Experimental and numerical design of a long-waist cone flow meter

• A long waist cone flow meter (LWC) is presented for flow measurement.
• Shape of LWC is optimized through CFD simulations and experimental validations.
• Effects of LWC shape on differential pressure and discharge coefficient are studied.
• LWCs are tested with different Newtonian fluids, and oil–water two-phase flow.

A long-waist cone flow meter is designed for steady differential pressure measurement and relatively small overall pressure drop. A constant-diameter annular flow channel is formed between cone element and pipe wall. The flow field of water flows through cone element is studied with 3-D CFD simulations. The constant-diameter annular channel is found being able to adjust the incoming fluid, and small rear angle of cone element could reduce flow separation and overall pressure difference. An optimized structure of long-waist cone flow meters, referred as LWC, is proposed based on the investigations on flow field analysis. A steady contracting differential pressure and an overall differential pressure can be tapped from a LWC. A set of LWCs was fabricated with diameter ratio β ranging from 0.55 to 0.75, and waist length L from 20 to 60 mm when β = 0.65 for experimental tests and CFD verifications. A decreasing trend of dimensionless differential pressure Δp* and δp* and an increasing trend of discharge coefficient Cd of LWCs under different Reynolds number are observed and analyzed, and flow rate prediction of different Newtonian single phase flow is experimentally studied. A case study of oil–water two-phase flow is then presented with a selected LWC and an average error below 5% is achieved when treating the mixture a homogeneous flow.