scholarly journals Comparative Analysis of Temperature Fields in Railway Solid and Ventilated Brake Discs

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7804
Author(s):  
Aleksander Yevtushenko ◽  
Michal Kuciej ◽  
Piotr Grzes ◽  
Piotr Wasilewski
Keyword(s):  
Spatial Models ◽  
Temperature Fields ◽  
Computational Time ◽  
Maximum Temperature ◽  
Railway Vehicle ◽  
Brake Disc ◽  
Transient Heating ◽  
Solid Disc ◽  
Energy Dissipated ◽  
Work Done

A new approach to numerical simulation using the finite element method (FEM) for the rotational motion of discs for railway vehicle disc brake systems was proposed. For this purpose, spatial models of transient heating due to the friction of such systems with solid and ventilated discs were developed. The performed calculations and the results obtained allowed justification of the possibility of simplifying the shape of the ventilated brake disc through elimination of ventilation channels. This contributes to a significant reduction in computational time, without compromising the accuracy of the results. The spatial and temporal temperature distributions in the ventilated and the solid disc of the same mass were analyzed. The share of energy dissipated due to convection and thermal radiation to the environment in relation to the total work done during a single braking was investigated. The maximum temperature values found as a result of computer simulations were consistent with the corresponding experimental results.

Fatigue life assessment for brake disc of railway vehicle

2009 ◽  
Vol 33 (1) ◽  
pp. 37-42 ◽  
Author(s):  
D.-J. KIM ◽  
C.-S. SEOK ◽  
J.-M. KOO ◽  
W.-T. WE ◽  
B.-C. GOO ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Life Assessment ◽  
Railway Vehicle ◽  
Brake Disc ◽  
Fatigue Life Assessment

scholarly journals A Modified Analytical Heat Source Model for Numerical Simulation of Temperature Field in Friction Stir Welding

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Xiangqian Liu ◽  
Yan Yu ◽  
Shengli Yang ◽  
Huijie Liu
Keyword(s):  
Heat Flux ◽  
Friction Stir Welding ◽  
Analytical Model ◽  
Heat Generation ◽  
Tilt Angle ◽  
Temperature Fields ◽  
Analytical Models ◽  
Maximum Temperature ◽  
Thermal Cycles ◽  
Friction Stir

In the conventional analytical model used for heat generation in friction stir welding (FSW), the heat generated at the pin/workpiece interface is assumed to distribute uniformly in the pin volume, and the heat flux is applied as volume heat. Besides, the tilt angle of the tool is assumed to be zero for simplicity. These assumptions bring about simulating deviation to some extent. To better understand the physical nature of heat generation, a modified analytical model, in which the nonuniform volumetric heat flux and the tilt angle of the tool were considered, was developed. Two analytical models are then implemented in the FEM software to analyze the temperature fields in the plunge and traverse stage during FSW of AA6005A-T6 aluminum hollow extrusions. The temperature distributions including the maximum temperature and heating rate between the two models are different. The thermal cycles in different zones further revealed that the peak temperature and temperature gradient are very different in the high-temperature region. Comparison shows that the modified analytical model is accurate enough for predicting the thermal cycles and peak temperatures, and the corresponding simulating precision is higher than that of the conventional analytical model.

scholarly journals Acceleration of a CFD Code with a GPU

2010 ◽  
Vol 18 (3-4) ◽  
pp. 193-201 ◽  
Author(s):  
Dennis C. Jespersen
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Graphics Processing Unit ◽  
Computational Time ◽  
Processing Unit ◽  
Graphics Processing ◽  
Work Done

The Computational Fluid Dynamics code OVERFLOW includes as one of its solver options an algorithm which is a fairly small piece of code but which accounts for a significant portion of the total computational time. This paper studies some of the issues in accelerating this piece of code by using a Graphics Processing Unit (GPU). The algorithm needs to be modified to be suitable for a GPU and attention needs to be given to 64-bit and 32-bit arithmetic. Interestingly, the work done for the GPU produced ideas for accelerating the CPU code and led to significant speedup on the CPU.

scholarly journals Numerical investigation of boiling and forced convection heat transfer in inclined porous enclosure using modified enthalpy formulation

2018 ◽  
Vol 240 ◽  
pp. 01001 ◽  
Author(s):  
Omar Rafae Alomar ◽  
Rafie Rushdy Mohammed ◽  
Karam Hashim Mohammed
Keyword(s):  
Inclination Angle ◽  
Convection Heat Transfer ◽  
Operating Conditions ◽  
Temperature Fields ◽  
Computational Time ◽  
Governing Equations ◽  
Two Phase ◽  
Recirculating Flow ◽  
Volume Method ◽  
H Formulation

