A compact x-ray system for two-phase flow measurement

Abstract

In this paper, a compact x-ray densitometry system consisting of a 50 kV, 1 mA x-ray tube and several linear detector arrays is developed for two-phase flow measurement. The system is capable of measuring void fraction and velocity distributions with a spatial resolution of 0.4 mm per pixel and a frequency of 1000 Hz. A novel measurement model has been established for the system which takes account of the energy spectrum of x-ray photons and the beam hardening effect. An improved measurement accuracy has been achieved with this model compared with the conventional log model that has been widely used in the literature. Using this system, void fraction and velocity distributions are measured for a bubbly and a slug flow in a 25.4 mm I.D. air–water two-phase flow test loop. The measured superficial gas velocities show an error within ±4% when compared with the gas flowmeter for both conditions.

An efficient algorithm for overlapping bubbles segmentation

“…Indeed, the number of bubbles involved in an image is perfectly known and each bubble is fully characterized, which is not the case for real bubbles images.For this purpose, a set of 50 synthetic images of 100 -150 overlapping circular and elliptical bubbles was considered. The semi-minor and semi-major axis (denoted a and b, respectively) of the bubble follow a uniform law in the intervals [5,15] and [10,40] pixels, respectively. Fig.…”

“…Typical intrusive techniques include conductivity probe [1,2] and phase sensitive constant temperature anemometry [3]. Non-intrusive techniques include laser doppler anemometry [4], X-ray and ɣ-ray computed tomography [5,6] and image processing techniques [7,8]. Among these methods, high-speed imaging is an efficient, convenient and broadly used tool in the bubbly flow visualization and measurement.…”

Frequency Domain Feature Extraction Investigation to Increase the Accuracy of an Intelligent Nondestructive System for Volume Fraction and Regime Determination of Gas-Water-Oil Three-Phase Flows

“…Advantages such as the ability to adjust the emitted photons energy of the X-ray tube, high-intensity photons emission, the ability to turn it on and off-this advantage is very important for the health of people working with these devices-, and the ability to transport it easily and steadily. Its energy retention over time has led current researchers to use X-ray tubes instead of radioisotopes [15][16][17][18]. In [15], an X-ray densitometry system was introduced.…”

Application of Feature Extraction and Artificial Intelligence Techniques for Increasing the Accuracy of X-ray Radiation Based Two Phase Flow Meter

“…Complete diagnosis of the kind of flow regime and determining the volume fraction with an RMSE of 1.28 were the research findings. In addition to radioisotope sources, it has been proved that X-ray tubes can be potentially used in radiation-based multiphase flowmeters [8,9]. The X-ray tube has some advantages over radioisotope sources, for example, it has the capability of energy adjustment of emitted photons, it releases photons more intensely than fundamental radioisotope sources; it has the capability of turning on and off, etc.…”