Research of heating during surfacing of crane wheels and support rollers

2021 ◽  
pp. 47-50
Author(s):  
V.A. Korotkov
Keyword(s):  
Cross Section ◽  
Temperature Difference ◽  
Crane Wheel

The surfacing of wheels and rollers with an uneven cross-section leads to an increased heating of the surfaces to be welded, upon cooling of which stresses are formed on a relatively cold product, causing the failure of the part. To prevent such failures, concomitant heating of the disc and rim parts is proposed, provided that the temperature difference with the surface to be welded does not exceed 100 °C. Keywords: crane wheel, welding stresses, failures. [email protected]

Heat Conduction Rectification in Nanostructure With Step Change in Cross-Section

2010 ◽  
Author(s):  
Xingang Liang ◽  
Bao Yue
Keyword(s):  
Heat Flux ◽  
Heat Conduction ◽  
Thermal Resistance ◽  
Cross Section ◽  
Temperature Difference ◽  
Flow Direction ◽  
Step Change ◽  
Dynamics Simulation ◽  
Rectification Effect ◽  
Thick Part

Heat conduction rectifier is attracting more attention due to its potential application to process thermal currents independently and convert them into electronic signals. This work reports an investigation by molecular dynamics simulation on the heat conduction rectification effect in the nanostructure whose cross-section have step change along the heat flux. It is found that thermal resistance is different with reversed heat flux direction, which is called the heat conduction rectification. The heat conduction rectification depends on the temperature difference. By reducing temperature difference across the nanostructure, the rectification could be reversed. When the temperature difference is small enough, the thermal resistance is larger when the heat flux flows from the thick part to the thin part when the length of the structure is about 10 nm. The larger variation in the cross-section leads the larger difference in the thermal resistance with opposite heat flux. The mechanism of the rectification is discussed. If we take phonons as liquid particles and consider the case of a liquid flowing through a channel with step expansion in cross-section, the flow resistance is less with liquid flowing from the narrow part to the wide part than that in the case with contrary flow direction. In fact, the scattering of phonons at the step face reduces the mean free path of phonon when heat flux conducts from the narrow end to the wide end.

Numerical Simulation on Temperature Field of CFST Member under Solar Radiation

2011 ◽  
Vol 354-355 ◽  
pp. 1241-1244
Author(s):  
Yan He ◽  
Man Ding ◽  
Qian Zhang
Keyword(s):  
Numerical Simulation ◽  
Temperature Field ◽  
Temperature Distribution ◽  
Solar Radiation ◽  
Cross Section ◽  
Temperature Difference ◽  
Steel Tube ◽  
Concrete Filled Steel Tube ◽  
Nonlinear Temperature ◽  
The Cross

In this paper the temperature field of Concrete Filled Steel Tube (CFST) member under solar radiation is simulated. The results show that temperature distribution caused by solar radiation is nonlinear over the cross-section of CFST member, and it is significantly varied with time and sections, the largest nonlinear temperature difference is over 26.3°C.

Theoretical Analysis of Temperature and Shrinkage Stresses of Box-Girder Section

2011 ◽  
Vol 243-249 ◽  
pp. 1885-1892
Author(s):  
Wei Zhao Li ◽  
Zong Lin Wang ◽  
Fadhil Naser Ali
Keyword(s):  
Tensile Stress ◽  
Cross Section ◽  
Temperature Difference ◽  
Negative Temperature ◽  
Shrinkage Stress ◽  
Box Girder ◽  
Stress Changes ◽  
Longitudinal Cracks ◽  
Bottom Slab ◽  
The Web

The objective of this study is to analyze the temperature and shrinkage stresses of the mid-span cross-section of a 20 meters box girder to find the reasons which cause the longitudinal cracks in the web and bottom of box girder. According to the results of damage inspeation, there are many longitudinal cracks in the web and bottom slab of box girders, especially the web of the edger beam, the crack is very clear. Ansys ver.10 software is used to analyze two dimensional finite element model of a typical cross section of a real bridge to calculate the temperature stresses caused by temperature difference between inside and out side of the box and the shrinkage stresses based on moisture diffusion. The results of analysis show that the outer surface of the web and bottom slab of the fabricated box girder will produce tensile stress at the effect of negative temperature difference. If the concrete reaches a certain age, the tensile stress does not cause creaks in the cross-section. The shrinkage stress changes with the moisture gradient in the box section. It will reach the maximum in 15 days and then decreases with the growth of the age. Shrinkage stress may cause cracking of the concrete surface because of the tensile strength is low in the early age.

