Study on Hydrodynamic Torque of a Butterfly Valve

2005 ◽  
Vol 128 (1) ◽  
pp. 190-195 ◽  
Author(s):  
Ju Yeop Park ◽  
Myung Kyoon Chung
Keyword(s):  
Iterative Scheme ◽  
Three Dimensional ◽  
Physical Reality ◽  
Two Dimensional ◽  
Butterfly Valve ◽  
Valve Design ◽  
Conventional Model ◽  
Torque Coefficient ◽  
Theoretical Results ◽  
Valve Model

Since knowledge on hydrodynamic torque of a butterfly valve is very important for butterfly valve design, its hydrodynamic torque is investigated theoretically. For this, a recently developed two-dimensional butterfly valve model is solved through the free-streamline theory with a newly devised iterative scheme and the resulting two-and three-dimensional torque coefficients are compared with previous theoretical results based on the conventional butterfly valve model and experiments. Comparison shows that the improvement due to the new butterfly valve model is marginal. That is, the three-dimensional torque coefficient is well represented by the new model. Otherwise, the two-dimensional torque coefficient is well predicted by the conventional model. In spite this fact, the present results can be used in further researches on butterfly valves because the improved butterfly valve model is mathematically correct and reflects physical reality more correctly than the conventional valve model.

An Investigation of the Predicting Capabilities of a Variable Flow Stress Machining Theory

2001 ◽  
Author(s):  
P. Mathew
Keyword(s):  
Flow Stress ◽  
Material Flow ◽  
Three Dimensional ◽  
Experimental Results ◽  
Two Dimensional ◽  
Variable Flow ◽  
Comparative Results ◽  
Intermittent Cutting ◽  
Theoretical Results ◽  
Modelling Approach

Abstract The Oxley Machining Theory, which has been developed over the last 40 years, is presented in this paper. The capability of the model is described with its initial two-dimensional machining approach followed by the extension to the generalised model for three-dimensional machining. The theoretical results from the model are compared with the experimental results to determine the model capability. A brief description of the work associated with the effect of strain hardening at the interface is presented and comparative results are shown. A further extension of the model to intermittent cutting process of reaming is also presented and a comparison with the experimental results indicates the model developed is quite capable of predicting cutting forces for reaming. In explaining the results obtain, the assumptions made are explained and the inputs required. The limitations of the modelling approach are presented. It is pointed out that the Oxley model is a versatile model as long as proper description of the material flow stress properties is presented.

scholarly journals A THEORETICAL AND EXPERIMENTAL STUDY OF UNDERTOW

1984 ◽  
Vol 1 (19) ◽  
pp. 151 ◽  
Author(s):  
J. Buhr Hansen ◽  
I.A. Svendsen
Keyword(s):  
Experimental Study ◽  
Mass Flux ◽  
Laboratory Experiments ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Rip Currents ◽  
Longshore Currents ◽  
Theoretical Results ◽  
Recent Laboratory

It is well known that on a three-dimensional beach large volumes of water carried shorewards by the breakers feed longshore currents, which eventually escape back through the breaker line, often as rip currents. In a steady two-dimensional situation, however, the mass flux represented by (among other things) the surface roller in the breakers returns as a seaward current close to the bottom. This current is called the undertow. In this paper theoretical results for the undertow are compared with the results of recent laboratory experiments.

Torque and Cavitation Characteristics of Butterfly Valves

1961 ◽  
Vol 28 (4) ◽  
pp. 511-518 ◽  
Author(s):  
Turgut Sarpkaya
Keyword(s):  
Approximate Solution ◽  
Three Dimensional ◽  
Relaxation Technique ◽  
Dimensional Case ◽  
Practical Case ◽  
Two Dimensional ◽  
Actual Flow ◽  
Theoretical Results ◽  
Good Agreement

The present study deals with torque and cavitation characteristics of idealized two-dimensional and axially symmetrical butterfly valves. Theoretical results obtained for the two-dimensional case are compared with the ones obtained experimentally and by a relaxation technique. Based on the results of the two-dimensional case, an approximate solution is presented for the more general and practical case of three-dimensional butterfly valves. The results are in good agreement with the actual flow tests.

