Controlled Temperature Distribution and Heat Transfer Process in the Unidirectional Solidification of Aluminium Alloys

2012 ◽  
Vol 188 ◽  
pp. 314-317
Author(s):  
Florin Ştefănescu ◽  
Gigel Neagu ◽  
Alexandrina Mihai ◽  
Iuliana Stan
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Temperature Distribution ◽  
Transfer Process ◽  
Thermal Conditions ◽  
Solidification Process ◽  
Heat Transfer Process ◽  
Solidification Structure ◽  
Major Influence ◽  
Cast Material

Abstract. The paper presents some theoretical and experimental data regarding the directional solidification, revealing the main factors (especially those which are related to the heat transfer process) which have influence on the crystals size and morphology. The crystalline structure of alloys is determined by three important factors: chemical composition, thermal conditions, and characteristics of germination and growth from liquid of solid nuclei. The solidification structure can be influenced by acting on the mould properties or directly on the cast material, both of these actions being based upon the change of temperature distribution in the alloy-mould system. Experimental data demonstrated the major influence of the thermal regime on the crystallization-solidification process, on the transcrystallization zone and they pointed out the limits to direct the crystals formation (size and shape) by changing the cooling regime.

scholarly journals Modeling of the heat transfer process in an air heat pump fanless evaporator

2018 ◽  
Vol 240 ◽  
pp. 05012
Author(s):  
Piotr Kopeć ◽  
Beata Niezgoda-Żelasko
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Mixed Convection ◽  
Heat Pump ◽  
Transfer Process ◽  
Experimental Studies ◽  
Heat Transfer Process ◽  
Cfd Modeling ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients

This paper analyses the mixed convection process in a fanless evaporator of an air heat pump. The text of the paper shows the authors’ experimental studies results of the temperature distribution and the local values of heat transfer coefficients on the outer surface of vertical tubes with longitudinal fins for the case of mixed convection and fins of a specific shape of their cross-section (prismatic, wavy fins). The experimental studies include the air velocities wa=2,3 m/s and the temperature differences between air and the refrigerant inside the heat exchanger tubes which is ΔT=24-40K. The results obtained were used for verification of CFD modeling of the heat transfer process for the discussed case of heat transfer and the geometry of the finned surface. The numerical analysis was performed for: the temperature distribution along the fin height, the tube perimeter and height, the distribution of local heat transfer coefficients on the finned tube perimeter and along its height. The simulated calculations were used to verify the method of determination of fin efficiency.

Thermal Characteristics of a Free Radial Liquid Jet Impinging on a Hot Surface

2001 ◽  
Author(s):  
Ahmed Hassaneen ◽  
Muhammad M. Rahman
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Nusselt Number ◽  
Transfer Process ◽  
Average Nusselt Number ◽  
Incidence Angle ◽  
Thermal Characteristics ◽  
Heat Transfer Process ◽  
Liquid Jet ◽  
Geometrical Parameters

Abstract This paper presents results of CFD computation of the heat transfer process in a radial impinging free liquid jet. The jet is impinging on a flat circular disk and the flow downstream of the impinging area spreads outward and inward on the disk. The solution is made under steady state and laminar flow conditions. The solution is obtained for the axisymmetric radial jet with two free surfaces. Different incidence angle of the jet and different flow Reynolds number (Re) were considered in the analysis. The effect of jet elevation from the disk is discussed in addition to different thickness of the hot plate. Due to lack of experimental data on this typical flow problem, the results were qualitatively compared with the available experimental data of the closest flow condition in the literature. The jet incidence angle and jet elevation were found to have strong effects on the velocity field and the free surface position of the spreading flow on the disk and consequently affected the heat transfer process. The disc thickness is also found to have a strong effect on the local and average Nusselt number. Results are documented by plotting the distribution of local and average Nusselt number versus the geometrical parameters.

