Numerical Modeling of Water Impingement and Heat Transfer With Solid Slabs During Secondary Cooling in a Continuous Caster

2018 ◽  
Author(s):  
Haibo Ma ◽  
Kaile Tang ◽  
Rui Liu ◽  
Michael Lowry ◽  
Armin Silaen ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Numerical Model ◽  
Continuous Caster ◽  
Cooling Water ◽  
Heat Removal ◽  
Heat Transfer Process ◽  
Standoff Distance ◽  
Slab Surface ◽  
Secondary Cooling ◽  
Cooling Effects

In the steel continuous casting process, cooling water is directly injected through multiple rows of nozzles to remove heat from the slab to allow the slab to solidify in secondary cooling. Effective heat removal from the slab without causing slab cracking and deformation is desired. The present study focuses on developing a reliable numerical model which can accurately predict the impingement and heat transfer between water droplet and solid slab. The flat fan atomizer is chosen as a representative nozzle to be simulated. The spray pattern on the slab surface, as well as the impingement behaviors of water droplets, are obtained through an Eulerian-Lagrangian approach. The wall jet model coupled with modified evaporation rate depending on the droplet Weber number has been applied in the numerical model. A series of parametric studies have been performed to investigate the effects of spray direction, standoff distance, and distance between adjacent nozzles on the impingement heat transfer process. Simulation results reveal that intense cooling effects can be found in the center of the spray, where the concentration of droplets is the highest regardless of the spray direction. Double the standoff distance can reduce the heat transfer coefficient on slab surface by 10%. Finally, the distance between two adjacent nozzles should be adjusted to be smaller than the standoff distance in order to avoid the “fountain” effect induced by the collision of the two neighboring wall jets.

Numerical Simulation for Microconvection Around Nano-Particle With Brownian Motion in Liquid

2003 ◽  
Author(s):  
B. X. Wang ◽  
H. Li ◽  
X. F. Peng ◽  
L. X. Yang
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Brownian Motion ◽  
Numerical Model ◽  
Temperature Gradient ◽  
Transfer Process ◽  
Heat Transfer Process ◽  
Nano Particles ◽  
Analytic Method ◽  
Nano Particle

The development of a numerical model for analyzing the effect of the nano-particles’ Brownian motion on the heat transfer is described. By using the Maxwell velocity distribution relations to calculate the most possible velocity of fluid molecules at certain temperature gradient location around the nano-particle, the interaction between fluid molecules and one single nano-particle is analyzed and calculated. Based on this, a syntonic system is proposed and the coupled effect that Brownian motion of nano-particles has on fluid molecules is simulated. This is used to formulate a reasonable analytic method, facilitating laboratory study. The results provide the essential features of the heat transfer process, contributed by micro-convection to be considered.

scholarly journals Experimental study of heat transfer through cooling water circuit in a reactor vault by using Al2O3 nano fluid

2018 ◽  
Vol 22 (2) ◽  
pp. 1149-1161 ◽  
Author(s):  
Maria Anish ◽  
Balakrishnan Kanimozh
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Base Fluid ◽  
Nuclear Reactor ◽  
Characteristic Curve ◽  
Reactor Core ◽  
Cooling Water ◽  
Heat Transfer Process ◽  
Nano Fluid ◽  
Al2o3 Nanoparticle

The heat produced in the nuclear reactor due to fission reaction must be kept in control or else it will damage the components in the reactor core. Nuclear plants are using water for the operation dissipation of heat. Instead, some chemical substances which have higher heat transfer coefficient and high thermal conductivity. This experiment aims to find out how efficiently a nanofluid can dissipate heat from the reactor vault. The most commonly used nanofluid is Al2O3 nanoparticle with water or ethylene as base fluid. The Al2O3 has good thermal property and it is easily available. In addition, it can be stabilized in various PH levels. The nanofluid is fed into the reactor?s coolant circuit. The various temperature distribution leads to different characteristic curve that occurs on various valve condition leading to a detailed study on how temperature distribution carries throughout the cooling circuit. As a combination of Al2O3 as a nanoparticle and therminol 55 as base fluid are used for the heat transfer process. The Al2O3 nanoparticle is mixed in therminol 55 at 0.05 vol.% concentration. Numerical analysis on the reactor vault model was carried out by using ABAQUS and the experimental results were compared with numerical results.

