scholarly journals Digital Holographic Interferometry for the Measurement of Symmetrical Temperature Fields in Liquids

Photonics ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 200
Author(s):  
Gramoz Cubreli ◽  
Pavel Psota ◽  
Petra Dančová ◽  
Vít Lédl ◽  
Tomáš Vít
Keyword(s):  
Experimental Investigation ◽  
Temperature Field ◽  
Holographic Interferometry ◽  
Temperature Fields ◽  
Water Tank ◽  
Back Projection ◽  
Field Change ◽  
Abel Transform ◽  
Higher Temperature ◽  
Heated Fluid

In this paper, we present a method of quantitatively measuring in real-time the dynamic temperature field change and visualization of volumetric temperature fields generated by a 2D axial-symmetric heated fluid from a pulsatile jet in a water tank through off-axis digital holographic interferometry. A Mach-Zehnder interferometer on portable platform was built for the experimental investigation. The pulsatile jet was submerged in a water tank and fed with water with higher temperature. Tomographic approach was used to reconstruct the temperature fields through the Abel Transform and the filtered back-projection. Averaged results, tomographic view, standard deviation and errors are presented. The presented results reveal digital holographic interferometry as a powerful technique to visualize temperature fields in flowing liquids and gases.

Study on the Large Fire Tests Temperature Spread Properties of External Thermal Insulation System

2011 ◽  
Vol 243-249 ◽  
pp. 6976-6983
Author(s):  
Zhi Rong Niu ◽  
Zhen Li Huang
Keyword(s):  
Temperature Field ◽  
Research Method ◽  
Fire Prevention ◽  
Fire Tests ◽  
Large Fire ◽  
Fire Performance ◽  
Field Change ◽  
Insulation System ◽  
System Temperature ◽  
Two Sides

The current domestic exterior insulation system fire incidents are frequent. The study of exterior insulation system fire performance gets more and more relevant national authorities and insiders' attention. Based on two sides wall exterior insulation system as the research object, fire prevention experimental research method of insulation system and the insulation system temperature spread rule are expounded. Reveals the insulation system burning speed and scope of the fire from spreading under the action of the fire. The temperature and temperature field change regularity and insulation system of damaged situation after combustion are compared, and structural measures to improve the insulation system fire performance role is drawn.

scholarly journals Study on the Temperature Field of Casting Process in ANSYS

2011 ◽  
Vol 2-3 ◽  
pp. 856-860
Author(s):  
Chang Li ◽  
Guang Bing Zhao ◽  
Shu Yu Zhang ◽  
Xing Han
Keyword(s):  
Temperature Field ◽  
Casting Process ◽  
Interface Temperature ◽  
Field Change ◽  
Ansys Software ◽  
Heat Process ◽  
Manufacture Process ◽  
Composite Interface ◽  
Non Linear ◽  
Changing Process

Cast molding is the main manufacture process in foundry, because the most disfigurements occurs in this step, while the foundry itself is a complex non-linear instantaneous transferring heat process, in which it should take the absorbing and releasing potential heat into account. In this paper, it simulates the temperature field changing process of the cast solidification in ANSYS software, gets the temperature field change rule for a typical cast, and analyzed the effect of different foundry technics parameters on composite interface temperature, which will provide numerical bases for optimizing foundry technics parameters in future.

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.

The Possibility of Visualizing Temperature Fields Using Digital Holographic Interferometry

2013 ◽  
Vol 284-287 ◽  
pp. 988-995 ◽  
Author(s):  
Tomáš Vít ◽  
Vít Lédl ◽  
Roman Dolecek ◽  
Pavel Psota
Keyword(s):  
Holographic Interferometry ◽  
Rapid Change ◽  
Optical Methods ◽  
Temperature Fields ◽  
Constant Current ◽  
Special Technique ◽  
Limiting Factor ◽  
Measured Temperature ◽  
Hot Wire ◽  
First Results

The presented paper compares results of measured temperature fields achieved by digital holographic interferometry (DHI) and hot wire anemometry. It shows the possibility of using holographic interferometry for the visualization of temperature fields in periodically moving fluids. The measurement of temperature fields in moving fluids has many inherent difficulties. The usage of point temperature measurement methods, such as Constant Current Anemometry (CCA), is limited to frequencies up to 3000 Hz. This frequency should be the limiting factor for using CCA in fluids when a rapid change of temperature occurs. This shortcoming of CCA measurements could be overcome through the use of optical methods such as digital holographic interferometry. It is necessary to employ a special holographic setup with double sensitivity instead of the commonly used Mach-Zehnder type of holographic interferometer in order to attain parameters sufficient for the studied case. This setup is not as light-efficient as the Mach-Zehnder type but has double sensitivity. The special technique of acquiring and phase averaging the results from holographic interferometry is presented. The paper also shows the first results of an evaluated 3D temperature field.

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.

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