A Study of Fan-Distortion Interaction Within the NASA Rotor 67 Transonic Stage

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
V. Jerez Fidalgo ◽  
C. A. Hall ◽  
Y. Colin
Keyword(s):  
Total Pressure ◽  
Three Dimensional ◽  
Measurement Data ◽  
Test Case ◽  
Complex Flow ◽  
Inlet Flow ◽  
Flow Features ◽  
Work Input ◽  
Flow Effects ◽  
Transonic Fan

The performance of a transonic fan operating within nonuniform inlet flow remains a key concern for the design and operability of a turbofan engine. This paper applies computational methods to improve the understanding of the interaction between a transonic fan and an inlet total pressure distortion. The test case studied is the NASA rotor 67 stage operating with a total pressure distortion covering a 120-deg sector of the inlet flow field. Full-annulus, unsteady, three-dimensional CFD has been used to simulate the test rig installation and the full fan assembly operating with inlet distortion. Novel post-processing methods have been applied to extract the fan performance and features of the interaction between the fan and the nonuniform inflow. The results of the unsteady computations agree well with the measurement data. The local operating condition of the fan at different positions around the annulus has been tracked and analyzed, and this is shown to be highly dependent on the swirl and mass flow redistribution that the rotor induces ahead of it due to the incoming distortion. The upstream flow effects lead to a variation in work input that determines the distortion pattern seen downstream of the fan stage. In addition, the unsteady computations also reveal more complex flow features downstream of the fan stage, which arise due to the three dimensionality of the flow and unsteadiness.

A Study of Fan-Distortion Interaction Within the NASA Rotor 67 Transonic Stage

2010 ◽  
Author(s):  
V. Jerez Fidalgo ◽  
C. A. Hall ◽  
Y. Colin
Keyword(s):  
Total Pressure ◽  
Three Dimensional ◽  
Measurement Data ◽  
Test Case ◽  
Complex Flow ◽  
Inlet Flow ◽  
Flow Features ◽  
Work Input ◽  
Flow Effects ◽  
Transonic Fan

The performance of a transonic fan operating within non-uniform inlet flow remains a key concern for the design and operability of a turbofan engine. This paper applies computational methods to improve the understanding of the interaction between a transonic fan and an inlet total pressure distortion. The test case studied is the NASA rotor 67 stage operating with a total pressure distortion covering a 120-degree sector of the inlet flow-field. Full-annulus, unsteady, three-dimensional CFD has been used to simulate the test rig installation and the full fan assembly operating with inlet distortion. Novel post-processing methods have been applied to extract the fan performance and features of the interaction between the fan and the non-uniform inflow. The results of the unsteady computations agree well with the measurement data. The local operating condition of the fan at different positions around the annulus has been tracked and analysed, and this is shown to be highly dependent on the swirl and mass flow redistribution that the rotor induces ahead of it due to the incoming distortion. The upstream flow effects lead to a variation in work input that determines the distortion pattern seen downstream of the fan stage. In addition, the unsteady computations also reveal more complex flow-features downstream of the fan stage, which arise due to the three-dimensionality of the flow and unsteadiness.

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.

scholarly journals Cold Flow Computations for the Diffuser-Combustor Section of an Industrial Gas Turbine

1996 ◽  
Author(s):  
Dadong Zhou ◽  
Ting Wang ◽  
William R. Ryan
Keyword(s):  
Gas Turbine ◽  
Total Pressure ◽  
Reverse Flow ◽  
Three Dimensional ◽  
Complex Flow ◽  
Pressure Losses ◽  
Structured Grid ◽  
Computational Fluid Dynamics Cfd ◽  
Enhance Efficiency ◽  
Industrial Gas Turbine

In the first part of a multipart project to analyze and optimize the complex three-dimensional diffuser-combustor section of a highly advanced industrial gas turbine under development, a computational fluid dynamics (CFD) analysts has been conducted. The commercial FEA code I-DEAS was used to complete the three-dimensional solid modeling and the structured grid generation. The flow calculation was conducted using the commercial CFD code PHOENICS. The multiblock method was employed to enhance computational capabilities. The mechanisms of the total pressure losses and possible ways to enhance efficiency by reducing the total pressure losses were examined. Mechanisms that contribute to the nonuniform velocity distribution of flow entering the combustor were also identified. The CFD results were informative and provided insight to the complex flow patterns in the reverse flow dump diffuser, however, the results are qualitative and are useful primarily as guidelines for optimization as opposed to firm design configuration selections.

