scholarly journals Transonic Turbomachinery Calculations Using a Hybrid Structured-Unstructured Grid Method

1994 ◽  
Author(s):  
Scott M. Richardson
Keyword(s):  
Unstructured Grid ◽  
Unstructured Mesh ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Grid Method ◽  
Navier Stokes ◽  
Flow Equations ◽  
Transonic Compressor ◽  
Flow Features ◽  
Grid Points

A method is presented for solving the two-dimensional Navier-Stokes equations on a solution-adaptive grid of both structured and unstructured meshes. Flow near airfoil surfaces is modeled using an implicit finite difference algorithm on a structured O-type mesh. The flow equations in the blade passages are written in a cell-vertex finite volume formulation and are solved on an unstructured mesh using a Runge-Kutta explicit algorithm. Both the structured and unstructured grid also include solution dependent adaptation to allow resolution of flow features with a minimum of grid points. The structured mesh divides to locally add grid lines, while the unstructured mesh allows the addition or removal of individual cells. An overlapping interface region is used to conservatively communicate flow variable information between the two grids. The quasi-three-dimensional effects of streamtube contraction and radius change are included to allow calculation of modern turbomachine designs. A study is included to determine the effect on cacade parameters of inclusion of viscous terms in the solution of the flow equations in the unstructured domain. Quasi-three-dimensional computations of flow through a transonic compressor and turbine cascade are compared with experimental data.

The Simulation of Three-Dimensional Viscous Flow in Turbomachinery Geometries Using a Solution-Adaptive Unstructured Mesh Methodology

1991 ◽  
Author(s):  
W. N. Dawes
Keyword(s):  
Unstructured Mesh ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Adaptive Mesh ◽  
Mean Value ◽  
Navier Stokes ◽  
Compressor Cascade ◽  
Three Dimensional Flow ◽  
Navier Stokes Equations ◽  
Transonic Compressor

This paper presents a numerical method for the simulation of flow in turbomachinery blade rows using a solution-adaptive mesh methodolgy. The fully three dimensional, compressible, Reynolds averaged Navier-Stokes equations with k-ε turbulence modelling (and low Reynolds number damping terms) are solved on an unstructured mesh formed from tetrahedral finite volumes. At stages in the solution, mesh refinement is carried out based on flagging cell faces with either a fractional variation of a chosen variable (like Mach number) greater than a given threshold or with a mean value of the chosen variable within a given range. Several solutions are presented, including that for the highly three-dimensional flow associated with the corner stall and secondary flow in a transonic compressor cascade, to demonstrate the potential of the new method.

The Simulation of Three-Dimensional Viscous Flow in Turbomachinery Geometries Using a Solution-Adaptive Unstructured Mesh Methodology

1992 ◽  
Vol 114 (3) ◽  
pp. 528-537 ◽  
Author(s):  
W. N. Dawes
Keyword(s):  
Unstructured Mesh ◽  
Turbulence Modeling ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Adaptive Mesh ◽  
Mean Value ◽  
Navier Stokes ◽  
Compressor Cascade ◽  
Navier Stokes Equations ◽  
Transonic Compressor

This paper presents a numerical method for the simulation of flow in turbomachinery blade rows using a solution-adaptive mesh methodology. The fully three-dimensional, compressible, Reynolds-averaged Navier–Stokes equations with k–ε turbulence modeling (and low Reynolds number damping terms) are solved on an unstructured mesh formed from tetrahedral finite volumes. At stages in the solution, mesh refinement is carried out based on flagging cell faces with either a fractional variation of a chosen variable (like Mach number) greater than a given threshold or with a mean value of the chosen variable within a given range. Several solutions are presented, including that for the highly three-dimensional flow associated with the corner stall and secondary flow in a transonic compressor cascade, to demonstrate the potential of the new method.

The Research on Numerical Simulation of the Centrifugal Pump and Configuration Perfected

2013 ◽  
Vol 694-697 ◽  
pp. 56-60
Author(s):  
Yue Jun Ma ◽  
Ji Tao Zhao ◽  
Yu Min Yang
Keyword(s):  
Numerical Simulation ◽  
Centrifugal Pump ◽  
Unstructured Grid ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Internal Flow ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Flow Phenomena ◽  
Simplec Algorithm

In the paper, on the basis of three-dimensional Reynolds-averaged Navier-Stokes equations and the RNG κ-ε turbulence model, adopting Three-dimensional unstructured grid and pressure connection the implicit correction SIMPLEC algorithm, and using MRF model which is supported by Fluent, this paper carries out numerical simulation of the internal flow of the centrifugal pump in different operation points. According to the results of numerical simulation, this paper analyzes the bad flow phenomena of the centrifugal pump, and puts forward suggests about configuration perfected of the centrifugal pump. In addition, this paper is also predicted the experimental value of the centrifugal pump performance, which is corresponding well with the measured value.

