Investigation Of Temperature Field Research Articles

Investigation of temperature fields of a glass furnace

The pricing policy of the fuel and energy market is constantly growing. The urgency of research is to adjust the optimization of fuel consumption in the glass furnace to obtain the maximum economic effect of production.
 Using the developed mathematical model of the glass furnace, the analysis was carried out: temperature modes of the furnace, temperature fields of glass and masonry. The temperature distribution in the sections of the glass furnace is performed by means of simulation modeling.
 The object of research consists of glass mass, gas space, masonry and divided into conditional sections (zones), according to the installation of temperature measuring instruments. In cross sections, the main ones are those that correspond to the position of the burners. In sections on the layers of glass mass, the starting point of the measurement is the surface of the glass mass, and the final bottom of the furnace. The longitudinal sections show the melting behavior of the charge pieces to the state of homogeneity - the transition of glass mass from the loading point of the charge to full melting. The dynamics of glass mass temperature change in the depth of the glass mass layer is the heating curve, the lower the layer considered - the lower the temperature due to the distance from the burners, but within one layer the temperature increases the closer the section to the point. Glass furnace refers to reversible - switching burners to the left or right group. Accordingly, the reverse switching takes place according to a given algorithm, which consists in adjusting the operating time of the group of burners depending on the temperature of the glass mass. The temperature distribution in the glass mass according to the temperature field at a depth of 0.1 m from the upper level of the glass mass is lower by 5-6% from the data of technological regulations. To do this, increased fuel consumption on the burners of the left group, made it possible to optimize fuel consumption. The study of the temperature field of the vault masonry made it possible to avoid problems with overheating and possible collapse of the masonry. Heating of the masonry within the permissible limits from a temperature of 10000C at the edges of the vault and 13800C in the central zone. The cross-section shows the loading channel of the charge, which borders the gas space, so the charge at the entrance to the cooking zone of the furnace receives additional heating and reduces fuel consumption in the first zone for heating the charge. The temperature distribution in the surface layer of the glass mass contains inhomogeneity in the first zone, to achieve uniformity increases fuel consumption on the first pair of burners, which optimizes the consumption of other pairs of burners and prevents excessive gas consumption. The overlap of two thirds of the corresponding plane when leaving the burner of the first section is increased from the required by 5%. In the second section, due to underheating of the selected plane, the value of fuel consumption increased by 12%. The temperature distribution is the lowest in the loading zone, the highest - after the third zone to the fifth (in the cave point). If the composition of the charge is changed (the action of uncontrolled perturbation), and the gas flow through the burners remains unchanged, it is impossible to achieve the value of temperature fields in accordance with the technological regulations.
 A scientific novelty is the study of cross-sections of glass mass in different planes, made it possible to analyze the temperature fields of glass mass at points where it is technologically impossible to organize measurements.

Modeling and investigation of temperature fields at phase boundaries in powder mixtures undergoing melting and chemical transformation

An important component of the process of hardening parts by induction surfacing is the heating of hard alloy and flux particles in the surfacing charge. The article describes complex studies on measuring and modeling temperatures at phase boundaries in complex melting and thermoreactive powder mixtures. To register the temperature in the process of induction surfacing, it is proposed to use the XA-microthermocouple method and the method of thermal indication using SHS compositions. The data of numerical modeling and solution of the non-stationary problem of heat conduction in the selected model of composite contact materials are presented. The developed methods of complex registration of temperature in the process of induction surfacing make it possible to determine the melting temperatures of the surfacing charge and its individual components, as well as the surface of the part.

Численное моделирование термоудара в упругом теле с учетом эффектов нелокальности среды

Creating mathematical simulations that allow material behaviour to be described for a wide range of variable external effects is an important stage of developing and utilising new structurally sensitive materials. At present, there exist several approaches to analytical simulation of materials featuring a complex internal structure. We used methods of generalized thermomechanics to derive constitutive equations for a mathematical model describing the temperature and dynamic stress distributions for the case of a thermal shock on the surface of an elastic body, taking spatial non-locality into account. We employed a medium model featuring internal state parameters to describe the process of non-steady-state thermal conductivity. The model proposed makes it possible to account for the spatial and temporal non-locality effects found in structurally sensitive materials; this may be used in further investigations of temperature fields and stresses occurring in structural elements as a result of various external effects. We propose an algorithm for developing numerical solutions based on a Galerkin finite element method. The paper presents temperature field and stress computations for a one-dimensional problem and analyses the effect the non-locality parameters have on these solutions

