The Investigation of Turbine and Exhaust Interactions in Asymmetric Flows: Part 1 — Blade-Row Models Applied

2002 ◽  
Author(s):  
J. J. Liu ◽  
T. P. Hynes
Keyword(s):  
Exhaust System ◽  
Numerical Approach ◽  
Flow Properties ◽  
Asymmetric Flow ◽  
Field Coupling ◽  
Disc Model ◽  
Blade Row ◽  
Actuator Disc ◽  
Sample Application ◽  
Asymmetric Flows

Part 1 of this paper describes the blade-row models applied to the asymmetric flow field coupling between turbine and exhaust system. Numerical actuator is applied to represent a turbine blade row around whole annulus and flow properties across the disc can jump to achieve required flow turning and entropy rise. The derivation of disc boundary conditions and the implementation in CFD solvers are described in detail. Validation of the actuator disc model and sample application of the present numerical approach are presented.

The Investigation of Turbine and Exhaust Interactions in Asymmetric Flows— Blade-Row Models Applied

2003 ◽  
Vol 125 (1) ◽  
pp. 121-127 ◽  
Author(s):  
J. J. Liu ◽  
T. P. Hynes
Keyword(s):  
Exhaust System ◽  
Numerical Approach ◽  
Flow Properties ◽  
Asymmetric Flow ◽  
Disk Model ◽  
Field Coupling ◽  
Actuator Disk ◽  
Blade Row ◽  
Sample Application ◽  
Asymmetric Flows

This paper describes the blade-row models applied to the asymmetric flow-field coupling between turbine and exhaust system. Numerical actuator disk is applied to represent a turbine blade row around the whole annulus and flow properties across the disk can jump to achieve required flow turning and entropy rise. The derivation of disk boundary conditions and the implementation in CFD solvers are described in detail. Validation of the actuator disk model and sample application of the present numerical approach are presented.

The Investigation of Turbine and Exhaust Interactions in Asymmetric Flows: Part 2 — Turbine-Diffuser-Collector Interactions

2002 ◽  
Author(s):  
J. J. Liu ◽  
T. P. Hynes
Keyword(s):  
Numerical Simulations ◽  
Steam Turbine ◽  
Flow Model ◽  
Model Analysis ◽  
Navier Stokes ◽  
Exhaust Hood ◽  
Disc Model ◽  
Actuator Disc ◽  
Asymmetric Flows ◽  
Exhaust Systems

Part 2 of this paper describes the investigation of steam turbine and exhaust hood interactions in asymmetric flows by using a multiblock multigrid 3D Navier–Stokes solver incorporating an actuator disc model. The interactions among the turbine, diffuser and collector are analyzed by using a flow model. Numerical simulations for two exhaust hoods are performed to understand the flow details and to verify the flow model analysis. Based on the understanding of turbine and exhaust interactions, suggestions for the design of efficient exhaust systems are given.

Trapped acoustic modes in aeroengine intakes with swirling flow

2000 ◽  
Vol 419 ◽  
pp. 151-175 ◽  
Author(s):  
A. J. COOPER ◽  
N. PEAKE
Keyword(s):  
Swirling Flow ◽  
Aircraft Engine ◽  
Acoustic Resonance ◽  
Axial Fan ◽  
System Parameters ◽  
Acoustic Modes ◽  
Resonant States ◽  
Blade Row ◽  
Actuator Disc ◽  
Axial Variation

A theoretical model of an aeroengine intake–fan system is developed in order to show the existence of acoustic resonance in the intake. In general this phenomenon can be linked to instabilities in aircraft engine inlets.The model incorporates a slowly varying duct intake and accounts for the swirling flow downstream of the fan. The slow axial variation in cross-section gives rise to turning points where upstream-propagating acoustic modes are totally reflected into downstream-propagating modes. The effect of the swirling flow downstream can be to cut off a mode which is cut on upstream of the fan. It is shown that these two aspects of the flow, coupled with the effects of the fan (represented by an actuator disc), can lead to acoustic modes becoming trapped in the intake, thus giving rise to pure acoustic resonance.A whole range of system parameters, such as axial, fan and swirl Mach numbers, which satisfy the conditions for resonance are identified. The effects of a stationary blade row behind the fan are also considered leading to a second family of resonant states. In addition we find resonance due to reflection of acoustic modes at the open (inlet) end of the duct.

scholarly journals An accurate semi-numerical approach for multilayer metasurfaces with near-field coupling

2021 ◽  
Author(s):  
xi Gao ◽  
Xiongbin Wu ◽  
Kexin Li ◽  
Jin-hui Shi ◽  
Guofu Wang ◽  
...  
Keyword(s):  
Near Field ◽  
Numerical Approach ◽  
Field Coupling

