Development of high accurate transient now rate measurement using pulse Ultrasound

研制了脉冲超声多普勒精确流量计量系统。该方法的原理是基于管道直径上的瞬时速度曲线的积分，因此有望消除诸如入口长度等安装问题，并精确地跟踪瞬态流量。因此，在本研究中，我们报告了采用该方法的多线流量测量结果。超声多普勒法在圆管内的流量测量原理取决于测量线的对中。在大多数情况下，金属管道用于发电厂。采用这种方法进行速率测量时，需要一些反射器来对水进行播种。因为清澈的水在发电厂的管道里流动。本文研究了几种金属管道在垂直管道中流量测量的比较。此外，对反射器采用了超声空化气泡，并与先前研究中使用的尼龙粉进行了对比。在本实验中，即使对于金属壁管，也可以使用多线系统进行高精度的流量测量。对于超声反射器，空化气泡是可以应用的。上述结果表明，目前采用超声多普勒法的多线流量计量系统具有很高的精度。该方法可以看作是一个多用途系统，因为它可以在非理想流动条件下测量流量，如非发达流动或非轴对称流动。本文提出了一种利用超声时域相关离子法（UTDC）测量速度剖面的新方法。该系统是基于超声脉冲的两个连续回波之间的相互关系来检测速度。与传统的超声脉冲多普勒方法相比，UTDC有两个优点。首先，该系统具有比脉冲多普勒方法更好的时间分辨率。其次，系统的最大可测速度不受Nyquist抽样定理的限制。本文采用UTDC法进行了速度剖面测量，结果表明，UTDC法测得的速度剖面与脉冲多普勒法测得的速度剖面吻合较好。少

Pulse Ultrasonic Doppler method for accurate flow metering system has been developed. The principle of this method is based on the integration of instantaneous velocity profile over a pipe diameter so that it is expected to be able to eliminate installation problems such as entry length as well as to follow transient flow rate precisely. Therefore, in the present study, we report the results of multiline flow rate measurement employing this method. Flow metering principle by ultrasonic Doppler method in a circular pipe depends on the alignment of measuring lines. In most cases, metallic pipes are used at power plants. And some reflectors are needed to seed the water for now rate measurement using this method. Because clear water flows in the pipes at power plants. In this study, the comparison among several kinds of metallic pipes on the flow rate measurements have been investigated in a vertical pipe. Additionally, for reflectors ultrasonic cavitation bubbles were applied and the effe … More ct was compared with nylon powder, which used in the previous study. In this experiment, even for the metallic wall pipe, it is possible to measure the flow rate using multiline system with high accuracy. And for the ultrasonic reflector cavitation bubbles are achievable to be applied. As mentioned above, it is indicated that the present multiline flow metering system by using ultrasonic Doppler method has very high accuracy. And this method can be considered as a multipurpose system, because the flow rate can be measured under non-Ideal flow conditions such as non-developed flow or non-axisymmetric flow.In the present study, a new velocity profile measurement technique using a ultrasound time-domain correlate ion method(UTDC) has been developed. The system is based on the cross-correlation between two consecutive echoes of ultrasonic pulses to detect the velocity. The UTDC has two advantages over the conventional ultrasound pulse Doppler method. First, the system has a better time resolution than the pulse Doppler method. Second, the system have no limitation in maximum measurable velocity, which is limited by Nyquist's sampling theorem. In this study, the velocity profile measurement using the UTDC is performed, and the velocity profiles measured by the UTDC method is good agreement with those results using the pulse Doppler method. Less