Experimental Investigation of Ground and Air Temperature Fields of a Cold‐Region Road Tunnel in NW China

To fully understand the temperature distribution of cold regions and the variation law of temperature fields in cold‐region tunnels, this paper presents a case‐history study on a tunnel located on the eastern Qinghai‐Tibet Plateau, China. The conclusion is as follows: the temperature outside the tunnel and the ambient temperature are affected by wind speed and light. The law of the temperature field in the tunnel is greatly affected by wind speed and wind direction. According to the field test, the wind speed in the tunnel is about 2.8 m/s in winter, and the daily average temperature at the exit of the tunnel is basically lower than that at the entrance. From the central to the entrance, the temperature in the tunnel decreases by 0.11°C every 10 meters along the longitudinal direction; from the central to the exit, the temperature in the tunnel increases by 0.07°C every 10 meters. In this regard, for the problems of lining frost damage and central drainage pipe freezing, it is suggested to adopt the way of heating and drainage, but heating the freezing area outside the drainage pipe should be avoided. The test results can provide references for the design, construction, and research of the temperature field of the tunnel antifreezing system in the cold region. It is hoped that the test results can be useful in the design and construction of frost damage prevention systems and the investigation of temperature fields in cold‐region tunnels.

Investigation of temperature fields in the air environment above wood subjected to thermal degradation

The paper deals with the visualization of thermal fields above the sample body while observing thermal loading of wood. Via holographic interferometry, thermal fields were visualized in a non-contact manner and the values were recorded in 0, 3, 7 and 15 minutes or earlier in case of degradation. In real time, the ongoing processes were recorded in the thermal boundary layer above the surface of sample bodies in dimensions of 43 mm × 40 mm × 10 mm of beech wood in three different directions: longitudinal, radial, tangential cut. The temperatures of isothermal curves above the heated samples and coefficients of heat transfer α were determined by a quantitative analysis of holographic interferograms. The heat transfer coefficient α ranged within 4.6-7.4 W/m2K. The simulation of heat transfer for the selected samples was prepared by the Fluent programme. Consequently, the measured values from the experiments were compared with the calculated values. There is a correlation between the measured and calculated values.

Численный анализ влияния нестационарности процессов теплопереноса в зонах размещения подземных теплопроводов на их тепловые режимы и тепловые потери

Актуальность исследования обусловлена необходимостью разработки новых подходов к анализу тепловых режимов и тепловых потерь подземных трубопроводов и подтверждается основными положениями Энергетической стратегии России на период до 2030 г. Подземные трубопроводы широко используются при транспортировке жидкостей в различных областях, например, таких как водоснабжение и теплоснабжение, нефтепроводы и газопроводы, технологические трубопроводы промышленных предприятий. При проектировании систем такого рода необходимо учитывать нестационарность теплообмена между грунтом и подземным трубопроводом, что во многих случаях оказывает существенное влияние на экономичность транспортировки энергоносителей. Цель: численный анализ нестационарных тепловых режимов и тепловых потерь подземных теплоопроводов и исследование температурных полей и закономерностей нестационарного теплопереноса в зонах размещения подземных бесканальных трубопроводов. Объекты: типичные для систем транспортировки энергоносителей подземные двухтрубные бесканальные трубопроводы. Трубопроводы изолированы пенополиуретаном и защитным покровным гидроизоляционным слоем из полиэтилена. Температуры на внутренней поверхности труб равны среднегодовым температурам энергоносителей в подающих и обратных трубопроводах водяных тепловых сетей при их работе по температурному графику 95/70 °С. Сезонное изменение температуры окружающей среды вычислялось по закону простого гармонического колебания. Исследования проводились для климатических условий г. Томск. Средний коэффициент теплоотдачи на поверхности раздела «грунт - окружающая среда» составлял 5 Вт/(м2  К). Методы: численное решение задач теплопереноса методом конечных элементов с использованием аппроксимации Галеркина, неравномерной конечно-элементной сетки, количество элементов которой выбирается из условий сходимости решения, сгущение сетки проводится методом Делоне. Результаты. Установлены масштабы тепловых потерь и закономерности нестационарного теплопереноса в зонах размещения подземных бесканальных трубопроводов. Показана необходимость учета нестационарности теплопереноса в зоне размещения подземных теплопроводов при прогностическом моделировании их тепловых режимов и тепловых потерь. Нестационарность теплопереноса в зоне размещения подземных тепловых сетей может оказать заметное влияние, например, в тех случаях, когда в зоне теплового влияния подземных трубопроводов расположены смежные коммуникации или инженерные сооружения.

