scholarly journals Mathematical Modeling and Simulation on the Stimulation Interactions in Coalbed Methane Thermal Recovery

Processes ◽  
2019 ◽  
Vol 7 (8) ◽  
pp. 526 ◽  
Author(s):  
Teng ◽  
Wang ◽  
He ◽  
Chen
Keyword(s):  
Modeling And Simulation ◽  
Coalbed Methane ◽  
Variable Temperature ◽  
Computational Simulation ◽  
Heating Time ◽  
Thermal Recovery ◽  
Gas Desorption ◽  
Simulation Results ◽  
Gas Coal ◽  
Stimulation Of

Heat stimulation of coalbed methane (CBM) reservoirs has remarkable promotion to gas desorption that enhances gas recovery. However, coalbed deformation, methane delivery and heat transport interplay each other during the stimulation process. This paper experimentally validated the evolutions of gas sorption and coal permeability under variable temperature. Then, a completely coupled heat-gas-coal model was theoretically developed and applied to a computational simulation of CBM thermal recovery based on a finite element approach of COMSOL with MATLAB. Modeling and simulation results show that: Although different heat-gas-coal interactions have different effects on CBM recovery, thermal stimulation of coalbed can promote methane production effectively. However, CBM thermal recovery needs a forerunner heating time before the apparent enhancement of production. The modeling and simulation results may improve the current cognitions of CBM thermal recovery.

scholarly journals Cheating at Craps

2021 ◽  
Vol 48 (4) ◽  
pp. 53-61
Author(s):  
Andrea Marin ◽  
Carey Williamson
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Modeling And Simulation ◽  
Analytical Model ◽  
Quantitative Evaluation ◽  
Mathematical Analysis ◽  
Simulation Modeling ◽  
Analytical Modeling ◽  
The World ◽  
Simulation Results

Craps is a simple dice game that is popular in casinos around the world. While the rules for Craps, and its mathematical analysis, are reasonably straightforward, this paper instead focuses on the best ways to cheat at Craps, by using loaded (biased) dice. We use both analytical modeling and simulation modeling to study this intriguing dice game. Our modeling results show that biasing a die away from the value 1 or towards the value 5 lead to the best (and least detectable) cheating strategies, and that modest bias on two loaded dice can increase the winning probability above 50%. Our Monte Carlo simulation results provide validation for our analytical model, and also facilitate the quantitative evaluation of other scenarios, such as heterogeneous or correlated dice.

scholarly journals A Comprehensive Coal Reservoir Classification Method Base on Permeability Dynamic Change and Its Application

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 644 ◽  
Author(s):  
Xinlu Yan ◽  
Songhang Zhang ◽  
Shuheng Tang ◽  
Zhongcheng Li ◽  
Yongxiang Yi ◽  
...  
Keyword(s):  
Coalbed Methane ◽  
Dynamic Change ◽  
Initial Permeability ◽  
Gas Production ◽  
Gas Desorption ◽  
Reservoir Permeability ◽  
Geological Conditions ◽  
Production Stages ◽  
Productivity Potential ◽  
Coal Reservoir

Due to the unique adsorption and desorption characteristics of coal, coal reservoir permeability changes dynamically during coalbed methane (CBM) development. Coal reservoirs can be classified using a permeability dynamic characterization in different production stages. In the single-phase water flow stage, four demarcating pressures are defined based on the damage from the effective stress on reservoir permeability. Coal reservoirs are classified into vulnerable, alleviative, and invulnerable reservoirs. In the gas desorption stage, two demarcating pressures are used to quantitatively characterize the recovery properties of permeability based on the recovery effect of the matrix shrinkage on permeability, namely the rebound pressure (the pressure corresponding to the lowest permeability) and recovery pressure (the pressure when permeability returns to initial permeability). Coal reservoirs are further classified into recoverable and unrecoverable reservoirs. The physical properties and influencing factors of these demarcating pressures are analyzed. Twenty-six wells from the Shizhuangnan Block in the southern Qinshui Basin of China were examined as a case study, showing that there is a significant correspondence between coal reservoir types and CBM well gas production. This study is helpful for identifying geological conditions of coal reservoirs as well as the productivity potential of CBM wells.

Modeling and Simulation of Ship Motion for Dynamic Positioning Vessel

2014 ◽  
Vol 919-921 ◽  
pp. 2127-2130
Author(s):  
Pei Wen Yu ◽  
Hui Chen
Keyword(s):  
Modeling And Simulation ◽  
Wind Wave ◽  
Ship Motion ◽  
Dynamic Positioning ◽  
Positioning System ◽  
Dynamic Positioning System ◽  
Oil Supply ◽  
Mmg Model ◽  
Simulation Results

The paper presents a method to build MMG model of ship motion for a oil supply vessel (OSV) with dynamic positioning system. It is assumed that the ship motion exposed to environment disturbances like wind, wave & currents, The simulation results show that the model of the vessel and environment disturbances are suitable, and the method is practicable .

