ISO-Gradient Lines in a Differentially Heated Cylindrical Fluid Layer Using Coherent Gradient Sensing Interferometer

2002 ◽  
Author(s):  
D. Mishra ◽  
S. L. Wong ◽  
J. P. Longtin ◽  
R. P. Singh ◽  
V. Prasad
Keyword(s):  
Temperature Field ◽  
Reference Beam ◽  
Laser Interferometry ◽  
Temperature Fields ◽  
Line Of Sight ◽  
Water Medium ◽  
Gradient Sensing ◽  
Fluid Medium ◽  
Coherent Gradient Sensing ◽  
Convective Fluid

Non-invasive flow visualization and measurement of temperature fields in convective fluid systems continues to be a challenging problem for researchers. Radiation based measurements such as laser interferometry are one of the few available tool for this purpose. Laser interferometry allows for an accurate and convenient full field visualization and measurement of fluid properties. In the present study a single-beam Coherent Gradient Sensing (CGS) interferometer is used to obtain line-of-sight projections of a three-dimensional temperature field in a convective fluid medium. Due to its inherent insensitivity to vibrations, simple and cost effective optical layout and, most importantly, the absence of a separate reference beam, this interferometer is an ideal choice for measurements in convective fluids. In the present study, line-of-sight interferometric projections of a differentially heated water medium in a cylindrical cavity are presented. The cavity employed has an aspect ratio (diameter/height) of 3.9. The interferograms represent contours of gradient in the temperature field. Each of the interferograms is evaluated to obtain the two-dimensional projection of the temperature field. The temperature field obtained shows the absence of a radial-symmetric pattern at a Rayleigh number of 1.6×105.

scholarly journals Reconstruction of Flame Local Temperature Field Using Tomographic Approach by Spectral Ratio Pyrometer

2019 ◽  
Author(s):  
Вячеслав Фланден ◽  
Vyacheslav Flanden ◽  
Антон Поройков ◽  
Anton Poroykov ◽  
Дмитрий Голенцов ◽  
...  
Keyword(s):  
Temperature Field ◽  
Signal Amplification ◽  
Flame Temperature ◽  
Spectral Ratio ◽  
Temperature Fields ◽  
Line Of Sight ◽  
Inverse Transformation ◽  
Transimpedance Amplifier ◽  
Interference Filters ◽  
Spectral Ranges

The paper presents an approach to the reconstruction of the flame temperature field using a spectral ratio pyrometer. The device registers the intensity of the radiation from the measured flame in several spectral ranges using interference filters and photodiodes. Signal amplification occurs using the developed transimpedance amplifier. The pyrometer determines the temperature by measuring the ratio of the radiation intensity in two different spectral ranges. The signal is determined by integrating the intensity of the flame radiation along the optical system line of sight. Measurement of flame from several angles allows to get the Radon transform for this area. Calculation of the inverse transformation allows to obtain the field of local flame temperatures. The work presents an experimental setup for measuring flame local temperatures and software that allows to automate the measurement process and restore tomograms of temperature fields.

Numerical Analysis of Flow Fields and Temperature Fields in a Regenerative Heating Furnace for Steel Pipes

2018 ◽  
Vol 10 (3) ◽  
Author(s):  
Yi Han ◽  
Feng Liu ◽  
Xin Ran
Keyword(s):  
Temperature Field ◽  
Flow Field ◽  
Flow Velocity ◽  
Gas Flow ◽  
Flow Fields ◽  
Heating Furnace ◽  
Temperature Fields ◽  
Turbulent Layer ◽  
Steel Pipes ◽  
Pipe Blanks

In the production process of large-diameter seamless steel pipes, the blank heating quality before roll piercing has an important effect on whether subsequently conforming piping is produced. Obtaining accurate pipe blank heating temperature fields is the basis for establishing and optimizing a seamless pipe heating schedule. In this paper, the thermal process in a regenerative heating furnace was studied using fluent software, and the distribution laws of the flow field in the furnace and of the temperature field around the pipe blanks were obtained and verified experimentally. The heating furnace for pipe blanks was analyzed from multiple perspectives, including overall flow field, flow fields at different cross sections, and overall temperature field. It was found that the changeover process of the regenerative heating furnace caused the temperature in the upper part of the furnace to fluctuate. Under the pipe blanks, the gas flow was relatively thin, and the flow velocity was relatively low, facilitating the formation of a viscous turbulent layer and thereby inhibiting heat exchange around the pipe blanks. The mutual interference between the gas flow from burners and the return gas from the furnace tail flue led to different flow velocity directions at different positions, and such interference was relatively evident in the middle part of the furnace. A temperature “layering” phenomenon occurred between the upper and lower parts of the pipe blanks. The study in this paper has some significant usefulness for in-depth exploration of the characteristics of regenerative heating furnaces for steel pipes.

