Thermo-Fluid Dynamics of Two-Phase Flow

Ultrasonic Doppler Technique for Application to Multiphase Flows: A Review

The simultaneous effects of nanoparticles and ultrasonic vibration on inlet turbulent flow: An experimental study

Flow velocity is an important process parameter that quantifies the volume or mass flow rate as well as monitors the process safety. To nonintrusively measure the flow velocity of horizontal gas–liquid two-phase flow, an ultrasonic Doppler sensor and a conductance sensor with dedicated measurement models are presented. The air superficial flow velocity can be directly obtained and the water superficial flow velocity can be calculated through a two-fluid model for bubble flow and plug flow. For slug flow, a correlation between the phase velocity in slug body and overall superficial flow velocity was built based on a slug closure model. In order to eliminate the influence of the changing velocity profile in the fluid, the sample volume was designed to cover the whole pipe cross section by installing a two-chip piezoelectric transducer with 1-MHz center frequency at the bottom of the pipe. The conductance sensor provided water holdup estimate to compensate the velocity measurement model. Experiments were carried out in a 50-mm inner diameter pipe to verify the proposed sensor and model. Three flow patterns (bubble flow, plug flow, and slug flow) were generated by adjusting the inlet flow rate of the air and the water. The results show that the mean relative error can achieve within 5%.

Gas–Liquid Two-Phase Flow Velocity Measurement With Continuous Wave Ultrasonic Doppler and Conductance Sensor

Oil–water two-phase flow commonly exists in many industries. The accurate measurement of flow velocity is beneficial for safety operation and economic efficiency. A combination of a pulse-wave ultrasonic Doppler (PWUD) sensor and a conductance/capacitance (CCC) sensor is proposed for flow velocity measurement in dispersed oil–water two-phase flow. The PWUD sensor estimates dispersed phase velocity, and the CCC sensor provides phase fraction. The overall superficial flow velocity ( $J$ ) and individual flow velocities are estimated by combining the outputs of the two sensors. The dual-modality sensing system was designed and experimentally verified on a horizontal multiphase flow loop. Ignoring the slippage between two phases, the $J$ is estimated with an average relative error (ARE) of 5.58%, water superficial velocity with 6.42%, and oil superficial velocity with 6.91%. To further improve the measurement accuracy, slip velocity-based measurement model is presented by introducing the drift-flux model. The distribution parameter of this model is derived from theoretical analysis. The correlation between relative velocity and $J$ is analyzed by the force analysis of dispersed phase in water/oil-continuous flow theoretically and experimentally. The results demonstrate that the proposed model estimates the $J$ with an ARE of 2.21%, water superficial velocity with 3.56%, and oil superficial velocity with 3.80%. Besides, ARE of different flow patterns shows a uniform distribution. The slip velocity-based measurement model has an advantage of less error in overall superficial flow velocity estimation, reduced by 60% compared with that of the nonslip velocity-based measurement model.

Dispersed Oil–Water Two-Phase Flow Measurement Based on Pulse-Wave Ultrasonic Doppler Coupled With Electrical Sensors

Measurement of Bubbly Two-phase Flow in Vertical Pipe Using Multiwave Ultrasonic Pulsed Dopller Method and Wire Mesh Tomography

Measurement of the condensation rate of vapor bubbles rising upward in subcooled water by using two ultrasonic frequencies

In the article, the application of the electrical spike, instead of the tone-burst, to the ultrasonic pulsed-Doppler velocity profiling the first time is presented. To generate ultrasound, the ultrasonic sensor is excited by the spike. For the Doppler method, the spike excitation was not used previously. It has been used with wideband signal processing methods. In our study, first, the fluid-velocity profile measurement using spike excitation has been carried out for single-phase pipe flow. The received data have been validated by the logarithmic law of the wall, for turbulent flow regime. The flow rate calculated by using the mean velocity profile well coincides with the flow-meter data. Furthermore, the spike signal and the Doppler method are used in the multiwave ultrasonic velocity profile (UVP) method, for the bubbly flow measurement. The experiments show that, if the spike signal is slowly damped, the generated ultrasonic wave is similar to the tone-burst that is required for the Doppler method, but in this case, usually the pulse length is smaller and depends on the damping and sensor characteristics. The autocorrelation technique is used for echo signal processing. The derived UVP systems inherit the advantages from both the spike excitation and Doppler method.

Ultrasonic Doppler Velocity Profile Measurement of Single-and Two-Phase Flows Using Spike Excitation

Development of Multiwave Method Using Ultrasonic Pulse Doppler Method for Measuring Two-phase Flow

Ultrasonic Velocity Profile (UVP) method for measurement of single-phase and two-phase flow in a vertical pipe has recently been developed in the Laboratory for Industrial and Environmental Fluid Dynamics, Institute of Mechanics, VAST. The signal processings of the UVP method include the ultrasonic pulse Doppler method (UDM) and the ultrasonic time-domain cross-correlation (UTDC) method. For two-phase flow, simultaneous measurements of both liquid and gas are enabled by using a multi-wave ultrasonic transducer (multi-wave TDX). The multi-wave TDX is able to emit and receive ultrasounds of two different center frequencies of 2 MHz and 8 MHz at the same time and position. 2 MHz frequency with beam diameter 10 mm is exploited for measurement of gas. 8 MHz one with beam diameter 3 mm is used for liquid. Measurements have been carried out for laminar and turbulent single-phase flows and bubbly counter-current twophase flows in two flow loops using two vertical pipes of 26 mm inner diameter (I.D.) and 50 mm I.D. respectively. Based on the measured results, assessment of each method is clarified. Applicability of each method for different conditions of pipe flow has been tested. Suggestions for application of the two methods have been recommended.

https://www.vjs.ac.vn/index.php/vjmech/article/download/3070/pdf

Measurements of single-phase and two-phase flows in a vertical pipe using ultrasonic pulse doppler method and ultrasonic time-domain cross-correlation method

Tat Thang Nguyen

Papers

Measurement of Bubbly Two-phase Flow in Vertical Pipe Using Multiwave Ultrasonic Pulsed Dopller Method and Wire Mesh Tomography

Measurement of the condensation rate of vapor bubbles rising upward in subcooled water by using two ultrasonic frequencies

Ultrasonic Doppler Velocity Profile Measurement of Single-and Two-Phase Flows Using Spike Excitation

Development of Multiwave Method Using Ultrasonic Pulse Doppler Method for Measuring Two-phase Flow

Measurements of single-phase and two-phase flows in a vertical pipe using ultrasonic pulse doppler method and ultrasonic time-domain cross-correlation method