Papers by Keyword: Multiphase

Abstract: The design and operation of subsea pipelines over the life-cycle of an asset is vital for continuous oil and gas production. Qualitative design and effective production operation of pipelines depend on fluid type(s) involved in the flow; and in the case of multiphase flow, the need to understand the behaviour of the fluids becomes more imperative. This work presented in this report is borne out of the need for more accurate ways of predicting multiphase flow parameters in subsea pipelines with hilly-terrain profiles by better understanding their flow behaviors. To this end, Computational Fluid Dynamics has been used as against existing experimental and mechanistic methods which have inherent shortcomings. The results showed that multiphase flow parameters including flow-regimes, liquid hold-up and pressure drop in hilly-terrain pipelines can be modelled without associated errors in existing techniques. Similarity in trend was found when results of pressure gradient in downward-incline pipe were compared with results from existing correlations and mechanistic method. CFD can be used as a design tool and also a research tool into the understanding of the complexities of multiphase flow in hilly-terrain pipelines towards qualitative design and effective operation of hilly-terrain pipelines.

Abstract: A multiphase Eulerian- eulerian model integrating the kinetic theory of granular particle (KTGF) was used to simulate the gasification of Malaysian low- rank coal (LRC), Merit- Pila inside a bubbling fluidised bed (BFB) gasifier. The model used includes the bubbling phenomenon and gasificationprocess that occurs inside a BFB gasifier. The gasification process simulated includes drying, heterogeneous reactions of char combustion, devolatilization, water- gas shift reaction, Boudourd reactionand gas phase homogenous reactions. The results from this model are compared to the results of Merit-Pila coal gasification, from which experimental data is available. Comparison of the pressure profile shows good agreement with experimental results. The temperature distribution shows that the maximum temperature is around 1100K which also shows good agreement with experimental values which is 1087K. Besides that, three out of six species mass fraction which is N₂, H₂ and CH₄ produced similar values with experimental values. This shows the simulation conducted was capable to predict the gasification process of Low- rank coal, namely Merit-Pila.

Abstract: Interdiffusion in two-phase Ni-Cr-Al diffusion couple was studied experimentally and simulated numerically. The diffusion multiples were prepared by hot isostatic pressing, HIP and post-annealing at 1200°C. The concentration profiles were measured with wide line EDS technique – a method suitable to study multiphases. Hence the diffusion paths were determined. The experimental profiles and diffusion paths were compared with numerical results simulated with application of the Darken bi-velocity method implemented to describe interdiffusion in a two-phase zone.

Abstract: The interests in multiphase (more than three) system are escalating recently especially in the motor drive applications. Thus, this paper introduces the graphical phasor diagram method in designing the multiphase transformer connection. The proposed method eases the design process of the static multiphase transformer that produces multiphase output from the standard three phase input. The transformer connection was simulated in ANSYS Maxwell and the multiphase waveform with appropriate phase angle was obtained. The design of five-phase transformer using graphical phasor and simulation results from the finite elements software are presented in this paper.

Abstract: A thin liquid film flow over horizontal spinning disk under influence of centrifugal field is one of the implementation and method in process intensification. Hydrodynamic studies and development of mechanistic model is desired to describe this film flow behaviours. CFD software package, Fluent^® 6.3 was used to simulate a multiphase volume of fraction (VOF) model of this flow. Then, experiments were carried out in a spinning disk test rig with variable speed of spinning and results were compared with CFD simulation. The result obtained have showed that CFD model for thin liquid film thickness was in satisfactory agreement with the experimental results with R² = 0.841 to 0.857.

Abstract: Electric mining haul trucks are one of the most challenging applications of power electronics in automotive systems. This paper presents some advances of AC drive system with multiphase induction motor in high power mining haul trucks used in the special operation and environment. It is established that the use of inverter-fed dual three-phase (DTP) induction motors with vector control is the preferred solution to reach the required high starting torque, widely variable-speed range and good dynamic performance required by these vehicles. Key technologies and design features for the drive systems under extreme operating conditions are discussed.

Abstract: Abstract. In this work, an e ective nite volume lattice Boltzmann method is implemented andvalidated for a range of di erent uid problems including wall bounded turbulent ows and multi-phase ows.

Abstract: In order to improve the comprehensive performance of concrete truck mixer, considering the kinetics between concrete and blade, a parametric design model is built to find the relation between the parameters of the blade and performance. Based on subdividing function, the drum is divided into different parts called helix, the helix is designed as different blades for each part, then all the blades are combined into a complete helix. According to the design requirements (slump, the bevel angle of the drum), the corresponding blades are created. The simulation and engineering test show that this parametric design model can improve the comprehensive performance, besides, this method provide a new way to solve the detail design problem between multiphase and blade.

Abstract: Multiphase La1-xSrxFe1-yCoyO3-δ has been synthesized by sol-gel method and characterized by powder X-diffraction. Structure refinements of multiphase were undertaken to analyze compositions of compounds, and structure parameters were determined by Rietveld method, respectively. It was found that products were easier to be prepared in the condition of a precursor dealed with by high-speed disintegrator, and products synthesized at 1173K were composed of two phases of which La0.75Sr0.25Co0.2Fe0.8O3-δ is an orthorhombic structure with space group Pbnm and La0.46Sr0.54Co0.2Fe0.8O3-δ trigonal structure with space group R-3c. Structure geometry becomes more regular with increasing Sr content.

Abstract: In the present work we report that the addition of inorganic nanoparticles to MWCNT epoxy composites leads to the formation of a hybrid structures which cause different states of dispersion for the multiphase nanocomposites containing either MWCNTs and titania or MWCNTs and silica. The microstructure is characterised by titania nanoparticles attached to the surface of MWCNTs leading to an enhanced dispersion of MWCNTs. The hydrophilic surface of fumed silica nanoparticles causes the formation of independent networks of silica and MWCNTs. Therefore, the change of the state of dispersion is less pronounced compared to the MWCNT/titania structures. Changes in the state of dispersion lead to a decrease in electrical conductivity for the MWCNT/titania systems. Conversely, an almost independent behaviour was found for the MWCNT/silica nanocomposites due to their interpenetrating networks. Besides the altered state of dispersion, the hybrid structure leads synergistic effects in terms of the glass transition of the nanocomposites. Although a decrease of the glass transition temperature (Tg) is observed for the nanocomposites containing only one kind of filler, the combination of nanoparticles can reduce the decrease of Tg.