The adaptation of waterjet cutting technology to underwater working conditions will allow solving various tasks when performing underwater technological operations, including maintenance of man-made hazardous objects. The implementation of such technology under water is possible with the application of mobile installations having low power, which imposes certain restrictions on its use. A method for improving the efficiency of mobile installations implementing underwater waterjet cutting is proposed. The method is based on the use of a built-up jet-forming path consisting of a diamond nozzle, an additional transition tube and a standard focusing tube. The structural externality of the diamond nozzle is given. A physical and mathematical model of the process of forming a high-speed jet which implements the technology of underwater hydro- or waterjet cutting, when the flow of a suspension under pressure passes through the jet-forming path of the proposed design, is described. Using calculations based on the developed model and results of field experiments, the effect of the structural element parameters of the built-up jet-forming path on the output characteristics of the formed jet flow is determined. The possibilities of applying such a design for controlling the output characteristics of the formed high-speed jet are assessed and the practicability of its use is indicated.
Obtaining the Selected Surface Roughness by Means of Mathematical Model Based Parameter Optimization in Abrasive Waterjet Cutting