Three-Dimensional Dynamic Simulation of Helical Compression Springs

1990 ◽  
Vol 112 (4) ◽  
pp. 529-537 ◽  
Author(s):  
Y. Y. Lin ◽  
A. P. Pisano
Keyword(s):  
Experimental Data ◽  
Numerical Solution ◽  
Numerical Algorithm ◽  
High Speed ◽  
Moving Boundary ◽  
Nonlinear Partial Differential Equations ◽  
Three Dimensional ◽  
Physical Reality ◽  
Dynamic Equations ◽  
Helical Springs

The dynamic equations for general helical springs are solved and classified according to the number of energy terms used to formulate them. Solutions of several sets of dynamic equations, each with a different number of energy terms, are compared with experimental data. It is found that at higher compression speeds the numerical solution with a traditional, fixed boundary represents a physically impossible situation. A moving boundary technique is applied to improve the numerical solution and bring it into agreement with physical reality. Since a convergence proof for a numerical algorithm for nonlinear partial differential equations with a moving boundary is not available, a grid study has been performed to demonstrate convergence. The agreement between the solutions of different grid sizes and the experimental data is taken to show that the numerical algorithm was convergent. This three dimensional spring simulation model can be used in the simulation of high-speed mechanical machinery utilizing helical springs, and in particular, for design optimization of automotive valve springs.

Three-Dimensional Dynamic Simulation of Helical Compression Springs

1989 ◽  
Author(s):  
Y. Lin ◽  
A. P. Pisano
Keyword(s):  
Experimental Data ◽  
Numerical Solution ◽  
Numerical Algorithm ◽  
High Speed ◽  
Moving Boundary ◽  
Nonlinear Partial Differential Equations ◽  
Three Dimensional ◽  
Physical Reality ◽  
Dynamic Equations ◽  
Helical Springs

Abstract The dynamic equations for general helical springs are solved and classified according to the number of energy terms used to formulate them. Solutions of several sets of dynamic equations, each with a different number of energy terms, are compared with experimental data. It is found that at higher compression speeds the numerical solution with a traditional, fixed boundary represents a physically impossible situation. A moving boundary technique is applied to improve the numerical solution and bring it into agreement with physical reality. Since a convergence proof for a numerical algorithm for nonlinear partial differential equations with a moving boundary is not available, a grid study has been performed to demonstrate convergence. The agreement between the solutions of different grid sizes and the experimental data is taken to show that the numerical algorithm was convergent. This three dimensional spring simulation model can be used in the simulation of high-speed mechanical machinery utilizing helical springs, and in particular, for design optimization of automotive valve springs.

Development and Validation of a Three-Dimensional Multiphase Flow CFD Analysis for Journal Bearings in Steam and Heavy Duty Gas Turbines

2012 ◽  
Author(s):  
Stephan Uhkoetter ◽  
Stefan aus der Wiesche ◽  
Michael Kursch ◽  
Christian Beck
Keyword(s):  
Experimental Data ◽  
Multiphase Flow ◽  
Gas Turbines ◽  
High Speed ◽  
Three Dimensional ◽  
Air Entrainment ◽  
Journal Bearings ◽  
Heavy Duty ◽  
Present Contribution ◽  
Two Phase

The traditional method for hydrodynamic journal bearing analysis usually applies the lubrication theory based on the Reynolds equation and suitable empirical modifications to cover turbulence, heat transfer, and cavitation. In cases of complex bearing geometries for steam and heavy-duty gas turbines this approach has its obvious restrictions in regard to detail flow recirculation, mixing, mass balance, and filling level phenomena. These limitations could be circumvented by applying a computational fluid dynamics (CFD) approach resting closer to the fundamental physical laws. The present contribution reports about the state of the art of such a fully three-dimensional multiphase-flow CFD approach including cavitation and air entrainment for high-speed turbo-machinery journal bearings. It has been developed and validated using experimental data. Due to the high ambient shear rates in bearings, the multiphase-flow model for journal bearings requires substantial modifications in comparison to common two-phase flow simulations. Based on experimental data, it is found, that particular cavitation phenomena are essential for the understanding of steam and heavy-duty type gas turbine journal bearings.

Secondary Flow Development In A Cascade Like Passage Of A Turbomachine

1983 ◽  
pp. 11-23
Author(s):  
Amer Nordin Darus
Keyword(s):  
Experimental Data ◽  
Numerical Solution ◽  
Three Dimensional ◽  
Momentum Equation ◽  
Rotational Flow ◽  
Simultaneous Solution ◽  
Analytical Formulation ◽  
Curved Duct ◽  
Flow Development ◽  
Vorticity Equations

Makalah ini memaparkan formulasi analitik dan penyelesaian numerik aliran dimensi tiga yang rotasional di dalam sebuah saluran yang melengkung. Formulasi ini berdasarkan perhitungan halaju aliran dan komponen vortisiti selari axis saluran tersebut. Halaju sekunder ditentukan melalui penyelesaian serentak persamaan-persamaan ke terusan dan vortisiti melalui penggunaan fungsi seperti fungsi arus. Hasil-hasil numerik diberikan dan dibandingkan dengan data-data eksperimen yang ada. This article presents the analytical formulation and numerical solution of the three-dimensional rotational flow in curved duct. The formulation is based on calculating the flow - wise velocity and vorticity. components from the momentum equation. The secondary velocities are determined from the simultaneous solution of the continuity and vorticity equations through the use of a streamlike function. The results presented arc compared with the existing experimental data.