Study on Temperature Distribution of Plasma Surface Alloying Furnace

2008 ◽  
Vol 575-578 ◽  
pp. 633-638
Author(s):  
Zhong Hou Li ◽  
Sha Sha Liu ◽  
Zhi Yong Cheng
Keyword(s):  
Heat Transfer ◽  
Numerical Calculation ◽  
Temperature Distribution ◽  
Transfer Process ◽  
Heat Transfer Process ◽  
Surface Alloying ◽  
Plasma Surface ◽  
Calculation Results ◽  
Heat Preservation ◽  
Plasma Surface Alloying

The objective of this research was to develop methods for improved the uniformity of temperature distribution within plasma surface alloying furnace by simulating the heat transfer process and numerical calculation. Results show that the structure of charging basket, hanging auxiliary cathode plates in both sides of charging basket and blackness of material influence strongly temperature distribution within the plasma surface alloying furnace. Discharge intensity of the center zone can be weakened through increasing the distance between backs both column blades in center of the furnace, which decreased the consumption of discharge power in center, depressed temperature of the center zone of the furnace. Intensity of discharge in fringe of the charging basket can be reinforced and that of discharge in center can be weakened when auxiliary cathode plates were hanged to outer flank of the charging basket, which increased boundary temperature of the system, at the same time the auxiliary cathode plate plays a heat preservation role. Decreasing the blackness of outside material of charging basket may decrease heat dissipating capacity of outside, decrease temperature difference of outside and center of the furnace and improve the uniform of temperature distribution in the furnace.

Research on Temperature Distribution for Tubing Liquid with Hot Natural Gas Injected Annulus Using Gas Lift

2014 ◽  
Vol 496-500 ◽  
pp. 1084-1087
Author(s):  
Luo Wei ◽  
Rui Quan Liao ◽  
Yong Li ◽  
Jian Wu
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Natural Gas ◽  
Transfer Process ◽  
Heat Transfer Process ◽  
Prediction Methods ◽  
Fluid Temperature ◽  
Temperature Prediction ◽  
Conservation Of Energy ◽  
Gas Lift

In light of the difficulty including the complicacy of heat transfer process with hot natural gas injected in gas lift annulus, regular temperature prediction methods are commonly used to consider the tubing fluid temperature for the heat transfer from tubing to annulus, actually the tubing fluid will not be the external heat transfer but it will be heated by annulus when the gas temperature in annulus is higher than the tubing fluid temperature, as well as especially the prediction of tubing wellhead temperature in terms of fluid temperature distribution traits in annulus and tubing, regular temperature prediction methods manifest limitation due to their applicability. Based on the fairly comprehensive tubing fluid temperature distribution prediction model with consideration of Thomson effect and such factors as kinetic energy, annular convection heat transfer and phase change etc. developed by the predecessors, and according to the basic principle of conservation of energy and heat transfer, the actual heat transfer process with hot natural gas injected in gas lift annulus was considered as a plus in this paper. The models for actual heat transfer and tubing fluid modified temperature prediction were established and eventually, the models were verified via multiple field tests. The reliability, capable of satisfying the requirements of engineering precision, in terms of temperature distribution of model prediction was proved.

scholarly journals Analysis of temperature distribution in the heating boiler equipped with afterburning chamber

2019 ◽  
Vol 128 ◽  
pp. 01009
Author(s):  
Wojciech Judt ◽  
Bartosz Ciupek ◽  
Rafał Urbaniak
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Temperature Distribution ◽  
Transfer Process ◽  
Solid Fuel ◽  
Heat Transfer Process ◽  
Heating Device ◽  
Afterburning Chamber ◽  
Vertical Tubes ◽  
Heating Boiler

Analysis of a heat transfer process for construction of solid fuel heating boiler equipped with additional afterburning chamber is presented. Analyzed construction of the heating device is intended for shouse heating and preparation of hot utility water. A heat exchanger in the analyzed boiler is composed of vertical tubes divided into three boiler draughts. Afterburning chamber connects main combusting chamber of the heating boiler with second and third boiler draught. The aim of this analysis is to identify the character of heat transfer through the heating boiler

