Abstract:

The flow velocity fields of YSC178A liquid-jet hammer with internal flow-dividing mechanism was investigated by means of CFD dynamic analysis. The influence of the flow-dividing holes in different shapes and sizes was analyzed. It is found that there exists the phenomenon of flow-dividing jet attached to the wall near the exit of cylindrical hole in a certain diameter. And there was a relatively good one-to-one correspondence relationship between the character of flow-dividing jet and the shapes as well as sizes of the erosion pits. This indicates that the eroded pits were caused by jet attachment as the liquid flowed out from flow-dividing hole in a great diameter,and the horn-like holes are superior to cylindrical flow-dividing holes. When the flow-diving dole is long enough and its diameter is very large, the degree of jet attachment at the exit of the proper horn-like hole decreases sharply, and even disappears, which reduces sharply the energy of high-speed jet and weakenes the erosion in the outer walls of the bottom and top plates of the fluidic element to avoid significant erosion pits.

Key words: liquid-jet hammer, flow-dividing holes, dynamic analysis, flow velocity, erosion, jet attachment