IGV-Rotor Interaction Analysis in a Transonic Compressor Using the Navier-Stokes Equations

1996 ◽  
Author(s):  
Andrea Arnone ◽  
Roberto Pacciani
Keyword(s):  
Stokes Equations ◽  
Interaction Analysis ◽  
Guide Vane ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Inlet Guide Vane ◽  
Operating Characteristics ◽  
Navier Stokes Equations ◽  
Transonic Compressor ◽  
Mass Flow Rates

A recently developed, time-accurate multigrid viscous solver has been extended to handle quasi-three-dimensional effects and applied to the first stage of a modern transonic compressor. Interest is focused on the inlet guide vane (IGV):rotor interaction where strong sources of unsteadiness are to be expected. Several calculations have been performed to predict the stage operating characteristics. Flow structures at various mass flow rates, from choke to near stall, are presented and discussed. Comparisons between unsteady and steady pitch-averaged results are also included in order to obtain indications about the capabilities of steady, multi-row analyses.

scholarly journals The Modelling of Flow in the Volute and Vanes of a High Pressure Radial Inflow Turbine

1993 ◽  
Author(s):  
M. Lobo ◽  
R. L. Elder
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Experimental Measurements ◽  
General Description ◽  
Navier Stokes Equations ◽  
Flow Modelling ◽  
Comparison With Experiment ◽  
Flow Features ◽  
Radial Inflow Turbine

The flow in a vaned volute of a radial inflow turbine is analysed using PHOENICS, a very general three-dimensional viscous CFD code based on finite-volume pressure-correction techniques for solving the Navier-Stokes equations. The study involves two physically complementary but mathematically very different problems — flow modelling in the vaneless section of the volute and flow modelling in the vanes. Each of these problems is considered in turn — and each presents characteristic hurdles. Particular attention is paid to grid-generation and the process is carried out alongside the flow computation, the grids being modified in such a way so as to facilitate convergence and accuracy. Numerical results are presented in the form of vector plots for purposes of general description and tables for comparison with experiment. Agreement with experiment is good. However experimental results, for comparison are available only in the vanes. In the vaneless section of the volute, the converged solution depicts some interesting secondary flow features — in regions inaccesible to the current experimental measurements.

IGV–Rotor Interaction Analysis in a Transonic Compressor Using the Navier–Stokes Equations

1998 ◽  
Vol 120 (1) ◽  
pp. 147-155 ◽  
Author(s):  
A. Arnone ◽  
R. Pacciani
Keyword(s):  
Stokes Equations ◽  
Interaction Analysis ◽  
Guide Vane ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Inlet Guide Vane ◽  
Operating Characteristics ◽  
Navier Stokes Equations ◽  
Transonic Compressor ◽  
Mass Flow Rates

A recently developed, time-accurate multigrid viscous solver has been extended to handle quasi-three-dimensional effects and applied to the first stage of a modern transonic compressor. Interest is focused on the inlet guide vane (IGV)-rotor interaction where strong sources of unsteadiness are to be expected. Several calculations have been performed to predict the stage operating characteristics. Flow structures at various mass flow rates, from choke to near stall, are presented and discussed. Comparisons between unsteady and steady pitch-averaged results are also included in order to obtain indications about the capabilities of steady, multi-row analyses.

Numerical Simulation of an Annular Combustor

1993 ◽  
Author(s):  
P. Di Martino ◽  
G. Cinque
Keyword(s):  
Stokes Equations ◽  
Turbulent Transport ◽  
Three Dimensional ◽  
Staggered Grid ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Turbulent Reactive Flows ◽  
Interpolation Technique ◽  
Annular Combustor ◽  
Grid Points

A numerical model to solve three-dimensional turbulent reactive flows in arbitrary shapes is presented. The conservative form of the primitive-variable formulation of steady density-weighted Navier Stokes equations written for a general curvilinear system is adopted. Turbulent transport is described by the k-ε model. The reactions associated with heat release are assumed sufficiently fast for chemical equilibrium to prevail on an instantaneous basis and the influence of local turbulent fluctuations in mixture strenght accounted for by a β-probability density function. The numerical scheme is based on a non-staggered grid (cartesian velocity components and pressure located at the same grid-points) and a special interpolation technique is used to avoid checkerboard oscillations. The present model was used to simulate an annular combustion chamber for which experimental results were available. The agreement between calculation and experiments ranges from fair to good.

