Seepage and Heat Flow in Soil Freezing

1982 ◽  
Vol 104 (2) ◽  
pp. 323-328 ◽  
Author(s):  
P. E. Frivik ◽  
G. Comini

In this paper we describe a system of computer programs based on the finite element method, which can be used for the calculation of coupled velocity and temperature fields during freezing and thawing of soils in the presence of seepage flow. In the programs, the mass and energy conservation equations are solved simultaneously, without the use of too limiting assumptions. The results of the computations are compared with experimental measurements made on a laboratory model of a soil freezing system, and the agreement between measured and computed values is good.

Author(s):  
Виктор Григорьевич Чеверев ◽  
Евгений Викторович Сафронов ◽  
Алексей Александрович Коротков ◽  
Александр Сергеевич Чернятин

Существуют два основных подхода решения задачи тепломассопереноса при численном моделировании промерзания грунтов: 1) решение методом конечных разностей с учетом граничных условий (границей, например, является фронт промерзания); 2) решение методом конечных элементов без учета границ модели. Оба подхода имеют существенные недостатки, что оставляет проблему решения задачи для численной модели промерзания грунтов острой и актуальной. В данной работе представлена физическая постановка промерзания, которая позволяет создать численную модель, базирующуюся на решении методом конечных элементов, но при этом отражающую ход фронта промерзания - то есть модель, в которой объединены оба подхода к решению задачи промерзания грунтов. Для подтверждения корректности модели был проделан ряд экспериментов по физическому моделированию промерзания модельного грунта и выполнен сравнительный анализ полученных экспериментальных данных и результатов расчетов на базе представленной численной модели с такими же граничными условиями, как в экспериментах. There are two basic approaches to solving the problem of heat and mass transfer in the numerical modeling of soil freezing: 1) using the finite difference method taking into account boundary conditions (the boundary, for example, is the freezing front); 2) using the finite element method without consideration of model boundaries. Both approaches have significant drawbacks, which leaves the issue of solving the problem for the numerical model of soil freezing acute and up-to-date. This article provides the physical setting of freezing that allows us to create a numerical model based on the solution by the finite element method, but at the same time reflecting the route of the freezing front, i.e. the model that combines both approaches to solving the problem of soil freezing. In order to confirm the correctness of the model, a number of experiments on physical modeling of model soil freezing have been performed, and a comparative analysis of the experimental data obtained and the calculation results based on the provided numerical model with the same boundary conditions as in the experiments was performed.


2007 ◽  
Vol 348-349 ◽  
pp. 941-944
Author(s):  
Li Juan Cao ◽  
Shou Ju Li ◽  
Zi Chang Shangguan

Freezing and thawing damage is one of the major problems of concrete dams in cold climate. Cracking and splitting are the most common results of freezing and thawing deterioration in concrete dam. The cracking problem owing to freezing and thawing was investigated by making sue of finite element methods. The interpretation of the mechanism of failure was also given. In order to compute the thermal stress fields of concrete dam caused by freezing and thawing, the temperature changes versus seasons is determined according to measured data. The temperature fields of concrete dam versus seasons are simulated by using finite element method. Basing on the computational results of the temperature fields of concrete dam, the thermal stress fields are calculated numerically. The researches show that the first principal stress of concrete dam at downstream surface can exceed the tensile strength of concrete material. The numerical simulation results of fractured regions of concrete dam agreed with practical observed data.


2019 ◽  
Vol 23 (3 Part B) ◽  
pp. 1889-1899
Author(s):  
Radovan Nikolic ◽  
Miroslav Lucic ◽  
Bogdan Nedic ◽  
Miroslav Radovanovic

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.


Author(s):  
José William Ribeiro Borges ◽  
Wellington da Silva Fonseca ◽  
Fernando de Souza Brasil ◽  
Ramon C.F. Araújo

The electrical insulation is one of the main sources of failures in hydro-generators, therefore it is important to research the insulation system of stator bars. In this paper, it is developed a steady-state multiphysics analysis of a stator bar using the Finite Element Method to assess its steady-state behavior in the electrical, magnetic and thermal domains. Different aspects are analyzed in simulations, such as capacitance, mechanical stress and thermal effects. Numerical results are compared with experimental measurements for validation.


2012 ◽  
Vol 61 (4) ◽  
pp. 471-482 ◽  
Author(s):  
Andrzej Waindok

Abstract The calculation results of the static field parameters for permanent magnet linear synchronous motor have been presented in this work. The influence of the construction temperature on the parameters has been analyzed mathematically. Models for magnetic and temperature fields determination have been formulated. Two kinds of permanent magnets (NdFeB and SmCo) have been considered. The distribution of the thermal field has been obtained using the finite element method (FEM).


Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 912
Author(s):  
Nicoleta Gillich ◽  
Nicolae Sîrbu ◽  
Sorin Vlase ◽  
Marin Marin

In the manufacture of commercial trucks, used in oil installations or the army, two identical engines are used on a single chassis, whose power is summed by a gearbox, a compact metal construction, which must meet multiple operating requirements. The paper studies the behavior of such an adding box, currently used in manufacturing, and an improved, welded solution that produces less noise and has a lower weight. The finite element method is used for modeling the gearbox in order to analyze stresses and strains and obtain a modal analysis of the system. The results obtained from the calculation are then verified by experimental measurements. The two versions are analyzed in parallel to highlight the advantages of the second version.


2021 ◽  
Vol 21 (3) ◽  
pp. 260-267
Author(s):  
A. V. Maistrenko

Introduction. The thermal calculation of a volumetric structure using the finite element method is considered. According to the plans of the Ministry of Energy of the Russian Federation, a powerful wind energy industry will be created in the country in the coming years. In this regard, calculations in the production of building structures of wind power plants are currently becoming a challenge. The production of such fiberglass structures is a complex thermochemical process, including the polymerization of the binder under strictly specified thermal conditions. The work objective is to develop a method for three-dimensional finite element calculation of the non-stationary heating mode of a complexshaped composite structure.Materials and Methods. The determination of the temperature fields of a complex-shaped structure made of inhomogeneous materials causes using numerical methods and, first of all, the finite element method. The finite element modeling of the behavior of composite materials under molding is still incomplete. For its partial solution, the well-known heat conduction equation is adapted for a specific problem based on the first law of thermodynamics. New finite element models describing the thermal fields in the structure during its manufacture are proposed. The accuracy of modeling thermal processes is specified. Numerical simulation of heating is carried out.Results. The solution to the problem was performed in the multifunctional software complex ANSYS with the implementation of the calculation method in the parametric programming language APDL. The temperature fields of the blade elements of wind power plants at the stage of their manufacture were calculated, which made it possible to identify the characteristic features of the production process of these structures and to obtain recommendations for clarifying the process of their gluing.Discussion and Conclusions. The results obtained can be used in thermal calculations of elements of complex layered structures made of composite materials in wind power, mechanical engineering, aircraft, shipbuilding, instrumentation, etc.


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