M.H. Fazalul Rahiman

Application of transmission-mode ultrasonic tomography to identify multiphase flow regime

This paper presents an application of ultrasonic tomography where the main objective is to identify the multiphase flow regime which is liquid, gas and solid at once. The system was designing non-invasively by using offline method. The transmission mode with fan shaped beam back projection had been implemented for sensing purposes where 8×8 projections were produced. Beside, the linear back projection (LBP) algorithm was implemented in the software system for the image reconstruction part. Experiments show that the multiphase flow regime for liquid, gas and solid at once can be identifying by using ultrasonic tomography. The results of experiments and possible future improvement were also discussed.

Improving gas component detection of an ultrasonic tomography system for monitoring liquid/gas flow

The development of an ultrasonic transmission tomography system is described. The system is intended for the imaging of two component flows (such as gas/water) inside pipes of industrial processes. Transmission-mode approach has been used for sensing the gas/liquid two-phase flow, which is a kind of strongly inhomogeneous medium. A prototype fixture of vertical column and a mobile prototype design of sensors jig for ultrasonic tomography imaging are used. The fixture of the vertical column is designed to hold the sensors jig that will have the 16-pairs of ultrasonic sensors attached to it. The investigations were based on the transmission and the reception of ultrasonic sensors that were mounted circularly on the surface of experimental vessel. This paper also explains the hardware and circuitry design for the Ultrasonic Tomography System. Detailed explanations are presented on relationship of the smallest resolution the system are able to detect with the characteristics of the installed ultrasonic sensor.

Simulation on using cross-correlation technique for two-phase liquid/gas flow measurement for Ultrasonic Transmission Tomography

Combining Ultrasonic Transmission Tomography (UTT) with the cross-correlation flow measurement technique can provide more information on the flow than usual. A simulated dual-plane UTT system for use on laboratory and plant-scale process equipment has been developed on the basis of this idea. This paper focuses on the correlator used to cross-correlate the tomogram images between the downstream and upstream plane of the simulated dual-plane ultrasonic transmission tomography system. This paper proposed the use of 2D correlation coefficient for the correlator and the result of its use is discussed. The principle of measurement of the local gas velocity distribution in a bubbly gas/liquid pipe flow which is based on cross-correlation of two plane images is also described. Initial experimental results illustrate the feasibility of the method presented here.