Annular flow experimental study in horizontal pipes using radial proximity probes

The development of a new technique to detect and measure the annular flow parameters is presented in this article, the liquid film thickness was detected and measured in eight different radial positions, and the experimental information obtained was used to analyze the liquid film behaviour in order to set the wall regions where the probability to dry is higher. For the above purpose, a measuring system was developed, it was formed by a Digital Signal Processor (DSP) and a proximity circuit based on the embedded technology, it was also implemented a calibration methodology based on the Mandhane map to set the annular flow region in the experimental set up. The Digital Signal Processor (DSP) was also used to interpret and construct the signals according to its time and frequency behaviour. Due to its capacity of making complex operations, including its programming in C language, the device becomes an excellent real time tool to observe and quantify this phenomenon. The measuring and description of the annular flow is carried out through a digital camera, getting time series and visual patterns, creating a data base with hundreds of tests from the experimental system. The liquid film time series are interpreted through lineal transformation with Fourier series, where they are analyzed controlling the frequency and time. Subsequently, they are compared with the original signals to detect measurements uncertainty. The measuring prototype is full described for future applications in the instrumentation and control of the two-phase and multiphase flows experimental studies.