Measurement of the Void Fraction of Gas-Liquid Two-Phase CO2 Flow Using Laser Attenuation Techniques

Carbon capture and storage (CCS) is a promising technology to reduce CO 2 emissions from industrial processes. However, void fraction measurement is one of the challenging issues to be solved for gas-liquid two-phase CO 2 flow measurement. This paper presents a novel measurement system using laser intensity attenuation techniques to measure the void fraction of two-phase CO 2 flow. The measurement system includes optical sensors, a laser detector array and a monolithic processor. The performance of the proposed measurement system is verified through experimental tests under various conditions, including stratified flow and bubbly flow. The void fraction of two-phase CO 2 flow ranges from 0 to 69%. Experimental results demonstrate that the system is capable of measuring the void fraction of CO 2 flow with an error between -2% and 3.6%

Application of Soft Computing Techniques to Multiphase Flow Measurement: A Review

After extensive research and development over the past three decades, a range of techniques have been proposed and developed for online continuous measurement of multiphase flow. In recent years, with the rapid development of computer hardware and machine learning, soft computing techniques have been applied in many engineering disciplines, including indirect measurement of multiphase flow. This paper presents a comprehensive review of the soft computing techniques for multiphase flow metering with a particular focus on the measurement of individual phase flowrates and phase fractions. The paper describes the sensors used and the working principle, modelling and example applications of various soft computing techniques in addition to their merits and limitations. Trends and future developments of soft computing techniques in the field of multiphase flow measurement are also discussed

Mass Flow Measurement of Gas-Liquid Two-Phase CO2_2 in CCS Transportation Pipelines using Coriolis Flowmeters

Carbon Capture and Storage (CCS) is a promising technology that stops the release of CO$_2$ from industrial processes such as electrical power generation. Accurate measurement of CO$_2$ flows in a CCS system where CO$_2$ flow is a gas, liquid, or gas-liquid two-phase mixture is essential for the fiscal purpose and potential leakage detection. This paper presents a novel method based on Coriolis mass flowmeters in conjunction with least squares support vector machine (LSSVM) models to measure gas-liquid two-phase CO$_2$ flow under CCS conditions. The method uses a classifier to identify the flow pattern and individual LSSVM models for the metering of CO2 mass flowrate and prediction of gas volume fraction of CO$_2$, respectively. Experimental work was undertaken on a multiphase CO$_2$ flow test facility. Performance comparisons between the general LSSVM and flow pattern based LSSVM models are conducted. Results demonstrate that Coriolis mass flowmeters with the LSSVM model incorporating flow pattern identification algorithms perform significantly better than those using the general LSSVM model. The mass flowrate measurement of gas-liquid CO$_2$ is found to yield errors less than ±2% on the horizontal pipeline and ±1.5% on the vertical pipeline, respectively, over flowrates from 250 kg/h to 3200 kg/h. The error in the estimation of CO$_2$ gas volume fraction is within ±10% over the same range of flow rates

Molecular Dynamics Simulation and Experimental Studies on the Thermomechanical Properties of Epoxy Resin with Different Anhydride Curing Agents

An investigation of the relationship between the microstructure parameters and thermomechanical properties of epoxy resin can provide a scientific basis for the optimization of epoxy systems. In this paper, the thermomechanical properties of diglycidyl ether of bisphenol A (DGEBA)/methyl tetrahydrophthalic anhydride (MTHPA) and DGEBA/nadic anhydride (NA) were calculated and tested by the method of molecular dynamics (MD) simulation combined with experimental verification. The effects of anhydride curing agents on the thermomechanical properties of epoxy resin were investigated. The results of the simulation and experiment showed that the thermomechanical parameters (glass transition temperature (Tg) and Young’s modulus) of the DGEBA/NA system were higher than those of the DGEBA/MTHPA system. The simulation results had a good agreement with the experimental data, which verified the accuracy of the crosslinking model of epoxy resin cured with anhydride curing agents. The microstructure parameters of the anhydride-epoxy system were analyzed by MD simulation, including bond-length distribution, synergy rotational energy barrier, cohesive energy density (CED) and fraction free volume (FFV). The results indicated that the bond-length distribution of the MTHPA and NA was the same except for C–C bonds. Compared with the DGEBA/MTHPA system, the DGEBA/NA system had a higher synergy rotational energy barrier and CED, and lower FFV. It can be seen that the slight change of curing agent structure has a significant effect on the synergy rotational energy barrier, CED and FFV, thus affecting the Tg and modulus of the system

Craniofacial Reconstruction Evaluation by Geodesic Network

International audienceCraniofacial reconstruction is to estimate an individual’s face model from its skull. It has a widespread application in forensicmedicine, archeology, medical cosmetic surgery, and so forth. However, little attention is paid to the evaluation of craniofacialreconstruction. This paper proposes an objective method to evaluate globally and locally the reconstructed craniofacial facesbased on the geodesic network. Firstly, the geodesic networks of the reconstructed craniofacial face and the original face are built,respectively, by geodesics and isogeodesics, whose intersections are network vertices. Then, the absolute value of the correlationcoefficient of the features of all corresponding geodesic network vertices between two models is taken as the holistic similarity,where the weighted average of the shape index values in a neighborhood is defined as the feature of each network vertex.Moreover,the geodesic network vertices of each model are divided into six subareas, that is, forehead, eyes, nose, mouth, cheeks, and chin,and the local similarity is measured for each subarea. Experiments using 100 pairs of reconstructed craniofacial faces and theircorresponding original faces show that the evaluation by our method is roughly consistent with the subjective evaluation derivedfrom thirty-five persons in five groups

Experimental investigation on GaAs/GaAlAs quantum confined stark effect and self electro-optic bistabe effect

A GaAs/GaAlAs Self Electro-optic Effect Device (SEED) with MQW pin structure has been fabricated. The measurement and analysis of the photocurrent spectrum, photocurrent-voltage Characteristics and photocurrent bistability are given. A discussion on the realization of its bistability is also concerned.link_to_subscribed_fulltex