In this study a clamp-on ultrasonic flow meter that can measure the liquid and gas flow rate in a high-pressure wet gas pipeline has been designed. The gas velocity is measured using a transit time technique. For liquid flow rate measurements, two different techniques have been used. In high acoustic impedance liquid such as water, for gas velocities less than 15 m/s, film thickness measurements were obtained using a pulse-echo technique. Film thickness measurements made at two transducer locations were cross-correlated to yield the liquid film velocity. Combination of film thickness and film velocity then yields the liquid flow rate. For low acoustic impedance liquid such as decane, film thickness is measured using a surface wave technique. The measured film thickness data is combined with a two-phase flow model to yield the liquid flow rate. This model, based on a momentum balance for two phase flow, requires insitu gas velocity, liquid wetted wall perimeter and system parameters as inputs to yield the liquid flow rate.; Experiments on gas transmission in steel pipes were conducted for pipe sizes ranging from 4 inches to 11 inches. Two different excitation signals, a sinusoidal tone burst and a chirp, were used. Due to the high impedance mismatch between a steel-air interface, a minimum gas pressure is required for successful transmission of ultrasonic waves. This pressure required is a function of pipe diameter and wall thickness. Frequencies in the 450 to 600 kHz range were found suitable. Gas velocity measurements were conducted in a 60 feet long, 4 inches I.D. acrylic flow loop and in a high-pressure wet gas flow loop at Colorado Engineering Experimentation. The gas velocity is predicted within 7% of the actual value.; Film thickness measurements were carried out in a 4-inch schedule 40 stainless test section. Frequencies in the 1 to 2 MHz range were found suitable. In a pulse-echo measurement, the multiple reflections observed within the pipe wall mask the reflection from the liquid film. A focused transducer based on geometrical acoustics was designed to reduce these reflections. Using this transducer film thickness measurement was successful for gas velocities up to 15 m/s.
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机译：在这项研究中，设计了一种可测量高压湿气管道中液体和气体流速的夹钳式超声波流量计。使用渡越时间技术测量气体速度。对于液体流速的测量，已经使用了两种不同的技术。在高声阻抗液体（例如水）中，对于小于15 m / s的气体速度，使用脉冲回波技术获得膜厚测量值。在两个换能器位置进行的膜厚测量结果互相关以产生液膜速度。膜厚度和膜速度的组合则产生液体流速。对于低声阻抗液体（例如癸烷），使用表面波技术测量膜厚。将测得的膜厚数据与两相流模型结合，以得出液体流速。该模型基于两相流的动量平衡，需要原位气体速度，液体湿壁周长和系统参数作为产生液体流速的输入。进行了在钢管中进行气体传输的实验，其管道尺寸为4英寸至11英寸。使用了两种不同的激励信号，即正弦音突发和a声。由于钢-空气界面之间的高阻抗不匹配，因此需要最小的气压才能成功传输超声波。所需的压力是管道直径和壁厚的函数。发现450至600kHz范围内的频率是合适的。气体速度测量是在60英尺长，4英寸内径下进行的。科罗拉多工程实验公司的丙烯酸流回路和高压湿气流回路中。气体速度预计在实际值的7％以内。膜厚测量是在4英寸时间表40不锈钢测试区中进行的。发现频率在1到2 MHz范围内是合适的。在脉冲回波测量中，在管壁内观察到的多次反射掩盖了液膜的反射。设计了基于几何声学的聚焦换能器以减少这些反射。使用此换能器可以成功测量气体速度高达15 m / s的薄膜厚度。
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