Local Radiation Heating Technique of Polymeric Materials Using Functional-Dye

2007 ◽  
Author(s):  
Takushi Saito ◽  
Isao Satoh ◽  
Tatsuya Kawaguchi
Keyword(s):  
Numerical Simulation ◽  
Local Heating ◽  
Polymeric Materials ◽  
Surface Region ◽  
Experimental Result ◽  
Radiation Absorption ◽  
Dimensional System ◽  
Radiation Heating ◽  
Initial State ◽  
Photochromic Dye

In this study, the authors added a functional dye to a material which was transparent in initial state, to locally change the radiation absorption coefficient of the material. By using this material, we proposed a radiation heating technique that can achieve a selective local heating in three-dimensional system and investigated its feasibility. Temperature change of the test sample was measured in the experiment, and the characteristic of the presenting technique was investigated. To obtain better understanding of the presenting technique, numerical simulation of the temperature distribution inside the sample was also performed. In the experiment, photochromic dye and thermochromic dye were used as functional dyes and they were individually added to thermoplastic polymeric material (polystyrene) by using organic solvent (tetrahydrofuran). Then the material containing the dye was dried and processed to give a certain shape for the experiment. He-Cd laser and Ar ion laser were properly used as the excitation and the heat sources according to the type of dye. Experimental result showed that local heating of the material was achieved only in quite thin surface region in case of photochromic dye. On the other hand, local heating inside the material was successfully achieved in case of thermochromic dye. However, it was also observed that the heating point was moved to the upstream direction of the laser beam. To examine the solution of this problem, effect of the laser irradiation conditions on the moving speed of the heating point was discussed based on the numerical simulation results.

Numerical simulation of the airflow field in vortex spinning processing

2018 ◽  
Vol 89 (6) ◽  
pp. 1113-1127 ◽  
Author(s):  
Shanshan Shang ◽  
Jianping Yang ◽  
Chongwen Yu
Keyword(s):  
Numerical Simulation ◽  
High Speed ◽  
Stable Process ◽  
Three Dimensional ◽  
Experimental Result ◽  
Initial State ◽  
Suction Force ◽  
Spinning Process ◽  
Airflow Field ◽  
Yarn Tenacity

Three-dimensional numerical simulation of the airflow characteristics during the whole vortex spinning process, including the initial state of the yarn drawing-in process and the normal stable process, were obtained and analyzed. Spinning experiments, with the aid of a scanning electron microscope, were adopted to verify the results of the numerical simulation. The numerical simulation results show that the turbulence phenomenon in the normal spinning process is much more obvious than that in the initial spinning process; the air streamlines move orderly in the initial spinning process, which will produce a strong suction force that will be conducive to drawing the fiber bundle into the nozzle successfully, but the trajectory of airflow is complex in the normal stable spinning process and there is an upstream airflow with the same direction as the rotating airflow to provide extra tension for the yarn, which can improve the strength of the resultant yarn. The spinning experimental result is consistent with the result predicted by numerical simulation. The research further reveals the flow regularity and the turbulent phenomenon of the high-speed rotating airflow, predicts the effect of airflow motion on the spinning effect, and is helpful for stabilizing the spinning process and improving the yarn tenacity.

scholarly journals Numerical Study of Pressure Attenuation Effect on Tunnel Structures Subjected to Blast Loads

2021 ◽  
Vol 11 (12) ◽  
pp. 5646
Author(s):  
Cheng-Wei Hung ◽  
Ying-Kuan Tsai ◽  
Tai-An Chen ◽  
Hsin-Hung Lai ◽  
Pin-Wen Wu
Keyword(s):  
Numerical Simulation ◽  
Orifice Plate ◽  
Experimental Result ◽  
Scale Model ◽  
Pressure Reduction ◽  
Expansion Chamber ◽  
Pressure Relief ◽  
Attenuation Effect ◽  
The One ◽  
Better Than

This study used experimental and numerical simulation methods to discuss the attenuation mechanism of a blast inside a tunnel for different forms of a tunnel pressure reduction module under the condition of a tunnel near-field explosion. In terms of the experiment, a small-scale model was used for the explosion experiments of a tunnel pressure reduction module (expansion chamber, one-pressure relief orifice plate, double-pressure relief orifice plate). In the numerical simulation, the pressure transfer effect was evaluated using the ALE fluid–solid coupling and mapping technique. The findings showed that the pressure attenuation model changed the tunnel section to diffuse, reduce, or detour the pressure transfer, indicating the blast attenuation effect. In terms of the effect of blast attenuation, the double-pressure relief orifice plate was better than the one-pressure relief orifice plate, and the single-pressure relief orifice plate was better than the expansion chamber. The expansion chamber attenuated the blast by 30%, the one-pressure relief orifice plate attenuated the blast by 51%, and the double-pressure relief orifice plate attenuated the blast by 82%. The blast attenuation trend of the numerical simulation result generally matched that of the experimental result. The results of this study can provide a reference for future protective designs and reinforce the U.S. Force regulations.

