Multiphase ultrasonic tomography technique for homogeneous and Non-homogeneuos media identification

Abstract

Multiphase flow characterization is an important task for monitoring, measuring or controlling industrial processes. This can be done by means of process tomography. The use of tomographic techniques has been used within the oil industry. One of the potential applications is flow visualization and measurement in producing wells. Research on industrial process tomography consists in obtaining estimated images of a cross section of a pipe or vessel containing or carrying the substances of the process. One category of process tomography is ultrasonic tomography technique. A simple tomography can be built by mounting a number of sensors around the circumference of a horizontal pipe. This paper describes the homogeneous and non-homogeneous ultrasonic tomography for multiphase flow such as liquid/gas and oil/gas flow which commonly found in chemical columns and industrial pipelines. The information obtained through this research has proven to be useful for further development of ultrasonic tomography. This includes acquiring and processing ultrasonic signals from the transducers to obtain the information of the spatial distributions of liquid and gas in an experimental column. Analysis on the transducers' signals has been carried out to distinguish between the observation time and the Lamb waves. The information obtain from the observation time is useful for further development of the image reconstruction. To obtain the time easily, zero crossing detector is used with producing square waves. The time will be calculated from the starting pulse of transmitter signal until the starting peak of receiver signal. The places can be distinguished referring the different value of time of each phase which is oil, water and gas. The Time of Flag (TOF) is adequate to distinguish the phases and monitor the internal process in the pipelines.