Modeling and Simulation of Clamp Band Dynamic Envelope in a LV/SC Separation System

2011 ◽  
Vol 141 ◽  
pp. 359-363 ◽  
Author(s):  
Jun Lan Li ◽  
Shao Ze Yan ◽  
Xue Feng Tan
Keyword(s):  
Friction Coefficient ◽  
Modeling And Simulation ◽  
Band System ◽  
Separation Process ◽  
Impact Behavior ◽  
Separation System ◽  
Lumped Mass ◽  
Lumped Mass Method ◽  
Simulation Results ◽  
Contact Impact

The clamp band system is a typical locked and separated device of the launch vehicle (LV) / the spacecraft (SC), and its release-separation process is one of the important factors that affect the LV/SC separation movement. A nonlinear spring-damper model was employed to describe the contact-impact behavior between the V-segment of the clamp band and the LV/SC interface, and lumped mass method was used to depict the clamp band. By using ADAMS, a dynamic model of the clamp band system was established. The simulation results show that the impulse of the explosive bolts and the stiffness of lateral-restraining springs have significant effects on the clamp band dynamic envelope. The shock of the satellite-vehicle separation is very vulnerable to the clamp band pretension and the friction coefficient between the V-segment and the LV/SC interface.

Methodology for Wheelchair Design Based on Simulation Analyses

2021 ◽  
Author(s):  
Grzegorz Dobrzynski ◽  
Michal Abramowski
Keyword(s):  
Modeling And Simulation ◽  
Control Systems ◽  
Simulation Results ◽  
And Control

The article presents the stages of modeling and simulation of a new design of a wheelchair with the option of moving up and down stairs. These analyzes were aimed at the synthesis of the de-sign parameters and parameters of the sensor and control systems. The simulation results were verified by experimentally testing the prototype.

scholarly journals Finite element simulation of sink pass round tubes using Ansys

2012 ◽  
pp. 179-188 ◽  
Author(s):  
M.P. Nagarkar ◽  
R.N. Zaware ◽  
S.G. Ghalme
Keyword(s):  
Modeling And Simulation ◽  
Product Quality ◽  
Metal Forming ◽  
Cold Working ◽  
Ansys Software ◽  
Simulation Techniques ◽  
Element Simulation ◽  
Simulation Results ◽  
Von Mises ◽  
Von Mises Stresses

Modeling and simulation of metal forming processes are increasingly in demand from the industry as the resulting models are found to be valuable tools considering the optimization of the existing and development of new processes. By the application of modeling and simulation techniques, it is possible to reduce the number of time-consuming experiments such as prototyping. Seamless tubes of various sizes and shapes are manufactured by various processes like sinking, fixed plug, floating plug, moving mandrel, cold working and hot working. The present work deals with the simulation of round tubes while passing through the sink pass, using ANSYS software. The simulation results are the displacement and von Mises stresses. The procedure can be used to improve the product quality and to study the effect of various parameters like die angle on the product quality.

Modeling and Simulation of an Improved Measure of MPPT in Photovoltaic System

2011 ◽  
Vol 88-89 ◽  
pp. 244-249 ◽  
Author(s):  
Shou Jiang Cai ◽  
Pei Liang Wang ◽  
Zhi Duan Cai ◽  
Jian Hua Mao
Keyword(s):  
Modeling And Simulation ◽  
Simulation System ◽  
Photovoltaic System ◽  
Storage Space ◽  
Maximum Power Point ◽  
Point Tracking ◽  
Power Point Tracking ◽  
Simulation Results ◽  
Power Point ◽  
Accuracy Of Results

Intermittent scan tracking (IST) is a maximum power point tracking (MPPT) method of photovoltaic system. The scanning approach of this method generally is order scanning. But this scanning mode has the weaknesses of the huge storage space and excessive amount of calculation. To eliminate these defects, this paper proposes a new scanning mode, i.e. nested scanning. To verify the effectiveness of the proposed method, a simulation system was modeled based on Matlab/Simulink. In the experiment two scanning modes above were compared and the simulation results proved that, on the premise that the accuracy of results is guaranteed, nested scanning mode can effectively decrease the quantity of required scanning voltages and currents, reduce the amount of calculation and improve the scanning efficiency.

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