Simulation of the subsonic flow in a high-speed centrifugal compressor impeller by the pressure-based method

1998 ◽  
Vol 212 (4) ◽  
pp. 269-287 ◽  
Author(s):  
Y Wang ◽  
S Komori
Keyword(s):  
High Speed ◽  
Compressible Flows ◽  
Incompressible Flows ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Centrifugal Impeller ◽  
Navier Stokes Equations ◽  
Compressor Impeller ◽  
Collocated Grid

A pressure-based finite volume procedure developed previously for incompressible flows is extended to predict the three-dimensional compressible flow within a centrifugal impeller. In this procedure, the general curvilinear coordinate system is used and the collocated grid arrangement is adopted. Mass-averaging is used to close the instantaneous Navier-Stokes equations. The covariant velocity components are used as the main variables for the momentum equations, making the pressure-velocity coupling easier. The procedure is successfully applied to predict various compressible flows from subsonic to supersonic. With the aid of the k-ɛ turbulence model, the flow details within a centrifugal impeller are obtained using the present procedure. Predicted distributions of the meridional velocity and the static pressure are reasonable. Calculated radial velocities and flow angles are favourably compared with the measurements at the exit of the impeller.

A Calculation Scheme for Three-Dimensional Viscous Incompressible Flows

1987 ◽  
Vol 109 (4) ◽  
pp. 345-352 ◽  
Author(s):  
M. Reggio ◽  
R. Camarero
Keyword(s):  
Incompressible Flows ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Numerical Procedure ◽  
Numerical Data ◽  
Momentum Balance ◽  
Navier Stokes ◽  
Test Cases ◽  
Pressure Gradients ◽  
Navier Stokes Equations

A numerical procedure to solve three-dimensional incompressible flows in arbitrary shapes is presented. The conservative form of the primitive-variable formulation of the time-dependent Navier-Stokes equations written for a general curvilinear coordiante system is adopted. The numerical scheme is based on an overlapping grid combined with opposed differencing for mass and pressure gradients. The pressure and the velocity components are stored at the same location: the center of the computational cell which is used for both mass and the momentum balance. The resulting scheme is stable and no oscillations in the velocity or pressure fields are detected. The method is applied to test cases of ducting and the results are compared with experimental and numerical data.

Numerical integration of the three-dimensional Navier-Stokes equations for incompressible flow

1969 ◽  
Vol 37 (4) ◽  
pp. 727-750 ◽  
Author(s):  
Gareth P. Williams
Keyword(s):  
Poisson Equation ◽  
Incompressible Flows ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Wave Flow ◽  
Trigonometric Interpolation ◽  
Time Step ◽  
Navier Stokes Equations ◽  
The Poisson Equation

A method of numerically integrating the Navier-Stokes equations for certain three-dimensional incompressible flows is described. The technique is presented through application to the particular problem of describing thermal convection in a rotating annulus. The equations, in cylindrical polar co-ordinate form, are integrated with respect to time by a marching process, together with the solving of a Poisson equation for the pressure. A suitable form of the finite difference equations gives a computationally-stable long-term integration with reasonably faithful representation of the spatial and temporal characteristics of the flow.Trigonometric interpolation techniques provide accurate (discretely exact) solutions to the Poisson equation. By using an auxiliary algorithm for rapid evaluation of trigonometric transforms, the proportion of computation needed to solve the Poisson equation can be reduced to less than 25% of the total time needed to’ advance one time step. Computing on a UNIVAC 1108 machine, the flow can be advanced one time-step in 2 sec for a 14 × 14 × 14 grid upward to 96 sec for a 60 × 34 × 34 grid.As an example of the method, some features of a solution for steady wave flow in annulus convection are presented. The resemblance of this flow to the classical Eady wave is noted.

