MATHEMATICAL MODEL AND ALGORITHM FOR CALCULATION OF THERMAL STATE OF A REGENERATOR ACCUMULATING CONVERTER GAS HEAT OF COMBUSTION AND HEATING AIR FOR A RECOVERY BOILER

2021 ◽  
Vol 3 (102) ◽  
pp. 38-55
Author(s):  
SERGEY V. LUKIN ◽  
DENIS V. PORODOVSKY ◽  
ANTON A. RAZINKOV ◽  
MAXIM A. BAHVALOV
Keyword(s):  
Mathematical Model ◽  
Oxygen Converter ◽  
Thermal State ◽  
Heat Of Combustion ◽  
Temperature Fields ◽  
Converter Production ◽  
Heating And Cooling ◽  
Heated Air ◽  
Recovery Boiler ◽  
Converter Gas

The heat of combustion of the converter gas, which is periodically formed in the oxygen-converter production at the metallurgical plant, is proposed to be used for alternate heating of the checkerwork of two regenerators (such as сowpers), and their alternate cooling by a continuous flow of air heated to a high temperature, and directed to the recovery boiler to generate steam. A mathematical model is presented that allows evaluating the thermal state of the regenerator, the temperatures of the heating gases and the heated air in the modes of heating and cooling the regenerator checkerwork. An algorithm for numerical calculation of the temperature fields of the regenerator checkerwork, gases and air is presented.

SUBSTANTIATION OF OPTIMAL PARAMETERS AND DEVELOPMENT OF HIGH-TEMPERATURE STERILIZATION MODES FOR COMPOTE FROM PEARS IN HEATED AIR FLOW

2020 ◽  
Author(s):  
М.Э. Ахмедов ◽  
А.Ф. Демирова ◽  
Г.И. Касьянов ◽  
Ю.Ф. Росляков ◽  
М.М. Рахманова
Keyword(s):  
Mathematical Model ◽  
High Temperature ◽  
High Speed ◽  
Heat Transfer Fluid ◽  
Initial Product ◽  
Hot Air ◽  
Heated Air ◽  
Sterilization Process ◽  
Thermal Sterilization ◽  
Heat Carriers

Разработаны новые режимы стерилизации компота из груш в стеклотаре СКО 1-82-1000 с использованием высокотемпературных скоростных теплоносителей. Получена математическая модель расчета продолжительности процесса стерилизации в зависимости от параметров теплоносителя. Для получения математической модели использован метод математического планирования эксперимента. Предложен технологический прием ускоренной стерилизации компота из груш в стеклобанке объемом 1 дм3. Разработаны новые режимы тепловой обработки (стерилизации) компота из груш в стеклобанке 1-82-1000 при различных параметрах горячего воздуха и разных начальных температурах продукта, °С: 70, 80, 85 и 90. Наименьшая продолжительность процесса тепловой стерилизации достигнута при скорости теплоносителя 7,5 м/с при начальной температуре продукта 90°С. New modes of sterilization of compote from pears in glass containers of SKO 1-82-1000 using high-temperature high-speed heat carriers have been developed. A mathematical model for calculating the duration of the sterilization process depending on the parameters of the heat carrier is obtained. To obtain a mathematical model, we used the method of mathematical planning of the experiment. A technological method for accelerated sterilization of pear compote in a glass jar with a volume of 1 dm3 is proposed. The research made it possible to develop new modes of heat treatment (sterilization) of compote from pears in a glass jar 1-82-1000 at different parameters of hot air and different initial temperatures of the product, °C: 70, 80, 85 and 90. The shortest duration of the thermal sterilization process is achieved at the heat transfer fluid speed of 7,5 m/s at the initial product temperature of 90°C.

Development of a Mathematical Model for a Workpiece Heating and Cooling in a Protective Medium while Treatment under Pressure

2021 ◽  
Vol 410 ◽  
pp. 115-122
Author(s):  
Victoria V. Devyatiarova ◽  
Eugenia E. Balakhnina ◽  
Lilya M. Valeeva
Keyword(s):  
Mathematical Model ◽  
Cross Section ◽  
Arbitrary Shape ◽  
Thermal Conductivity Coefficient ◽  
Regression Equations ◽  
Heating And Cooling ◽  
Temperature Problem ◽  
Protective Medium ◽  
Computer Calculations ◽  
The Mathematical Model

The paper reviews and develops the mathematical model of plastic flow during the hot-forming processes. A flat non-stationary temperature problem for a cross-section of a long solid (rolled product) of arbitrary shape with different heat transfer conditions along the perimeter of the cross-section was considered. Equations for calculation of the thermal conductivity coefficient and heat capacity of tungsten billets were obtained in the temperature range of 700 - 1500°C, based on the literature data. Analytical dependences in form of regression equations were obtained, allowing for computer calculations of physical specifications of 11x11 mm VA grade tungsten billets in form of temperature functions with accuracy sufficient for practical calculations.