Validation of 3-D Euler Methods for Vibrating Cascade Aerodynamics

1994 ◽  
Author(s):  
Georg A. Gerolymos ◽  
Isabelle Vallet
Keyword(s):  
Subsonic Flow ◽  
Three Dimensional ◽  
Computational Results ◽  
Two Dimensional ◽  
Flat Plates ◽  
Dimensional Theory ◽  
Code Comparison ◽  
Euler Solver ◽  
Euler Methods ◽  
Theoretical Results

The purpose of this work is to validate a time-nonlinear three-dimensional Euler solver for vibrating cascades aerodynamics by comparison with available theoretical semi-analytical results from flat-plate cascades. First the method is validated with respect to the purely two-dimensional theory of Verdon (for supersonic flow) by computing two-dimensional vibration (spanwise constant) in linear three-dimensional cascades. Then the method is validated by comparison with the theoretical results of Namba and the computational results of He and Denton, for subsonic flow in a linear three-dimensional cascade with three-dimensional vibratory mode. Finally the method is compared with results of Chi from two subsonic rotating annular cascades of helicoïdal flat-plates. Quite satisfactory agreement is obtained for all the cases studied. A first code-to-code comparison is also presented.

Square-pattern convection in fluids with strongly temperature-dependent viscosity

1985 ◽  
Vol 150 ◽  
pp. 451-465 ◽  
Author(s):  
F. H. Busse ◽  
H. Frick
Keyword(s):  
Numerical Solutions ◽  
Fluid Layer ◽  
Three Dimensional ◽  
Square Lattice ◽  
Two Dimensional ◽  
Temperature Dependent ◽  
Temperature Dependent Viscosity ◽  
The Stability ◽  
Dependent Viscosity ◽  
Theoretical Results

Three-dimensional numerical solutions are obtained describing convection with a square lattice in a layer heated from below with no-slip top and bottom boundaries. The limit of infinite Prandtl number and a linear dependence of the viscosity on temperature are assumed. The stability of the three-dimensional solutions with respect to disturbances fitting the square lattice is analysed. It is shown that convection in the form of two-dimensional rolls is stable for low variations of viscosity, while square-pattern convection becomes stable when the viscosity contrast between upper and lower parts of the fluid layer is sufficiently strong. The theoretical results are in qualitative agreement with experimental observations.

Validation of Three-Dimensional Euler Methods for Vibrating Cascade Aerodynamics

1996 ◽  
Vol 118 (4) ◽  
pp. 771-782 ◽  
Author(s):  
G. A. Gerolymos ◽  
I. Vallet
Keyword(s):  
Subsonic Flow ◽  
Three Dimensional ◽  
Computational Results ◽  
Two Dimensional ◽  
Flat Plates ◽  
Dimensional Theory ◽  
Code Comparison ◽  
Euler Solver ◽  
Euler Methods ◽  
Theoretical Results

The purpose of this work is to validate a time-nonlinear three-dimensional Euler solver for vibrating cascades aerodynamics by comparison with available theoretical semi-analytical results from flat-plate cascades. First the method is validated with respect to the purely two-dimensional theory of Verdon (for supersonic flow) by computing two-dimensional vibration (spanwise constant) in linear three-dimensional cascades. Then the method is validated by comparison with the theoretical results of Namba and the computational results of He and Denton, for subsonic flow in a linear three-dimensional cascade with three-dimensional vibratory mode. Finally the method is compared with results of Chi from two subsonic rotating annular cascades of helicoi¨dal flat plates. Quite satisfactory agreement is obtained for all the cases studied. A first code-to-code comparison is also presented.

A Viscous/Inviscid Interactive Approach for the Prediction of Performance of Hydrofoils and Propellers with Nonzero Trailing Edge Thickness

2011 ◽  
Vol 55 (01) ◽  
pp. 45-63
Author(s):  
Yulin Pan ◽  
Yulin Pan
Keyword(s):  
Degrees Of Freedom ◽  
Iterative Scheme ◽  
Three Dimensional ◽  
Current Method ◽  
3D Models ◽  
Cavity Surface ◽  
Two Dimensional ◽  
Cavity Pressure ◽  
Interactive Approach ◽  
Trailing Edge