A Numerical Analysis of the Three-Dimensional Viscous Flow in a Transonic Compressor Rotor and Comparison With Experiment

1987 ◽  
Vol 109 (1) ◽  
pp. 83-90 ◽  
Author(s):  
W. N. Dawes
Keyword(s):  
Boundary Layer ◽  
Numerical Analysis ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Axial Flow ◽  
Tip Clearance ◽  
Navier Stokes ◽  
Viscous Effects ◽  
Transonic Compressor ◽  
Compressor Rotor

The numerical analysis of highly loaded transonic compressors continues to be of considerable interest. Although much progress has been made with inviscid analyses, viscous effects can be very significant, especially those associated with shock–boundary layer interactions. While inviscid analyses have been enhanced by the interactive inclusion of blade surf ace boundary layer calculations, it may be better in the long term to develop efficient algorithms to solve the full three-dimensional Navier–Stokes equations. Indeed, it seems that many phenomena of key interest, like tip clearance flows, may only be accessible to a Navier–Stokes solver. The present paper describes a computer program developed for solving the three-dimensional viscous compressible flow equations in turbomachine geometries. The code is applied to the study of the flowfield in an axial-flow transonic compressor rotor with an attempt to resolve the tip clearance flow. The predicted flow is compared with laser anemometry measurements and good agreement is found.

scholarly journals The Subgrid-Scale Approach for Modeling Impingement Cooling Flow in the Combustor Pedestal Tile

2017 ◽  
Vol 140 (4) ◽  
Author(s):  
Dalila Ammour ◽  
Gary J. Page
Keyword(s):  
Heat Transfer ◽  
Three Dimensional ◽  
Computation Time ◽  
Navier Stokes ◽  
Subgrid Scale ◽  
Validation Data ◽  
Eddy Simulation ◽  
Flow Features ◽  
Grid Points ◽  
Impinging Flow

The widely used gas turbine combustor double-walled cooling scheme relies on very small pedestals. In a combustor it is impractical for computational fluid dynamics (CFD) to resolve each pedestal individually as that would require a very large amount of grid points and consequent excessive computation time. These pedestals can be omitted from the mesh and their effects captured on the fluid via a pedestal subgrid-scale (SGS) model. The aim is to apply the SGS approach, which takes into account the effects on pressure, velocity, turbulence, and heat transfer, in an unstructured CFD code. The flow inside a two-dimensional (2D) plain duct is simulated to validate the pedestal SGS model, and the results for pressure, velocity, and heat transfer are in good agreement with the measured data. The conjugate heat transfer inside a three-dimensional (3D) duct is also studied to calibrate the heat source term of the SGS model due to the pedestals. The resolved flow in the combustor pedestal tile geometry is numerically investigated using Reynolds-averaged Navier–Stokes (RANS) and large eddy simulation (LES) in order to first assess the viability of the RANS and LES to predict the impinging flow and second to provide more validation data for the development of the SGS pedestal correlations. It is found that the complexity of such a flow, with high levels of curvature, impingement, and heat transfer, poses a challenge to the standard RANS models. The LES provides more details of the impinging flow features. The pedestal model is then applied to the complete tile to replace the pedestals. The results are close to both the fully resolved CFD and the measurements. To improve the flow features in the impingement zone, the first two rows were resolved with the mesh and combined with the SGS modeling for the rest of the tile; this gave optimum results of pressure, velocity, and turbulence kinetic energy (TKE) distribution inside the pedestal cooling tile.

Effect of rocket exhaust of canisterized missile on adjoining launching system

2016 ◽  
Vol 231 (11) ◽  
pp. 2085-2097 ◽  
Author(s):  
MSR Chandra Murty ◽  
PK Sinha ◽  
D Chakraborty
Keyword(s):  
Stokes Equations ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Test Configuration ◽  
Instantaneous Position ◽  
Flow Features ◽  
Scale Down ◽  
Parametric Studies

Transient numerical simulations are carried out to study missile motion in a vertical launch system and to estimate the effect of missile exhaust in the adjoining launch structure. Three-dimensional Navier–Stokes equations along with k–ɛ turbulence model and species transport equations are solved using commercial computational fluid dynamics software. Dynamic grid movement is adopted and one degree of freedom trajectory equations are integrated with the computational fluid dynamic solver to obtain the instantaneous position of the missile. Multi-zone grid generation approach with sliding interface method through layering technique is adopted to address the changing boundary problem. The computational methodology is applied to study the missile motion in a scale-down test configuration as well as in the flight condition. The computations capture all essential flow features of test and flight conditions in active cell as well as in adjacent cells. Parametric studies are conducted to study the effect geometrical features and measurement uncertainty in the input data. Computed pressures in the adjacent cells in the launch system match better (∼12%) with the experimental and flight results compared to distant cells.

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