Two-Phase flow in an inclined rectangular porous media, under unsteady-state condition, has been numerically investigated in this article, based on the modified h-formulation of Two-Phase Mixture Model (TPMM). The governing equations have been discretised using Finite Volume Method (FVM) and solved iteratively in a SIMPLE-like manner. Effects of various parameters on the flow and temperature fields have been investigated, which clearly demonstrated that the inclination angle strongly affect the boiling initiation. Recirculating flow has been observed when the inclination angle θ>0˚. The results clearly indicated that the operating conditions and the porous medium properties have significant effects on the initiation and termination of phase change process. A closer inspection of the results reveals that the presence of a critical inclination angle depending on the value of K* and, Re1 which correspond to a maximum values of vapour volume. The modified h-formulation requires significantly less computational time as compared with the existing H-formulation of TPMM.

scholarly journals Investigation on the effect of electrode tip on formation of metal droplets and temperature profile in a vibrating electrode electroslag remelting process

Open Physics ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. 743-751 ◽  
Author(s):  
Fang Wang ◽  
Jakov Baleta ◽  
Qiang Wang ◽  
Baokuan Li
Keyword(s):  
Temperature Profile ◽  
Electroslag Remelting ◽  
Temperature Fields ◽  
Maximum Temperature ◽  
Periodic Pattern ◽  
Coupled Modelling ◽  
Frequency Changes ◽  
Volume Method ◽  
Peak Value ◽  
Metal Droplets

Abstract In the present work, a transient full-coupled modelling approach has been put forward to study the effect of electrode tip on formation of metal droplets and temperature profile in the electromagnetically-controlled electroslag-remelting furnace with vibrating electrode. The electromagnetic field, momentum and energy conservation equations are solved simultaneously based on the finite volume method. The interface of slag and metal is traced using the volume of fluid approach. The results show that in the case of cone tip electrode the average dimension of metal droplets is smaller compared to the flat tip electrode. In addition, the bigger and stretched metal droplets are not observed with the cone tip electrode. The temperature fields with the cone tip electrode are distributed in a prominent periodic pattern compared to the case with flat tip electrode. The maximum temperature zone with the cone tip electrode is located along the z axial in the upper part of slag, not in the lower part. When the frequency changes from 0.17 Hz to 1 Hz, the maximum temperature reduces from 2050 K to 1985 K and the peak value of velocity decreases from 0.20 m/s to 0.125 m/s. When the vibration amplitude varies from 3mm to 6mm, the maximum temperature in the slag cover drops by 3.9% and the peak value of velocity rises by 16.7%.

A Ventilation Cooling Solution to Improve Thermal Environment of High Energy Density Li-Ion Battery Packs

2015 ◽  
Author(s):  
Zhiqiang Li ◽  
Xiaowei Fan ◽  
Fang Wang ◽  
Dasi He ◽  
Shifei Wei
Keyword(s):  
Energy Density ◽  
Thermal Environment ◽  
High Energy ◽  
High Energy Density ◽  
Temperature Fields ◽  
Maximum Temperature ◽  
Li Ion Battery ◽  
Battery System ◽  
Li Ion ◽  
Battery Cells

This paper focuses on the cooling solution to a high energy density and large capacity Li-ion battery system which consist of four packs of 26650 cells. The cooling measure is a critical technology for many Li-ion battery systems especially that designed for hybrid electric vehicles, in which, high energy density within a limited space is very common in these systems. Both the safety and efficiency of Li-ion battery cells rely on the temperature which is under control of the battery thermal management system. In this study, temperature fields within battery boxes are simulated with the computational fluid dynamic (CFD) method. With the help of an airconditioner, a cooling solution is proposed for a relatively large dimensional, high energy density Li-ion battery cells array using by vehicles. Through the proposed solution, the maximum single-cell temperature is restricted to a reasonable level, and the maximum temperature difference throughout the battery system is also improved.

Free Convection in a Two-Dimensional Porous Loop

1986 ◽  
Vol 108 (2) ◽  
pp. 277-283 ◽  
Author(s):  
L. Robillard ◽  
T. H. Nguyen ◽  
P. Vasseur
Keyword(s):  
Steady State ◽  
Rayleigh Number ◽  
Porous Layer ◽  
Outer Boundary ◽  
Convective Motion ◽  
Steady State Solution ◽  
Temperature Fields ◽  
Maximum Temperature ◽  
Two Dimensional ◽  
Convective Cells

A study is made of the natural convection in an annular porous layer having an isothermal inner boundary and its outer boundary subjected to a thermal stratification arbitrarily oriented with respect to gravity. For such conditions, no symmetry can be expected for the flow and temperature fields with respect to the vertical diameter and the whole circular region must be considered. Two-dimensional steady-state solutions are sought by perturbation and numerical approaches. Results obtained indicate that the circulating flow around the annulus attains its maximum strength when the stratification is horizontal (heating from the side). This circulating flow is responsible for an important heat exchange between the porous layer and its external surroundings. The flow field is also characterized by the presence of two convective cells near the inner boundary, giving rise to flow reversal on this surface. When the maximum temperature on the outer boundary is at the bottom of the cavity, the convective motion becomes potentially unstable; for a Rayleigh number below 80, there exists a steady-state solution symmetrical with respect to both vertical and horizontal axes; for a Rayleigh number above 80, an unsteady periodic situation develops with the circulating flow alternating its direction around the annulus.

