Measurement of Orifice Plate Edge Sharpness

1973 ◽  
Vol 6 (9) ◽  
pp. 377-383 ◽  
Author(s):  
T. J. S. Brain ◽  
J. Reid
Keyword(s):  
Large Diameter ◽  
Orifice Diameter ◽  
Casting Method ◽  
Plate Edge ◽  
Precise Shape ◽  
Edge Sharpness ◽  
Instrument Engineer ◽  
Considerable Benefit ◽  
Lead Foil ◽  
Good Agreement

A significant factor which affects the accurate prediction of the discharge coefficients of square edged orifice plates is the precise shape of the edge. A rounding of only 0·002 of the orifice diameter can increase the coefficient by 1% so that a reliable method of assessing the edge sharpness is of considerable benefit to the instrument engineer. In the work described in this paper, a systematic intercomparison of three methods of measuring orifice edge sharpness has been undertaken. The methods tested involved casting, lead foil impression and optical techniques, and their relative reliability and effectiveness has been assessed. While the results obtained from the casting and lead foil methods showed good agreement, the foils did not follow the edge profiles as closely as the castings. The casting procedure can also be used to determine the shapes of re-entrant profiles which will not be detected using lead foil impressions. However, the casting method required more skill and considerably more time to complete measurements than the impression method. The optical method proved to be the least reliable, since measurements depended on subjective judgment. Nevertheless, this measuring procedure could be completed more quickly than the others, and these tests indicated that it may be used to examine large diameter plates for burrs or excessive rounding.

Influence of Diameter and Number of Orifice on Static Characteristics of Radial-Thrust Aerostatic Bearing

2012 ◽  
Vol 497 ◽  
pp. 78-82
Author(s):  
Fei Hu Zhang ◽  
Sheng Fei Wang ◽  
Qiang Zhang ◽  
Peng Qiang Fu
Keyword(s):  
Machine Tool ◽  
Fluid Dynamic ◽  
Load Capacity ◽  
Large Diameter ◽  
Orifice Diameter ◽  
Static Characteristics ◽  
Aerostatic Bearing ◽  
Supporting System ◽  
Manufacturing Technologies ◽  
Radial Thrust

The working performance of the spindle system is the most important factor to embody the overall performance of the machine tool. To ensure the advanced capabilities, besides the high-precision manufacturing technologies, it is mainly depending on the bearing module and the forces on the spindle. In this paper, a new strategy of the vertical spindle supporting system is presented to meet the high stiffness requirement for the aerostatic bearing. Based on the computational fluid dynamics and finite volume method, a fluid dynamic model and structure model of the large diameter incorporate radial-thrust aerostatic bearing is developed and simulated to find out the pressure distribution laws of the spindle supporting system. The grid subdivision in the direction of film thickness is paid more attentions when establishing the grid of the whole gas film. Simulation results show that this special structure of bearing module can supply enough load capacity and stiffness for the machine tool. The results also indicate that the static characteristics of the bearing are improved as the supply pressure increases and as the supply orifice diameter decreases.

A Reinforcement Design Method Based on Analysis of Large Openings in Cylindrical Pressure Vessels

1996 ◽  
Vol 118 (4) ◽  
pp. 502-506 ◽  
Author(s):  
M. D. Xue ◽  
K. C. Hwang ◽  
W. Lu¨ ◽  
W. Chen
Keyword(s):  
Fourier Series ◽  
Present Method ◽  
Fourier Coefficients ◽  
Design Method ◽  
Large Diameter ◽  
Pressure Vessels ◽  
Diameter Ratio ◽  
Cylindrical Coordinates ◽  
Reinforcement Design ◽  
Good Agreement

The analytical solution is given for two orthogonally intersecting cylindrical shells with large diameter ratio d/D subjected to internal pressure. The modified Morley equation is used for the shell with cutout and the Love equation for the tube with nonplanar end. The continuity conditions of forces and displacements at the intersection are expressed in 3-D cylindrical coordinates (ρ, θ, z), and are expanded in Fourier series of θ. The Fourier coefficients are obtained by numerical quadrature. The present results are in good agreement with those obtained by tests and by FEM for ρ0 = d/D ≤ 0.8. The typical curves of SCF versus t/T and d/DT and reinforcement coefficients g, h versus D/T0 for each ρ0 are given on the present method.

