No (257)
Yes (87)
Number of found documents:
344
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to
Hydro-abrasive machining of rotating workpieces from graphite and aluminium alloy
Cárach, J.; Hloch, Sergej; Klich, Jiří; Hlaváček, Petr; Klichová, Dagmar
2015 - English
The paper compares the quality of machined surface of graphite and aluminium alloy by abrasive water jet using the focusing tube with a diameter of df1 = 0.5 mm and df2 = 0.78 mm. The machining was carried out using the technology of rotating workpiece disintegration by abrasive water jet. Abrasive tangential water jet was used to carry out the experiment (water pressure p = 400 MPa). Workpieces were clamped in the rotating chucking appliance with rotation frequency n = 300 min-1. The change in focusing tube diameter caused the change in values of roughness parameters, and also caused the change of resulting shape of workpieces. Values of roughness parameters were measured using the MicroProf FRT optic profilometer.
Keywords:
abrasive water jet; machining; roughness parameters
Available in digital repository of the ASCR
Hydro-abrasive machining of rotating workpieces from graphite and aluminium alloy
The paper compares the quality of machined surface of graphite and aluminium alloy by abrasive water jet using the focusing tube with a diameter of df1 = 0.5 mm and df2 = 0.78 mm. The machining was ...
Effect of pulsating water jet peening on stainless steel
Hlaváček, Petr; Kruml, T.; Foldyna, Josef; Tobiáš, J.; Man, J.
2015 - English
Effects of action of pulsating water jet on polished surface of the stainless steel AISI 316L are presented. Surface slip bands appeared after this treatment. In the most severe conditions, microcracks were formed. Hardness measurement showed that the affected layer was thinner than 60 μm. Application of the pulsating water jet has beneficial effect on the fatigue life of the material.
Keywords:
pulsating water jet; surface treatment; fatigue life
Available in digital repository of the ASCR
Effect of pulsating water jet peening on stainless steel
Effects of action of pulsating water jet on polished surface of the stainless steel AISI 316L are presented. Surface slip bands appeared after this treatment. In the most severe conditions, ...
Surface strengthening of a stainless steel using pulsating water jet technology - evaluation by means of microhardness measurements
Hloch, Sergej; Ščučka, Jiří; Lehocká, D.; Simkulet, V.
2015 - English
Results of an experiment focused on surface strengthening of AISI 304 stainless steel using pulsating water jet technology is presented in the paper. The tested material was subjected to the action of pulsating water jet under changing technological conditions (water pressure, traverse speed, stand-off distance, and diameter of nozzle orifice). Microhardness measurements at various distances from the created traces were applied for assessing the material strengthening. Based on the results, it can be stated that the dynamic effects of pulsating water jet on the tested steel samples cause the material deformations leading to the formation of a zone of strengthened material along the disintegrated area.
Keywords:
pulsating water jet; stainless steel; surface strengthening; microhardness
Available in digital repository of the ASCR
Surface strengthening of a stainless steel using pulsating water jet technology - evaluation by means of microhardness measurements
Results of an experiment focused on surface strengthening of AISI 304 stainless steel using pulsating water jet technology is presented in the paper. The tested material was subjected to the action ...
CFD model of mixture gas flow in the vacuum column D-6501
Říha, Zdeněk
2015 - English
The report contains CFD results and description of the gas mixture flow in the vacuum column D-6501. Two rotationally opposite (swirl) input nozzles S1 and S2 (ID 0,835m) create main input of vapour into the vacuum column. There are two enhanced vapour horn (EVH) distributor, for given input nozzle (S1, S2) separately. Enhanced vapour horn makes redistribution of vapour leaded from above mentioned nozzles. There also is next input of vapor given by bottom striping section. The inner diameter of the column is 7,464m and solved domain has height c. 15m. Aim of the calculation is to show distribution of calculated variables (velocity, pressure, density, etc.) on given slices. Mainly, we would like to know if the distribution of velocity is sufficiently uniform at the input into the packing bed SECTION “B”.
Keywords:
CDF model; gas flow; vacuum column
Available on request at various institutes of the ASCR
CFD model of mixture gas flow in the vacuum column D-6501
The report contains CFD results and description of the gas mixture flow in the vacuum column D-6501. Two rotationally opposite (swirl) input nozzles S1 and S2 (ID 0,835m) create main input of vapour ...
Geomythology: a useful tool for geoconservation and geotourism purposes
Kirchner, Karel; Kubalíková, L.
2015 - English
The relationship between the geosciences and myths is studied by geomythology which is understood as an explanation of the geological and geomorphological features using the supernatural forces and beings. The geomythological aspect can be regarded in relation to cultural, historical and spiritual meaning or value of geodiversity and it can be included into the holistic concept of geotourism. The article briefly discuss the reasons why geomythological aspect could be used for geoconservation and geotourism purposes and it presents several examples (especially geosites and geomorphosites) from the Czech Republic where the geomythological value is (or can be) used for these purposes.
