Analysis of the dynamic characteristics of gas flow inside a laser cut kerf under high cut-assist gas pressure

被引:47
作者
Man, HC [1 ]
Duan, J [1 ]
Yue, TM [1 ]
机构
[1] Hong Kong Polytech Univ, Dept Mfg Engn, Laser Proc Ctr, Kowloon, Peoples R China
关键词
D O I
10.1088/0022-3727/32/13/306
中图分类号
O59 [应用物理学];
学科分类号
摘要
The behaviour of the cut-assist gas jet inside a simulating laser cut kerf for a supersonic and a conical nozzle tip were studied by a shadowgraphic technique under conditions of inlet stagnation pressure from 3 to 7 bar. The effects of the stand-off distance, kerf width, material thickness and the inlet stagnation pressure upon the dynamic characteristics and momentum thrust of the gas flow inside the cut kerf were investigated. It was found that under a gas pressure of 7 bar, the gas jet from a conical nozzle tip expands radially and the jet momentum deteriorates rapidly inside the kerf. The behaviour of the jet is strongly influenced by the stand-off distance and thickness of the workpiece. On the other hand, the gas jet from a supersonic nozzle inside the cut kerf has tidy boundary and uniform distribution of pressure and thrust. The sensitivity to the stand-off distance and the workpiece thickness of the supersonic nozzle are much less as compared with the conical nozzle. With the supersonic nozzle, a dress free clean cut on 5 mm stainless steel can be achieved at an inert cut-assist gas pressure as low as 5 bar instead of the normal operating range of 10 bar or above for the conical nozzle.
引用
收藏
页码:1469 / 1477
页数:9
相关论文
共 18 条
[1]  
[Anonymous], 1989, INT J ISLAMIC ARABIC
[2]  
[Anonymous], P 1 INT C LAS MAN BR
[3]  
[Anonymous], P LAS 75 OPT MUN GER
[4]  
BERGER P, 1989, P LAS 89 MUN, P630
[5]  
BRANDT AD, 1996, P INT C APPL LAS EL, P10
[6]  
BRODEN G, 1991, JOINING/WELDING 2000, P119
[7]  
Chapman A. J., 1971, INTRO GAS DYNAMICS
[8]  
EDLER R, 1992, ECLAT 92, P111
[9]  
KAMALU JK, 1981, LASER METALLURGY, V3, P263
[10]   Design and characteristic analysis of supersonic nozzles for high gas pressure laser cutting [J].
Man, HC ;
Duan, J ;
Yue, TM .
JOURNAL OF MATERIALS PROCESSING TECHNOLOGY, 1997, 63 (1-3) :217-222