A new design approach for the determination of the buckling load of rectangular plates

2012 ◽  
Vol 227 (7) ◽  
pp. 1417-1428
Author(s):  
H Ahmed ◽  
JF Durodola ◽  
RG Beale
Keyword(s):  
Analysis Procedure ◽  
Preliminary Design ◽  
Rectangular Plates ◽  
Finite Element Analyses ◽  
Support Condition ◽  
Plate Edge ◽  
Buckling Loads ◽  
Plate Buckling ◽  
Good Agreement

The objective of this article is to introduce and assess a new plate buckling analysis procedure which can be used for quick, approximate analysis of buckling loads in preliminary design. The method is applied to a range of plate edge support condition combinations including many where results are not readily available. The results obtained using the new procedure were compared against theoretical formulae available in the literature and by finite element analyses with good agreement.

The Measurement and Effects of Edge Sharpness on the Flow Coefficients of Standard Orifices

1973 ◽  
Vol 95 (2) ◽  
pp. 271-274 ◽  
Author(s):  
K. A. Crockett ◽  
E. L. Upp
Keyword(s):  
Impression Technique ◽  
Edge Sharpness ◽  
Work Done ◽  
Lead Foil

An investigation of the lead foil impression technique of determining orifice edge-sharpness and the resultant effects on orifice coefficient of the rounding of the square-edge as determined by water calibration are discussed. The data to date are encouraging and correlate well with similiar work done originally in Germany and more recently in England.

A Numerical Study of Labyrinth Seal Flutter

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
L. di Mare ◽  
M. Imregun ◽  
J. S. Green ◽  
A. I. Sayma
Keyword(s):  
Numerical Study ◽  
Large Diameter ◽  
Labyrinth Seal ◽  
Navier Stokes ◽  
Time Step ◽  
Modal Model ◽  
Flutter Analysis ◽  
Time Histories ◽  
Structural Motion ◽  
Good Agreement

A numerical study of a labyrinth-type turbine seal flutter in a large turbofan engine is described. The flutter analysis was conducted using a coupled fluid-structure interaction code, which was originally developed for turbomachinery blade applications. The flow model is based on an unstructured, implicit Reynolds-averaged Navier–Stokes solver. The solver is coupled to a modal model for the structure obtained from a standard structural finite element code. During the aeroelasticity computations, the aerodynamic grid is moved at each time step to follow the structural motion, which is due to unsteady aerodynamic forces applied onto the structure by the fluid. Such an integrated time-domain approach allows the direct computation of aeroelastic time histories from which the aerodynamic damping, and hence, the flutter stability, can be determined. Two different configurations of a large-diameter aeroengine labyrinth seal were studied. The first configuration is the initial design with four fins, which exhibited flutter instability during testing. The second configuration is a modified design with three fins and a stiffened ring. The steady-state flow was computed for both configurations, and good agreement was reached with available reference data. An aeroelasticity analysis was conducted next for both configurations, and the model was able to predict the observed flutter behavior in both cases. A flutter mechanism is proposed, based on the matching of the structural frequencies to the frequencies of waves traveling in the fluid, in the interfin cavities and in the high- and low-pressure cavities.

Effects of Mould on Crimping of Large Diameter Welding Pipe

2014 ◽  
Vol 623 ◽  
pp. 129-132
Author(s):  
Jia Xin Yan ◽  
Jian Bin Yun ◽  
Li Feng Fan
Keyword(s):  
Finite Element ◽  
Arc Welding ◽  
Large Diameter ◽  
Forming Process ◽  
Simulation Data ◽  
Welding Pipe ◽  
X80 Steel ◽  
Submerged Arc ◽  
Good Agreement

Crimping is widely used in production of large diameter submerged-arc welding pipes. In crimping process, mould is one of the main factors which influences the quality of forming and should be considered at the stage of designing the forming die and process. So, Effects of mould on crimping is researched using finite element method. Taking the crimping of X80 steel Φ1219mm×22mm×12000mm welding pipe for instance, the crimping forming process is simulated by finite element (FE) code ABAQUS. In this paper, the simulation data is validated by product and a comparison showed a good agreement with product results. The stress/strain from simulation is discussed. Thus, the results of research provides a basis to choose mould.

