scholarly journals Three-Dimensional Navier–Stokes Computations of Transonic Fan Flow Using an Explicit Flow Solver and an Implicit κ–ε Solver

1993 ◽  
Vol 115 (2) ◽  
pp. 261-272 ◽  
Author(s):  
I. K. Jennions ◽  
M. G. Turner
Keyword(s):  
Boundary Layer ◽  
Three Dimensional ◽  
Layer Growth ◽  
Test Facility ◽  
Navier Stokes ◽  
Tip Leakage Flow ◽  
Flow Solver ◽  
Boundary Layer Interaction ◽  
Transonic Fan ◽  
Solid Bodies

Computational fluid dynamics (CFD) has become a powerful ally of the experimental test facility in revealing the flow physics of some highly complex flows. For certain classes of flow, CFD has reached maturity and is therefore being increasingly used in industry by designers. This paper is intended to show current transonic prediction capability at GE Aircraft Engines in terms of a recently developed three-dimensional Navier–Stokes code. The flow simulations addressed are concerned with transonic fan design and illustrate those issues that are important to designers such as tip leakage flow, shock boundary layer interaction, boundary layer growth, and account of internal solid bodies such as part-span shrouds and engine splitters. In this respect, three successively more complex Navier–Stokes simulations representative of modern fans—NASA Rotor 67, GE/Wennerstrom Rotor 4, and the GE/NASA E3 fans—are considered in this paper.

scholarly journals Three-Dimensional Navier-Stokes Computations of Transonic Fan Flow Using an Explicit Flow Solver and an Implicit κ–ϵ Solver

1992 ◽  
Author(s):  
I. K. Jennions ◽  
M. G. Turner
Keyword(s):  
Boundary Layer ◽  
Three Dimensional ◽  
Layer Growth ◽  
Test Facility ◽  
Navier Stokes ◽  
Tip Leakage Flow ◽  
Flow Solver ◽  
Boundary Layer Interaction ◽  
Transonic Fan ◽  
Solid Bodies

Computational fluid dynamics (CFD) has become a powerful ally of the experimental test facility in revealing the flow physics of some highly complex flows. For certain classes of flow, CFD has reached maturity and is therefore being increasingly used in industry by designers. This paper is intended to show current transonic prediction capability at GE Aircraft Engines in terms of a recently developed 3D Navier-Stokes code. The flow simulations addressed are concerned with transonic fan design and illustrate those issues that are important to designers such as tip leakage flow, shock boundary layer interaction, boundary layer growth and account of internal solid bodies such as part-span shrouds and engine splitters. In this respect, three successively more complex Navier-Stokes simulations representative of modern fans: NASA Rotor 67, GE/Wennerstrom Rotor 4, and the GE/NASA E3 fan, are considered in this paper.

Aerodynamics of Boundary Layer Ingesting Fans

2014 ◽  
Author(s):  
E. J. Gunn ◽  
C. A. Hall
Keyword(s):  
Boundary Layer ◽  
Three Dimensional ◽  
Low Speed ◽  
Turbofan Engines ◽  
Unsteady Separation ◽  
Fuel Burn ◽  
Boundary Layer Interaction ◽  
Flow Features ◽  
Structure Strength ◽  
Transonic Fan

Boundary Layer Ingesting (BLI) turbofan engines could offer reduced fuel burn compared with podded engines, but the fan stage must be designed to run continuously with severe inlet distortion. This paper aims to explain the fluid dynamics and loss sources in BLI fans running at a cruise condition. High-resolution experimental measurements and full-annulus unsteady CFD have been performed on a low-speed fan rig running with a representative BLI inlet velocity profile. A three-dimensional flow redistribution is observed, leading to an attenuation of the axial velocity non-uniformity upstream of the rotor and to non-uniform swirl and radial angle distributions at rotor inlet. The distorted flow field is shown to create circumferential and radial variations in diffusion factor with a corresponding loss variation around the annulus. Additional loss is generated by an unsteady separation of the casing boundary layer, caused by a localised peak in loading at the rotor tip. Non-uniform swirl and radial angles at rotor exit lead to increased loss in the stator due to the variations in profile loss and corner separation size. An additional CFD calculation of a transonic fan running with the same inlet profile is used to show that BLI leads to wide variations in rotor shock structure, strength and position and hence to loss generation through shock-boundary layer interaction, but otherwise contained the same flow features as the low-speed case. For both fan geometries, BLI was found to reduce the stage efficiency by around 1–2% relative to operation with uniform inlet flow.

