Kazuyoshi Shimizu

CFD Aided Investigation of Multipath Ultrasonic Gas Flow Meter Performance Under Complex Flow Profile

This paper presents a systematic investigation of the influence of complex flow profiles on the performance of multipath ultrasonic gas flow meter by using computational fluid dynamics (CFDs) simulation. To guarantee the overall agreement between the CFD predictions and the measurements, the meshing approaches, generation of boundary layers, turbulence models, and wall treatment methods for CFD simulation are elaborated carefully. The performances of a multipath ultrasonic gas flow meter under complex flow profiles, regarding to an out-plane double-elbow with a half-moon block and an out-plane double-elbow with a half-moon block equipped with a Spearman conditioner, are investigated. The simulation results demonstrate that for complex flows with strong asymmetric and swirling velocity profiles inside an out-plane double-elbow pipeline with a half-moon block, a four-path ultrasonic flow meter located at 20-D right after the second elbow together with a Spearman conditioner installed 16-D upstream the meter is of providing a flow velocity estimation that the error is within ±0.5%, while the Reynolds number ranges from 3.25×103 to 3.25×105. The effect of sound path orientation on the performance of flow meter is also discussed.

CFD-Aided Investigation of Sound Path Position and Orientation for a Dual-Path Ultrasonic Flowmeter With Square Pipe

This paper discusses the issues with a dual-path ultrasonic flowmeter with square-shaped pipe using CFD simulations, which include the sound path position, installation orientation, and effect of straight pipe length on the performance of the meter. By analyzing the flow field inside a single-elbow pipeline and T-shaped pipeline, the correction factor for the dual-path square-shaped ultrasonic flowmeter with respect to the change of Reynolds number is calculated. The optimal sound path position and orientation are investigated. Simulation results indicate that the optimal sound path position is located at the position of 0.65 times the half side length of square pipe cross-section. The upstream straight pipe length requirements for a single-elbow pipeline and a T-shaped pipeline are determined, which are at least 20-D and 50-D, respectively. Preliminary experiments are carried out and validate the simulations. The results are helpful for the design and practical applications of square-shaped ultrasonic flowmeter.