Cavitation in Hydraulic Tools Based on Thermodynamic Properties of Liquid and Gas

2002 ◽  
Vol 124 (4) ◽  
pp. 1011-1017 ◽  
Author(s):  
U. Iben ◽  
F. Wrona ◽  
C.-D. Munz ◽  
M. Beck
Keyword(s):  
Thermodynamic Properties ◽  
Mass Flow ◽  
Wave Motion ◽  
Cavitation Model ◽  
Model Based ◽  
Physical Phenomena

The simulation of cavitation phenomena plays an important role for development of modern hydraulic tools and injection systems. Cavitation leads to a reduction of mass flow and influences the wave motion in hydraulic components significantly. The article deals with the simulation of a homogeneous cavitation model based on thermodynamic properties of the liquid and steam to understand basic physical phenomena.

scholarly journals A new cavitation model based on bubble-bubble interactions

2018 ◽  
Vol 30 (12) ◽  
pp. 123301 ◽  
Author(s):  
M. Adama Maiga ◽  
O. Coutier-Delgosha ◽  
D. Buisine
Keyword(s):  
Cavitation Model ◽  
Bubble Interactions ◽  
Model Based

A New Cavitation Model Based on Evaporation and Condensation Theory

2009 ◽  
Author(s):  
Gang Chen ◽  
Shuhong Liu ◽  
Guangjun Cao ◽  
Yulin Wu ◽  
Suhong Fu ◽  
...  
Keyword(s):  
Surface Tension ◽  
Aerodynamic Drag ◽  
Water Pressure ◽  
Bubble Diameter ◽  
Simulation Models ◽  
Cavitation Model ◽  
Local Pressure ◽  
Two Phase ◽  
Evaporation And Condensation ◽  
Model Based

Cavitation is a phenomenon which occurs where the local pressure falls off under the vapor pressure. Over the past few years, numerical simulation models for cavitation have been developed significantly in order to investigate the mechanism of cavitation. In the paper, A local homogeneous cavitation model based on the theory of evaporation and condensation has been deduced, which is used to describe the phase change between water and vapor. The RNG k–ε turbulence model is used to simulate the turbulent flow and the finite volume method is employed to discrete the governing equations. The effects of surface tension of water, pressure fluctuations and non-condensable gases are included in the mass transfer cavitation model. Also in order to neglect the effects of the quantities such as the bubble number and bubble diameter, which is difficult to measure, the relations between the aerodynamic drag and surface tension forces is used to describe the bubble diameter. In order to evaluate the new cavitation model, the two phase cavitation flows around a NACA0015 hydrofoil at different attack angle and different cavitation number are simulated by the new cavitation model, and compared with references, which showed good agreement with the experiments.

Numerical Performance and Flow Field Study of Centrifugal Compressor With Supercritical Carbon-Dioxide (SCO2)

2019 ◽  
Author(s):  
Hemant Kumar ◽  
Chetan S. Mistry
Keyword(s):  
Carbon Dioxide ◽  
Thermodynamic Properties ◽  
Critical Point ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Centrifugal Compressor ◽  
Numerical Study ◽  
Pressure Ratio ◽  
Compressor Inlet

Abstract The Supercritical carbon-dioxide Brayton cycle main attraction is due to the Supercritical characteristic of the working fluid, carbon-dioxide (SCO2). Some of the advantages of using SCO2 are relatively low turbine inlet temperature, the compression work will be low, and the system will be compact due to the variation of thermodynamic properties (like density, and specific heat ratio) of SCO2 near the critical point. SCO2 behave more like liquid when its state is near the critical point (Total Pressure = 7.39 MPa, Total Temperature = 305 K), operating compressor inlet near critical point can minimize compression work. For present study the centrifugal compressor was designed to operate at 75,000 rpm with pressure ratio (P.R) = 1.8 and mass flow rate = 3.53 kg/s as available from Sandai report. Meanline design for centrifugal compressor with SCO2 properties was done. The blade geometry was developed using commercial CAD Ansys Bladegen. The flow domain was meshed using Ansys TurboGrid. ANSYS CFX was used as a solver for present numerical study. The thermodynamic properties of SCO2 were imported from the ANSYS flow material library using SCO2.RPG [NIST thermal physics properties of fluid system]. In order to ensure the change in flow physics the mesh independence study was also conducted. The present paper discuss about the performance and flow field study targeting different mass flow rates as exit boundary condition. The comparison of overall performance (Pressure Ratio, the Blade loading, Stage efficiency and Density variation) was done with three different mass flow rates. The designed and simulated centrifugal compressor meets the designed pressure rise requirement. The variation of mass flow rate on performance of centrifugal compressor was tend to be similar to conventional centrifugal compressor. The paper discusses about the effect of variation in density, specific heat ratio and pressure of SCO2 with different mass flow outlet condition. The performance map of numerical study were validated with experiment results and found in good agreement with experimental results. The change in flow properties within the rotor flow passage are found to be interesting and very informative for future such centrifugal compressor design for special application of SCO2 Brayton cycle. 80% mass flow rate has given better results in terms of aerodynamic performance. Abrupt change in thermodynamic properties was observed near impeller inlet region. Strong density variations are observed at compressor inlet.

scholarly journals Surrogate model-based strategy for cryogenic cavitation model validation and sensitivity evaluation

2008 ◽  
Vol 58 (9) ◽  
pp. 969-1007 ◽  
Author(s):  
Tushar Goel ◽  
Siddharth Thakur ◽  
Raphael T. Haftka ◽  
Wei Shyy ◽  
Jinhui Zhao
Keyword(s):  
Model Validation ◽  
Surrogate Model ◽  
Cavitation Model ◽  
Model Based ◽  
Sensitivity Evaluation

Thermometric Methods of Measuring the Rate of Mass Flow

1965 ◽  
Vol 180 (1) ◽  
pp. 1035-1044
Author(s):  
A. A. R. El Agib
Keyword(s):  
Thermodynamic Properties ◽  
Mass Flow ◽  
Unit Mass ◽  
Flowing Fluid ◽  
Field Investigations ◽  
Methods Of Application

By measurement of the unit-mass and the unit-time rates of exchange of energy between a flowing fluid and a heating or actuating source, the rates of mass flow can be directly determined, provided that certain thermodynamic properties of the fluid are known. Various methods of application of this principle are described and an account of proving tests is given. In these tests special techniques of precision thermometry were used. The results obtained were very promising and warrant further laboratory and field investigations.

Investigation of bubble dynamics in different solvents for nanomaterial fabrication by laser ablation in liquid

2019 ◽  
Vol 85 (3) ◽  
pp. 30401
Author(s):  
Leyun Shen ◽  
Ying Shi ◽  
Zhen Yang ◽  
Kai Liu ◽  
Yi Wei ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Thermodynamic Properties ◽  
Organic Solvents ◽  
Analytical Model ◽  
Chemical Reactions ◽  
Bubble Dynamics ◽  
Laser Ablation In Liquid ◽  
Model Based ◽  
Al Nanoparticles ◽  
Physical And Chemical

Laser ablation in liquid (LAL) is one of the important technologies for preparing nanomaterials. In this article, Al nanoparticles (NPs) are fabricated by laser ablation in three different organic solvents. The thermodynamic properties within the bubble are studied using ultrafast camera and an analytical model based on Rayleigh–Plesset equation. Combined with the NPs characterization, the correlation between the bubble dynamics and the formation of NPs is discussed. The results show that complex physical and chemical reactions inside the bubble affect the bubble dynamics. At the same time, the bubble dynamics in turn affect the morphology and properties of the nanoproducts.

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