Keywords:
geosites; geomorphosites; Bohemian-Moravian Highland
Available in digital repository of the ASCR
Geomythology: a useful tool for geoconservation and geotourism purposes
The relationship between the geosciences and myths is studied by geomythology which is understood as an explanation of the geological and geomorphological features using the supernatural forces and ...
Study of quality of nine aluminium alloys surfaces created using abrasive waterjet
Klichová, Dagmar; Klich, Jiří; Gurková, Lucie
2015 - English
The article focuses on the normalized method of measurement and evaluation of a surface texture created using the abrasive waterjet. It detects selected amplitude parameters of a roughness profile providing a form of a quantified description of properties of a surface topography. It studies the change in quality of machined surfaces created by the abrasive waterjet in nine selected materials of aluminium alloys when changing the traverse speed. Studied samples were measured by an optical profilometer MicroProf FRT and further analyzed with the SPIP software.
Keywords:
surface roughness; abrasive waterjet; aluminium alloy
Available in digital repository of the ASCR
Study of quality of nine aluminium alloys surfaces created using abrasive waterjet
The article focuses on the normalized method of measurement and evaluation of a surface texture created using the abrasive waterjet. It detects selected amplitude parameters of a roughness profile ...
Measurement and analysis of abrasive particles velocities in AWJ
Zeleňák, Michal; Foldyna, Josef; Martinec, Petr; Cárach, J.; Gurková, Lucie; Nováková, Daria
2015 - English
Abrasive water jet (AWJ) is a progressive technology commonly used in many industrial applications. Potential of this technology is high and research in the field of optimal geometry design of an injection system has not been completed yet. New designs of the injection cutting head based on numerical simulation of the flow provide important information about processes occurring during the formation of AWJ. Detailed knowledge of velocities of abrasive particles during the abrasive water jet generation is vital for the verification of the numerical model. The aim of the experimental work was to test the applicability of the LIF (Laser Inducted Fluorescence) technique combined with the PTV (Particle Tracking Velocity) processing algorithms to analyze particle velocities at the output of the focusing tube. The combination of commonly used water pressures with abrasive mass flow rate was tested and the obtained results of abrasive particles velocities are presented in this paper.
Keywords:
abrasive particle velocity; LIF; PIV
Available in digital repository of the ASCR
Measurement and analysis of abrasive particles velocities in AWJ
Abrasive water jet (AWJ) is a progressive technology commonly used in many industrial applications. Potential of this technology is high and research in the field of optimal geometry design of an ...
Hardness and elasticity of abrasive particles measured by instrumented indentation
Hvizdoš, P.; Zeleňák, Michal; Hloch, Sergej
2015 - English
Basic mechanical properties of seven types (from seven different sites) of abrasive garnet particles used for water jet cutting were measured using the technique of instrumented indentation (also called depth sensing indentation or nanoindentation). Hardness and modulus of elasticity were evaluated and compared. All the abrasives had similar measured mechanical properties (hardness 20 – 24.16 GPa), the highest values were found for the Czech garnet.
Keywords:
abrasive; garnet; hardness; elasticity; instrumented indentation
Available in digital repository of the ASCR
Hardness and elasticity of abrasive particles measured by instrumented indentation
Basic mechanical properties of seven types (from seven different sites) of abrasive garnet particles used for water jet cutting were measured using the technique of instrumented indentation (also ...
CFD model of multiphase flow in the abrasive water jet tool
Říha, Zdeněk
2015 - English
The possibility of using CFD fluid flow modeling in area of tools with abrasive water jet is described in the paper. The correct function of such tool is based on proper setting of multiphase flow of water, air and solid particles in the inner space of the tool. The multiphase fluid flow numerical simulation can provide information which show relation between the geometry and the flow field. Then, this stable CFD model of multiphase flow creates key to design of the tool able to work with higher efficiency.
Keywords:
abrasive water jet; multiphase flow; CFD model
Available in digital repository of the ASCR
CFD model of multiphase flow in the abrasive water jet tool
The possibility of using CFD fluid flow modeling in area of tools with abrasive water jet is described in the paper. The correct function of such tool is based on proper setting of multiphase flow ...
An a posteriori error estimate for the Stokes-Brinkman problem in a polygonal domain
Burda, P.; Hasal, Martin
2015 - English
We derive a residual based a posteriori error estimate for the Stokes-Brinkman problem on a two-dimensional polygonal domain. We use Taylor-Hood triangular elements. The link to the possible information on the regularity of the problem is discussed.
Keywords:
a posteriori error estimate; Stokes-Brinkman problem; Taylor-Hood triangular elements
Fulltext is available at external website.
An a posteriori error estimate for the Stokes-Brinkman problem in a polygonal domain
We derive a residual based a posteriori error estimate for the Stokes-Brinkman problem on a two-dimensional polygonal domain. We use Taylor-Hood triangular elements. The link to the possible ...
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