Application of computational fluid dynamics and laser Doppler velocimetry to liquid ultrasonic flow meter design

This study was carried out to assess the ability of a computational fluid dynamics (CFD) code to predict the scavenging flow in the cylinder of a two-stroke cycle engine. Predictions were obtained from a CFD simulation of the flow within the cylinder. Due to the apparent sym-metry of the engine port layout, only half of the cylinder volume was modelled. Boundary conditions for the CFD model were obtained from experimentally measured pressure-time histories in the crankcase and exhaust. The two-stroke cycle engine was modified to allow laser Doppler velocimetry (LDV) measurements to be made of the in-cylinder flow. The engine was operated under motoring conditions at 500 r/min with a delivery ratio of 0.7. Although the engine scavenge port layout was geometrically symmetrical, an asymmetrical flow field was identified in the cylinder. As a result of this, a direct comparison of the in-cylinder LDV measured and CFD computed results was not possible. However, LDV and CFD results for the in-cylinder flow are presented to help highlight the dissimilarity between the measured and predicted flow fields. Two-dimensional LDV measurements were made in the cylinder at the transfer ports for a portion of the cycle. A comparison of these LDV measurements with CFD predictions of the in-cylinder velocities at the same locations showed that the CFD model could replicate reasonably well the general trend of the flow. The measured cylinder averaged turbulent kinetic energy was compared with that of the CFD model. The qualitative trend of the overall turbulence generating capacity of the engine was well replicated by the CFD model.

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Performance optimization of ultrasonic flow meter based on computational fluid dynamics

Advances in Mechanical Engineering ◽

10.1177/1687814018793264 ◽

2018 ◽

Vol 10 (8) ◽

pp. 168781401879326 ◽

Cited By ~ 6

Author(s):

Shanbi Peng ◽

Wen Liao ◽

Huan Tan

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Performance Optimization ◽

Evaluation Method ◽

Flow Meter ◽

Rectification Effect ◽

Ultrasonic Flow Meter ◽

Accuracy Of Measurement ◽

Nature Gas ◽

Measuring Tool

As a common nature gas measuring tool, ultrasonic flow meter is more and more put into use. Therefore, the accuracy of measurement is what we concern the most. The performance of ultrasonic flow meter is closely related to fluid state which flows through it. This article identified the evaluation method of rectification effect of gasotron and its implementation steps. It proposed an assessing index Lmin based on dichotomy. Computational fluid dynamics method is used to simulate the model of an upstream straight pipe section with a header and plate gasotron, which obtained the assessing index Lmin in five different transmission conditions. Finally, the feasibility of the gasotron is validated against comparing indication errors in different installation conditions: with a header, benchmark, with a header and gasotron.

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