Method and apparatus for determining characteristics of fluid flow

A process for measuring the mass of a fluid flowing through a conduit, comprising the steps of:

• inserting within the conduit a fluid flow displacement member of smaller size than the conduit comprised of two frustums joined at their larger ends and mounted coaxially in the conduit substantially normal to the direction of fluid flow and with the peripheries of the frustums spaced symmetrically inwardly from the inner wall of the conduit,
• deflecting the fluid flowing through the conduit through an annular region defined between the peripheries of the frustums and the inner wall of the conduit for substantially linearizing the velocity profile of the fluid over a predetermined range of flow rates through the conduit,
• measuring the pressure differential between the upstream and downstream sides of the displacement member,
• inserting a flowmeter within the conduit downstream of the displacement member at a location where the velocity profile of the fluid is linearized and stable,
• measuring with the flowmeter the velocity of fluid flow through the conduit, and
• determining from the measured pressure differential and the measured velocity of flow the mass of fluid flow through the conduit.

Fluid flow stabilizing and conditioning apparatus comprising, in combination,

• a conduit for conveying a fluid therethrough in a given direction,
• and within said conduit, in sequence in the direction of fluid flow,
• first flow straightening means for mitigating swirl of fluid flowing through the conduit,
• a fluid flow displacement member of smaller size than said conduit comprised of two frustums joined at their larger ends and mounted coaxially in said conduit substantially normal to the direction of fluid flow and with the peripheries of said frustums spaced symmetrically inwardly from the conduit, said displacement member deflecting the fluid and causing the fluid to flow through a region defined between the peripheries of said frustums and the inner wall of the conduit and being effective to substantially linearize the velocity profile of the fluid over a predetermined range of flow rates through said conduit, and
• second flow straightening means,
• said first and second flow straightening means mounting said displacement member coaxially in said conduit.