Stress analysis of cylindrical shells with nozzles due to external run pipe moments

2000 ◽  
Vol 35 (3) ◽  
pp. 159-170 ◽  
Author(s):  
M. D Xue ◽  
H. H Wang ◽  
K. C Hwang
Keyword(s):  
Thin Shell ◽  
Cylindrical Shells ◽  
Large Diameter ◽  
Three Dimensional ◽  
Diameter Ratio ◽  
Test Results ◽  
Present Solution ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Good Agreement

In this paper the analytical results of two normally intersecting cylindrical shells subjected to external moments on the ends of main shells are presented. The thin shell theoretical solutions are obtained on the basis of the modified Morley equation for the main shell with a cut out with large diameter ratio and of the Goldenveizer equation for the branch tube with a nonplaner end. The results are in good agreement with the previous test results and with Moffat's three-dimensional finite element method results. The design curves based on the present solution can be applied to d/D ≤ 0.8 successfully.

Downwind Two-Bladed Wind Turbine Aerodynamic Performance Evaluation Implementing Actuator Line Model

2018 ◽  
Author(s):  
Sebastian Henao ◽  
Aldo G. Benavides ◽  
Omar D. López
Keyword(s):  
Wind Turbine ◽  
Structural Integrity ◽  
Large Diameter ◽  
Current Trend ◽  
Aerodynamic Performance ◽  
Cfd Simulations ◽  
Line Model ◽  
Power Extraction ◽  
Actuator Line Model ◽  
Good Agreement

The current trend in the wind power market is to develop large diameter rotors in order to maximize the power extraction from the wind. Those rotors exhibit issues related to blade deflection and structural integrity that can be mitigated implementing design variations that were present on the early wind turbine designs, such as rotors with less than three blades located behind the tower in downwind configuration. This work assesses the aerodynamic performance of a downwind two-bladed wind turbine based on CFD simulations coupled with the Actuator Line Model (ALM). This design is compared with the MEXICO project upwind three-bladed wind turbine, for which experimental data is available. The simulations showed good agreement with measurements especially upstream the rotor and for higher inlet velocities. Furthermore, the downwind configuration was successfully modeled using ALM and the performance prediction of the turbines was physically accurate since realistic variations were obtained between the evaluated wind turbines and none of their performance coefficients exceeded Betz theoretical limit.

scholarly journals Contrast-tuneable microscopy for single-shot real-time imaging

2020 ◽  
Vol 91 (3) ◽  
pp. 30701
Author(s):  
Isao Shimizu ◽  
Yoshinori Saikawa ◽  
Katsuhiro Uno ◽  
Hideaki Kano ◽  
Seishi Shimizu
Keyword(s):  
Real Time ◽  
Large Diameter ◽  
Focal Depth ◽  
Single Shot ◽  
Cell Dynamics ◽  
Real Time Imaging ◽  
Edge Sharpness ◽  
Simple Pair ◽  
Laser Holography ◽  
Sub Wavelength

A novel real image in-line laser holography has enabled a tuneable image contrast, edge sharpness, and visualization of sub-wavelength structures, using a simple pair of filters and large-diameter lenses that can incorporate higher-order scattered beams. Demonstrated also are the accuracy in object sizing and the ease of imaging along the focal depth, based on a single-shot imaging via holographic principle. In addition, the use of broad, collimated laser beam for irradiation has led to a wider field of view, making it particularly useful for an extensive monitoring of, and sweeping search for, cells and microbial colonies and for the real-time imaging of cancer-cell dynamics.

A study on the mechanical properties of graphene oxide/epoxy nanocomposites

2021 ◽  
pp. 096739112110111
Author(s):  
Rahim Eqra ◽  
Mohammad Hadi Moghim ◽  
Navid Eqra
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Graphene Oxide ◽  
Solution Casting ◽  
Casting Method ◽  
Epoxy Nanocomposites ◽  
Epoxy Nanocomposite ◽  
Solution Casting Method ◽  
Good Agreement

The aims of this research are to elucidate the role of graphene oxide on the mechanical properties of epoxy and also to obtain an equation for the modeling of its behavior. Accordingly, graphene oxide/epoxy nanocomposite samples are fabricated using the solution casting method. Tensile, flexural, SEM and FTIR tests are conducted on epoxy and the nanocomposite samples afterwards. The obtained results show that the tensile strength of epoxy improves even at low contents of graphene oxide such that 0.3 wt.% of GO yields an improvement of approximately 11.5%. The flexural strength of epoxy is also enhanced by 5.8% with 0.5 wt.% GO. Then, it decreases due to the agglomeration with increasing the GO content. In order to predict the tensile strength of GO/epoxy nanocomposites, a modified Halpin–Tsai equation is obtained with a new introduced correction factor as K = 39.5 Vf 1.135exp(2.9−1644.6 Vf). The obtained equation is in good agreement with the experimental data.

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