There has been considerable debate as to the optimal geometry for the focusing tube of aconventional abrasive waterjet nozzle. In order to carry out a simple, yet relativelyinexpensive comparison, steel nozzles were manufactured with one of four cone anglesinto the throat, and a throat of four different lengths (for a total of 16 combinations).The nozzles were tested using steel abrasive as the cutting particle; since this allowedtesting without unacceptable nozzle wear (garnet eroded a nozzle in seconds). Theresults also compared two different mixing chamber geometries. The first series of testsshowed that the shorter the focusing tube length (over the range tested) the moreeffective the nozzles cut, while an optimal angle for the converging cone changed withmixing chamber geometry.Results of the second series of tests, in which shorter nozzles were tested at the optimalcutting angle are also included and compared with existing commercial designs.
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