|
| |
|
|
New possibilities in the area of using of water jet technology for the removal of concrete surface layers
Bodnárová, L. ; Hela, R. ; Foldyna, Josef ; Sitek, Libor
The contribution deals with problems of using of water jet technology for the removal of concrete surface layers. Realized experimental tests were focused on the possibility of using of water jet technology in the stage of concrete surface preparation for the repair of concrete structures. The contribution specifies some new possibilities in the use of water jet technology for the concrete disintegration. The circumstances of surface layers removal through various types of water jet were investigated on concrete samples with different characteristics of surface layers. In the paper, possibilities of high-speed water jet technology are extended to the application of so-called flat water jet. Interesting results in relatively low energy demands can be achieved during disintegration of very hard concrete in conjunction with an acoustic pulse generator.
|
|
| |
|
|
Advances in pulsating water jet technology
Foldyna, Josef
A research in the area of pulsating water jets is carried out systematically at the Institute of Geonics of the ASCR, v. v. i., in Ostrava since 2000. The research was oriented primarily at the study of processes of generating and forming of pulsating water jets and their effects on various materials. The paper presents results obtained in the area of numerical modelling of the process of generation of pulsating water jets and results of tests of pulsating water jets effects on materials.
|
|
|
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.
|
|
| |
|
|
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.
|
|
|
Research in the area of pulsating water jets
Foldyna, Josef
A research in the area of pulsating water jets is carried out systematically in the Institute of Geonics AS CR, v. v. i., in Ostrava since 2000. The research was oriented primarily at the study of processes of generating and forming of pulsating water jets and their effects on various materials. The presented paper summarizes results obtained in the above mentioned areas during the period from 2000 to 2007.
|
|
|
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.
|
|
| |
guest ::