Metallurgical Secondary Cooling of Continuous Casting Based on Neural Network Adaptive System Design of Water Distribution

2014 ◽  
Vol 926-930 ◽  
pp. 802-805
Author(s):  
Jun Li Jia ◽  
Jin Hong Zhang ◽  
Guo Zhen Wang
Keyword(s):  
Heat Transfer ◽  
Continuous Casting ◽  
Water Distribution ◽  
Cooling System ◽  
Control Level ◽  
Cooling Water ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Secondary Cooling ◽  
Water Control

Efficient secondary cooling water control level slab continuous casting process and quality are closely related. Casting solidification heat transfer model is the basis of process control and optimization, heat transfer model based on determining the secondary cooling system is the most widely used method for casting production process can be simulated. However, when considering the many factors affecting the production and input conditions change significantly, real-time and strain of this method is not guaranteed. Therefore, the artificial intelligence optimization algorithms such as genetic algorithms, neural networks, fuzzy controllers, introducing continuous casting secondary cooling water distribution and dynamics of optimal control methods, the rational allocation of caster secondary cooling water and dynamic control is important.

Research on Heat-Transfer Process of the Radiant Ceiling Cooling System

2012 ◽  
Vol 512-515 ◽  
pp. 2171-2174 ◽  
Author(s):  
Quan Ying Yan ◽  
Ran Huo ◽  
Li Li Jin
Keyword(s):  
Heat Transfer ◽  
Surface Temperature ◽  
Cooling System ◽  
Numerical Models ◽  
Cooling Water ◽  
Lower Surface ◽  
Cooling Capacity ◽  
Heat Transfer Process ◽  
Lower Surface Temperature ◽  
Selection Of

Physical and numerical models of the radiant ceiling cooling system were built and numerically simulated. The results showed that the lower the temperature of cooling water is, the lower surface temperature the ceiling has, and the bigger the cooling capacity is. The bigger the depth of tubes is, the higher the surface temperature and the smaller the cooling capacity. The differences are not evident. The bigger the distance of tubes is, the bigger the surface temperature is and the smaller the cooling capacity is. The diameter of tubes has a few influences on the surface temperature and the cooling capacity. Results in this paper can provide basis and guide for the design of the project, the selection of parameters and the feasibility of the system.

Numerical Simulation of Billet Continuous Casting Solidification Based on the Measurement of Shell Thickness and Surface Temperature

2011 ◽  
Vol 80-81 ◽  
pp. 81-85
Author(s):  
Jiao Cheng Ma ◽  
Hui Zhao Sun ◽  
Xue Bin Wang ◽  
Xia Lv
Keyword(s):  
Heat Transfer ◽  
Continuous Casting ◽  
Surface Temperature ◽  
Shell Thickness ◽  
Casting Machine ◽  
Cooling Water ◽  
Solidification Process ◽  
Transfer Model ◽  
Secondary Cooling ◽  
Billet Continuous Casting

In order to more accurate simulation the solidification of billet continuous casting. The measured shell thickness and surface temperature have been used to revise the heat transfer model. The calculated results of the model are in excellent agreement with the experimental ones based on an actual casting machine. The revised model can excellent to simulate the billet solidification process. So it provides the possibility for better simulation the dynamic solidification process and optimizing of the secondary cooling water.

scholarly journals Actual problems of the thermal hydraulic reliability ensuring of prospective nuclear reactors with supercritical parameters

2021 ◽  
Vol 20 ◽  
pp. 27-38
Author(s):  
I. G. Sharayevsky ◽  
◽  
N. M. Fialko ◽  
A. V. Nosovskyi ◽  
L. B. Zimin ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermodynamic Parameters ◽  
Experimental Studies ◽  
Heat Removal ◽  
Heat Transfer Process ◽  
Critical Area ◽  
Water Coolant ◽  
Operational Parameters ◽  
Reliable Determination ◽  
Light Water

There is a significant lack of reliable information on the physical characteristics of thermohydraulic processes in emergency heat transfer modes when cooling the surface of fuel rods with light water coolant with supercritical thermodynamic parameters, in particular, on the physics of heat transfer processes and hydromechanics in the critical area. It is shown that in these conditions there is physical uncertainty about the causes of deteriorating heat transfer, which limits the possibility of creating effective calculation techniques for reliable determination of the upper limit of safe forcing of the heat transfer process in the core. At present, the vast majority of theoretical and experimental studies of thermohydraulic processes in the near-critical area have been performed only for the socalled “normal” heat transfer, which corresponds to the heat removal conditions with mixed turbulent convection of superheated to “gas” state of light water coolant in its inertial mode. Attention is paid to the possible appearance of macromolecular ensembles on this surface in the form of pseudo-vapor formations, which are capable of causing an emergency mode of pseudo-film boiling. On the basis of the given experimental data of various authors existence of rather deep physical analogy between processes of heat exchange in supercritical thermodynamic system and unheated boiling at subcritical parameters of the heat carrier is proved. Existence of the pseudo-boiling process in the conditions of supercritical thermodynamic parameters makes it impossible to use in the thermohydraulic calculation the empirical dependences for “hot” gas for the range of active zones operational parameters.

