Establishment and analysis of new heat-transfer model on high-power CO 2 laser beam welding

1998 ◽  
Author(s):  
Jinhe Liu ◽  
Fengming Zhang
2005 ◽  
Vol 896 ◽  
Author(s):  
Salil Mohan ◽  
Yuriy L Shoshin ◽  
Edward L Dreizin

AbstractThis paper presents an experimental methodology, respective heat transfer model, and initial results describing ignition of rapidly heated, aerosolized powders of different materials. The experimental setup uses a CO2 laser as a heat source. The interaction of the laser beam with particles is particle size-dependent and only a narrow range of particle sizes is heated effectively. Therefore, the heat transfer model needs to be only analyzed for the particles with this specific size, which greatly simplifies the interpretation of experiments. The powder is aerosolized inside a plate capacitor by charging particles contacting the capacitor’s electrodes. A thin, laminar aerosol jet is carried out by an oxidizing gas through a small opening in the top electrode and is fed into a laser beam. The velocities of particles in the jet are about 1 m/s. The laser power is increased until the particles are observed to ignite. The ignition is detected optically. The ignition thresholds for spherical magnesium and aluminum powders were measured. The experimental data for magnesium, for which ignition kinetics is well known, were used to calibrate the detailed heat transfer model. The model was used to evaluate the ignition kinetics for aluminum powder.


2018 ◽  
Vol 1 (1) ◽  
pp. 142-150
Author(s):  
Murat Tunc ◽  
Ayse Nur Esen ◽  
Doruk Sen ◽  
Ahmet Karakas

A theoretical post-dryout heat transfer model is developed for two-phase dispersed flow, one-dimensional vertical pipe in a post-CHF regime. Because of the presence of average droplet diameter lower bound in a two-phase sparse flow. Droplet diameter is also calculated. Obtained results are compared with experimental values. Experimental data is used two-phase flow steam-water in VVER-1200, reactor coolant system, reactor operating pressure is 16.2 MPa. On heater rod surface, dryout was detected as a result of jumping increase of the heater rod surface temperature. Results obtained display lower droplet dimensions than the experimentally obtained values.


2006 ◽  
Author(s):  
Filip Kitanoski ◽  
Wolfgang Puntigam ◽  
Martin Kozek ◽  
Josef Hager

2021 ◽  
Vol 71 ◽  
pp. 104456
Author(s):  
Zhuoran Zhang ◽  
Pratik Krishnan ◽  
Zeren Jiao ◽  
M. Sam Mannan ◽  
Qingsheng Wang

2016 ◽  
Vol 289 ◽  
pp. 371-380 ◽  
Author(s):  
Alexander Yu. Chebotarev ◽  
Andrey E. Kovtanyuk ◽  
Gleb V. Grenkin ◽  
Nikolai D. Botkin ◽  
Karl-Heinz Hoffmann

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