Calculation of a Three-Dimensional Turbomachinery Rotor Flow With a Navier-Stokes Code

1987 ◽  
Author(s):  
Matthew J. Warfield ◽  
B. Lakshminarayana
Keyword(s):  
Boundary Layer ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Streamwise Velocity ◽  
Reynolds Stress Model ◽  
Layer Growth ◽  
Navier Stokes ◽  
Laser Doppler Velocimeter ◽  
Eddy Viscosity Model ◽  
Compressor Rotor

This paper deals with a numerical solution of the full Navier-Stokes equations governing the flowfield in a turbomachinery rotor. The incompressible equations are solved using a pseudocompressibility time marching code. A two-equation turbulence model (k-ε) coupled with a vectorial eddy viscosity model based on an Algebraic Reynolds Stress Model is used to account for the anisotropic effects of rotation and three dimensionality. The predictions are compared with laser doppler velocimeter and hot wire data acquired in a compressor rotor passage at two different flow coefficients. The predicted blade to blade profiles of velocity at various radial locations as well as the streamwise velocity profiles in the blade boundary layer show good agreement with experimental data. The radial velocities are qualitatively predicted but good comparison with data was not achieved. Boundary layer growth is predicted reasonably well.

Unsteady Three-Dimensional Analysis of Inlet Distortion in a Transonic Fan

2006 ◽  
Author(s):  
Peng Sun ◽  
Guotal Feng
Keyword(s):  
Shock Wave ◽  
Total Pressure ◽  
Large Scale ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Inlet Distortion ◽  
Flow Loss ◽  
Large Scale Vortex ◽  
Total Temperature ◽  
Transonic Fan

A time-accurate three-dimensional Navier-Stokes solver of the unsteady flow field in a transonic fan was carried out using "Fluent-parallel" in a parallel supercomputer. The numerical simulation focused on a transonic fan with inlet square wave total pressure distortion and the analysis of result consisted of three aspects. The first was about inlet parameters redistribution and outlet total temperature distortion induced by inlet total pressure distortion. The pattern and causation of flow loss caused by pressure distortion in rotor were analyzed secondly. It was found that the influence of distortion was different at different radial positions. In hub area, transportation-loss and mixing-loss were the main loss patterns. Distortion not only complicated them but enhanced them. Especially in stator, inlet total pressure distortion induced large-scale vortex, which produced backflow and increased the loss. While in casing area, distortion changed the format of shock wave and increased the shock loss. Finally, the format of shock wave and the hysteresis of rotor to distortion were analyzed in detail.

Direct simulation of evolution and control of three-dimensional instabilities in attachment-line boundary layers

1995 ◽  
Vol 291 ◽  
pp. 369-392 ◽  
Author(s):  
Ronald D. Joslin
Keyword(s):  
Boundary Layer ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Plate Boundary ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Computationally Efficient ◽  
Simulation Results ◽  
Dimensional Simulation ◽  
Attachment Line

The spatial evolution of three-dimensional disturbances in an attachment-line boundary layer is computed by direct numerical simulation of the unsteady, incompressible Navier–Stokes equations. Disturbances are introduced into the boundary layer by harmonic sources that involve unsteady suction and blowing through the wall. Various harmonic-source generators are implemented on or near the attachment line, and the disturbance evolutions are compared. Previous two-dimensional simulation results and nonparallel theory are compared with the present results. The three-dimensional simulation results for disturbances with quasi-two-dimensional features indicate growth rates of only a few percent larger than pure two-dimensional results; however, the results are close enough to enable the use of the more computationally efficient, two-dimensional approach. However, true three-dimensional disturbances are more likely in practice and are more stable than two-dimensional disturbances. Disturbances generated off (but near) the attachment line spread both away from and toward the attachment line as they evolve. The evolution pattern is comparable to wave packets in flat-plate boundary-layer flows. Suction stabilizes the quasi-two-dimensional attachment-line instabilities, and blowing destabilizes these instabilities; these results qualitatively agree with the theory. Furthermore, suction stabilizes the disturbances that develop off the attachment line. Clearly, disturbances that are generated near the attachment line can supply energy to attachment-line instabilities, but suction can be used to stabilize these instabilities.

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