Three-Dimensional Finite Element Analysis on Heavy Cutting for High Strength Steel

2013 ◽  
Vol 274 ◽  
pp. 3-6 ◽  
Author(s):  
Yuan Sheng Zhai ◽  
Xian Li Liu ◽  
Yu Wang
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Feed Rate ◽  
Cutting Forces ◽  
High Strength Steel ◽  
Three Dimensional ◽  
High Strength ◽  
Temperature Fields ◽  
Maximum Temperature ◽  
Element Modeling

The finite element modeling and experimental validation of three-dimensional heavy cutting of high strength steel (2.25Cr-1Mo-0.25V) are presented. The commercial software Deform 3D applied for the finite element modeling is studied the effect of feed rate on the principal cutting forces and the temperature fields. The friction between the tool and the chip is assumed to follow a shear model and the local adaptive remeshing technique is used for the formation of chip. The feed rate significantly affects the cutting forces, but slightly influences the maximum temperature of the chip. The simulation results are compared with experimental data and found to be in good agreement.

Model and Imitation of the Cycle Temperature Fields and Deformations of Coke Drum

2011 ◽  
Vol 197-198 ◽  
pp. 1389-1394
Author(s):  
Sun Yi Chen
Keyword(s):  
Temperature Field ◽  
Temperature Difference ◽  
Cooling Water ◽  
Physical Property ◽  
Temperature Fields ◽  
Maximum Temperature ◽  
Kinetic Temperature ◽  
Maximum Temperature Difference ◽  
Radial Temperature ◽  
Inside Wall

When the operating process of delay coking is cyclically changing from 25°C to 500°C, it would usually induce the effect of heat treatment on the shell of coke drum. After a special model of the kinetic medium climbing along the inside-wall of the coke drum at a steady rate set up, the resulting two-dimensional kinetic temperature field of shell in radial and axial directions has been calculated and analyzed by FEM. The relation between the material physical property of the shell and its temperature has been considered. The results show that the radial temperature difference or the axial temperature difference caused by the cooling water is more than that caused by the hot oil. The maximum temperature difference between the inside-wall and the outside-wall is 40°C below the medium level, 30mm by the hot oil and 60 °C or 25 mm by the cooling water. The circumferential uneven temperature field, location and concave/convex or incline/bend of body have been surveyed and analyzed. The lat-circle deformation of transverse section has been discussed.

scholarly journals Effect of heater size on heat transfer in a falling liquid film

2021 ◽  
pp. 50-55
Author(s):  
В.В. Кузнецов
Keyword(s):  
Heat Transfer ◽  
Three Dimensional ◽  
Analytical Formula ◽  
Temperature Fields ◽  
Maximum Temperature ◽  
Physical Factors ◽  
Thermocapillary Effect ◽  
Average Value ◽  
Surface Deformations ◽  
Falling Liquid Film

Проведены расчеты полей скорости и температуры, а также положение границы раздела жидкость-газ при стекании тонкой пленки жидкости по плоской подложке, наклоненной к горизонту. На подложке расположен нагреватель квадратной формы, мощность которого фиксирована, а размеры варьировались в ходе расчетов:- одним из перспективных методов отвода высоких тепловых потоков от электронного оборудования являются технологии, использующие тонкие пленки жидкости, движущиеся по охлаждаемой поверхности. Целью работы было исследование зависимости динамики и теплообмена в пленки от размера нагревателя;- на основе разработанной трехмерной нестационарной модели движения проведены расчеты теплообмена в движущейся поенке. При этом учитывалось действие всех основных физческих факторов при их взаимодействии: диффузионный и конвективный теплопереносы, зависимость вязкости от температуры, термокапиллярный эффект, появление и эволюция поверхностных деформаций;- установлено, что размер нагревателя существенно влияет на поля температуры и поверхностные деформации, а также на значение температурных экстремумов. Выведена аналитическая формула для расчета наибольшего достигаемого на подложке превышения температуры её среднего значения;- результаты могут применяться при проектировании систем охлаждения электронного оборудования. On the basis of the developed three-dimensional non-stationary model of motion, calculations of heat transfer in a moving roll were carried out. In this case, the action of all the main physical factors during their interaction was taken into account: diffusion and convective heat transfer, the dependence of viscosity on temperature, the thermocapillary effect, the appearance and evolution of surface deformations.  it was found that the size of the heater significantly affects the temperature fields and surface deformations, as well as the value of temperature extremes. An analytical formula is derived for calculating the maximum temperature rise attainable on the substrate of its average value.

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