|
|
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.
|
|
| |
|
|
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.
|
|
| |
|
| |
|
|
Simulation of transmission of pressure pulsations in high-pressure system
Foldyna, Josef ; Říha, Zdeněk ; Sitek, Libor ; Švehla, B.
The paper presents results of numerical simulation of 3D, unsteady, turbulent flow of compressible water in a high-pressure system equipped with an acoustic generator. The generator vibrates at frequency of 20 kHz with amplitude of 6 µm. Acoustic waves (pressure pulsations), generated in water pressurized to 30 MPa and amplified by appropriately designed liquid waveguide, results in generation of very high velocity pulsations at the nozzle outlet. The influence of various geometrical configurations on acoustic wave propagation in the high-pressure system was simulated and results were verified by laboratory measurement of pressure pulsations upstream to the nozzle exit.
|
|
| |
|
|
Flow in the nozzle with moving wall
Foldyna, Josef ; Říha, Zdeněk ; Sitek, Libor
The paper presents simulation of 3D, unsteady, turbulent flow of water in the high-pressure nozzle device with moving wall. The wall performs rectilinear reciprocating motion with high frequency and very small amplitude that results in generation of very high velocity pulsations at the nozzle outlet. The pulsations lead to the break-up of continuous jet into regular slugs of water. The objective of the simulation was to verify whether dynamic meshes can be used to simulate above mentioned problem and satisfactory agreement of the simulation and reality can be obtained.
|
guest ::
RSS feed.