Influence of Temperature Fields on the Quality of Dried Wood Products

2021 ◽  
Vol 1038 ◽  
pp. 336-344
Author(s):  
Olena Pinchevska ◽  
Andriy Spirochkin ◽  
Denys Zavialov ◽  
Rostislav Oliynyk
Keyword(s):  
Experimental Studies ◽  
Wood Products ◽  
Temperature Fields ◽  
Drying Process ◽  
Wood Moisture ◽  
Adequate Model ◽  
Heating And Cooling ◽  
White Spots ◽  
The Cost ◽  
Wood Heating

The reasons of white spots appearance in the middle of oak timber are determined. These white spots reduce the cost of the lamina made of oak timbers - the front covering of floorboards. It is proposed to intensify the drying process by using oscillating drying schedules to avoid this defect. A method for calculating the duration of such drying is proposed. This method includes the peculiarities of heating and cooling periods kinetics of oak timbers with 25 mm and 30 mm thickness. The inexpediency of using the oscillation of the drying agent parameters in the range of wood moisture content below 20% has been established. An adequate model for calculating wood temperature and air humidity during wood heating and cooling periods has been developed using heat and mass transfer criteria and experimentally determined oak wood moisture conductivity coefficient. Based on the results of theoretical and experimental studies oscillating drying schedules of different thickness oak timbers are offered. Tests of the proposed schedules in industrial conditions showed no discoloration of the central layers of European oak (Quercus robur) timbers. The drying process duration was reduced by 1.5–2.4 times and energy consumption were reduced by 1.53 times.

scholarly journals SIMULATION OF A WATER CURTAIN APPLICATION TO PROTECT WORKERS FROM THERMAL INJURIES

2021 ◽  
pp. 28-35
Author(s):  
M. BILIAIEV ◽  
O. BERLOV ◽  
V. BILIAIEVA ◽  
O. VERGUN
Keyword(s):  
Mass Transfer ◽  
Numerical Model ◽  
Computational Experiment ◽  
Energy Equation ◽  
Computer Code ◽  
Temperature Fields ◽  
Water Droplets ◽  
Water Curtain ◽  
Heated Air ◽  
Potential Flow Model

Problem statement. The problem of evaluating the effectiveness of using the water curtain to reduce the risk of thermal injury to people in a fire is considered. The problem is to determine the temperature fields when supplying water for air cooling. The purpose of the article. Development of a numerical model for calculating the process of propagation of water droplets in the air, their evaporation to reduce the temperature of heated air due to fire. Methodology. For mathematical modeling of the process of propagation of water droplets in air, thermal air pollution, the convective-diffusion equation of mass transfer, the energy equation and the equation describing the motion of an ideal liquid (potential flow model) are used. The potential flow model allows you to quickly determine the field of air flow velocity in areas with a complex geometric shape. Implicit difference splitting schemes are used for numerical integration of the convective-diffusion mass transfer equation and the energy equation. Physical splitting of basic equations is used to construct a difference analogue of modeling equations. The Richardson method and the conditional approximation scheme are used to solve the aerodynamics problem of determining the velocity potential field and the components of the air velocity vector. An engineering method for calculating the process of evaporation of a drop of water based on Sreznevsky's law has been developed. Scientific novelty. An effective numerical model has been developed that allows the method of computational experiment to determine the efficiency of using the water curtain to reduce the level of thermal pollution of atmospheric air due to fire. The numerical model is based on the integration of the fundamental equations of aerodynamics, heat and mass transfer. The model takes into account the most significant physical factors that affect the process under study: the movement of heated air, the movement of water droplets in the air, evaporation of the droplet, and so on. Practical significance. Based on the built model, a computer code has been created that allows you to quickly determine the temperature fields in the air when using a water curtain. The numerical model will be useful when conducting computational experiments for the purpose of scientifically sound choice of the location of the water curtain in case of fire. Conclusions. A computer code has been created that allows a computational experiment to investigate the effectiveness of using a water curtain in a fire. The developed computer program can be implemented on low and medium power computers. The results of a computational experiment are presented.

