scholarly journals Study Of The Thermal Processes Dynamics In The Feedstuff Disinfection By Electric Contact Heating

2022 ◽  
Vol 1211 (1) ◽  
pp. 012019
Author(s):  
T M Khalina ◽  
M V Khalin ◽  
M V Dorozhkin
Keyword(s):  
Heat Transfer ◽  
Operating Mode ◽  
Heat Transfer Process ◽  
Heat Losses ◽  
Electric Contact ◽  
Transfer Processes ◽  
Contact Heating ◽  
Different Shapes ◽  
Basic Equations ◽  
Disinfection Chamber

Abstract The article is dedicated to the study of the heat transfer processes that occur in the feedstuff disinfection chamber that relies upon electric contact heating. The mechanism of the temperature gradient appearance, which is the main cause of the heat losses has been investigated. The basic equations of heat conduction are considered. A method is proposed for determining the key parameters of the heat transfer process. A functional diagram of the experimental setup with a description of the operation of individual units is presented. The dependence for the transient operating mode of the unit on the growth of heat losses has been established. Thermal images of different shapes of the unit dielectric chambers have been provided as well as temperature field distribution through the chamber wall.

scholarly journals Self-Similar Heat Transfer Processes in a Radiation-Transparent Solid Body Containing an Absorptive Inclusion with the System Featuring Phase Transitions

2019 ◽  
pp. 60-70
Author(s):  
A.V. Attetkov ◽  
I.K. Volkov ◽  
K.A. Gaydaenko
Keyword(s):  
Heat Transfer ◽  
Phase Transitions ◽  
Solid Body ◽  
Transfer Process ◽  
Sufficient Conditions ◽  
Heat Transfer Process ◽  
Similar Process ◽  
Transfer Processes ◽  
Self Similar ◽  
Phase Transition Boundary

The paper considers the problem of determining temperature field parameters in a radiation-trans-parent isotropic solid body containing an absorptive inclusion, when the system features phase transitions. We identify sufficient conditions, meeting which ensures the possibility of self-similar heat transfer process taking place in the system under con-sideration. We qualitatively investigated physical properties of the self-similar process under study and determined its specifics. We provide a theoretical validation of implementing a thermostating mode of the moving phase transition boundary in the heat transfer process investigated

Boiling-Curve Measurements From a Controlled Heat-Transfer Process

1971 ◽  
Vol 93 (4) ◽  
pp. 408-412 ◽  
Author(s):  
W. C. Peterson ◽  
M. G. Zaalouk
Keyword(s):  
Heat Transfer ◽  
Transfer Process ◽  
Boiling Heat Transfer ◽  
Saturation Temperature ◽  
Heat Transfer Process ◽  
Stable Operation ◽  
Heater Surface ◽  
Transfer Processes ◽  
New Information ◽  
A New Technique

Feedback has been introduced around a boiling heat-transfer process in such a way that stable operation of the process has been obtained in all boiling regions including the transition region, in which, as is well known, the process itself is unstable. This system makes it possible to obtain much new information concerning both the steady-state and dynamic characteristics of boiling heat-transfer processes. Pool-boiling data which were obtained by the use of this system are presented. Accurate measurements of heater voltage and current were obtained by a new technique involving the use of digital instruments. These data are presented in the form of plotted experimental points in the nucleate, transition, and film boiling regions. The new measurement technique is described. Values of n in the equation q/As = CTdn are determined for all three boiling regions, where q = Btu/hr, As is heater surface area, and Td is temperature difference between heater surface and ambient liquid. The ambient liquid is distilled water maintained at saturation temperature under atmospheric pressure.

scholarly journals Application of Mathematical Models in Analysis of Heat Losses in the Buildings

2006 ◽  
Vol 1 ◽  
pp. 341
Author(s):  
S. Gendels
Keyword(s):  
Heat Transfer ◽  
Thermal Comfort ◽  
Heat Balance ◽  
Heat Transfer Process ◽  
Heat Losses ◽  
Balance Model ◽  
Living Room ◽  
Transfer Coefficients ◽  
Multiple Parameters ◽  
Quantity Of Heat

Physical model of heat balance for separate living room is discussed, which allows to analyse the distributions of the flow of air and temperature depending on the physical conditions and geometry. The model enables to choose the optimal surface area of building elements and their properties in order to decrease the heat losses and improve the conditions of thermal comfort. Room with bounding constructions and real dimensions is modelled that helps to understand the peculiarities of heat transfer process in the room as well as distribution of various characteristic quantities and their dependence on the different conditions. Multiple parameters are varied in 2D calculations and their influence on the distributions of temperature and velocity fields is analysed, which characterises the conditions of the thermal comfort. On the basis of considered model, the quantity of heat has been estimated that inflows or outflows through the bounding constructions. The power of convector is estimated, too, at a given temperature of the surface of convector. It is possible to estimate the heat transfer coefficients of the surfaces of bounding constructions with various properties, what requires considerable effort in real conditions of exploitation. One of the conditions of comfort is the temperature difference between frontal walls of the room – it should be less than some degrees. Essential role is played also by the intensity of air flow mostly because it increases heat transfer. Hence, flows between the room and outside environment are created with significant heat losses (so called convective heat losses). The influence of various geometric parameters on the character of the flow of air is analysed. The software ANSYS/FLOTRAN 5.5, where the turbulence is described by k- ? model, has been used for the elaboration of the heat balance model of the room.

