Temat: cavitating - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Validation of Numerical Simulations of Cavitating Flow in Convergent-Divergent Nozzle
Autorzy:: Niedźwiedzka, A.
Lipiński, S.
Powiązania:: https://bibliotekanauki.pl/articles/114485.pdf
Data publikacji:: 2016
Wydawca:: Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:: cavitating flow
numerical simulations
homogenous models
optoelectronic validation
Opis:: In the article, validation of results of numerical simulations of cavitating flow in a convergent-divergent nozzle is presented. In validation, a new optoelectronic system is used in order to extract the changes in the bubbles volume fraction of the mixture in freely specified cross-sections. Three homogeneous models (Schnerr and Sauer, Singhal et al. and Zwart et al.) are analysed. The assessment of usefulness of the new system in experimental measurements of cavitation is the main aim of the article. Looking for new opportunities to replace image analysis, which is a traditional validation method in numerical simulations of cavitating flows, is motivation for the research. The results obtained with the use of the system show a good agreement with the simulation’s results for the two chosen cross-sections. The described optoelectronic system gives promising results and can be regarded as an alternative to traditional validation methods in the cavitation research area.
Źródło:: Measurement Automation Monitoring; 2016, 62, 10; 329-332
2450-2855
Pojawia się w:: Measurement Automation Monitoring
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Dynamic interaction of the cavitating propeller tip vortex with the rudder
Autorzy:: Szantyr, J. A.
Powiązania:: https://bibliotekanauki.pl/articles/260364.pdf
Data publikacji:: 2007
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:: propeller blades
rudder
cavitating
tip vortex shed
Opis:: The hydrodynamic interaction between the ship propeller and the rudder has many aspects. One of the most interesting is the interaction between the cavitating tip vortex shed from the propeller blades and the rudder. This interaction leads to strongly dynamic behaviour of the cavitating vortex, which in turn generates unusually high pressure pulses in its vicinity. Possibly accurate prediction of these pulses is one of the most important problems in the hydrodynamic design of a new ship. The paper presents a relatively simple computational model of the propeller cavitating tip vortex behaviour close to the rudder leading edge. The model is based on the traditional Rankine vortex and on the potential solution of the dynamics of the cylindrical sections of the cavitating kernel passing through the strongly variable pressure field in the vicinity of the rudder leading edge. The model reproduces numerically the experimentally observed process of initial compression of the vortex kernel in the high pressure region near the stagnation point at the rudder leading edge and subsequent explosive growth of the kernel in the low pressure region further downstream. Numerical simulation of this process enables computation of the additional pressure pulses generated due to this phenomenon and transmitted onto the hull surface. This new numerical model of the cavitating tip vortex is incorporated in the modified unsteady lifting surface program for prediction of propeller cavitation, which has been successfully used in the process of propeller design for several years and which recently has been extended to include the effects of propeller – rudder interaction. The results of calculations are compared with the experimental measurements and they demonstrate reasonable agreement between theory and physical reality.
Źródło:: Polish Maritime Research; 2007, 4; 10-14
1233-2585
Pojawia się w:: Polish Maritime Research
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Cavitating Venturi as a Mass Flow Controller in a Deep Throttling Liquid Rocket Engine
Autorzy:: Sekrecki, Michał
Powiązania:: https://bibliotekanauki.pl/articles/36825330.pdf
Data publikacji:: 2023
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:: cavitating venturi
throttling
regulatory valve
HTP
ethanol
green propulsion
Opis:: The most common solutions for rocket engines are the single operation point (thrust level) units. Oxidiser and fuel mass flow rates and the oxidiser-to-fuel mass flow rate ratio (OFR) are some of the determinants of the thrust level. Based on these, planetary ascent and descent; space rendezvous; orbital manoeuvring, including orientation and stabilisation in space; hovering, hazard avoidance during planetary landing; and ballistic missile trajectory control propulsion systems could use throttleable liquid engines. Several engine throttling methods, such as supply pressure variation and variable injector area, can be applied. Among others, a cavitating venturi propellant regulatory valve is one of the most promising throttling method. This type of valve can provide steady mass flow, despite the downstream pressure disturbance (i.e. from the combustion chamber), which sustains a stable engine thrust as the mass flow is kept. The article presents the valve sizing method, design and prototype test results of the cavitating venturi valve that has potential for utilisation in a deep throttling rocket engine. Mass flow stability and repeatability are presented for valve operating points in the 10%-110% nominal mass flow range. Valve design optimisation, based on CFD, to sustain cavitation for a higher downstream-to-upstream pressure ratio is shown.
Źródło:: Transactions on Aerospace Research; 2023, 3 (272); 72-86
0509-6669
2545-2835
Pojawia się w:: Transactions on Aerospace Research
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Experimental analysis on unsteady characteristics of sheet/cloud cavitating Venturi flow under the effect of dissolved air
Autorzy:: Malekshah, Emad Hasani
Wróblewski, Włodzimierz
Bochon, Krzysztof
Majkut, Mirosław
Rusin, Krzysztof
Powiązania:: https://bibliotekanauki.pl/articles/2134932.pdf
Data publikacji:: 2022
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: cavitating flow
venturi nozzle
dissolved air
unsteady characteristic
experimental observation
Opis:: The highly dynamic and unsteady characteristics of the cavitating flow cause many negative effects such as erosion, noise and vibration. Also, in the real application, it is inevitable to neglect the dissolved air in the water, although it is usually neglected in the previous works to reduce the complexity. The novelty of the present work is analysing the impact of dissolved air on the average/unsteady characteristics of Venturi flow by conducting sets of experimental tests. For this purpose, two different amounts of dissolved air at five pressure levels (i.e. five different sets of cavitation numbers) were considered in the study of cavitating flow inside a Venturi nozzle. The fast Fourier transform analysis of pressure fluctuations proved that the shedding frequency reduces almost by 50% to 66%, depending on the case, with adding the amount of dissolved air. However, the reduction of 14% to 25% is achieved by the vibration transducers. On the other hand, the cavity enlarges as well as bubbly flow is observed in the test chamber at a higher level of dissolved air. Furthermore, it is observed that the re-entrant jet, as the main reason for the cavity detachment, is more effective for the detachment process in cases with a lower level of dissolved air, where the re-entrant jet front penetrates more toward the leading edge.
Źródło:: Archives of Thermodynamics; 2022, 43, 3; 63--84
1231-0956
2083-6023
Pojawia się w:: Archives of Thermodynamics
Dostawca treści:: Biblioteka Nauki

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