Hasil Pencarian  ::  Simpan CSV :: Kembali

"The present Volume 4 of the successful monograh package “Multiphase flow dynamics”is devoted to selected chapters of the multiphase fluid dynamics that are important for practical applications but did not find place in the previous volumes. The state of the art of the turbulence modeling in multiphase flows is presented. As introduction, some basics of the single phase boundary layer theory including some important scales and flow oscillation characteristics in pipes and rod bundles are presented. Then the scales characterizing the dispersed flow systems are presented. The description of the turbulence is provided at different level of complexity: simple algebraic models for eddy viscosity, simple algebraic models based on the Boussinesq hypothesis, modification of the boundary layer share due to modification of the bulk turbulence, modification of the boundary layer share due to nucleate boiling. The role of the following forces on the mathematical description of turbulent flows is discussed: the lift force, the lubrication force in the wall boundary layer, and the dispersion force. A pragmatic generalization of the k-eps models for continuous velocity field is proposed containing flows in large volumes and flows in porous structures. A Methods of how to derive source and sinks terms for multiphase k-eps models is presented. A set of 13 single- and two phase benchmarks for verification of k-eps models in system computer codes are provided and reproduced with the IVA computer code as an example of the application of the theory. This methodology is intended to help other engineers and scientists to introduce this technology step-by-step in their own engineering practice.In many practical application gases are solved in liquids under given conditions, released under other conditions and therefore affecting technical processes for good of for bad. Useful information on the solubility of oxygen, nitrogen, hydrogen and carbon dioxide in water under large interval of pressures and temperatures is collected, and appropriate mathematical approximation functions are provided. In addition methods for the computation of the diffusion coefficients are described. With this information solution and dissolution dynamics in multiphase fluid flows can be analyzed. For this purpose the non-equilibrium absorption and release on bubble, droplet and film surfaces under different conditions is mathematically described. A systematic set of internally consistent state equations for diesel fuel gas and liquid valid in broad range of changing pressure and temperature is provided."

"This book contains a collection of the main contributions from the first five workshops held by Ercoftac Special Interest Group on Synthetic Turbulence Models (SIG42. It is intended as an illustration of the sig’s activities and of the latest developments in the field.This volume investigates the use of Kinematic Simulation (KS) and other synthetic turbulence models for the particular application to environmental flows.This volume offers the best syntheses on the research status in KS, which is widely used in various domains, including Lagrangian aspects in turbulence mixing/stirring, particle dispersion/clustering, and last but not least, aeroacoustics. "

"Multi-phase flows are part of our natural environment such as tornadoes, typhoons, air and water pollution and volcanic activities as well as part of industrial technology such as power plants, combustion engines, propulsion systems, or chemical and biological industry. The industrial use of multi-phase systems requires analytical and numerical strategies for predicting their behavior. .In its fourth extended edition the successful monograph package “Multiphase flow daynmics” contains theory, methods and practical experience for describing complex transient multi-phase processes in arbitrary geometrical configurations, providing a systematic presentation of the theory and practice of numerical multi-phase fluid dynamics. In the present second volume the methods for describing the mechanical interactions in multiphase dynamics are provided."

"Multi-phase flows are part of our natural environment such as tornadoes, typhoons, air and water pollution and volcanic activities as well as part of industrial technology such as power plants, combustion engines, propulsion systems, or chemical and biological industry. The industrial use of multi-phase systems requires analytical and numerical strategies for predicting their behavior. In its fourth extended edition the successful monograph package “Multiphase flow daynmics” contains theory, methods and practical experience for describing complex transient multi-phase processes in arbitrary geometrical configurations, providing a systematic presentation of the theory and practice of numerical multi-phase fluid dynamics.In the present first volume the local volume and time averaging is used to derive a complete set of conservation equations for three fluids each of them having multi components as constituents. Large parts of the book are devoted on the design of successful numerical methods for solving the obtained system of partial differential equations. Finally the analysis is repeated for boundary fitted curvilinear coordinate systems designing methods applicable for interconnected multi-blocks. "

"Multi-phase flows are part of our natural environment such as tornadoes, typhoons, air and water pollution and volcanic activities as well as part of industrial technology such as power plants, combustion engines, propulsion systems, or chemical and biological industry. The industrial use of multi-phase systems requires analytical and numerical strategies for predicting their behavior. .In its fourth extended edition the successful monograph package “Multiphase flow daynmics” contains theory, methods and practical experience for describing complex transient multi-phase processes in arbitrary geometrical configurations, providing a systematic presentation of the theory and practice of numerical multi-phase fluid dynamics.In the present third volume methods for describing of the thermal interactions in multiphase dynamics are provided. In addition a large number of valuable experiments is collected and predicted using the methods introduced in this monograph. In this way the accuracy of the methods is revealed to the reader."