Single-Phase Microscale Jet Stagnation Point Heat Transfer

2009 ◽  
Vol 131 (11) ◽  
Author(s):  
Gregory J. Michna ◽  
Eric A. Browne ◽  
Yoav Peles ◽  
Michael K. Jensen
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Single Phase ◽  
Heat Transfer Process ◽  
Heat Losses ◽  
Transfer Coefficients ◽  
Normal Surface ◽  
Impingement Zone ◽  
Order Of Magnitude

An investigation of the pressure drop and impingement zone heat transfer coefficient trends of a single-phase microscale impinging jet was undertaken. Microelectromechanical system (MEMS) processes were used to fabricate a device with a 67-μm orifice. The water jet impinged on an 80-μm square heater on a normal surface 200 μm from the orifice. Because of the extremely small heater area, the conjugate convection-conduction heat transfer process provided an unexpected path for heat losses. A numerical simulation was used to estimate the heat losses, which were quite large. Pressure loss coefficients were much higher in the range Red,o<500 than those predicted by available models for short orifice tubes; this behavior was likely due to the presence of the wall onto which the jet impinged. At higher Reynolds numbers, much better agreement was observed. Area-averaged heat transfer coefficients up to 80,000 W/m2 K were attained in the range 70<Red<1900. This corresponds to a 400 W/cm2 heat flux at a 50°C temperature difference. However, this impingement zone heat transfer coefficient is nearly an order-of-magnitude less than that predicted by correlations developed from macroscale jet data, and the dependence on the Reynolds number is much weaker than expected. Further investigation of microjet heat transfer is needed to explain the deviation from expected behavior.

scholarly journals Heat Transfer Process During Filtration Drying of Grinded Sunflower Biomass

2021 ◽  
Vol 15 (1) ◽  
pp. 118-124
Author(s):  
Diana Kindzera ◽  
◽  
Roman Hosovskyi ◽  
Volodymyr Atamanyuk ◽  
Dmytro Symak ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Process ◽  
Biofuel Production ◽  
Design Stage ◽  
Transfer Coefficients ◽  
Number Range ◽  
Velocity Increase ◽  
Heat Transfer Coefficients ◽  
Transfer Processes ◽  
Solid Biofuel

Filtration drying of grinded sunflower stems as the unit operation of the technological line for solid biofuel production has been proposed. Theoretical aspects of heat transfer processes during filtration drying have been analyzed. The effect of the drying agent velocity increase from 0.68 to 2.05 m/s on the heat transfer intensity has been established. The values of heat transfer coefficients have been calculated on the basis of the thin-layer experimental data and equation . Calculated coefficients for grinded sunflower stems have been correlated by the dimensionless expression within Reynolds number range of and the equation has been proposed to calculate the heat transfer coefficients, that is important for forecasting the heat energy costs at the filtration drying equipment design stage.

Whole Field Measurements to Understand the Role of Varying Depths of Nucleation Site on Vapor Bubble Dynamics and Heat Transfer Rates

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Surya Narayan L ◽  
Pasi Vijaykumar ◽  
Atul Srivastava
Keyword(s):  
Heat Transfer ◽  
Vapor Bubble ◽  
High Speed ◽  
Bubble Formation ◽  
Nucleation Site ◽  
Heat Transfer Process ◽  
Cavity Depth ◽  
Bulk Fluid ◽  
Transfer Rates ◽  
Transfer Processes

Abstract This work studies the possible effects of varying depths of cavity on bubbling features and the associated heat transfer rates in nucleate pool boiling regime. A single vapor bubble has been generated on a substrate with a cylindrical cavity at its center that acts as the nucleation site. Experiments have been conducted for three cavity depths (250, 500, and 1000 μm), while keeping its throat diameter constant at 200 μm. With the bulk fluid maintained under saturated conditions, for each cavity depth, surface superheat level has been varied in the range of ΔTsuperheat = 8, 10 and 12 °C. A gradient-based visualization technique, coupled with a high speed camera, has been employed to simultaneously map the changes in thermal gradients during the formation of the vapor bubble as well as bubble dynamic parameters. The image sequence obtained has been qualitatively and quantitatively analyzed to elucidate the dependence of bubbling features and various heat transfer processes on cavity depth. With an increase in the depth of cavity, the net effect of reduction in the available thermal energy due to the increased convection effects and significant depletion of superheated layer are identified as the dominant heat transfer processes that influence the bubbling features. Furthermore, based on the statistics of bubble departure characteristics, the cavity with higher depth (1000 μm) showed a much stable bubble formation with minimal variation in the bubble departure frequency as compared to the bubbling features from a cavity with smaller depth (250 μm). Evaporative heat transfer process has been identified as the primary cause for increased inconsistency of bubbling features at high superheat conditions for experiments performed for low cavity depths.

