Schwartz-Christoffel analysis of cavitating flow in a two dimensional mitered elbow

  • 36 Pages
  • 3.15 MB
  • English
Cavitation., Hydrodyna
Statementby John William Hyden.
The Physical Object
Pagination36 leaves, bound :
ID Numbers
Open LibraryOL14298929M

A SCHWARTZ-CH1iISTOFFEL ANALYSIS OF CAVITATING FLOW IN A TWO-DIMENSIONAL MITERED ELBOW by JOIfl WILLIAN HYDEN A THE3IS submitted to OREGON STATE COLLEGE in partial fulfillment of the reciuirements for the degree of MASTiR OF SCIENCi June Graduate Thesis Or Dissertation A Schwartz-Christoffel analysis of cavitating flow in a two dimensional mitered elbow Public Deposited.

Analytics × Add to Author: John William Hyden. Download PDF: Sorry, we are unable to provide the full text but you may find it at the following location(s): (external link).

Most studies are based on Schnerr-Sauer and Merkle et al. cavitation models in the two-dimensional super-cavitating flow.

Roohi et al. [21] have numerically investigated the super-cavitating flow behind the three-dimensional disk with comparison of different turbulence and mass transfer by: Cavitation phenomena occuring in converging-diverging nozzle (Venturi tube) are described in the paper.

A closed test circuit with possibility to control both flow rate and static pressure level were used. Loss coefficient was evaluated for different sigma numbers resulting in full "static" characterization of the nozzle.

Description Schwartz-Christoffel analysis of cavitating flow in a two dimensional mitered elbow FB2

Visualizations of the cavitation pattern development were acquired and. Equations (1), (2) and (3) constitutes a simple model of one-dimensional two phase bubbly flow bubbly with a nonlinear bubble dynamics equation.

Steady-state solutions distance along the axis. In the present work Assuming steady-state conditions, all the partial time derivative terms in Equations (1) to (3) disappear. Then, Equation set (1) to. rely on the potential flow theory [16].

This approach is now able to correctly describe partially cavitating two-dimensional hydrofoils, including the re-entrant jet cavity closure model [12]. However, extension to 3D problems and other types of cavitating flows seems to be out of reach for the potential flow model. Navier–Stokes equations including cavitation bubble clusters are solved in finite-difference form by a time-marching scheme, where the growth and collapse of a bubble cluster is given by a modified Rayleigh's equation.

Computation was made on a two-dimensional flow field around a hydrofoil NACA at angles of attack of 8° and 20°. Another approach in modelling cavitating flows - Volume - H.

Lemonnier, A. Rowe. Non-contact Method for Analysis of Cavitating Flows and the multiphase flow nature, the selection of flow analysis methods is limited. The Pressure fluctuations in cavitating flow As one of the most important physical quantities in cavitation phenomena, pressure is an.

Analysis of cavitating flow through a venturi Article (PDF Available) in Scientific research and essays 10(11) June with Reads How we measure 'reads'. Density contours: Re = 50, K = x Two-phase modeling of cavitated flows cavitation region from the inlet to the orifice.

Furness and Hutton [3] have noted similar oscillations in two-dimensional cavitating Venturis. 3 Medvitz R B, Kunz R F, Boger D A, et al.

Performance analysis of cavitating flow in centrifugal pumps using multiphase CFD. J Fluids Eng,– 4 Coutier-Delgosha O, Fortes-Patella R, Reboud J, et al. Experimental and numerical studies in a centrifugal pump with two-dimensional curved blades in cavitating condition.

The comparative analysis of numerical results highlights a good agreement for the non-cavitating steady flow predictions, whereas for the cavitating flow, discrepancies in cavity extent are observed.

Details Schwartz-Christoffel analysis of cavitating flow in a two dimensional mitered elbow EPUB

Three-dimensional (3D) simulations with ansys cfx as well as measurements of the cavitating flow in a low specific speed centrifugal pump (n q = 12 min −1) are performed for different operation conditions and varying surface e roughness is considered by wall functions in the flow simulations.

Good agreement between measured and calculated head is achieved for. Introduction the Main Features of Cavitating Flows. Chapter. Cavitation Number Turbulent Shear Flow CAVITATING Flow Wu T.Y.T. — — A free streamline theory for two-dimensional fully cavitated hydrofoils.

Math. Phys, – zbMATH MathSciNet Google Scholar. An experimental program has been carried out to determine the effects of wall interference on the drag and vortex shedding characteristics of cavitating two-dimensional triangular prisms and circular cylinders.