Preliminary Numerical Investigation of Effect of Interceptor on Ship Resistance

2011 ◽  
Vol 97-98 ◽  
pp. 1085-1090 ◽  
Author(s):  
Rui Deng ◽  
De Bo Huang ◽  
Guang Li Zhou ◽  
Hua Wei Sun
Keyword(s):  
Experimental Data ◽  
Flow Field ◽  
Numerical Investigation ◽  
Satisfactory Agreement ◽  
High Speed ◽  
Three Dimensional ◽  
Numerical Results ◽  
Two Dimensional ◽  
Ship Resistance ◽  
The Right

In the present work, the CFD software FLUENT is used to calculate the ship resistance and simulate the flow field around it. Comparison of the numerical results with experimental data of the ship without interceptor shows basically satisfactory agreement in the case of high-speed. In order to get the right parameters of the interceptor for the ship, some two dimensional calculation is taken to study the influence of interceptor with different size. The simulation of the three dimensional vessel with interceptor is also included, and the effect is discussed.

A Viscous Flow Study of Shock-Boundary Layer Interaction, Radial Transport, and Wake Development in a Transonic Compressor

1992 ◽  
Vol 114 (3) ◽  
pp. 538-547 ◽  
Author(s):  
C. Hah ◽  
L. Reid
Keyword(s):  
Experimental Data ◽  
Boundary Layer ◽  
Numerical Solution ◽  
Three Dimensional ◽  
Numerical Results ◽  
Radial Transport ◽  
Layer Interaction ◽  
Transonic Compressor ◽  
Shock Boundary Layer Interaction ◽  
Boundary Layer Interaction

A numerical study based on the three-dimensional Reynolds-averaged Navier–Stokes equation has been conducted to investigate the detailed flow physics inside a transonic compressor. Three-dimensional shock structure, shock-boundary layer interaction, flow separation, radial mixing, and wake development are all investigated at design and off-design conditions. Experimental data based on laser anemometer measurements are used to assess the overall quality of the numerical solution. An additional experimental study to investigate end-wall flow with a hot film was conducted, and these results are compared with the numerical results. Detailed comparison with experimental data indicates that the overall features of the three-dimensional shock structure, the shock-boundary layer interaction, and the wake development are all calculated very well in the numerical solution. The numerical results are further analyzed to examine the radial mixing phenomena in the transonic compressor. A thin sheet of particles is injected in the numerical solution upstream of the compressor. The movement of particles is traced with a three-dimensional plotting package. This numerical survey of tracer concentration reveals the fundamental mechanisms of radial transport in this transonic compressor. Strong radially outward flow is observed inside a separated flow region and this outward flow accounts for about 80 percent of the total radial transport. The radially inward flow is mainly due to the traditional secondary flow.

Unsteady Loads on Supercavitating Hydrofoils of Finite Span

1966 ◽  
Vol 10 (02) ◽  
pp. 107-118
Author(s):  
Sheila Evans Widnall
Keyword(s):  
Numerical Solution ◽  
Numerical Method ◽  
Integral Equations ◽  
Digital Computer ◽  
High Speed ◽  
Three Dimensional ◽  
Numerical Results ◽  
Oscillatory Motion ◽  
Surface Theory ◽  
Finite Span

Linearized three-dimensional lifting-surface theory is derived for a supercavitating hydrofoil with finite span in steady or oscillatory motion through an infinite fluid. The resulting coupled-integral equations are solved on a high-speed digital computer using a numerical method of assumed modes similar to that used for fully wetted surfaces. Numerical results for lift and moment for both steady and oscillating foils are compared with other theories and experiments. Results of these calculations indicate that this numerical solution gives an efficient and accurate prediction of loads on a supercavitating foil.

scholarly journals Explosive generators of high-speed preformed fragment flows

2018 ◽  
pp. 23-29
Author(s):  
K. A. Zaplohova ◽  
G. S. Isaev ◽  
A. E. Kurepin ◽  
E. V. Sidorova
Keyword(s):  
Experimental Data ◽  
Initial Data ◽  
Satisfactory Agreement ◽  
High Speed ◽  
Experimental Studies ◽  
Three Dimensional ◽  
The Creation ◽  
Target Design ◽  
Research Show

When assessing the effectiveness of ammunition designed to destroy various aerodynamic and ballistic targets, as the initial data on the vulnerability of the destruction objective, we use indicators obtained during experimental studies of the processes of fragments and fragment flow collision with various fragments of the target design. The results depend not only on the speed and mass of individual fragments, but also on their shape and location in the flow. The paper gives the results of the testing of an explosive thrower which provides the creation of a high-speed, i.e. ~5 km/s, flow of fragments of a given shape. Findings of research show satisfactory agreement between the results of calculations carried out in two- and three-dimensional statements with experimental data on high-speed throwing of a group of compact, parallelepiped, steel preformed fragments weighing 20 g each

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