A Geometry Generation Framework for Contoured Endwalls

2019 ◽  
Author(s):  
L. E. Wood ◽  
R. R. Jones ◽  
O. J. Pountney ◽  
J. A. Scobie ◽  
D. A. S. Rees ◽  
...  
Keyword(s):  
Secondary Flow ◽  
Three Dimensional ◽  
Aerodynamic Loss ◽  
Construction Methods ◽  
Novel Approach ◽  
Wide Range ◽  
Blade Row ◽  
Flow Features ◽  
Flow Effects ◽  
Geometric Variation

Abstract The mainstream, or primary, flow in a gas turbine annulus is characteristically two-dimensional over the mid-span region of the blading, where the radial flow is almost negligible. Contrastingly, the flow in the endwall and tip regions of the blading is highly three-dimensional, characterised by boundary layer effects, secondary flow features and interaction with cooling flows. Engine designers employ geometric contouring of the endwall region in order to reduce secondary flow effects and subsequently minimise their contribution to aerodynamic loss. Such is the geometric variation of vane and blade profiles — which has become a proprietary art form — the specification of an effective endwall geometry is equally unique to each blade-row. Endwall design methods, which are often directly coupled to aerodynamic optimisers, are widely developed to assist with the generation of contoured surfaces. Most of these construction methods are limited to the blade-row under investigation, while few demonstrate the controllability required to offer a universal platform for endwall design. This paper presents a Geometry Generation Framework (GGF) for the generation of contoured endwalls. The framework employs an adaptable meshing strategy, capable of being applied to any vane or blade, and a versatile function-based approach to defining the endwall shape. The flexibility of this novel approach is demonstrated by recreating a selection of endwalls from the literature, which were selected for their wide-range of contouring approaches.

Flow Field Analysis of Inlet Distortion in a Transonic Fan With Straight and Bowed Stator Blade

2007 ◽  
Author(s):  
Peng Sun ◽  
Jingjun Zhong ◽  
Guotai Feng
Keyword(s):  
Flow Field ◽  
Total Pressure ◽  
Three Dimensional ◽  
Field Analysis ◽  
Navier Stokes ◽  
Fan Performance ◽  
Inlet Distortion ◽  
Flow Loss ◽  
Stator Blade ◽  
Transonic Fan

The performance and stability of a fan in clean and distorted inlet flow can be improved through the use of bowed stator blades. Measurements between the blade rows in transonic and supersonic flow are too complex to provide any useful insights, so 3D flow simulations are required. In this paper, a time-accurate three-dimensional Navier-Stokes solver of the unsteady flow field in a transonic fan is carried out using “Fluent-parallel” in a parallel supercomputer. Two sets of simulations are performed. The first simulation focuses on a better understanding of inlet total pressure distortion effects on a transonic fan. The second set of numerical simulation aims at studying the improvements of fan performance made by bowed stator blades. Three aspects are contained in this paper. The first is about the distortion effects on characteristics of the fan stage with straight stator. The effects of bowed stator on fan performance with inlet distortion are demonstrated secondly. One hand bowed stator increases the loss in rotor. On the other hand, it reduces the flow loss in stator. Finally, the patterns of flow loss caused by total pressure distortion with straight/bowed stator are compared. The scale of vortex in stator induced by inlet total pressure distortion is weakened by bowed blades, which decreases the stator loss.

CFD Analysis of Engines: An Advanced Approach Based on Codes Dynamically Coupled

2003 ◽  
Author(s):  
Angelo De Vita ◽  
Luca Di Angelo ◽  
Luca Andreassi
Keyword(s):  
Data Exchange ◽  
Internal Combustion Engines ◽  
Gas Flow ◽  
Three Dimensional ◽  
Test Case ◽  
3D Effects ◽  
Flow Effects ◽  
Race Cars ◽  
Direct Feedback ◽  
Physical Phenomena

An advanced approach to evaluate the gas flow in internal combustion engines has been carried out. It is based on an interactive procedure which dynamically couples one-dimensional (1D) and three dimensional (3D) computational fluid dynamics codes. Direct feedback between the codes has been assured allowing 3D fluid flow effects to be fed back into the 1D system. A cycle-by-cycle convergence of results in the data exchange sections has been guaranteed. The capability of describing physical phenomena increases and some numerical problems, as the reflection of pressure waves on the 3D grid boundaries, can be avoided. The procedure has been applied to a simple test case and to a typical engine application where 3D effects are not negligible: flow field definition within an air box for race cars. The procedure has proven effective and could be easily adapted for further different applications.