Multigrid Computation of Incompressible Flows Using Two-Equation Turbulence Models: Part II—Applications

1997 ◽  
Vol 119 (4) ◽  
pp. 900-905 ◽  
Author(s):  
X. Zheng ◽  
C. Liao ◽  
C. Liu ◽  
C. H. Sung ◽  
T. T. Huang
Keyword(s):  
Turbulent Flows ◽  
Incompressible Flows ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Time Stepping ◽  
Grid Algorithm ◽  
High Reynolds

In this paper, computational results are presented for three-dimensional high-Reynolds number turbulent flows over a simplified submarine model. The simulation is based on the solution of Reynolds-Averaged Navier-Stokes equations and two-equation turbulence models by using a preconditioned time-stepping approach. A multiblock method, in which the block loop is placed in the inner cycle of a multi-grid algorithm, is used to obtain versatility and efficiency. It was found that the calculated body drag, lift, side force coefficients and moments at various angles of attack or angles of drift are in excellent agreement with experimental data. Fast convergence has been achieved for all the cases with large angles of attack and with modest drift angles.

A Finite Element Analysis of the Navier-Stokes Equations Applied to High Speed Thin Film Lubrication

1987 ◽  
Vol 109 (1) ◽  
pp. 71-76 ◽  
Author(s):  
J. O. Medwell ◽  
D. T. Gethin ◽  
C. Taylor
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Navier Stokes ◽  
The Finite Element Method ◽  
Thin Film Lubrication ◽  
Element Analysis ◽  
Navier Stokes Equations ◽  
Film Lubrication

The performance of a cylindrical bore bearing fed by two axial grooves orthogonal to the load line is analyzed by solving the Navier-Stokes equations using the finite element method. This produces detailed information about the three-dimensional velocity and pressure field within the hydrodynamic film. It is also shown that the method may be applied to long bearing geometries where recirculatory flows occur and in which the governing equations are elliptic. As expected the analysis confirms that lubricant inertia does not affect bearing performance significantly.

Peristaltic Pumping

2000 ◽  
Author(s):  
M. Tadjfar ◽  
T. Yamaguchi ◽  
R. Himeno
Keyword(s):  
Pressure Wave ◽  
Incompressible Flows ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Cylindrical Tube ◽  
Parallel Architecture ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Flow Solver ◽  
Peristaltic Pumping

Abstract Peristaltic pumping in a cylindrical tube is simulated. The unsteady, three-dimensional, incompressible Navier-Stokes equations are solved numerically. A flow solver written for parallel architecture and capable of dealing with moving boundaries and moving grids is used. The solver uses a second-order in time and third-order upwind finite volume method for solving time-accurate incompressible flows utilizing pseudo-compressibility technique. In this study, the flow of an axisymmetric “Wine-glass” shaped, single, peristaltic wave is analyzed. The wall wave, quickly, establishes a pressure wave in the flow which pumps fluid in the tube as it moves down the tube. The pressure wave, established by the contracting geometric wall wave, grows and diffuses into the upstream and downstream direction in time due to the action of viscosity.

Parallel, Multi-Zone, Multi-Block Solver to Study Arterial Branches in Human Vascular System

2001 ◽  
Author(s):  
M. Tadjfar ◽  
R. Himeno
Keyword(s):  
Message Passing ◽  
Incompressible Flows ◽  
Stokes Equations ◽  
Vascular System ◽  
Three Dimensional ◽  
Data Partitioning ◽  
Parallel Execution ◽  
Navier Stokes ◽  
Computational Domain ◽  
Navier Stokes Equations

Abstract The unsteady, three-dimensional, incompressible Navier-Stokes equations are solved numerically to study arterial branches in human vascular system. The solver is capable of dealing with moving boundaries and moving grids. It is designed to handle complex, three-dimensional vascular systems. The computational domain is divided into multiple block subdomains. At each cross section the plane is divided into twelve sub-zones to allow flexibility for handling complex geometries and, if needed, appropriate parallel data partitioning. A second-order in time and third-order upwind finite volume method for solving time-accurate incompressible flows based on pseudo-compressibility and dual time-stepping technique is used. For parallel execution, the flow domain is partitioned. Communication between the subdomains of the flow on Riken’s VPP/700E supercomputer is implemented using MPI message-passing library. The code is capable of running on both shared and/or distributed memory architectures.