Modelling and investigation of temperature field in the boundary layer of biological bodies

A problem on finding temperature field in the boundary layer of biological body when blood perfusion coefficient depends on coordinate is solved. Temperature distribution is caused by the temperature differences between the inside and outside of a body and by the outside heat sources and metabolic heat generation. Heat transfer problem is formulated by using generalized Heaviside functions. Applying the variation of constants method this problem is reduced to the Fredholm integral equation of the second kind. Numerical method of Simpson quadratures was used to solve integral equation. Analysis of temperature distribution in the boundary layer for some cases of boundary conditions is performed. Dependence on temperature inside body from metabolic heat generation and outside heat source is analyzed.

Исследование температурных полей в элементах микроэлектронных устройств слоистой структуры со сквозными включениями

Исследование температурных полей в элементах микроэлектронных устройств слоистой структуры со сквозными включениями

Investigation of Temperature Fields in a Heat-Sensitive Layer with Through Inclusion

We consider a nonlinear axially symmetric boundary-value problem of heat conduction for a heat-sensitive isotropic layer with through foreign cylindrical inclusion. A heat flux is concentrated on one of the boundary surfaces of this inclusion. By using an introduced linearizing function, we perform partial linearization of the initial problem. As a result of piecewise linear approximation of temperature on the boundary surface of the inclusion, the boundary-value problem becomes completely linearized. With the help of the Hankel integral transformation, we obtain a numerical-analytic solution of the problem of determination of the linearizing function. We also present the computational formulas for temperature in the case of linear temperature dependence of the coefficients of thermal conductivity of structural materials. We also compute and analyze the temperature field in the “layer–inclusion” structure (the materials of the layer and inclusion are VK94-I ceramic and silver, respectively).

Rough-cut fast numerical investigation of temperature fields in selective laser sintering/melting

This paper investigates selective laser sintering/melting (SLS/SLM) processes by a thermal model solved with a finite difference scheme. The density equation is semi-empirical based on the Arrhenius equation and experimental results taken from literature. Energy distribution function in the laser beam is appropriately considered. The main input parameters studied were as follows: laser speed, preheating temperature and laser power. The output parameters were maximum temperature and consolidation area. SLS was tried on polycarbonate powder and SLM on a Ni superalloy. Variations of temperature and density with time at the centre of the beam and at another two points at increasing distances from it were found to be qualitatively similar irrespective of the laser speed and power. Maximum temperature reached is not affected significantly by preheating temperature, by contrast to the consolidated depth and consolidation area. The latter are also affected by laser power. Increase in laser speed leads, as expected, to a decrease in consolidation depth and area as well as a decrease in maximum temperature. Continuous and pulsed lasers exhibited large differences; e.g. for the same speed and power, a pulsed laser results in much lower temperature gradients during cooling. The model can be used to obtain a preliminary picture of the response of any material to SLS/SLM processing provided that the appropriate input data is available, which is a crucial factor not to be underestimated.

Experimental investigation of temperature fields in a synthetic jet

The paper deals with the measurement of temperature fields in a synthetic jet. This type of experiment presents several challenges; therefore, to ensure the best precision possible, two experimental methods were used - digital holographic interferometry (DHI) and thermo-anemometry in constant current mode as an auxiliary method to verify DHI.

Investigation of Temperature Field of the Canned Motor of Nuclear Primary Pump

The safe operation of canned motor in nuclear primary pump is very important for nuclear power station. Taken a 5500KW large canned motor of nuclear primary pump as an example, physical model of three dimensional fluid and temperature coupled field was established. The motor temperature distribution under nominal working condition was calculated by using finite volume method. By calculation, revealing the temperature distribution regularity of stator strands, rotor bars, stator core and rotor core, which have significant reference value to structure design of canned motor.

