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Water Jet 2009. Proceedings
Sitek, Libor
Conference Water Jet 2009 - Research, Development, Application, which is organized by the Department of material disintegration of the Institute of Geonics of the ASCR, v. v. i., is the first meeting of producers, users, designers and other people interested in technology of high speed water jet in the Czech Republic. The main objective of the conference is to provide forum for exchange of knowledge, information and experiences in areas of research, development and application of water jet. Although the conference was originally intended as a more or less local meeting of experts from the Czech Republic, a number of foreign participants proves that this issue is very attractive far beyond the borders of the CR. Problems solved in contributions are very diverse: they range from basic research through traditional and less traditional application of technology in practice to reflection on the impact of the current economic crisis on job shops.
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Turning by high-speed abrasive water jet – our experiences
Sitek, Libor
The paper describes and analyses our own experiences concerning technology of turning by high speed abrasive water jet. Technology development as well as present stay-of–the-art in given area are introduced in brief. Possibilities of application of such machining method especially for shaping and preparation of testing rock specimens suitable for determination of physical-mechanical properties of rocks are also discussed.
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Comparison of Continuous High-Pressure Generated and Pulsing Low-Pressure Generated Water Jets on Concrete
Mádr, V. ; Sitek, Libor ; Hela, R. ; Hlaváč, L. M. ; Bodnárová, L. ; Pustelník, J. ; Janurová, E.
The concrete samples with various erosion states were disintegrated by pure continuous water jets generated from pressure 380 MPa in the Liquid jet laboratory at the VŠB - Technical University of Ostrava. Simultaneously, the identical concrete samples were tested by pulsing water jets generated by low pressure 30 MPa in the Department of Material Disintegration at the Institute of Geonics of the AS CR. The erosion states of samples were prepared by application of several laboratory techniques simulating the concrete aging under the natural conditions due to the real applications in practice. They were prepared at the 127 Institute of Technology of Building Materials and Components of the Brno University of Technology. The influence of the erosion state on the disintegration rate was tested and the surface topography was studied. The comparison of both the depth of penetration and the volume disintegration ratio regarding the input power is performed.
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Study of propagation of pressure pulsations in high-pressure system
Foldyna, Josef ; Říha, Zdeněk ; Sitek, Libor
Various alternatives of high pressure-system geometry including square elbows and prolongation of liquid waveguide were elaborated to be able to simulate real tools used to generate high-speed water jets. Variable geometrical parameters of the model were selected and the computational model was prepared in such a way that the geometry and meshing of the model is generated automatically after entering the parameters. This approach facilitates and speeds up preparation of models for simulation of propagation of pressure pulsations in high-pressure system for generation of pulsating water jets. The paper presents results of simulation of propagation of pressure pulsations through various geometries of the high-pressure system.
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Zkoušení kvality trysek
Foldyna, Josef ; Sitek, Libor ; Ščučka, Jiří
The report describes results of quality tests of nozzles for generation of high-speed water jet. The nozzle quality was evaluated by the determination of their discharge coefficient and by visual inspection of the nozzle and the water jet.
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Calculation of natural frequency of high-pressure system
Foldyna, Josef ; Říha, Zdeněk ; Sitek, Libor
The paper presents results of numerical simulation of 3D, unsteady, turbulent flow of compressible water in a high-pressure system equipped with acoustic generator of pressure pulsations and its response to a pressure impulse. Results of numerical simulation are compared to the laboratory measurement of response of high-pressure system to a pressure impulse using dynamic pressure sensor placed upstream to the nozzle exit.
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