Computer Modeling of Fixed Bed Underground Coal Gasification Using the Permeation Method

1987 ◽  
Vol 109 (1) ◽  
pp. 11-20 ◽  
Author(s):  
Eed A. A. Abdel-Hadi ◽  
T. R. Hsu
Keyword(s):  
Finite Element ◽  
Coal Gasification ◽  
Moving Boundary ◽  
Fixed Bed ◽  
Element Formulation ◽  
Underground Coal Gasification ◽  
The Finite Element Method ◽  
Coal Consumption ◽  
Numerical Case Study

A two-dimensional computational model has been developed as a pilot study for the multidimensional simulation of fixed bed underground coal gasification (UCG). The analysis is based on the finite element method and incorporates a moving boundary algorithm to model the permeation linked vertical well in a forward gasification mode. In order to account for the motion of the combustion front with time, an immobilization transformation of coordinates technique is introduced in the finite element formulation. A numerical case study is included to illustrate the capability of the model. Predictions on temperatures, gas composition, pressure, and coal consumption in space and time are possible by using this model.

scholarly journals Stability charts based on the finite element method for underground cavities in soft carbonate rocks: validation through case-study applications

2019 ◽  
Vol 19 (10) ◽  
pp. 2079-2095 ◽  
Author(s):  
Michele Perrotti ◽  
Piernicola Lollino ◽  
Nunzio Luciano Fazio ◽  
Mario Parise
Keyword(s):  
Finite Element ◽  
Safety Margin ◽  
Structural Elements ◽  
The Finite Element Method ◽  
Geometrical Features ◽  
Overall Stability ◽  
Underground Cavities ◽  
The Stability ◽  
Rock Mechanical Properties

Abstract. The stability of man-made underground cavities in soft rocks interacting with overlying structures and infrastructures represents a challenging problem to be faced. Based upon the results of a large number of parametric two-dimensional (2-D) finite-element analyses of ideal cases of underground cavities, accounting for the variability both cave geometrical features and rock mechanical properties, specific charts have been recently proposed in the literature to assess at a preliminary stage the stability of the cavities. The purpose of the present paper is to validate the efficacy of the stability charts through the application to several case studies of underground cavities, considering both quarries collapsed in the past and quarries still stable. The stability graphs proposed by Perrotti et al. (2018) can be useful to evaluate, in a preliminary way, a safety margin for cavities that have not reached failure and to detect indications of predisposition to local or general instability phenomena. Alternatively, for sinkholes that already occurred, the graphs may be useful in identifying the conditions that led to the collapse, highlighting the importance of some structural elements (as pillars and internal walls) on the overall stability of the quarry system.

Frontal Impact Analysis of an Interprovincial Bus Using the Finite Element Method: Case Study in Ecuador

2020 ◽  
pp. 312-320
Author(s):  
Luis Santos-Correa ◽  
Diego Pineda-Maigua ◽  
Fernando Ortega-Loza ◽  
Jhonatan Meza-Cartagena ◽  
Ignacio Abril-Naranjo ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Impact Analysis ◽  
Frontal Impact ◽  
The Finite Element Method ◽  
Element Method

scholarly journals A Framework for Extension of Dynamic Finite Element Formulation to Flexural Vibration Analysis of Thin Plates

2021 ◽  
Author(s):  
Mohammad M. Elahi ◽  
Seyed M. Hashemi
Keyword(s):  
Finite Element ◽  
Solution Space ◽  
Flexural Vibration ◽  
Finite Element Formulation ◽  
Thin Plates ◽  
Element Formulation ◽  
The Finite Element Method ◽  
Good Convergence ◽  
Dynamic Finite Element ◽  
Numerical Testing

Dynamic Finite Element formulation is a powerful technique that combines the accuracy of the exact analysis with wide applicability of the finite element method. The infinite dimensionality of the exact solution space of plate equation has been a major challenge for development of such elements for the dynamic analysis of flexible two-dimensional structures. In this research, a framework for such extension based on subset solutions is proposed. An example element is then developed and implemented in MAT LAB software for numerical testing, verification, and validation purposes. Although the presented formulation is not exact, the element exhibits good convergence characteristics and can be further enriched using the proposed framework.

Structural-Acoustic Design at High Frequency Using the Energy Finite Element Method

1995 ◽  
Author(s):  
Robert J. Bernhard ◽  
John E. Huff
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
High Frequency ◽  
Energy Flow ◽  
Flow Analysis ◽  
Element Formulation ◽  
Joint Models ◽  
Energy Flow Analysis ◽  
Element Method

Abstract Energy flow analysis methods, particularly as implemented using the finite element method, are useful as design techniques for high frequency structural-acoustic applications. In this paper, the derivation of energy flow analysis techniques are summarized. Particular attention is given to the specification of joint models for situations where there is a discontinuity in either geometric properties or material properties. The finite element formulation of this approach is also summarized. A case study is included to illustrate the utility of the method as a design technique.