Method of Lines to Solve 2-D Steady Temperature Field of FGM

2007 ◽  
Vol 353-358 ◽  
pp. 2003-2006 ◽  
Author(s):  
Wei Tan ◽  
Chang Qing Sun ◽  
Chun Fang Xue ◽  
Yao Dai
Keyword(s):  
Thermal Conductivity ◽  
Temperature Field ◽  
Transfer Problem ◽  
Method Of Lines ◽  
Main Idea ◽  
Functionally Graded ◽  
Temperature Fields ◽  
Steady Temperature ◽  
Thermal Transfer ◽  
Steady Temperature Field

Method of Lines (MOLs) is introduced to solve 2-Dimension steady temperature field of functionally graded materials (FGMs). The main idea of the method is to semi–discretized the governing equation of thermal transfer problem into a system of ordinary differential equations (ODEs) defined on discrete lines by means of the finite difference method. The temperature field of FGM can be obtained by solving the ODEs with functions of thermal properties. As numerical examples, six kinds of material thermal conductivity functions, i.e. three kinds of polynomial functions, an exponent function, a logarithmic function, and a sine function are selected to simulate spatial thermal conductivity profile in FGMs respectively. The steady-state temperature fields of 2-D thermal transfer problem are analyzed by the MOLs. Numerical results show that different material thermal conductivity function has obvious different effect on the temperature field.

scholarly journals A Method for Reconstruction of Boiler Combustion Temperature Field Based on Acoustic Tomography

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Yuhui Wu ◽  
Xinzhi Zhou ◽  
Li Zhao ◽  
Chenlong Dong ◽  
Hailin Wang
Keyword(s):  
Temperature Field ◽  
Temperature Distribution ◽  
Optimal Parameter ◽  
Interpolation Method ◽  
Least Square Method ◽  
Reconstruction Algorithm ◽  
Least Square ◽  
Temperature Fields ◽  
Acoustic Tomography ◽  
Measured Temperature

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.

scholarly journals Influence of Rectifiers on Permanent Magnet Wind Generator Electromagnetic and Temperature Fields

2016 ◽  
Vol 10 (1) ◽  
pp. 205-219
Author(s):  
Qiu Hongbo ◽  
Dong Yu ◽  
Yang Cunxiang
Keyword(s):  
Electromagnetic Field ◽  
Temperature Field ◽  
Permanent Magnet ◽  
Core Loss ◽  
Harmonic Distortion ◽  
Temperature Fields ◽  
Stator Core ◽  
Current Harmonics ◽  
Copper Loss ◽  
Wind Generator

Power rectifiers are very necessary in the wind power generation systems since they are the necessary channels that link the generator and power gird together. However, they have some effects on the permanent magnet wind generator due to their work on fast on-off transitions. Taking an 8kW 2000r/min wind-driven permanent magnet generator as an example, the system model and external circuit were established. Firstly, based on the field-circuit coupling calculation method, the voltage and current harmonics have been studied respectively when the generator was connected to rectifier loads and pure resistance loads, so did the total harmonic distortion. The mechanism of harmonic impacted by rectifiers was revealed. Secondly, combined the harmonic electromagnetic field theory, the stator core loss, armature winding copper loss and rotor eddy loss were analyzed when the generator connected different loads. Furthermore, according to the definition of nonlinear circuits PF, the numerical analysis method was adopted to calculate the power factor when the generator connected two loads respectively. The change mechanism of PF impacted by rectifiers has been revealed. In addition, the temperature field model has been established and the generator temperature was also analyzed. The temperature distributions were obtained when the wind generator was connected to different loads. Then, the relationship between losses and temperature was combined, the change rules of permanent magnet temperature by the eddy current loss were studied under different load. At last, it can prove that the rectifiers have influences on both electromagnetic field and temperature field through comparing the simulation results with experimental test data.

Temperature Field Analysis and Cooling Structure Design of Ironless Permanent Magnet Synchronous Linear Motor

2021 ◽  
Vol 14 ◽  
Author(s):  
Xiaoting Lu ◽  
Yang Li ◽  
Zailiang Chen
Keyword(s):  
Temperature Field ◽  
Permanent Magnet ◽  
Heat Loss ◽  
Linear Motor ◽  
Structure Design ◽  
Servo Control ◽  
Field Analysis ◽  
Temperature Fields ◽  
Water Cooling ◽  
Linear Motors

Objective: Ironless, permanent magnet, synchronous linear (IPMSL) motors are applied widely in precision servo control for the nonexistence of cogging forces and comparatively small fluctuations in thrust and speed. Method: The air and water cooling structures are designed by assuming the heat loss in the motor operations is the source for the distribution of the temperature field in the analysis under natural cooling. Conclusion: The temperature fields of the linear motor under the two cooling modes are compared and analyzed, which helps monitor the temperature of linear motors during development and operations.

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