Aerodynamic Simulation of the Air Flow beneath the High Speed Train

2012 ◽  
Vol 253-255 ◽  
pp. 2035-2040
Author(s):  
Ye Bo Liu ◽  
Zhi Ming Liu
Keyword(s):  
High Speed ◽  
Stokes Equations ◽  
Air Flow ◽  
Pressure Coefficient ◽  
Three Dimensional ◽  
Navier Stokes ◽  
High Speed Train ◽  
Navier Stokes Equations ◽  
Pressure Distributions ◽  
High Speed Trains

Numerical simulations were carried out to investigate the air flow and pressure distributions beneath high speed trains, based on the three-dimensional Reynolds-averaged Navier-Stokes equations with the SST k-ω two-equation turbulence model. The simulation scenarios were of the high speed train, the CRH2, running in the open air at four different speeds: 200km/h, 250km/h, 300km/h and 350km/h. The results show that, the highest area of pressure is located at the front underbody part of the train whist the pressure for rest of the train is relatively small. Increasing speed does not visibly increase the pressure coefficient, indicating that the pressure increases with the square of the operational speed.

Three Dimensional Simulation of Bore Flow Using SPH

2010 ◽  
Author(s):  
Huaxing Liu ◽  
Soon Keat Tan ◽  
Jing Li ◽  
Xikun Wang
Keyword(s):  
High Speed ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Smooth Particle Hydrodynamic ◽  
Navier Stokes ◽  
Initial Water ◽  
Navier Stokes Equations ◽  
Sph Model ◽  
Complex Fluid ◽  
Dimensional Simulation

Tidal bore is a fascinating and powerful hydraulic phenomenon. In this paper, the tidal bore’s process is studied using 3D Smooth Particle Hydrodynamic (SPH) model. The Lagrangian nature of SPH suits well to the modeling of the complex fluid flow phenomenon. In the SPH method, the Navier-Stokes equations are discretized with fluid particles in the Lagrangine sense. Boundary conditions, including both no slip wall and bottom wall, are implemented using dynamic boundary particles. Using SPH, the bore’s generation together with its traverse along the channel are presented, including the description of flow field and bore’s configuration. Different types of bores’ behavior are investigated. It is observed that there is a splash of water surge up the wall and the front of the bore becomes a breaker wave when the initial water column travels at high speed. The velocity field and bore heights at different locations are visualized and discussed as well.

Research of Train Wind Characteristics in High-Speed Railway Tunnel

2014 ◽  
Vol 919-921 ◽  
pp. 865-868 ◽  
Author(s):  
Rui Zhen Fei ◽  
Li Min Peng ◽  
Wei Chao Yang ◽  
Wei Guang Yan
Keyword(s):  
High Speed ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Time History ◽  
Space Distribution ◽  
Navier Stokes ◽  
Railway Tunnel ◽  
High Speed Railway ◽  
Navier Stokes Equations ◽  
Tunnel Cross Section

According to the 100㎡ high-speed tunnel cross-section which is generally used in high-speed railway of China, this paper develops a tunnel-air-train simulation model, based on the three-dimensional incompressible Navier-Stokes equations and the standard k-e turbulence model. Time-history variation rules and space distribution characteristics of train wind are studied respectively. The results show that: train wind is complex three-dimensional flow changing with time and space, air at the front of train flows away from the train head, while air at the rear of train flows to the train tail.

Experimental and Numerical Analysis of Compressor Inlet Volutes

1997 ◽  
Author(s):  
V. Michelassi ◽  
M. Giachi
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Computer Code ◽  
Navier Stokes ◽  
Complex Flow ◽  
Flow Distortion ◽  
Navier Stokes Equations ◽  
Flow Angle ◽  
Compressor Impeller ◽  
Compressor Inlet

A typical compressor inlet volute is studied by using both experimental and numerical approaches. The highly distorted and complex flow pattern is measured in two typical configurations. Measurements include velocity, flow angle, Mach number and losses. The same geometries are analyzed by using a computer code which solves the three-dimensional Navier-Stokes equations. Turbulence effects are modeled by a two-equation turbulence model. The set of measurements shows the flow distortion induced by the volute, and also highlights how this distortion can be controlled or largely reduced by small modifications to the geometry. The computational results indicate an overall good agreement with the measurements and allow reproducing the changes in the pattern induced by the changes in volute geometry. Both the measurements and computations prove the importance of the optimal design of this component which controls the uniformity of the flow approaching the compressor impeller.

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