scholarly journals Experimental Investigation on Condensation of Vapor in the Presence of Non-Condensable Gas on a Vertical Tube

2018 ◽  
Author(s):  
Shengjun Zhang ◽  
Feng Shen ◽  
Xu Cheng ◽  
Xianke Meng ◽  
Dandan He
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Total Pressure ◽  
Mass Fraction ◽  
Heat Removal ◽  
Heat Transfer Process ◽  
Transfer Model ◽  
Operation Conditions ◽  
The Heat Transfer Coefficient

According to the operation conditions of time unlimited passive containment heat removal system (TUPAC), a separate effect experiment facility was established to investigate the heat transfer performance of steam condensation in presence of non-condensable gas. The effect of wall subcooling temperature, total pressure and mass fraction of the air on heat transfer process was analyzed. The heat transfer model was also developed. The results showed that the heat transfer coefficient decreased with the rising of subcooling temperature, the decreasing of the total pressure and air mass fraction. It was revealed that Dehbi’s correlation predicted the heat transfer coefficient conservatively, especially in the low pressure and low temperature region. The novel correlation was fitted by the data obtained in the following range: 0.20~0.45 MPa in pressure, 20% ~ 80% in mass fraction, 15°C ~ 45°C in temperature. The discrepancy of the correlation and experiment data was with ±20%.

scholarly journals Heat load of bimetallic ribbed tube

2021 ◽  
Vol 33 (5) ◽  
pp. 271-282
Author(s):  
Elena Sergeevna Baimetova ◽  
Albina Firdavesovna Gizzatullina ◽  
Maria Ravilevna Koroleva ◽  
Olga Vladimirovna Mishchenkova ◽  
Fyodor Nikolaevich Pushkarev ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Conjugate Heat Transfer ◽  
Heat Removal ◽  
Cylindrical Tube ◽  
Longitudinal Section ◽  
Heat Transfer Process ◽  
Finned Tube ◽  
Qualitative Comparison ◽  
Bimetallic Finned Tube ◽  
Metal Metal

This study is devoted to the problem of numerical modeling of the conjugate heat transfer in a closed-type power installation. The working elements of that are ribbed bimetallic tubes using the openFoam toolbox. The heat transfer process modeling in bimetallic tubes is associated with solving the problem of determining the value of the contact thermal resistance at the metal / metal interface. Considered design of a bimetallic tube involves crimping copper washers on the surface of an aluminum cylindrical tube. Hence, the contact surface of the tube is not isotropic in its properties. A mathematical model of conjugate heat transfer for air / bimetal / coolant medium is proposed. The features of the organization of thermophysical processes at the metal contact interface and at the metal / air and metal / coolant medium are shown. A qualitative comparison of the obtained results with the famous experimental data is carried out. Generalized temperature profiles in the rib longitudinal section are obtained by mathematical modeling. The given distributions of temperature and heat flux make it possible to estimate the contribution of each individual rib to the investigated heat removal process from the air environment. The efficiency of the considered technology of manufacturing a bimetallic finned tube is shown.

scholarly journals A CASE STUDY ON MAINTENANCE OF OVERHEAT - SPOT WELDING MACHINE

2018 ◽  
Author(s):  
Dessy Agustina Sari
Keyword(s):  
Heat Transfer ◽  
Spot Welding ◽  
Cooling Tower ◽  
Cooling Water ◽  
Heat Transfer Process ◽  
Hot Water ◽  
Time Production ◽  
Standard Temperature ◽  
Standard Operation

Indicator overheat on robot transformer of spot welding was gun thermos alarm. Thermostat which adheringin the machine could be shut down the robot if this component detected the excessive warm below the standard operation. Impurities (scale, and deposit) existence caused heat transfer process disturbed, exchanged thermal between cold and hot water. This research methods were replacement part filler of the cooling tower and flushing the pipeline by chemical. The result showed a step progressing which cooling water reached the standard temperature, 30oC. Performance spot welding was being better so time production worked normally.

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