Ignition of Liquid Fuel Droplet in a Hot, Stagnant Oxidizing Atmosphere-Numerical Computations

1984 ◽  
Vol 2 (6) ◽  
pp. 400-414 ◽  
Author(s):  
Andrzej Teodorczyk
Keyword(s):  
Mathematical Model ◽  
Finite Element Method ◽  
Finite Element ◽  
Ambient Temperature ◽  
Oxygen Concentration ◽  
Liquid Fuel ◽  
Droplet Diameter ◽  
Fuel Droplet ◽  
The Finite Element Method ◽  
Initial Droplet

The paper describes the physical and mathematical model of the ignition of a liquid fuel droplet suddenly immersed in a hot oxidizing medium. The model was solved numerically by the finite element method. The ignition lags in terms of ambient temperature, oxygen concentration and initial droplet diameter were computed.

Model calculations in reconstructions of measured fields

Open Physics ◽  
2003 ◽  
Vol 1 (1) ◽  
Author(s):  
Mihály Makai ◽  
Yuri Orechwa
Keyword(s):  
Mathematical Model ◽  
Finite Element Method ◽  
Finite Element ◽  
Group Theory ◽  
Point Group ◽  
Iterative Solution ◽  
The Finite Element Method ◽  
Technological Systems ◽  
Convergence Problem ◽  
Model Calculations

AbstractThe state of technological systems, such as reactions in a confined volume, are usually monitored with sensors within as well as outside the volume. To achieve the level of precision required by regulators, these data often need to be supplemented with the solution to a mathematical model of the process. The present work addresses an observed, and until now unexplained, convergence problem in the iterative solution in the application of the finite element method to boundary value problems. We use point group theory to clarify the cause of the non-convergence, and give rule problems. We use the appropriate and consistent orders of approximation on the boundary and within the volume so as to avoid non-convergence.

scholarly journals УЗАГАЛЬНЕННЯ МОДЕЛІ ФОЛЬКЕРСЕНА НА ВИПАДОК ОСЬОВОЇ СИМЕТРІЇ

2021 ◽  
pp. 78-89
Author(s):  
К. П. Барахов
Keyword(s):  
Mathematical Model ◽  
Finite Element Method ◽  
Finite Element ◽  
Stress State ◽  
Boundary Conditions ◽  
Classical Model ◽  
The Finite Element Method ◽  
Premature Failure ◽  
One Dimensional ◽  
Element Method

Thin-walled structures may contain defects as cracks and holes that are leftovers of the material the construction, is made of or they occur during the operation as a result of, for example, mechanical damage. The presence of holes in the plate causes a concentration of stresses at the boundary of the holes and ultimately leads to premature failure of the structural element. Repair of local damage of modern aircraft structures can be made by creating overlays that are glued to the main structure. The overlay takes on part of the load, unloading the damaged area. This method of repair provides tightness and aerodynamic efficiency to the structure. The calculation of the stress state of such glued structures is usually performed by using the finite element method. The classic models of the stress state of overlapped joints are one-dimensional. That is, the change of the stress state along only one coordinate is considered. At the same time, the connections of a rectangular form are also considered. The purpose of this work is to create a mathematical model of the stress state of circular axisymmetric adhesive joints and to build an appropriate analytical solution to the problem. It is assumed that the bending of the plates is absent; the deformation of the plates is even by thickness. The adhesive layer works only on the shift. The main plate and the overlay are considered isotropic. The solution is built on polar coordinates. The stress state of the connection depends only on the radial coordinate, i.e. one-dimensional. The solution is obtained in analytical form. This mathematical model is a generalization of the classical model of the adhesive connection of Volkersen to a circular or annular region and is considered for the first time. Boundary conditions are met exactly. The satisfaction of marginal conditions, as well as boundary conditions, leads to a system of linear equations with respect to the unknown coefficients of the obtained solutions. The model problem is solved and the numerical results are compared with the results of calculations performed by using the finite element method. It is shown that the proposed model has sufficient accuracy for engineering problems and can be used to solve problems of the design of aerospace structures.

scholarly journals Calculation of temperature fields during lathe machining with thermoelectric cooling by using the finite element method

2019 ◽  
Vol 23 (3 Part B) ◽  
pp. 1889-1899
Author(s):  
Radovan Nikolic ◽  
Miroslav Lucic ◽  
Bogdan Nedic ◽  
Miroslav Radovanovic
Keyword(s):  
Mathematical Model ◽  
Finite Element Method ◽  
Finite Element ◽  
Temperature Field ◽  
Cutting Tool ◽  
Thermoelectric Module ◽  
Temperature Fields ◽  
Prototype Model ◽  
The Finite Element Method ◽  
Element Method

The aim of this work is to explore the possibilities of the implementation of systems based on a thermoelectric module for cooling the cutting tool. This cooling becomes significant when it is not possible to use conventional coolants and lubricants. Starting from existing mathematical models for the calculation of the temperature field of the cutting tool, a mathematical model is developed that takes into account the cooling based on the thermoelectric module. The use of the finite element method determines temperature field when dry lathe machining in the cooling conditions based on the thermoelectric module. The Software package, PAK-T, is used for the calculations and was developed at the Department of Applied Mechanics, Faculty of Engineering in Kragujevac, Serbia. The system for cooling the cutting tool based on the thermoelectric module was realized under laboratory conditions on a prototype model, which consists of a cutting tool and a thermoelectric module. Verification of the obtained results was carried out on the basis of a mathematical model by experimental research of the temperature field of the cutting tool in terms of cooling based on a thermoelectric module.

