A New Vector-Based Signal Processing Method of Four-Sensor Probe for Measuring Local Gas–Liquid Two-Phase Flow Parameters Together with Its Assessment against One Bubbly Flow

Abstract

A multiphase flow measurement technique plays a critical role in the studies of heat and mass transfer characteristics and mechanism of the gas–liquid two-phase, the practical measurement of the gas–liquid flow and the improvement of multiphase theoretical models. The four-sensor electrical probe as an emerging measurement method has been proved to be able to get the local flow parameters of multi-dimensional two-phase flow. However, few studies have been reported using the four-sensor probe to obtain the interface information (e.g., the interface direction and velocity). This paper presents a new signal processing method by which the interface direction and velocity can be obtained, besides void fraction, interfacial area concentration (IAC) and bubble chord length. The key solution is to employ the vector-based calculating method, which possesses the merits of simplicity and efficiency, to gain the interface velocity vector through legitimately assuming a direction of the interface velocity. A miniaturized four-sensor electrical probe was made and a gas–liquid two-phase flow experiment was performed to test the proposed signal process scheme. The two-phase flow was controlled to be in cap-bubble flow regime. To validate the availability and reliability of the proposed method, the local flow parameters obtained by the probe measurement were compared with the results from visual measurement technique in the same flow conditions. The comparison indicates that the above local flow parameters from four-sensor probe measurement are in good agreement with the visual measurement results, with maximum deviations of chord length of 8.7%, thereby proving the correctness of the proposed method.

Study on a new four‐fiber sensor signal processing algorithm of hydrodynamic characteristics in liquid–liquid two‐phase flow

“…It has also been used to measure the size and velocity of the dispersed phase droplets/bubbles on a smaller scale. [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] Optical fiber probe technology was originally utilized in gas-liquid two-phase flow systems, and now is used extensively in both gas-liquid and liquid-liquid twophase systems. Optical fiber probes are classified as mono, double, triple, four, and five optical fibers based on the number of optical fibers in the sensor probe.…”

“…The four-optical fiber probe method is more suitable for measuring three-dimensional velocity and size of the droplet/bubble. 23,24 Mishra 25 and Lucas 26 measured the velocity vector of a spherical droplet and nonspherical bubble by an orthogonal arrangement. It was indicated that the geometric arrangement of four probes has an impact on the measurement error; the triangle arrangement generates less error than the orthogonal arrangement.…”

“…It is frequently used to measure physical characteristics including temperature, pressure, liquid level, and flow rate in the hydrodynamic analysis of various chemical processes, such as gas–liquid separation and mixing operations. It has also been used to measure the size and velocity of the dispersed phase droplets/bubbles on a smaller scale 14–33 …”

“…Tri‐optical fiber probe can be used to determine the droplet velocity and size; 22 however, the measured velocity is two‐dimensional but not three‐dimensional, and the measured droplet size is actually a projection of the real size of the fiber plane. The four‐optical fiber probe method is more suitable for measuring three‐dimensional velocity and size of the droplet/bubble 23,24 . Mishra 25 and Lucas 26 measured the velocity vector of a spherical droplet and nonspherical bubble by an orthogonal arrangement.…”

Effect of bubble volume on the sweeping velocity of air bubbles in horizontal pipelines in water supply system

“…Bak et al (2020) proposed a semi-theoretical correlation developed from a steady-state bubble number density transport equation for predicting the distribution of local bubble size. To obtain physical mechanism governing the air-water interaction, a new method to determine the bubble velocity magnitude was proposed (Qu et al, 2020). Giorgio et al (2016) provided an experimental method to observe the motion of air bubbles by using a light-field camera, and then analyzed the flow properties and distribution of the air bubbles.…”