scholarly journals Mathematical modeling of thermal technical characteristics of external protections with air layers

2019 ◽  
Vol 97 ◽  
pp. 06007
Author(s):  
Rustam Mansurov ◽  
Tatyana Rafalskaya ◽  
Dmitry Efimov
Keyword(s):  
Mathematical Modeling ◽  
Heat Transfer ◽  
Software Package ◽  
Outer Wall ◽  
Heat Transfer Process ◽  
Building Envelope ◽  
Ansys Software ◽  
Air Gaps ◽  
Transfer Processes ◽  
Air Layers

A screened enclosing structure of the outer wall of the building without the use of thermal insulation materials is proposed. To ensure the required thermal resistance of the outer fence, screens (cement-containing slabs) and closed air gaps between them are used. Using the ANSYS software package, the heat transfer processes were modeled in a shielded building envelope, consisting of the main (carrier) part and screens with air gaps closed between them. The features of the heat transfer process in the thickness of the outer enclosure are revealed.

scholarly journals ANALISIS EFISIENSI BOILER DENGAN METODE INPUT– OUTPUT DI PT. JAPFA COMFEED INDONESIA Tbk. UNIT BANJARMASIN

2019 ◽  
Vol 4 (1) ◽  
pp. 37-46
Author(s):  
Imam Muzaki ◽  
Aqli Mursadin
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Transfer Process ◽  
Transfer Rate ◽  
Heat Transfer Process ◽  
Heat Losses ◽  
Input Output ◽  
Research Results ◽  
Boiler Efficiency

This paper shows some of the research results. The result of this research shows that the boiler efficiency at operational condition (present) is 79,32% decreased efficiency equal to 9,19% compared with operational condition with efficiency as big as 88,51%. One of the factors analyzing the declining efficiency of the boiler is greatly influencing the heat transfer process, because if there is dirt or crust on the boiler pipe and the fouling, it will result in the process of heat transfer will decrease so that the heat transfer rate will decrease, and will also affect the amount of heat losses in the boiler.

scholarly journals WALLING THERMAL PROPERTIES INFLUENCED BY HEAT-STRESSED ELEMENTS IN EXTERNAL CORNER AREA

2019 ◽  
Vol 21 (5) ◽  
pp. 127-137
Author(s):  
A. N. Kozlobrodov ◽  
E. A. Ivanova
Keyword(s):  
Heat Transfer ◽  
Thermal Properties ◽  
Thermal State ◽  
Negative Impact ◽  
Heat Losses ◽  
Design Stage ◽  
Ansys Software ◽  
Transfer Processes ◽  
Building Heat ◽  
Important Design

It is known that heat-stressed elements greatly affect the thermal properties of walling and contribute to the heat losses of a building. Heat-stressed elements decrease the temperature on the inner walling surface adjacent to the external corners. In addition to increasing heat losses, heat-stressed elements increase the condensation on the inner walling surface leading to mold appearance. This is one of the reasons that shows that the modeling of heat-stressed elements is a very important design stage. The article discusses the effect from these elements on thermal properties of multilayer walling in the external corner of a building. Using the ANSYS software package, the influence of heat-stressed elements on the heat transfer processes is modeled in the external corner area. A quantitative assessment of the thermal state of typical walling fragments under extreme heat-transfer conditions is given. The obtained research results can be used to increase the temperature in the area of heat-stressed elements and reduce their negative impact.

scholarly journals Simulation of heat transfer processes during the growth of crystals of the NiFeGaCo alloy

2021 ◽  
Vol 2103 (1) ◽  
pp. 012083
Author(s):  
M G Vasil’ev ◽  
V M Krymov ◽  
Yu G Nosov ◽  
S I Bakholdin
Keyword(s):  
Heat Transfer ◽  
Dendritic Growth ◽  
Crystallization Front ◽  
Normal Growth ◽  
Growth Zone ◽  
Heat Transfer Process ◽  
Transfer Processes ◽  
Thermal Growth ◽  
Axial Temperature ◽  
Growth Experiments

Abstract Long crystals of NiFeGaCo alloy with shape memory effect, including magnetically controlled ones, were obtained by the methods of Czochralski and Stepanov. A strong influence on the properties of crystals of dendritic formations, especially noticeable in the initial part of the crystal, has been revealed. In order to optimize the growth experiments, the heat transfer process in the thermal growth zone was simulated. It is shown that the formation of dendrites is due to a change in heat transfer during growth, which leads to an increase in the axial temperature gradient near the crystallization front as the crystal grows. This fits into the framework of the classical concepts of the transition from dendritic growth to normal growth.

Sign in / Sign up

Export Citation Format

Share Document