THE EFFECT OF THE DOUBLE-DECK FILAMENT SETUP ON ENHANCING THE UNIFORMITY OF TEMPERATURE FIELD ON LONG-FLUTE CUTTING TOOLS

2014 ◽  
Vol 21 (06) ◽  
pp. 1450078 ◽  
Author(s):  
BIN SHEN ◽  
SULIN CHEN ◽  
LEI CHENG ◽  
FANGHONG SUN

In the present study, a double-deck filament setup is proposed for the hot filament chemical vapor deposition (HFCVD) method and an optimization method is presented to determine its optimal geometry that is able to produce a highly uniform temperature field on the whole flute surface of long-flute cutting tools. The optimization method is based on the finite volume method (FVM) simulation and the Taguchi method. The simulation results show that this double-deck filament setup always produce a highly uniform temperature distribution along the filament direction. Comparatively, for the temperature uniformity along the drill axis, the heights of the two filament decks present virtually significant influence, while the separations between the two filaments in either deck exhibit a relative weak effect. An optimized setup is obtained that can produce a highly uniform temperature field with an average temperature of 834°C, a standard deviation (σ) of 2.59°C and a temperature range (R) of 11.75°C. Finally, the precision of the proposed simulation method is verified by an additional temperature measurement. The measured temperature results show that a highly uniform temperature fields with σ/R = 9.6/35.2°C can be generated by the optimized setup and the deviation of the simulated results from the measured actual temperatures are within 0.5–3.5%, which justifies the correctness of the simulation method proposed in present study.

2020 ◽  
Vol 10 (15) ◽  
pp. 5255
Author(s):  
Wucheng Xu ◽  
Deshen Chen ◽  
Hongliang Qian

Due to the dynamic coupling effects of solar radiation, longwave radiation, convective heat transfer, shadows, and other factors, the temperature field and effect of steel structures are significantly non-uniform, differing from traditional concepts that regard the temperature variation of steel structures as a slow and uniform progress. This difference can hinder the correct understanding of the thermal behavior of steel structures and ignore some potential safety hazards. This paper provides a review of the studies for the non-uniform temperature field and effect of steel structures, and presents some outlooks on future developments on the basis of the current research situation. A summary of research on the temperature field and effect of space structures, bridges and radio telescopes initially establishes the basic cognitive framework for this field. In addition, then, the basic principles of the numerical simulation of temperature fields are introduced through heat transfer mechanism, and the experimental test methods of temperature and its effects are described based on typical test cases. Finally, with a view to the future, some suggestions and opinions are provided in consideration of deficiencies in the current research status. This paper hopes to provide some valuable references for future research in this field through research summary, method introduction and outlook.


2021 ◽  
Vol 21 (11) ◽  
pp. 293
Author(s):  
Shan-Xiang Wei ◽  
De-Qing Kong ◽  
Qi-Ming Wang

Abstract The non-uniform temperature distribution of the main reflector of a large radio telescope may cause serious deformation of the main reflector, which will dramatically reduce the aperture efficiency of a radio telescope. To study the non-uniform temperature field of the main reflector of a large radio telescope, numerical calculations including thermal environment factors, the coefficients on convection and radiation, and the shadow boundary of the main reflector are first discussed. In addition, the shadow coverage and the non-uniform temperature field of the main reflector of a 70-m radio telescope under solar radiation are simulated by finite element analysis. The simulation results show that the temperature distribution of the main reflector under solar radiation is very uneven, and the maximum of the root mean square temperature is 12.3°C. To verify the simulation results, an optical camera and a thermal imaging camera are used to measure the shadow coverage and the non-uniform temperature distribution of the main reflector on a clear day. At the same time, some temperature sensors are used to measure the temperature at some points close to the main reflector on the backup structure. It has been verified that the simulation and measurement results of the shadow coverage on the main reflector are in good agreement, and the cosine similarity between the simulation and the measurement is above 90%. Despite the inevitable thermal imaging errors caused by large viewing angles, the simulated temperature field is similar to the measured temperature distribution of the main reflector to a large extent. The temperature trend measured at the test points on the backup structure close to the main reflector without direct solar radiation is consistent with the simulated temperature trend of the corresponding points on the main reflector with the solar radiation. It is credible to calculate the temperature field of the main reflector through the finite element method. This work can provide valuable references for studying the thermal deformation and the surface accuracy of the main reflector of a large radio telescope.


2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Yuhui Wu ◽  
Xinzhi Zhou ◽  
Li Zhao ◽  
Chenlong Dong ◽  
Hailin Wang

Acoustic tomography (AT), as a noninvasive temperature measurement method, can achieve temperature field measurement in harsh environments. In order to achieve the measurement of the temperature distribution in the furnace and improve the accuracy of AT reconstruction, a temperature field reconstruction algorithm based on the radial basis function (RBF) interpolation method optimized by the evaluation function (EF-RBFI for short) is proposed. Based on a small amount of temperature data obtained by the least square method (LSM), the RBF is used for interpolation. And, the functional relationship between the parameter of RBF and the root-mean-square (RMS) error of the reconstruction results is established in this paper, which serves as the objective function for the effect evaluation, so as to determine the optimal parameter of RBF. The detailed temperature description of the entire measured temperature field is finally established. Through the reconstruction of three different types of temperature fields provided by Dongfang Boiler Works, the results and error analysis show that the EF-RBFI algorithm can describe the temperature distribution information of the measured combustion area globally and is able to reconstruct the temperature field with high precision.


2019 ◽  
pp. 45-46
Author(s):  
N. N. Matveev ◽  
V. V. Saushkin ◽  
N. Yu. Evsikova ◽  
N. S. Kamalova ◽  
V. I. Lisitsyn

For the first time, a method based on the registration of polarization and depolarization currents arising in wood in a non-uniform temperature field was used to study the properties of cellulose. The purpose of the method used is to record the relaxation of bound charges with a change in the temperature of the sample under study. It is shown that the detected low-temperature transitions have a crystal-crystal polarization mechanism, and the natural polymer cellulose is an active dielectric.


2014 ◽  
Vol 22 (4) ◽  
pp. 970-978 ◽  
Author(s):  
钱宏亮 QIAN Hong-liang ◽  
柳叶 LIU Ye ◽  
范峰 FAN Feng ◽  
金晓飞 JIN Xiao-fei

2012 ◽  
Vol 426 ◽  
pp. 330-334 ◽  
Author(s):  
Ying Guang Li ◽  
C.Y. Fu ◽  
D.S. Li ◽  
S.M. Wan

Aiming at the problems of composites of anisotropic, poor in dimensional and uneven temperature field in the designing of composite tool in autoclave, the techniques of designing the composite tool of aircraft components were constructed, involving in the following aspects: Taking advantage of design flexibility of composites, the thermal expansion coefficient between the moulding board and composite components matched. By analyzing the cure process curve of fiber-reinforced composites, the result that the crisis point without stress between component and tool, which the shape of composite component decided was concluded. By the temperature field analysis, and contrasted with the experimental results, the maximum difference was 4.95°C,after analysis, optimized the structure of the tool, obtaining the relatively uniform temperature field of the board.


Sign in / Sign up

Export Citation Format

Share Document