摘要
超声流量计从原理上讲是可以实现非实流标定的一类流量计,但目前国内外仍未普遍推行该技术的一个重要原因是超声换能器对流场扰动影响的研究尚需深入,特别对于中、小口径超声流量计,换能器对流场的扰动作用、对测量精度的影响更为严重。利用计算流体力学数值仿真方法研究换能器对流场的扰动机理,前期已通过实流试验验证仿真方法正确性,在此基础上重点分析DN100超声流量计分别在单面、交叉1、2、4六种声道布置形式下,换能器插入深度对流速分布、测量误差的影响规律。研究结果表明,换能器对流场的节流作用使得采用交叉声道布置形式、换能器全部插入管道时的测量效果最好,测量误差最小;随着布置声道数目逐渐增多,换能器对测量误差的负向影响越大。
Ultrasonic flowmeters can be achieved dry calibraiton in principle. However, dry calibration technology has not been implemented widespread because of an important factor influencing measurement performance to be fiarther studied. The flow field is disturbed by acoustic transducers in ultrasonic flowmeter, This effect is more sever especially for the medium or small diameter, which perturbation effect on measurement accuracy is more serious. The disturbance mechanism was studied in computational fluid dynamics numerical simulation method which had been verified by experiments. Six acoustic path arrangement types for DN100 flowmeter were compared to research on flow distribution and measurement error caused by different transducer positions, including 1-path, 2-path, 4-path in single and cross measurement planes. It is showed that best measurement performance can be achieved when transducers with cross arrangement are fully inserted into pipe because of throttle effect on flow. Besides, negative measurement error is larger when more acoustic paths are arranged.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2014年第4期18-24,共7页
Journal of Mechanical Engineering
基金
国家自然科学基金(61101227)
天津市应用基础与前沿技术研究计划(13JCQNJC03300)资助项目
关键词
超声流量计
数值仿真
换能器
声道布置
ultrasonic flowmeter
numerical simulation
acoustic transducer~ acoustic path arrangement