Tracheal Smooth Muscle Response to Vibrations

2004 ◽  
Author(s):  
Y. Du ◽  
A. M. Al-Jumaily
Keyword(s):  
Finite Element ◽  
Smooth Muscle ◽  
Smooth Muscles ◽  
Variable Stiffness ◽  
Tracheal Smooth Muscle ◽  
Element Formulation ◽  
The Finite Element Method ◽  
External Excitation ◽  
Stiffness Variation ◽  
Smooth Muscle Contractions

An experimental and theoretical investigation is conducted to study the dynamic response of a tracheal smooth muscle under isometric conditions. The stiffness variation due to external vibration is investigated experimentally using trachea smooth muscles from excised pigs. The finite element method is used to model the muscle as a 2-D strip with variable stiffness and subjected to an external excitation. The Cauchy’s first law is invoked to describe the motion and Galerkin’s method is used to develop the finite element formulation. Different boundary conditions are considered to simulate the vibration characteristics and to get realistic compatibility with actual muscle conditions. The model predicts the stiffness variation due to vibration that is observed experimentally. The main outcome from this investigation is the fact that smooth muscle contractions could be relaxed by tuning the excitation within predetermined frequencies.

scholarly journals Assessing Structural Damage after a Severe Wildfire: A Case Study

Buildings ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 171
Author(s):  
Angeliki Papalou ◽  
Dimitrios K. Baros
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Temperature Distribution ◽  
Structural Damage ◽  
Extreme Heat ◽  
The Finite Element Method ◽  
Residential Areas ◽  
Severe Damage ◽  
Construction Type

Wildfires have always been a threat to forests and areas of high combustible vegetation. When they are not kept under control, they can spread to residential areas, creating severe damage and destruction. This paper examines the effects of the extreme heat conditions that developed during a wildfire on buildings as a function of their construction type. One of the deadliest wildfires in Greece (July 2018) is considered as a case study, and the damage that occurred to buildings during this event is presented. The temperature of the various structural subsystems in extreme heat conditions was estimated using the finite element method. Parameters that influenced the corresponding temperature distribution were identified. Simple guidelines are given to prevent or reduce damage in buildings exposed to wildfires.

An Investigation of the Shell Nosing Process by the Finite-Element Method. Part 1: Nosing at Room Temperature (Cold Nosing)

1982 ◽  
Vol 104 (3) ◽  
pp. 305-311 ◽  
Author(s):  
Ming-Ching Tang ◽  
Shiro Kobayashi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Room Temperature ◽  
Moving Boundary ◽  
Thickness Distribution ◽  
The Finite Element Method ◽  
Forming Process ◽  
Finite Element Program ◽  
Strain Rate Effects ◽  
Element Method

The metal-forming process of shell nosing at room temperature was analyzed by the finite-element method. The strain-rate effects on materials properties were included in the analysis. In cold nosing simulations, the nine-node quadrilateral elements with quadratic velocity distribution were used for the workpiece. The treatment of a moving boundary in the analysis of nosing is discussed and successfully implemented in the finite-element program. FEM simulations of 105-mm dia. shells of AISI 1018 steel and aluminum 2024 were performed and solutions were obtained in terms of load-displacement curves, thickness distribution, elongation, and strain distributions. Comparisons with experimental data show very good agreement.

scholarly journals Subsidence and heat propagation modeling on the underground coal gasification (Case study at Muara Enim Formation, South Sumatera)

2020 ◽  
Vol 23 (2) ◽  
pp. 83-98
Author(s):  
Zulfahmi Zulfahmi ◽  
◽  
Ildrem Syafri ◽  
Abdurrokhim Abdurrokhim ◽  
Ridho Wattimena ◽  
...  
Keyword(s):  
Coal Gasification ◽  
Mechanical Characteristics ◽  
Heat Propagation ◽  
Surface Subsidence ◽  
Underground Coal Gasification ◽  
Propagation Modeling ◽  
External Conditions ◽  
Cap Rock ◽  
Physical And Mechanical Characteristics

One of the important issues to study underground coal gasification (UCG) is the prediction of surface subsidence. Several parameters that influence these conditions are the thickness of cap rock, the physical and mechanical characteristics, the structure condition, the minerals composition of the rock, and external conditions. This study had been carried out simulation and modeling to determine the level of surface subsidence risk and the effect of high temperatures due to the activities. The modeling results show that the thickness of the rock above the UCG coal seam greatly affects the surface subsidence. The depth is more than 200 m and found that the SF value is 1.59 which indicates UCG reactor depth of ≥ 200 m is safe from the risk of subsidence. From the characteristic aspect of the cap rock, the claystone types which not contain kaolinite minerals are more prone to collapse than those of contain kaolinite minerals. From this models, the gasifier at 150 m depth was estimated that there will be a decline of -7.23 m, and the minimum subsidence is at 275 m about 0.1 m. The heat propagation modeling results show that at 50 m the temperature is estimated to be 213- 289°C, but if the thickness of the cap rock is > 200 m depth, the temperature is around 29-28°C.

Fundamentals and Applications of the Finite-Element Method in Analyzing Structural and Nonstructural Marine Problems

1982 ◽  
Vol 19 (03) ◽  
pp. 272-292
Author(s):  
Donald Liu ◽  
Yung-Kuang Chen
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Boundary Integral ◽  
Boundary Integral Method ◽  
Element Formulation ◽  
The Finite Element Method ◽  
Static And Dynamic Analysis ◽  
Marine Industry ◽  
Wide Range ◽  
Element Method

The finite-element method has become a popular and effective tool not only for structural analysis, but also for a wide range of physical problems which are of particular interest to the marine industry. A brief review of the finite-element formulation for structural and nonstructural problems is presented. Applications to marine structures, including static and dynamic analysis and fracture mechanics, are given. Nonstructural applications to heat transfer and ship hydrodynamic problems are also demonstrated. Recent developments in the coupled fluid-structural interaction problem using the boundary integral method, which is considered as an extension of the finite-element method, are also described.

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