Numerical Simulation Study of Metal Transfer in MIG Welding with Magnetic Control

2014 ◽  
Vol 532 ◽  
pp. 545-548 ◽  
Author(s):  
Chao Yang ◽  
Shu Yuan Jiang ◽  
Hai Bo Bi
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Mathematical Model ◽  
Simulation Study ◽  
Electromagnetic Theory ◽  
Metal Transfer ◽  
Experimental Result ◽  
Magnetic Control ◽  
Mig Welding ◽  
Model Based

This paper simulate the mode of metal transfer in MIG magnetic control welding by using CFD software FLUENT, establishing mathematical model based on fluid dynamics and electromagnetic theory, and simulate the form, grow and drop process of metal transfer with and without magnetic. Meanwhile, do experiments to confirm the simulate result, and it is well consistent with the experimental result.

Behavior of Bubble in Small Water Tank Used for Food Processing Using Underwater Shock Wave

2011 ◽  
Vol 673 ◽  
pp. 225-230 ◽  
Author(s):  
Hideki Hamashima ◽  
Manabu Shibuta ◽  
Shigeru Itoh
Keyword(s):  
Numerical Simulation ◽  
Shock Wave ◽  
Food Processing ◽  
High Speed ◽  
Underwater Explosion ◽  
Video Camera ◽  
Experimental Result ◽  
Water Tank ◽  
Underwater Shock Wave ◽  
Small Water

The food processing technology using a shock wave can prevent deterioration of the food by heat because it can process food in a short time. Generally, since the shock wave used for food processing is generated by underwater explosion, the load of a shock wave to the food becomes very complicated. Therefore, in order to process safely, it is important to clarify the behaviors of the shock wave and the bubble pulse generated by underwater explosion. In this research, in order to investigate the behavior of the shock wave in the water tank used for food processing, the optical observation experiment and the numerical simulation were performed. In the experiment, the shock wave generated by underwater explosion was observed with the high-speed video camera. The numerical simulation about the behavior of bubble pulse was performed using analysis software LS-DYNA. Comparing and examining were performed about the experimental result and the numerical simulation result. The result of the numerical simulation about the behavior of the shock wave generated by underwater explosion and the shock wave generated by the bubble pulse and the bubble pulse was well in agreement with the experimental result.

scholarly journals Numerical simulation of changes in the electric properties of biological tissues under local heating by laser radiation

2021 ◽  
Vol 2090 (1) ◽  
pp. 012049
Author(s):  
N V Kovalenko ◽  
A V Smirnov ◽  
O A Ryabushkin
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Laser Radiation ◽  
Optical Radiation ◽  
Local Heating ◽  
Biological Tissues ◽  
Electric Properties ◽  
Reliable Tool ◽  
The Mathematical Model

Abstract The mathematical model that describes the local heating of biological tissues by optical radiation is introduced. Changes of the electric properties of biological tissues in such process can be used as a reliable tool for analyzing heating and damage degrees of tissues.

scholarly journals Numerical Simulation and Experimental Study of Capacitive Imaging Technique as a Non-Destructive Testing Method

2021 ◽  
Author(s):  
Farima Abdollahi Mamoudan ◽  
Sebastien Savard ◽  
Tobin Filleter ◽  
Clemente Ibarra-Castanedo ◽  
Xavier Maldague
Keyword(s):  
Numerical Simulation ◽  
Surface Defects ◽  
Capacitive Sensor ◽  
Experimental Result ◽  
Destructive Testing ◽  
Fe Modelling ◽  
Inspection Method ◽  
Physical Experiments ◽  
Imaging Performance ◽  
Non Destructive

It was recently demonstrated that a co-planar capacitive sensor could be applied to the evaluation of materials without the disadvantages associated with the other techniques. This technique effectively detects changes in the dielectric properties of the materials due to, for instance, imperfections or variations in the internal structure, by moving a set of simple electrodes on the surface of the specimen. An AC voltage is applied to one or more electrodes and signals are detected by others. This is a promising inspection method for imaging the interior structure of the numerous materials, without the necessity to be in contact with the surface of the sample. In this paper, Finite Element (FE) modelling was employed to simulate the electric field distribution from a co-planar capacitive sensor and the way it interacts with a non-conducting sample. Physical experiments with a prototype capacitive sensor were also performed on a Plexiglas sample with sub-surface defects, to assess the imaging performance of the sensor. A good qualitative agreement was observed between the numerical simulation and experimental result.

Numerical and Experimental Evaluation of Turbulent Flow in Volute

2003 ◽  
Author(s):  
Akitomo Igarashi ◽  
Kazuyuki Toda ◽  
Makoto Yamamoto ◽  
Toshimichi Sakai
Keyword(s):  
Numerical Simulation ◽  
Cross Section ◽  
Three Dimensional ◽  
Experimental Result ◽  
Centrifugal Fan ◽  
Flow Conditions ◽  
Flow Angle ◽  
Fan Performance ◽  
Centrifugal Fans ◽  
Good Agreement

The performance of centrifugal fans is considerably influenced by the design of tongue at the re-circulation port. The flow in the volute of a centrifugal fan was studied both experimentally and numerically. In this experiment, flow angle, pressure and velocity profiles were measured at a large number of locations in the volute. The flow field in the volute passage was analyzed using Computational Fluid Dynamics. The flow was assumed to be three dimensional, turbulent and steady. The numerical simulation produced qualitatively good agreement with the experimental result. The results from experiment and numerical simulation indicated that the adoption of a re-circulating flow port improved fan performance for all flow conditions. In addition, the existence of strong secondary flow was apparent at the cross-section of the volute passage.

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