Laser Welding Analysis and Experiments

1995 ◽  
Vol 11 (02) ◽  
pp. 102-110 ◽  
Author(s):  
Jon J. Yagla ◽  
Richard S. Haag ◽  
Matthew E. Scott
Keyword(s):  
Laser Welding ◽  
Carbon Dioxide Laser ◽  
Mechanical Design ◽  
Steel Plates ◽  
Temperature Fields ◽  
Transient Temperature ◽  
Heating And Cooling ◽  
Transient Temperature Field ◽  
Welding Steel ◽  
Five Axis

A "seamless engineering" approach for mechanical design and laser welding manufacturing combines a method for welding analysis with a method for stress analysis through the development of radiant heating models for use in a nonlinear finite-element computer program. Experiments were performed welding steel plates, using a five-axis computer numerical controlled (CNC) workstation to translate welding specimens under a 5-kW CO2 (carbon dioxide) laser. Thermocouples installed near the weld seam were used to measure the transient temperature field during welding. The measured temperatures were compared with the analytical predictions, and the welds were sectioned so that predictions of properties in the heat-affected zone could be compared with experimental data. This paper presents analytical results using classical methods of analysis and includes solutions for temperature fields, heating and cooling rates, and metallurgical properties in heat-affected zones.

scholarly journals Analysis of the potential use of Trombe walls in Brazil: design recommendations

2020 ◽  
Vol 5 ◽  
pp. 4
Author(s):  
Fernando Antonio de Melo Sá Cavalcanti ◽  
Rosana Maria Caram
Keyword(s):  
Solar Radiation ◽  
Computer Simulations ◽  
Thermal Performance ◽  
Natural Ventilation ◽  
Solar Heating ◽  
Heating And Cooling ◽  
Heated Air ◽  
Trombe Wall ◽  
Potential Use ◽  
Passive Strategy

In this paper, the thermal performance of a standard environment was evaluated based on the use of a Trombe wall with different configurations and types of use, as the potential for using this passive strategy is still little studied in Brazil. This device is capable of absorbing energy from solar radiation by heating the air in this greenhouse and this heated air can be directed to the interior or exterior of the building depending on the purpose. This air can be used to heat the room or cool it by means of natural ventilation. The analysis of this research was based on a series of computer simulations using the EnergyPlus software, version 7.0 in order to quantify and classify the thermal performance of a standard environment equipped with this component, under the various construction configurations. Both for heating and cooling environments. The use of Trombe walls improved the thermal comfort of users in buildings located in Brazil, depending on the climate where they are located, promoting natural ventilation and passive solar heating, allowing the potential of this device to be investigated in the most diverse Brazilian regions.

scholarly journals The Z Velocity Dispersion of Outer H I Disks

1996 ◽  
Vol 169 ◽  
pp. 489-495
Author(s):  
John M. Dickey
Keyword(s):  
Velocity Distribution ◽  
Velocity Dispersion ◽  
Spiral Galaxies ◽  
Thermal State ◽  
Stellar Disk ◽  
Interstellar Gas ◽  
Heating And Cooling ◽  
Outer Disk ◽  
Atomic Gas

The velocity dispersion of the interstellar gas measured perpendicular to the disk in face-on spiral galaxies shows a remarkable consistency. Typically the width of the velocity distribution decreases monotonically with increasing galactic radius through the luminous, stellar disk; but in the outer disk where there is gas but no stars the velocity dispersion is συ ≃ 7 km s−1 with a scatter of 2 km s–1 at most from one position to another and from one galaxy to another. Trying to understand this number raises questions about the thermal state of the H I in outer, gaseous disks. The most important issue is to understand the dominant heating and cooling processes for the atomic gas.

scholarly journals Optimizing air velocity for the underfloor forced ventilation to protect a refrigerated warehouse from frost heaving

2018 ◽  
Vol 38 (3) ◽  
pp. 321-327
Author(s):  
Jingfu Jia ◽  
Manjin Hao ◽  
Jianhua Zhao
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Three Dimensional ◽  
Temperature Fields ◽  
Frost Heave ◽  
Forced Ventilation ◽  
Air Velocity ◽  
Set Up

Forced or natural ventilation is the most common measure of frost heave protection for refrigerated warehouse floor. To optimize air velocity for the underfloor forced ventilation system of refrigerated warehouse, a steady state three-dimensional mathematical model of heat transfer is set up in this paper. The temperature fields of this system are simulated and calculated by CFD software PHOENICS under different air velocity, 1.5m/s, 2.5m/s or 3.5m/s. The results show that the optimized air velocity is 1.5m/s when the tube spacing is 1.5m.

Sign in / Sign up

Export Citation Format

Share Document