A Model for Dynamic Loss Response in Axial-Flow Compressors

1981 ◽  
Author(s):  
M. R. Sexton ◽  
W. F. O’Brien
Keyword(s):  
Response Function ◽  
Fourier Transforms ◽  
Axial Flow ◽  
Rotating Stall ◽  
Mathematical Representation ◽  
Physical Mechanisms ◽  
Compressor Rotor ◽  
Disc Model ◽  
Actuator Disc ◽  
Dynamic Loss

An experimentally-determined dynamic loss response function was developed and incorporated in a model to predict the rotating stall behavior of an experimental compressor. The loss response model was developed employing Fourier transforms. The basis of the compressor model is a mathematical representation of the flow fields upstream and downstream of the compressor rotor. The compressor rotor is represented in the model by a semi-actuator disc. The results of the investigation show that the physical mechanisms which control the onset and propagation velocity of rotating stall in a single-stage compressor can be modeled with the use of the loss response function in a semi-actuator disc model of the compressor. The function represents the dynamic loss characteristics of the compressor rotor row, and provides important advantages over previous techniques.

scholarly journals Comparative study on the wake description using actuator disc model with increasing level of complexity

2019 ◽  
Vol 1256 ◽  
pp. 012017 ◽  
Author(s):  
Gonzalo P. Navarro Diaz ◽  
A. Celeste Saulo ◽  
Alejandro D. Otero
Keyword(s):  
Comparative Study ◽  
Disc Model ◽  
Actuator Disc

Towards Improved Throughflow Capability: The Use of 3D Viscous Flow Solvers in a Multistage Environment

1990 ◽  
Author(s):  
W. N. Dawes
Keyword(s):  
Experimental Evidence ◽  
Steam Turbine ◽  
Guide Vane ◽  
Navier Stokes ◽  
Flow Properties ◽  
Transonic Compressor ◽  
Compressor Rotor ◽  
Blade Row ◽  
Nozzle Guide Vane ◽  
Nozzle Guide

A methodology is presented for simulating turbomachinery blade rows in a multistage environment by deploying a standard 3D Navier-Stokes solver simultaneously on a number of blade rows. The principle assumptions are that the flow is steady relative to each blade row individually and that the rows can communicate via inter-row mixing planes. These mixing planes introduce circumferential averaging of flow properties but preserve quite general radial variations. Additionally, each blade can be simulated in 3D or axisymmetrically (in the spirit of throughflow analysis) and a series of axisymmetric rows can be considered together with one 3D row to provide, cheaply, a machine environment for that row. Two applications are presented: a transonic compressor rotor and a steam turbine nozzle guide vane simulated both isolated and as part of a stage. In both cases the behaviour of the blade considered in isolation was different to when considered as part of a stage and in both cases was in much closer agreement with the experimental evidence.

The Simulation of Turbomachinery Blade Rows in Asymmetric Flow Using Actuator Disks

1997 ◽  
Vol 119 (4) ◽  
pp. 723-732 ◽  
Author(s):  
W. G. Joo ◽  
T. P. Hynes
Keyword(s):  
Supersonic Flow ◽  
Flow Field ◽  
Boundary Conditions ◽  
High Speed ◽  
Axial Position ◽  
Numerical Implementation ◽  
Asymmetric Flow ◽  
Actuator Disk ◽  
Blade Row ◽  
Flow Through

This paper describes the development of actuator disk models to simulate the asymmetric flow through high-speed low hub-to-tip ratio blade rows. The actuator disks represent boundaries between regions of the flow in which the flow field is solved by numerical computation. The appropriate boundary conditions and their numerical implementation are described, and particular attention is paid to the problem of simulating the effect of blade row blockage near choking conditions. Guidelines on choice of axial position of the disk are reported. In addition, semi-actuator disk models are briefly described and the limitations in the application of the model to supersonic flow are discussed.

Numerical Simulation of Asymmetric Exhaust Flows Using an Actuator Disc Blade Row Model

2002 ◽  
Author(s):  
Jianjun Liu
Keyword(s):  
Numerical Simulation ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Solution Procedure ◽  
Navier Stokes ◽  
Exhaust Hood ◽  
Navier Stokes Equations ◽  
Multigrid Algorithm ◽  
Blade Row ◽  
Actuator Disc

This paper describes the numerical simulation of the asymmetric exhaust flows by using a 3D viscous flow solver incorporating an actuator disc blade row model. The three dimensional Reynolds-Averaged Navier-Stokes equations are solved by using the TVD Lax-Wendroff scheme. The convergence to a steady state is speeded up by using the V-cycle multigrid algorithm. Turbulence eddy viscosity is estimated by the Baldwin-Lomax model. Multiblock method is applied to cope with the complicated physical domains. Actuator disc model is used to represent a turbine blade row and to achieve the required flow turning and entropy rise across the blade row. The solution procedure and the actuator disc boundary conditions are described. The stream traces in various sections of the exhaust hood are presented to demonstrate the complicity of the flow patterns existing in the exhaust hood.

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