A New Method to Quickly Optimize the Thickness of Multi-Holes Plate

2014 ◽  
Vol 915-916 ◽  
pp. 205-208
Author(s):  
Sheng Bin Wu ◽  
Xiao Bao Liu
Keyword(s):  
Mathematical Model ◽  
Finite Element Method ◽  
Finite Element ◽  
Design Method ◽  
New Method ◽  
The Finite Element Method ◽  
Design Error ◽  
Theory Of Plates ◽  
Plates And Shells ◽  
Element Method

The theory of plates and shells is not adapted to design thickness for the multi-holes plates in engineering. A new method to quickly optimize the thickness based on the finite element method theory was put forward. The method combined the theory of plate with the finite element method to establish a mathematical model and analyzed the influences of load, constraint and complexity on design error. The practices demonstrated that the proposed design method is effective and feasible.

Temperature Distribution and Thermal Stress Analysis of Ball-Tank Subjected to Solar Radiation

2005 ◽  
Vol 127 (2) ◽  
pp. 119-122 ◽  
Author(s):  
Vishnu Verma ◽  
A. K. Ghosh ◽  
H. S. Kushwaha
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Thermal Stress ◽  
Temperature Distribution ◽  
Solar Radiation ◽  
Ambient Temperature ◽  
Research Reactor ◽  
The Finite Element Method ◽  
Large Structure ◽  
Seasonal And Diurnal Variation

The ball tank of the research reactor CIRUS is exposed to solar radiation. The ambient temperature undergoes seasonal and diurnal variation. The resulting thermal stress could be significant for the large structure. The temperature distribution has been obtained by the finite element method. The paper presents temperature distribution and the resulting thermal stress.

Evaluating quinoa stem lodging susceptibility by a mathematical model and the finite element method under different agronomic practices

2021 ◽  
Vol 271 ◽  
pp. 108241
Author(s):  
Ning Wang ◽  
Feng-Xin Wang ◽  
Clinton C. Shock ◽  
Chao-Biao Meng ◽  
Ze-Jun Huang ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Finite Element Method ◽  
Finite Element ◽  
The Finite Element Method ◽  
Agronomic Practices ◽  
Element Method

A Material Selection Method Based on Finite Element Method

2014 ◽  
Vol 887-888 ◽  
pp. 1013-1016
Author(s):  
Sheng Bin Wu ◽  
Xiao Bao Liu
Keyword(s):  
Mathematical Model ◽  
Finite Element Method ◽  
Finite Element ◽  
Material Selection ◽  
Selection Method ◽  
Structure Design ◽  
The Finite Element Method ◽  
The Mathematical Model ◽  
Selection Of ◽  
Element Method

A new method for material selection in structure design based on the theory of the finite element method was presented. The method made material selection and structure design working at the same time. The mathematical model was established based on the finite element method. Finally, the material selection of an excavator's boom was verified, the results show that the proposed method is effective and feasible.

scholarly journals Modelling the Laser Cladding of Geometrically More Complex Tracks and Its Experimental Verification

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1403
Author(s):  
Ivo Doležel ◽  
Václav Kotlan ◽  
Roman Hamar ◽  
Karel Slobodník
Keyword(s):  
Mathematical Model ◽  
Finite Element Method ◽  
Finite Element ◽  
Temperature Field ◽  
Substantial Improvement ◽  
Time Variable ◽  
Variable Geometry ◽  
The Finite Element Method ◽  
Corrosion Resistant ◽  
Wear And Corrosion

In this paper, a methodology for depositing wear- and corrosion-resistant layers of geometrically more complex tracks on metal substrates is presented. The corresponding mathematical model includes the temperature field produced by the laser beam, the field of residual mechanical stresses, and the efficiency of utilization of the delivered powder material. The computations are realized using the finite element method, with a substantial improvement in processing the time-variable geometry of the investigated system being found, based on the introduction of two specific matrices that characterize both the surface on which the tracks are cladded as well as the track itself. The proposed technique is illustrated by cladding an angled helix on a metal surface. Selected results are successfully verified by experiments.

scholarly journals Dynamic Analysis of a Drillstring-Riser System Drilling in Deep Water

2018 ◽  
Vol 148 ◽  
pp. 16010
Author(s):  
Maolin Liao ◽  
Yingcao Zhou ◽  
Yinao Su ◽  
Zhilong Lian ◽  
Hongwei Jiang
Keyword(s):  
Mathematical Model ◽  
Finite Element Method ◽  
Finite Element ◽  
Dynamic Response ◽  
Deep Water ◽  
Safety Margin ◽  
The Finite Element Method ◽  
Friction Units ◽  
Proposed Model ◽  
Safe Condition

A mathematical model of a drillstring-riser system is developed to analyze the system dynamics when drilling in deep water. For the proposed model, a riser and a drillstring are combined as a pipe-in-pipe structure, along which the interactions between the riser and the drillstring are introduced by a series of spring-friction units. Numerical simulations of the developed mathematical model are carried out by Abaqus in which the finite element method is adopted. Comparing with the riser deflection calculated by previously published models which exclude the influences of the drillstring-riser interactions, the maximal riser deflection obtained by using the proposed drillstring-riser system is relatively small. Namely, the drillstring-riser interactions restrict the riser deflection. This finding indicates that, in a given safety margin of the riser deflection, the drillstring-riser system has stronger capacity of anti-deflection. Additionally, the influence of sea depth is investigated; the dynamic response of a drillstring-riser system drilling in deep water is obviously different from the corresponding condition drilling in shallow water. In order to maintain the drillstring-riser system work in a safe condition, the operations, such as thickening the riser wall, enhancing the control of the top drift, removing a part of buoyancy modules, decreasing WOB, and increasing the top tension of the riser, are suggested to be applied.

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