ДослідженнЯ температурнОгО полЯ В поперечномУ перерІзІ корпУсУ тепловоЇ трубИ З аксіальнИмИ канавкамИ

Наведено аналітичні залежності для визначення одновимірного температурного поля і двовимірна чисельна модель температурного поля в поперечному перерізі корпусу зон нагріву та конденсації теплової труби. Результати розрахунків порівняно з експериментальними даними для алюмінієвої теплової труби з аксіальними канавками, заповненої аміаком

Numerical investigation of temperature field of different mechanisms in laser forming

In laser forming, deformation of a plate is different when different mechanisms play dominant roles. A deformation field depends on a temperature field that is related to process parameters, material properties and plate size. Numerical investigations of temperature distribution with different process parameters were carried out when different mechanisms were active. A critical temperature for generating plastic deformation was investigated. Four temperature feature parameters were defined based on the temperature distribution characteristics of the high-temperature zone. The numerical results show that the temperature gradient is obviously different under different mechanism conditions. The temperature distribution features for the different mechanisms have a larger difference, which is helpful for the discrimination of different mechanisms according to the temperature field in real industrial applications.

Investigation of temperature fields in supersonic flow behind a backward-facing step

The results of numerical modelling and experimental investigations of high-enthalpy turbulent flows in the neighborhood of 90-degree backward-facing steps at the Mach numbers M∞ = 2–4 are presented. The experiments were conducted in the hot-shot wind tunnel IT-302M of ITAM SB RAS. The computations were carried out on the basis of the full Favres-averaged Navier — Stokes equations augmented by the Wilcox turbulence model. The temperature factor influence on the flow structure in the separated zone and temperature distributions was investigated numerically for different Mach numbers. The wall temperature is shown to affect significantly the quantity and sizes of recirculation vortices as well as the temperature distribution in the zone of flow separation and reattachment. The computational results are compared with experimental data on the pressure distribution on the model surface and the wave structure of the flow.

Investigation of temperature fields on the surface of tungsten cathode of a high-current arc using a high-speed matrix

A method is suggested of time-space analysis of temperature fields on the surface of tungsten cathode of a high-current electric arc using a VS-FAST high-speed video camera (manufactured by VideoScan, Moscow). The importance of contribution made by plasma radiation to the cathode surface emissivity being measured is considered, and the methods of taking this contribution into account are identified. Experiments reveal the possibility of using this high-speed video camera as a pyrometer providing for time resolution up to 2 μs and space resolution of about 30 μm.

Numerical investigation of temperature fields in the duct of uranium-graphite reactor with fuel elements of bush type

A two-dimensional mathematical model has been developed for unsteady thermophysical processes in the industrial duct of an uranium-graphite reactor with conversion fuel elements of the bush type. The numerical algorithm and computer code have been developed on the basis of the proposed model to investigate the temperature fields in an aluminum core, fuel, shell as well as in the cooling water with regard for the design and technological assembly peculiarities. The results of some computational experiments are presented, which characterize the distribution of temperature fields in the column of fuel elements and in the cooling water.

Distributed thermoprofilometers and their capabilities in oceanographic investigations

We describe the principles of design of distributed thermoprofilometers and analyze their characteristics and the required hardware, algorithms, and software. The capabilities of these instruments in the investigation of temperature fields, vertical displacements, and the parameters of internal waves are evaluated. The results of measurements and numerical calculations are presented.

Investigation of temperature fields in the contact zone of droplets (splashes) on molten metal with the surface of welded metal

Investigation of temperature fields in the contact zone of droplets (splashes) on molten metal with the surface of welded metal

Numerical simulation of temperature fields in elastomeric structures with cracks on the basis of singular finite elements

We describe a method used for the investigation of temperature fields of dissipative heating in elastomeric structures with cracks. Determining relations are constructed on the basis of a moment scheme of finite elements with application of singular quadratic elements. The\({1 \mathord{\left/ {\vphantom {1 {\sqrt r }}} \right. \kern-\nulldelimiterspace} {\sqrt r }}\)-type singularities of the stress and strain fields at the crack tip are simulated by shifting the intermediate nodes by a quarter of the length of the side toward the crack tip in the basic coordinate system, while the functions of shape remain unchanged in the process of construction of the stiffness matrix. As an example, we study the problem of determination of temperature fields in continuous cylindrical, trough-shaped, and rectangular shock absorbers of complex geometry with cracks. The proposed method is realized in the form of a software complex for personal computers called KODETOM.