The Structure of High Speed Fluid Jets and their Use in Cutting Various Soil and Material Types


This reports an investigation into the effect of fluid additives upon the structure of high speed water jets, and the resulting change in the cutting ability of the jets when such additives are used. A literature review indicates that the effects of change in jet viscosity and surface tension upon jet structure are reduced with increasing jet velocity, and that while increasing jet viscosity improves jet cohesion, it reduces jet cutting ability. The study was directed towards the effect of viscoelastic additives, polymerized ethylene oxide and polyacrylamides, the results from which were compared with results from nonionic soaps and guar guns. The viscoelastic additives were found to give improved jet cohesion. Photographic analysis of jet structure indicated that the most cohesive jet was the pulymerized ethylene oxide. Tests on soil types suggested that a Nalco polyacrylamide was superior for that application. Cutting tests on soils indicated that, for effective soil removal at a distance of 6ft. from the nozzle, a nozzle diameter in excess of 0.04 in. should be used, and good results could then be achieved with jet pressures of 2500 psi. (A)


Mining Engineering

Second Department

Chemical and Biochemical Engineering

Document Type

Technical Report

Document Version


File Type




Publication Date

01 Jan 1975

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