摘要
涡街流量传感器在测量小流量时由于信号微弱而不易检测,为解决这一问题从而扩展其测量下限,从传感器设计入手,研究在二维流场中压电探头与旋涡发生体的位置关系,找到适合信号检测的最佳位置.通过在三元回流式风洞中试验,利用热线测速以及压电探头测压得到发生体下游不同位置处的速度和压力信号,分析了信号强度、信噪比、小波系数和小波能量随检测位置的变化规律,最终给出了风洞中3种尺寸旋涡发生体下游的最佳检测位置:宽度14 mm发生体的最佳检测区域为距发生体50～75 mm,宽度22.5 mm发生体的最佳位置在100～150 mm,宽度28 mm发生体的最佳位置在150～200 mm.根据试验结果提出了估算最佳位置的公式,即最佳检测位置与发生体距离为涡街波长的二分之一.试验的分析方法和结论具有普适性,可推广到管道三维涡街流场中探头位置的研究.
The vortex signal is rather weak at low flowrate and hardly extracted from disturbances by a piezoelectric pressure probe, which results in a limited measuring range of the vortex flow sensor, In order to solve the problem, the sensor design was analyzed to optimize the distance between the bluff body and probe in 2D flow field. Experiments were carded out in a 3D reflux wind tunnel. The 2D hot-wire anemometer system and the pressure probe were applied to the determination of the velocity and pressure at different tested positions. Then the signal intensity, signal-to-noise ratio, wavelet coefficient and wavelet power of these signals were discussed. Finally, the optimum detected regions for three bluff bodies were obtained： the distance between bluff body and detected position is 50-75 mm when the width of bluff body is 14 mm; the distance is 100-150 mm when the width is 22.5 mm; the distance is 150-200 mm when the width is 28 mm. Moreover, an estimation formula for the optimum detected position was proposed, i.e. the distance between the optimum detected position and bluff body is half the wavelength of vortex street. The method and conclusions of the experiments are applicable to research on the optimum detected position in 3D pipe.
出处
《天津大学学报》
EI
CAS
CSCD
北大核心
2008年第8期895-903,共9页
Journal of Tianjin University(Science and Technology)
基金
国家高技术研究发展计划(863计划)资助项目(2007AA04Z180)
天津大学优秀博士学位论文基金资助项目(0505111303)
关键词
涡街流量传感器
压电探头
热线风速仪
信号强度
信噪比
连续小波变换
vortex flow sensor
piezoelectric pressure probe
hot-wire anemometer
signal intensity
signal-to- noise ratio
continuous wavelet transform