Three-Dimensional Flow Calculations of the Stator in a Highly Loaded Transonic Fan

1998 ◽  
Vol 120 (1) ◽  
pp. 141-146 ◽  
Author(s):  
P. R. Emmerson
Keyword(s):  
Three Dimensional ◽  
Flow Visualisation ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Efficiency Condition ◽  
Flow Effects ◽  
High Level ◽  
Transonic Fan ◽  
Very High ◽  
Highly Loaded

A three-dimensional viscous solver has been used to model the flow in the stator of a highly loaded single-stage transonic fan. The fan has a very high level of aerodynamic loading at the hub, which results in a severe hub endwall stall. Prediction of the flow at the 100 percent speed, peak efficiency condition has been carried out and comparisons are made with experiment, including stator exit traverses and fixed blade surface pressure tappings and flow visualisation. Comparisons are also made with an analysis of the rotor and stator rows using the DERA S1–S2 method. The three-dimensional predictions show good qualitative agreement with measurements in all regions of the flow field. Quantitatively the flow away from the hub region agreed the best. The general trends of the severe hub endwall stall were predicted, although the shape and size did not match experiment exactly. The S1–S2 system was unable to predict the hub endwall stall, since it arises from fully three-dimensional flow effects.

scholarly journals Static Analysis of Unsteady Aerodynamics Wake of Simplified Helicopter Model Via Simulation Work

2021 ◽  
Vol 89 (1) ◽  
pp. 142-153
Author(s):  
Nurain Othman ◽  
Iskandar Shah Ishak ◽  
Md. Nizam Dahalan
Keyword(s):  
Total Pressure ◽  
Research Work ◽  
Three Dimensional ◽  
Unsteady Aerodynamics ◽  
Simplified Model ◽  
Computational Domain ◽  
Complex Flow ◽  
Computational Tools ◽  
Model Helicopter ◽  
Interaction Phenomena

Computational tools have led and helped researchers in providing advanced results, notably in rotorcraft research, as flow around the helicopter is dominated by complex aerodynamics and flow interaction phenomena. This research work aimed to evaluate the aerodynamic computational results on a simplified model helicopter when the model was subjected to the angles of attack 0°, -5°, -15°, and -20°, respectively. The study also examined the unsteady flow behaviour on the three-dimensional elliptical shape of a fuselage equipped with a rotor hub of the single rotor blade. The computational domain for the aerodynamic flow field was created within the size of 7 m (length) x 5 m (width) x 5 m (height). Results showed that an increase in the angle of attack in the rotor component caused additional drag of about 34% to 45% whilst the fuselage component contributed about 55% to 65% to drag increment. Also, a significant value of total pressure from -235 Pa to 250 Pa demonstrated along the simplified model helicopter distinctly showed that the complexity of geometry caused adverse pressure. The findings of this research work could potentially improve the understanding of complex flow surrounding the helicopter that has always baffled the aerodynamicists.

Experimental Investigation of the Aerothermal Performance of a High Blockage Rib-Roughened Cooling Channel

2005 ◽  
Vol 127 (3) ◽  
pp. 580-588 ◽  
Author(s):  
Luca Casarsa ◽  
Tony Arts
Keyword(s):  
Heat Transfer ◽  
Experimental Investigation ◽  
Flow Field ◽  
Three Dimensional ◽  
Heat Transfer Process ◽  
Cooling Channel ◽  
Complex Flow ◽  
Turbine Blade Cooling ◽  
Flow Features ◽  
Rib Roughened

The present study deals with a detailed experimental investigation of the turbulent flow inside a rib-roughened turbine blade cooling channel. The measurements are carried out in a stationary straight channel with high blockage ribs installed on one wall. The main objective is to enhance the understanding and deepen the analysis of this complex flow field with the help of highly resolved particle image velocimetry measurements. A quasi-three-dimensional view of the flow field is achieved, allowing the identification of the main time-averaged coherent structures. The combined analysis of the present aerodynamic results with available heat transfer data emphasizes the role of the mean and fluctuating flow features in the heat transfer process. In particular, the stream wise/normal to the wall component of the Reynolds stress tensor is shown to be strictly related to the heat transfer rate on the channel surfaces. A correlation to estimate the heat transfer field from the aerodynamic data is presented for the high blockage rib roughened channel flow.

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