in this paper, thermal effect of plasma arc welding is investigated, and temperature field of ferrite stainless steel is acquired. thermal effect of plasma arc and subsequently the generated temperature field in the work piece is the key for analysis and optimization of this welding process, which is the main goal of this paper. finite element simulation of welding process by simplec method and...

Particle beams have traditionally been produced by supersonic expansion of aparticle-ladengas through a single nozzle to vacuum. However, it has been shown that, by passing the particle-laden gas through a series of axi-symmetric subsonic contractions and expansions (an aerodynamic lens system) prior to the supersonic expansion to vacuum through a single nozzle, beam divergence can be signiŽ ca...

A numerical study of three-dimensional effects on the performance of a micronozzle fabricated from  at silicon wafers is performed by use of both continuum and kinetic approaches. The nozzle operates in a low-Reynoldsnumber regime, and viscous effects dominate the gas expansion. Thrust losses occur because the shear on the wall is greater in a  at nozzle conŽ guration than in an axisymmetric ...

The nozzle shape was investigated in order to develop a high performance nozzle for pulsed Nd:YAG laser cutting, and its effect on fine cutting of thin metal plate was also discussed. In the case of 0.5mm throat diameter Laval throat nozzle with an initial expansion zone, the pressure on workpiece increased, and the straightness of gas flow was improved compared to a traditional straight throat...

Planar Laser-Induced Fluorescence PLIF is employed to measure rotational temperatures at the nozzle exit of a free-piston shock tunnel. The ow is at approximately Mach 7 and chemical eeects have been reduced by using a nitrogen test gas and low total enthalpy 5 MJJkg. Vibrational freezing in the nozzle expansion has an appreciable effect on the nozzle-exit rotational temperature, and therefore ...

Making soap bubbles by blowing air on a soap film is an enjoyable activity, yet a poorly understood phenomenon. Working either with circular bubble wands or long-lived vertical soap films having an adjustable steady state thickness, we investigate the formation of such bubbles when a gas is blown through a nozzle onto a film. We vary film size, nozzle radius, space between the film and nozzle, ...

A nozzle conŽ guration for the production of an intense and collimated supersonic cluster beam is presented and characterized by numerical modeling. A simple lens added to a cylindrical nozzle exploits aerodynamic focusing effects. The effect of the focalizing nozzle is an enrichment of the core of the jet with clusters of an arbitrary size interval depending on carrier gas pressure and tempera...

An experimental approach is proposed to investigate the gas-solid structure in the vicinity of a sparger nozzle in a fluidized bed. The local hydrodynamics were studied under injection velocities ranging between 0 and 100 m/s and three orientations. A fiber-optic probe was used to measure the instantaneous local particle holdup near the tip of the sparger nozzle. Under the investigated conditio...

An experimental study is performed on air-liquid-particle mixing, resulting from an air-particle mixture injected into a liquid flowing through a slender ladle. Flow visualization combined with image processing is employed to investigate the bubble and particle behavior at the nozzle outlet. Effort is directed to particle discrimination in both the liquid and the bubbles to determine particle d...