Effects of Dissolved Air on Cavitating Flow around Isolated Hydrofoil

2016 ◽  
Vol 2016 (0) ◽  
pp. 0905
Author(s):  
Soichiro KITAMURA ◽  
Wakana TSURU ◽  
Haruki DAIDO ◽  
Satoshi WATANABE ◽  
Shin-ichi TSUDA
Keyword(s):  
Cavitating Flow ◽  
Dissolved Air

An experimental/numerical assessment over the influence of the dissolved air on the instantaneous characteristics/shedding frequency of cavitating flow

2021 ◽  
Vol 240 ◽  
pp. 109960
Author(s):  
Włodzimierz Wróblewski ◽  
Krzysztof Bochon ◽  
Mirosław Majkut ◽  
Emad Hasani Malekshah ◽  
Krzysztof Rusin ◽  
...  
Keyword(s):  
Cavitating Flow ◽  
Numerical Assessment ◽  
Shedding Frequency ◽  
Dissolved Air

Linearized Theory of Non-Uniform Cavitating Flow

1964 ◽  
Vol 1964 (115) ◽  
pp. 42-48
Author(s):  
Tatsuro Hanaoka
Keyword(s):  
Cavitating Flow ◽  
Linearized Theory

Behaviour of air injection nozzles in dissolved air flotation

1995 ◽  
Vol 31 (3-4) ◽  
pp. 25-35 ◽  
Author(s):  
E. M. Rykaart ◽  
J. Haarhoff
Keyword(s):  
Bubble Coalescence ◽  
Second Phase ◽  
Initial Growth ◽  
Two Phase ◽  
Dissolved Air Flotation ◽  
Nozzle Orifice ◽  
Pressure Release ◽  
Air Volume ◽  
Air Flotation ◽  
Dissolved Air

A simple two-phase conceptual model is postulated to explain the initial growth of microbubbles after pressure release in dissolved air flotation. During the first phase bubbles merely expand from existing nucleation centres as air precipitates from solution, without bubble coalescence. This phase ends when all excess air is transferred to the gas phase. During the second phase, the total air volume remains the same, but bubbles continue to grow due to bubble coalescence. This model is used to explain the results from experiments where three different nozzle variations were tested, namely a nozzle with an impinging surface immediately outside the nozzle orifice, a nozzle with a bend in the nozzle channel, and a nozzle with a tapering outlet immediately outside the nozzle orifice. From these experiments, it is inferred that the first phase of bubble growth is completed at approximately 1.7 ms after the start of pressure release.

Enhanced rapid gravity filtration and dissolved air flotation for pre-treatment of river thames reservoir water

1998 ◽  
Vol 37 (2) ◽  
pp. 35-42 ◽  
Author(s):  
M. J. Bauer ◽  
R. Bayley ◽  
M. J. Chipps ◽  
A. Eades ◽  
R. J. Scriven ◽  
...  
Keyword(s):  
Water Treatment ◽  
Water Supply ◽  
21St Century ◽  
Reservoir Water ◽  
Dissolved Air Flotation ◽  
Lowland Rivers ◽  
Air Flotation ◽  
Pre Treatment ◽  
Counter Current ◽  
Dissolved Air

Thames Water treats approximately 2800Ml/d of water originating mainly from the lowland rivers Thames and Lee for supply to over 7.3million customers, principally in the cities of London and Oxford. This paper reviews aspects of Thames Water's research, design and operating experiences of treating algal rich reservoir stored lowland water. Areas covered include experiences of optimising reservoir management, uprating and upgrading of rapid gravity filtration (RGF), standard co-current dissolved air flotation (DAF) and counter-current dissolved air flotation/filtration (COCO-DAFF®) to counter operational problems caused by seasonal blooms of filter blocking algae such as Melosira spp., Aphanizomenon spp. and Anabaena spp. A major programme of uprating and modernisation (inclusion of Advanced Water Treatment: GAC and ozone) of the major works is in progress which, together with the Thames Tunnel Ring Main, will meet London's water supply needs into the 21st Century.

Fat recovery from dissolved air flotation sludge

2016 ◽  
Vol 2016 (9) ◽  
pp. 3543-3551
Author(s):  
H.W.H Menkveld ◽  
N. C Boelee ◽  
G.O.J Smith ◽  
S Christian
Keyword(s):  
Dissolved Air Flotation ◽  
Air Flotation ◽  
Dissolved Air

Discrete Bubble Modeling of Unsteady Cavitating Flow

2006 ◽  
Vol 4 (5-6) ◽  
pp. 601-616 ◽  
Author(s):  
Zhiliang Xu ◽  
Myoungnyoun Kim ◽  
Tianshi Lu ◽  
Wonho Oh ◽  
James Glimm ◽  
...  
Keyword(s):  
Cavitating Flow ◽  
Unsteady Cavitating Flow

scholarly journals Numerical simulation and experimental validation of cavitating flow in a multi-hole diesel fuel injector

2021 ◽  
pp. 146808742199863
Author(s):  
Aishvarya Kumar ◽  
Ali Ghobadian ◽  
Jamshid Nouri
Keyword(s):  
Computational Cost ◽  
Cavitating Flow ◽  
Field Analysis ◽  
Navier Stokes ◽  
Fuel Injector ◽  
Fluid Behavior ◽  
Flow Field Analysis ◽  
Charged Couple Device ◽  
Biodiesel Fuels ◽  
High Level

This study assesses the predictive capability of the ZGB (Zwart-Gerber-Belamri) cavitation model with the RANS (Reynolds Averaged Navier-Stokes), the realizable k-epsilon turbulence model, and compressibility of gas/liquid models for cavitation simulation in a multi-hole fuel injector at different cavitation numbers (CN) for diesel and biodiesel fuels. The prediction results were assessed quantitatively by comparison of predicted velocity profiles with those of measured LDV (Laser Doppler Velocimetry) data. Subsequently, predictions were assessed qualitatively by visual comparison of the predicted void fraction with experimental CCD (Charged Couple Device) recorded images. Both comparisons showed that the model could predict fluid behavior in such a condition with a high level of confidence. Additionally, flow field analysis of numerical results showed the formation of vortices in the injector sac volume. The analysis showed two main types of vortex structures formed. The first kind appeared connecting two adjacent holes and is known as “hole-to-hole” connecting vortices. The second type structure appeared as double “counter-rotating” vortices emerging from the needle wall and entering the injector hole facing it. The use of RANS proved to save significant computational cost and time in predicting the cavitating flow with good accuracy.

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