denoted by Ac, the following relationship being respected:
• Ac/Aa>10.