"This Volume 5 of the successful book package "Multiphase flow dynamics" is devoted to nuclear thermal hydraulics which is a substantial part of nuclear reactor safety. It provides knowledge and mathematical tools for adequate description of the process of transferring the fission heat released in materials due to nuclear reactions into its environment. It step by step introduces into the heat release inside the fuel, temperature fields in the fuels, the "simple" boiling flow in a pipe described using ideas of different complexity like equilibrium, non equilibrium, homogeneity, non homogeneity. Then the "simple" three-fluid boiling flow in a pipe is described by gradually involving the mechanisms like entrainment and deposition, dynamic fragmentation, collisions, coalescence, turbulence. All heat transfer mechanisms are introduced gradually discussing their uncertainty. Different techniques are introduced like boundary layer treatments or integral methods. Comparisons with experimental data at each step demonstrate the success of the different ideas and models. After an introduction of the design of the reactor pressure vessels for pressurized and boiling water reactors the accuracy of the modern methods is demonstrated using large number of experimental data sets for steady and transient flows in heated bundles. Starting with single pipe boiling going through boiling in the rod bundles the analysis of complete vessel including the reactor is finally demonstrated. Then a powerful method for nonlinear stability analysis of flow boiling and condensation is introduced. Models are presented and their accuracies are investigated for describing critical multiphase flow at different level of complexity. Therefore the book presents a complete coverage of the modern nuclear thermal hydrodynamics."

"This Handbook provides readers with the current cutting edge of multiphase flow technology. It reviews the rapid development of multiphase flow technology, demonstrates the latest development of the technology, and showcase the very latest applications. It provides readers with comprehensive updated reference information covering theory, modelling and numerical methods, design and measurement, and new applications in multiphase flow systems.The Handbook consists of three parts or volumes:1. Theory: describes the fundamentals including the concepts and definitions of multiphase flows. Classifications of multiphase flows. Basic understanding of different length scales involved – micro/nano, meso and macro. Treatment of such flows by different solution frameworks.2. Modelling and Measurement: covers both classical and state-of the-art measurement and modelling approaches to resolve different classifications of multiphase flows.3. Applications: highlights the very latest applications of measurement and modelling approaches in tackling different classification of multiphase flows in a variety of natural, biological and industrial systems and different length scales."

"Dalam proses mengalirkan hasil eksplorasi minyak dan gas, pola aliran slug menjadi jenis aliran multifasa yang sering muncul (slugging). Fenomena ini tidak diinginkan karena dapat menyebabkan getaran mekanik yang dapat merusak pipa, pengurangan laju produksi minyak dan gas, kerusakan peralatan proses seperti separator,  kerusakan pada pipeline dan flowline yang disebabkan oleh erosi dan fatigue sebagai hasil dari penumpukan liquid dan variasi kecepatan dari partikel fluida. Berbagai teknologi digunakan dalam mengatasi permasalah tersebut, salah satu teknologi terbaru yang murah dan mudah digunakan adalah pompa multifasa. Penelitian ini bertujuan untuk mengetahui dampak penggunaan pompa multiphase terhadap pengurangan potensi terbentuknya slugging dalam pipa multifasa campuran minyak bumi dan gas alam. Dalam studi ini, simulasi dilakukan menggunakan simulator OLGA Dynamic Multiphase Flow 2017 2.0 dengan bantuan PVTSim 20 sebagai input perangkat lunak untuk karakteristisasi fluida menggunakan data suatu lapangan gas di Kalimantan. Variasi parameter ini dilakukan untuk mendapatkan fenomena yang terjadi pada pipa dan efeknya terhadap pola aliran, laju produksi, liquid hold-up, dan tekanan di pipeline sebagai akibat penggunaan MPP. Hasil penelitian menunjukkan semakin besar laju alir minyak dan gas, semakin stabil dan terjaminnya fluida mengalir di pipeline dengan mengalami sedikit gangguan slugging, baik terrain slugging ataupun riser-based slugging. Selain itu, peletakan posisi pompa multifasa pada jarak 20 m dari wellhead adalah jarak yang menjadi rekomendasi untuk laju alir 5 kg/s, 10 kg/s, dan 15 kg/s. Penggunaan pompa multifasa dapat menurunkan nilai liquid hold-up 0.05 hingga 0.1, meningkatkan production rate (QLT) pada bagian top riser dengan rentang 200 – 600 m3/d, dan menurunkan pressure drop sebesar 1-4 bara.

---

In the process of flowing the results of the oil and gas exploration, the slug flow pattern is a type of multiphase flow that often appears (slugging). This phenomenon is not desirable because it can cause mechanical vibrations that can damage pipes, reduce the rate of oil and gas production, damage process equipment such as separators, damage to pipelines and flowlines caused by erosion and fatigue as a result of liquid build-up and speed variations of fluid particles. Various technologies are used in overcoming these problems, one of the latest cheap and easy to use technologies is multiphase pumps. This study aims to determine the impact of the use of multiphase pumps on reducing the potential for the formation of slugging in multiphase pipes in a mixture of petroleum and natural gas. In this study, simulations were carried out using the OLGA Dynamic Multiphase Flow 2017 2.0 simulator with the help of PVTSim 20 as input software for fluid characterization using data from a gas field in Kalimantan. This parameter variation is done to obtain the phenomena that occur in the pipeline and their effects on flow patterns, production rates, liquid hold-ups, and pressure in the pipeline as a result of using MPP. The results showed that the greater the oil and gas flow rate, the more stable and guaranteed fluid flows in the pipeline with a slight slugging disturbance, either terrain slugging or riser-based slugging. In addition, laying the position of the multiphase pump at a distance of 20 m from the wellhead is the distance that is recommended for the flow rates of 5 kg / s, 10 kg / s, and 15 kg / s of each oil and gas used. The use of multiphase pumps can reduce the liquid hold-up value from 0.05 to 0.1, increase the rate of production (QLT) in the top riser section with a range of 200 - 600 m3 / d, and decrease in pressure drop by 1-4 bar."