Experimental Research on the Characteristics of Thermal Bow in an Aeroengine HP Spool

2020 ◽  
Author(s):  
Xiangyu Yu ◽  
Zhansheng Liu ◽  
Zhaohua Zhou ◽  
Jigang Feng ◽  
Peng He
Keyword(s):  
Temperature Distribution ◽  
Cross Section ◽  
Temperature Difference ◽  
Vibration Amplitude ◽  
Structural Deformation ◽  
Dynamic Experiment ◽  
Cooling Process ◽  
Hot Air ◽  
Dynamic Experiments ◽  
Static Experiment

Abstract During the cooling process after shut down for aeroengines, internal hot air rises and cold air drops due to natural convection, which makes uneven temperature distribution in the casing and creates temperature difference in radial and axial directions, causing uneven deformation of rotor. Once aeroengine starts after a little time of cooling, thermal bow forms more easily, causing excessive vibration. In some cases, the thermal bow can be so severe that the engine will be unable to start. Based on the rotor for one certain type of aeroengine, the paper describes an experiment of thermal bow failure, which is divided into a static one and a dynamic one, both having simulated the uneven temperature field. Firstly, the static experiment measures temperature difference and deformation of rotor in different temperature environments and dissimilar cold blowing conditions. Results show temperature difference of each cross section increases with the growth of casing temperature. And cold blowing can quickly and effectively eliminate uneven temperature distribution and structural deformation. Secondly, the dynamic experiment produces the results that the vibration amplitude increases obviously when rotating frequency approaches critical speeds (2365r/min and 2892r/min). As the cooling time increases, the amplitude decreases until normal, which is the most important feature different from that in failure of initial mass imbalance. Thermal bow mainly influences the fundamental frequency vibration. Cold blowing can quickly and effectively reduce vibration amplitude. The conclusions obtained from the dynamic experiments are consistent with the known regulations from engineering experience.

Effect of Process Parameters on the Temperature of 4Cr9Si2 Martensite Refractory Steel during CWR

2012 ◽  
Vol 572 ◽  
pp. 148-153
Author(s):  
Jiang Hua Huang ◽  
Jin Ping Liu ◽  
Bao Yu Wang ◽  
Zheng Huan Hu
Keyword(s):  
Heat Conduction ◽  
Cross Section ◽  
Process Parameters ◽  
Temperature Difference ◽  
Rolling Speed ◽  
Plastic Work ◽  
Constitutive Relationship ◽  
Preheat Temperature ◽  
Cross Wedge Rolling ◽  
Refractory Steel

Based on the constitutive relationship of 4Cr9Si2 martensite refractory steel obtained by Gleeble-1500 hot simulation isothermal compression, a finite element model of Cross Wedge Rolling was build up for 4Cr9Si2 Martensite and the heat conduction, convection, plastic work and friction work were taken in account in the model. The forming process of 4Cr9Si2 martensite refractory steel by cross wedge rolling was simulated by means of DEFORM-3D software. The influence regularities of temperature of rolling process parameters were obtained: temperature rise rapidly result from plastic work and friction work in the cross-section at the process of rolling, with the completion of rolled piece cross-section, temperature descending due to heat conduction and radiation with atmosphere. The rolled piece temperature difference decrease with rolling speed and die preheat temperature increasing, the billet heating temperature is little for rolled piece temperature difference compared with rolling speed and die preheat temperature.

Investigation of Mixing Flow Process Using PIV and PLIF Techniques

2013 ◽  
Vol 816-817 ◽  
pp. 1054-1058
Author(s):  
Ezddin Hutli ◽  
Dániel Tar ◽  
Valer Gottlasz ◽  
Gyorgy Ezsol
Keyword(s):  
Temperature Distribution ◽  
Fuel Assembly ◽  
Cross Section ◽  
Temperature Difference ◽  
Power Distribution ◽  
Coolant Temperature ◽  
Mixing Process ◽  
Flow Process ◽  
Flow Rates ◽  
Rod Bundle

A coolant mixing investigation in a head of a half-size model of VVER-440 fuel assembly (simulator) has been performed at KFKI. The PIV and PLIF measurements have been done under a selected list of power distribution options, flow rates and powers. The experiments were focused on obtaining a data for investigating the trends in temperature difference between the value registered by a thermocouple and that obtained using PLIF technique. The coolant temperature distribution has been measured in many positions along the coolant trajectory and where coolant flow leaves the rod bundle and in the cross section location of thermocouple, thus the dynamics of effect of mixing process is also declared. PIV and LPIF results show their ability to verify the primary results of CFD calculations.

scholarly journals Design and Optimization of Cooling Plate for Battery Module of an Electric Vehicle