A viscous/inviscid interactive (VII) approach is applied to predict the performance of hydrofoils and propellers with nonzero trailing edge thickness. The emphasis has been put on developing VII models for flow separation. The investigation starts from a two-dimensional (2D) hydrofoil. The current method uses an iterative scheme to find a nonlifting closing extension behind the trailing edge. Two kinds of schemes are applied for the iteration process:a non-lifting extension with 1 or 2 degrees of freedom, in fully wetted condition andan extension which is treated like a cavity surface, but with a nonconstant cavity pressure distribution. The results from these schemes are compared with those from a commercial RANS Solver (Fluent). Next, the current schemes using flap extensions are extended to three-dimensional (3D) propeller flows. The 3D models are developed so that all the span-wise strips of the propeller satisfy similar conditions to those used in 2D. A propeller with significant nonzero trailing edge thickness is analyzed, using several 3D models, and the results are compared with existing experimental data.

Three-Dimensional Analysis of Partially Open Butterfly Valve Flows

1996 ◽  
Vol 118 (3) ◽  
pp. 562-568 ◽  
Author(s):  
Chendong Huang ◽  
Rhyn H. Kim
Keyword(s):  
Numerical Simulation ◽  
Numerical Analysis ◽  
Flow Field ◽  
Dimensional Analysis ◽  
Three Dimensional ◽  
Fluid Flows ◽  
Butterfly Valve ◽  
Valve Design ◽  
Incompressible Fluid Flows ◽  
Physical Phenomena

A numerical simulation of butterfly valve flows is a useful technique to investigate the physical phenomena of the flow field. A three-dimensional numerical analysis was carried out on incompressible fluid flows in a butterfly valve by using FLUENT, which solves difference equations. Characteristics of the butterfly valve flows at different valve disk angles with a uniform incoming velocity were investigated. Comparisons of FLUENT results with other results, i.e., experimental results, were made to determine the accuracy of the employed method. Results of the three-dimensional analysis may be useful in the valve design.

High Resolution Microscopy of Multi-Layered Biological Crystals

1982 ◽  
Vol 40 ◽  
pp. 80-83
Author(s):  
H.A. Cohen ◽  
T.W. Jeng ◽  
W. Chiu
Keyword(s):  
High Resolution ◽  
Low Dose ◽  
Three Dimensional ◽  
Data Interpretation ◽  
Two Dimensional ◽  
Biological Objects ◽  
Density Maps ◽  
Density Map ◽  
Complex Crystal ◽  
High Resolution Microscopy

This tutorial will discuss the methodology of low dose electron diffraction and imaging of crystalline biological objects, the problems of data interpretation for two-dimensional projected density maps of glucose embedded protein crystals, the factors to be considered in combining tilt data from three-dimensional crystals, and finally, the prospects of achieving a high resolution three-dimensional density map of a biological crystal. This methodology will be illustrated using two proteins under investigation in our laboratory, the T4 DNA helix destabilizing protein gp32*I and the crotoxin complex crystal.

Instrumentation For Quantitative Microscopy

1977 ◽  
Vol 35 ◽  
pp. 206-209
Author(s):  
B. Ralph ◽  
A.R. Jones
Keyword(s):  
Volume Fraction ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Automatic Data ◽  
Phase Volume Fraction ◽  
Statistical Confidence ◽  
Resultant Data ◽  
Automatic Data Collection ◽  
Third Dimension ◽  
Evolution Of Microstructure

In all fields of microscopy there is an increasing interest in the quantification of microstructure. This interest may stem from a desire to establish quality control parameters or may have a more fundamental requirement involving the derivation of parameters which partially or completely define the three dimensional nature of the microstructure. This latter categorey of study may arise from an interest in the evolution of microstructure or from a desire to generate detailed property/microstructure relationships. In the more fundamental studies some convolution of two-dimensional data into the third dimension (stereological analysis) will be necessary.In some cases the two-dimensional data may be acquired relatively easily without recourse to automatic data collection and further, it may prove possible to perform the data reduction and analysis relatively easily. In such cases the only recourse to machines may well be in establishing the statistical confidence of the resultant data. Such relatively straightforward studies tend to result from acquiring data on the whole assemblage of features making up the microstructure. In this field data mode, when parameters such as phase volume fraction, mean size etc. are sought, the main case for resorting to automation is in order to perform repetitive analyses since each analysis is relatively easily performed.

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