scholarly journals Physical modelling of the motion of a liquid metal melt along the surface of a heated rod

2019 ◽  
Vol 196 ◽  
pp. 00009 ◽  
Author(s):  
Pavel D. Lobanov ◽  
Eduard V. Usov ◽  
Ilya A. Klimonov ◽  
Alexander E. Kutlimetov ◽  
Anton A. Butov ◽  
...  
Keyword(s):  
Liquid Metal ◽  
Test Section ◽  
High Speed ◽  
Physical Modelling ◽  
Quartz Tube ◽  
Melt Flow ◽  
Metal Melt ◽  
High Speed Video ◽  
Air Atmosphere ◽  
Droplet Movement

The investigation of the melt flow of a liquid metal along the surface of a heated rod is carried up. In the experiments, the metal from the upper volume was drained over the surface of a quartz tube, heated from the inside. This pipe is used to simulate a fuel column. A high-speed video of the process was produced. Data are obtained on the features of the flow of a metal melt. The stages of formation of droplets are shown. The data on the shape and velocity of the droplet movement are given. It is shown that in the air atmosphere around the test section when the first drop passes on the surface of quartz, a trace is formed, along which the metal moves in the future. Direct and curvilinear rivulet flows on the rod's surface are also observed.

Transport Phenomena and the Associated Humping Formation in Laser Welding

2005 ◽  
Author(s):  
J. Zhou ◽  
H. L. Tsai ◽  
P. C. Wang
Keyword(s):  
Heat Transfer ◽  
Liquid Metal ◽  
Laser Welding ◽  
High Speed ◽  
Solidification Rate ◽  
Transport Phenomena ◽  
Metal Flow ◽  
Welding Process ◽  
Solidification Process ◽  
Melt Flow

Humping is a frequently observed welding defect in laser welding which is caused when the welding speed exceeds a certain limit while the other welding conditions remain unchanged. Humping is characterized by the appearance of unsmooth and discontinuity of humps at the surface of the weld. The formation of humping is generally understood to be caused by the complex heat transfer and melt flow in a high speed welding process. However, so far the fundamental mechanisms causing humping are not fully understood, and research on determining the onset of humping has been based on the “trial-and-error” procedure. In this paper, mathematical models previously developed by the authors for the transport phenomena in laser welding have been extended to investigate the formation of the humping defect. In this study, the transient heat transfer and melt flow in the weld pool during the keyhole formation and collapse, and melt solidification are calculated for a 3-D moving laser welding. Different humping patterns have been predicted by the present study in different laser power levels and welding speeds. From the present study, it was found that the formation of humping in laser welding is caused by the interplay between two important factors: a) the strong liquid metal flow in the real part of the keyhole induced mainly by the laser recoil pressure and b) the rapid solidification rate of the liquid metal. The humping pattern can be well explained by the calculated melt flow and the solidification process.

scholarly journals Quantitative study of melt flow dynamics inside laser cutting kerfs by in-situ high-speed video-diagnostics

Procedia CIRP ◽  
2018 ◽  
Vol 74 ◽  
pp. 640-644
Author(s):  
D. Arntz ◽  
D. Petring ◽  
S. Stoyanov ◽  
N. Quiring ◽  
R. Poprawe
Keyword(s):  
Quantitative Study ◽  
Laser Cutting ◽  
High Speed ◽  
Flow Dynamics ◽  
Melt Flow ◽  
High Speed Video

APPLICATION OF THE EARLY DAMAGE DIAGNOSTICS TECHNIQUE TO EXAMINATION OF THE AVIATION PANEL

2019 ◽  
Vol 85 (6) ◽  
pp. 53-63 ◽  
Author(s):  
I. E. Vasil’ev ◽  
Yu. G. Matvienko ◽  
A. V. Pankov ◽  
A. G. Kalinin
Keyword(s):  
Acoustic Emission ◽  
Damage Detection ◽  
High Speed ◽  
Early Stage ◽  
Video Data ◽  
High Speed Video ◽  
Damage Diagnostics ◽  
Subsurface Defect ◽  
Sensitive Coating ◽  
Early Damage

The results of using early damage diagnostics technique (developed in the Mechanical Engineering Research Institute of the Russian Academy of Sciences (IMASH RAN) for detecting the latent damage of an aviation panel made of composite material upon bench tensile tests are presented. We have assessed the capabilities of the developed technique and software regarding damage detection at the early stage of panel loading in conditions of elastic strain of the material using brittle strain-sensitive coating and simultaneous crack detection in the coating with a high-speed video camera “Video-print” and acoustic emission system “A-Line 32D.” When revealing a subsurface defect (a notch of the middle stringer) of the aviation panel, the general concept of damage detection at the early stage of loading in conditions of elastic behavior of the material was also tested in the course of the experiment, as well as the software specially developed for cluster analysis and classification of detected location pulses along with the equipment and software for simultaneous recording of video data flows and arrays of acoustic emission (AE) data. Synchronous recording of video images and AE pulses ensured precise control of the cracking process in the brittle strain-sensitive coating (tensocoating)at all stages of the experiment, whereas the use of structural-phenomenological approach kept track of the main trends in damage accumulation at different structural levels and identify the sources of their origin when classifying recorded AE data arrays. The combined use of oxide tensocoatings and high-speed video recording synchronized with the AE control system, provide the possibility of definite determination of the subsurface defect, reveal the maximum principal strains in the area of crack formation, quantify them and identify the main sources of AE signals upon monitoring the state of the aviation panel under loading P = 90 kN, which is about 12% of the critical load.

A High Speed Video/Audio Stream Splitter for 4K Digital-Cinema

2006 ◽  
Author(s):  
Hirokazu Takahashi ◽  
Takahiro Murooka ◽  
Kan Toyoshima ◽  
Hitoshi Uematsu ◽  
Tetsuro Fujii
Keyword(s):  
High Speed ◽  
Digital Cinema ◽  
High Speed Video

Paper 23: The Collision of Drops with Dry and Wet Surfaces in an Air Atmosphere

1969 ◽  
Vol 184 (7) ◽  
pp. 57-63
Author(s):  
G. J. Parker ◽  
E. Bruen
Keyword(s):  
Steam Turbine ◽  
High Speed ◽  
Size Range ◽  
Drop Surface ◽  
Wet Steam ◽  
Air Atmosphere ◽  
Made In

This paper describes an investigation into the behaviour of drops which impinge upon dry and wet surfaces. This is of particular interest in the context of the wet steam turbine. Two approaches have been made in the studies; these are: (1) Drops were made to impinge normally on to various types of dry, stationary surfaces. The drops were in the size range 300–1500 μm diameter with velocities of 2–9 m/s. (2) Drops were made to impinge on to surfaces moving with considerable velocity at right angles to the motion of the drop. Surface velocities ranged up to 45 m/s. The latter study is of direct interest for the splashing of drops on turbine casings at small glancing angles, as occurs near drainage belts. Analysis of the mechanisms involved is made from the records of high-speed ciné photography.

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