2019 ◽  
Vol 9 (4) ◽  
pp. 754 ◽  
Author(s):  
Ben Ye ◽  
Md Rubel ◽  
Hongjun Li
Keyword(s):  
Pressure Drop ◽  
Cross Section ◽  
Temperature Difference ◽  
Thermal Model ◽  
Lithium Iron Phosphate ◽  
Orthogonal Experimental Design ◽  
Transfer Model ◽  
Air Cooling ◽  
Cooling Plate ◽  
The Cross

With the development of electric vehicles, much attention has been paid to the thermal management of batteries. The liquid cooling has been increasingly used instead of other cooling methods, such as air cooling and phase change material cooling. In this article, a lithium iron phosphate battery was used to design a standard module including two cooling plates. A single battery numerical model was first created and verified as the basis of the module heat transfer model. Orthogonal experimental design method was adopted in the module thermal model to optimize the main parameters in the module: Battery gap, the cross-section size, and the number of coolant channels of the cooling plate. The Surrogate Model was then utilized to further optimize geometry of the cooling plate. Finally, the optimized geometry was rebuilt in the module thermal model for analysis. The comparison showed that the maximum and minimum temperature difference in the cooling plate was reduced by 9.5% and the pressure drop was reduced by 16.88%. It was found that the battery temperature difference and the pressure drop decreased with the increase of the cross-section and number of the coolant channel when the coolant flow rate was constant at the inlet.

Simulation of the Temperature Distribution of Gradient Ti-TiB Composites Prepared by Spark Plasma Sintering Process

2011 ◽  
Vol 295-297 ◽  
pp. 2321-2324
Author(s):  
Sai Wei ◽  
Zhao Hui Zhang ◽  
Xiang Bo Shen ◽  
Fu Chi Wang ◽  
Shu Kui Li
Keyword(s):  
Temperature Distribution ◽  
Spark Plasma Sintering ◽  
Cross Section ◽  
Temperature Difference ◽  
Axial Direction ◽  
Element Model ◽  
Sintering Process ◽  
Radial Temperature ◽  
Plasma Sintering ◽  
Spark Plasma

An electrical – thermal coupled finite element model (FEM) is developed to investigate the temperature distribution during spark plasma sintering (SPS) with a pre-designed graded graphite die. The sample used in this investigation consists of five layers with different contents of Ti and TiB (45 wt % Ti, 55 wt %Ti, 65 wt % Ti, 75 wt % Ti and 85 wt % Ti). The temperature distribution in gradient Ti-TiB composites was obtained. Owing to the use of the die with changing cross section, a temperature difference of 142K in the axial direction inside the sample is achieved, while the maximum radial temperature difference is 6.2 times less than the axial one.

Numerical Analysis of the Process of Heating of a Bed of Steel Bars / Numeryczna Analiza Procesu Nagrzewania Złoza Pretów Stalowych

2013 ◽  
Vol 58 (1) ◽  
pp. 63-66 ◽  
Author(s):  
D. Musiał
Keyword(s):  
Cross Section ◽  
Temperature Difference ◽  
Hot Forging ◽  
Medium Temperature ◽  
Cross Sectional ◽  
Parabolic Distribution ◽  
Steel Bars ◽  
The Cross ◽  
Constant Heating ◽  
Thermal Conductivity Λ

The article describes the computation of the time of heating of a bed of bars in the heat treatment process. The charge was subjected to under-annealing, which is used in industry, e.g., to facilitate sawing of bars or billets into a sections intended for hot forging. The beds under examination were regarded as solid elements, which was possible thanks to the knowledge of the effective thermal conductivity, λ. The value of this quantity for the temperature range under consideration was determined based on the author’s original investigation. During heating of a bundle of bars at a constant heating medium temperature, a temperature difference occurs on the charge cross-section, which is significantly greater than that provided for by the technology. It is therefore essential to carry out a second soaking stage in order to achieve the cross-sectional temperature difference at a level of 20°C. The computation of soaking was conducted for the assumed conditions of a constant temperature on the charge surface and the parabolic distribution of temperature on the cross-section.

XUV Absorption Spectra of Carbon Ions

1988 ◽  
Vol 102 ◽  
pp. 71-73
Author(s):  
E. Jannitti ◽  
P. Nicolosi ◽  
G. Tondello
Keyword(s):  
Absorption Spectra ◽  
Cross Section ◽  
Theoretical Calculations ◽  
Photoionization Cross Section ◽  
Carbon Ions

AbstractThe photoabsorption spectra of the carbon ions have been obtained by using two laser-produced plasmas. The photoionization cross-section of the CV has been absolutely measured and the value at threshold, σ=(4.7±0.5) × 10−19cm2, as well as its behaviour at higher energies agrees quite well with the theoretical calculations.

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