The former shapes were chosen to eliminate effects of Reynolds number in. The problem of cavitating flow past a two‐dimensional curved obstacle is considered. Surface tension is included in the dynamic boundary condition.

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The problem is solved numerically by series trunc. PIV analysis of cavitating flow behind square multi-orifice plates Zhiyong Dong, Wenqian Zhao College of Civil Engineering and Architecture at Zhejiang University of Technology, HangzhouChina Corresponding author: [email protected] Abstract.

Currently, in water supply engineering, the conventional technique of disinfection. complex three-dimensional flow structures, vortices and vapor distributions. In comparison of 2D and 3D simulation, the two-dimensional approach gives wrong information in 2 out of 6 critical regions pertaining cavitation failing in both, over- and under-prediction of cavitation.

In summary, a new numerical model. Cavitating flow is often observed in various propulsion systems and high-speed underwater objects, such as marine propellers, impellers of turbomachinery, hydrofoils, nozzles, injectors and torpedoes.

This phenomenon usually causes severe noise, vibration and erosion. Even though cavitating flow is a. 1 EXPERIMENTS AND MODELLING OF CAVITATING FLOWS IN VENTURI: ATTACHED SHEET CAVITATION S.

Barre *, J. Rolland, G. Boitel, E. Goncalves, R. Fortes Patella Laboratoire des Ecoulements Géophysiques et Industriels (LEGI – CNRS –INPG – UJF), BP53, Grenobl e, France. The effect of viscoelasticity on turbulent cavitating flow inside a nozzle is simulated for Phan-Thien-Tanner (PTT) fluids.

Two different flow configurations are used to show the effect of viscoelasticity on different cavitation mechanisms, namely, cloud cavitation inside a step nozzle and string cavitation in an injector nozzle.

Cavitation in an Oriflce Flow Bunnell et al.5 studied the unsteady cavitating °ow in a slot and found that partially cavitated slots Thompson et al solved the two-dimensional Poisson equation with an arbitrariness in choice of source terms to generate the orthogonal coordinates.

Instead of solving the 2-D Poisson equations, we. divergent channel with a rectangular cross -section from a viewpoint of a two- dimensional plane flow.

As a re sult, it has been demonstrated [2] [3] [15] that 1) the reentrant motion can be triggered by the pressure wave propagation which is caused through the collapse of the cloud shed downstream, 2) it moves toward the throat of the con.

pressure within the flow. Then the p∞ in equations and will be the local pressure in the liquid surrounding the bubble, and p∞ must be less than p V for explosive cavitation growth to occur. It is clear from the above analysis that all of the nuclei whose size, R, is greater than some critical value will become unstable, grow explosively, and cavitate, whereas those.

Only two-dimensional aspects of the cavitating flow were simulated by taking only three grids in the span wise direction. The angle of attack and the Reynolds number were kept equal to 8 degrees andrespectively, and the cavitation number was varied over a range of – in order to simulate various flow.

• Flowrate through cavitating venturi is calculated from the following equation: • There has been no published reference of an effort to model cavitating venturi by CFD or network analysis methods • Modeling of phase change and two-phase flow are required to compute flow through cavitating venturi.

Physics and Control of Cavitation RTO-EN-AVT 2 - 2 Subscripts 0 initial d desinence i inception A liquid min minimum ref reference v vapor ∞ infinity INTRODUCTION Vapour Pressure The development of cavitation in a liquid flow is characterized by a phase change from liquid to vapour at.

The flow-through diesel fuel injector nozzles is important because of the effects on the spray and the atomization process.

Modeling this nozzle flow is complicated by the presence of cavitation inside the nozzles. This investigation uses a two-dimensional, two-phase, transient model of cavitating. Cavitation is a phenomenon in which rapid changes of pressure in a liquid lead to the formation of small vapor-filled cavities in places where the pressure is relatively low.

When subjected to higher pressure, these cavities, called "bubbles" or "voids", collapse and can generate shock wave that is strong very close to the bubble, but rapidly weakens as it propagates away from the bubble.

A transient simulation of tutorial number 5. Here you can see the development of the cavitation bubbles along the orifice. The contour plot of mixed density os plotted.The object of this paper is to propose a model to simulate steady and unsteady cavitating flows.

In the engineering practice, cavitation flow is often modeled as a single-phase flow (mixture), where the cavitation area is handled as an area with the pressure lower than the vapor pressure.