An experimental investigation was conducted of the intensified boiling heat transfer of R 11 in the narrow spaces of a compact heat transfer tube bank consisting of rolled surfaces.

On the basis of our experimental observation an analysis of boiling heat transfer mechanism in narrow space is developed and a model of boiling heat transfer is provided as fol-lows:There exists a eritical gap size(Bond=0.

The monolithic assembly and lifting of a large struct ural member were carried out on ground in narrow space,using fully the per formance of a hoist.

This paper discuss obstruct explode shell in bottleneck obstruct explode organ reply flammable gas tramp material explode combustion products across bottleneck gap process degradation affect, and point out remainder energy pass on factor about bottleneck gap.

Based on the experiment of twin-wire narrow gap welding in single pool mode by employing alternative pulsed arcs, the influences of welding parameters on the appearance of weld and welding process stability were investigated.

Lateral oscillation arc welding, high-speed-rotating arc welding, twin-wire welding, and ultra NGW(narrow gap welding) can all assure the fusion of side wall and improve the oppearance of weld in relatively small welding variables.

The hollow-axis motor drives the offset nozzle and rotates the arc on the tip of wire at high speed,so as to ensure enough penetration into the sidewalls in narrow gap welding.