Research on Effective Factors of Heat Transfer of Thin Heating Floor

2012 ◽  
Vol 446-449 ◽  
pp. 2920-2923
Author(s):  
Quan Ying Yan ◽  
Li Li Jin ◽  
Ran Zhou ◽  
Sui Lin Wang
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Air Temperature ◽  
Transfer Process ◽  
Indoor Air ◽  
Heat Transfer Process ◽  
Hot Water ◽  
Effective Factors ◽  
Average Temperature ◽  
Surface Temperature Distribution

In this paper, numerical simulations of heat transfer process in thin heating floor were done by ANSYS. The influence of tube spacing, the average temperature of hot water and indoor air temperature on surface temperature distribution of heating floor and heat density were analyzed. The results can provide reference and basis for optimization, application and promotion of the thin heating floor.

The Simulation and Analysis of Heat Transfer Process of Honeycomb Regenerator

2011 ◽  
Vol 130-134 ◽  
pp. 1810-1815 ◽  
Author(s):  
Ye Tian ◽  
Xun Liang Liu ◽  
Zhi Wen ◽  
Xiao Hong Feng ◽  
Zhi Li ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Transfer Process ◽  
Rational Design ◽  
Distribution Curve ◽  
Mathematic Model ◽  
Heat Transfer Process ◽  
Structure Parameter ◽  
Regenerative Burner ◽  
Ceramic Honeycomb

On the basis of established mathematic model of regenerator heat transfer process, the process of heat transfer of ceramic honeycomb regenerator with the method of simulation is studied. The temperature distribution curve of regenerator and gas is obtained, the temperatures curve of regenerator and gas are closely related to time is investigated ,and the influence of operation and structure parameter to heat transfer of regenerator is discussed. All this work is to provide guides of rational design of single-ended regenerative burner.

Design of the Blast Furnace Wall Structure Made of Efficient Materials. Part 4. Calculation Examples

2020 ◽  
Vol 786 (11) ◽  
pp. 30-34
Author(s):  
A.M. IBRAGIMOV ◽  
◽  
L.Yu. GNEDINA ◽  
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Blast Furnace ◽  
Boundary Value Problems ◽  
Transfer Process ◽  
Rational Design ◽  
Boundary Value ◽  
Heat Transfer Process ◽  
Furnace Wall ◽  
Time Interval

This work is part of a series of articles under the general title The structural design of the blast furnace wall from efficient materials [1–3]. In part 1, Problem statement and calculation prerequisites, typical multilayer enclosing structures of a blast furnace are considered. The layers that make up these structures are described. The main attention is paid to the lining layer. The process of iron smelting and temperature conditions in the characteristic layers of the internal environment of the furnace is briefly described. Based on the theory of A.V. Lykov, the initial equations describing the interrelated transfer of heat and mass in a solid are analyzed in relation to the task – an adequate description of the processes for the purpose of further rational design of the multilayer enclosing structure of the blast furnace. A priori the enclosing structure is considered from a mathematical point of view as the unlimited plate. In part 2, Solving boundary value problems of heat transfer, boundary value problems of heat transfer in individual layers of a structure with different boundary conditions are considered, their solutions, which are basic when developing a mathematical model of a non-stationary heat transfer process in a multi-layer enclosing structure, are given. Part 3 presents a mathematical model of the heat transfer process in the enclosing structure and an algorithm for its implementation. The proposed mathematical model makes it possible to solve a large number of problems. Part 4 presents a number of examples of calculating the heat transfer process in a multilayer blast furnace enclosing structure. The results obtained correlate with the results obtained by other authors, this makes it possible to conclude that the new mathematical model is suitable for solving the problem of rational design of the enclosing structure, as well as to simulate situations that occur at any time interval of operation of the blast furnace enclosure.

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