Research Of Installation Position Of The Probe And Flow Numerical Integration Method On Ultrasonic Flowmeter

Ultrasonic flowmeter develops very rapidly. Compared with the traditionalflowmeter, it has the advantage of no pressure loss, wide measuring range, highrepeatability and so on. The multi-channel ultrasonic flowmeter which is developedand applied in recent years has become the best choice of large diameter flowmeasurement, because its manufacture is free from the pipe diameter and themulti-channel configurations can adapt to the more complex structure and flowdistribution. In the process of using, the installation position of the ultrasonic probeand non-ideal flow field downstream the baffles have an effect on the measurementperformance of ultrasonic flowmeter. In order to improve the effect, the main workcompleted as follows：（1）The experiments are conducted in the condition of straight tube and elbowwith SCL-9multi-channel ultrasonic flowmeter of Tangshan HuizhongInstrumentation Co. Ltd. The measurement performance of the ultrasonic flowmeter isanalyzed in different installation position of probe, channel arrangement and positiondownstream single elbow. The results show that double-sided channel arrangement isbetter than the single-sided channel arrangement when the probe is in full contractionextension installation, while the probe is in full contraction installation, there is littledifference between them; in the condition of the single elbow, its measurementperformance is affected, and the results are poor than those of straight tube.（2）The research to the flow field of DN100multi-channel ultrasonic flowmeteris carried out based on computational fluid dynamics (CFD) simulation method whenthe probe in full extension or full contraction and the channel arranged withsingle-sided or double-sided under straight tube condition. The variation of the flowfield near the probe as well as its effect mechanism on the measuring results areanalyzed. Moreover, the reason of the difference between single-sided arrangementand double-sided arrangement is explained.（3）The simulation model is established based on CFD simulation method. Inthe model, the probe is installed with full extension, the channel is arranged withdouble sides and the baffles type are single elbow and double elbows. Themeasurement performance of the ultrasonic flowmeter downstream the two baffles is studied through analyzing the internal flow field of them. The results show that theeffect of the double elbows is higher than that of the single elbow, the error increaseswith the shortening of the length of front straight pipe under the condition of singleelbow. However, the error decreases slightly with the shortening of the length of frontstraight pipe under the condition of double elbows.（4）The flow numerical integration methods of multi-channel ultrasonicflowmeter is unable to meet the requirements of measurement performance under thenon-ideal flow field. A numerical integration optimization method is proposed, whichis based on the actual pipe flow profile. It is verified by simulation and experiment.The results show that the optimization result of simulation is significantly better thanthe experiment. Meanwhile, by comparing the average optimization and separateoptimization, the average optimization is deemed to be better.