The Impact of Geometric Variation on Compressor Two-Dimensional Incidence Range

2014 ◽  
Vol 137 (2) ◽  
Author(s):  
Martin N. Goodhand ◽  
Robert J. Miller ◽  
Hang W. Lung
Keyword(s):  
Design Process ◽  
Design Space ◽  
Leading Edge ◽  
Critical Value ◽  
Two Dimensional ◽  
Suction Surface ◽  
Design Intent ◽  
Manufacture Process ◽  
The Impact ◽  
Geometric Variation

An important question for a designer is how, in the design process, to deal with the small geometric variations which result from either the manufacture process or in-service deterioration. For some blade designs geometric variations will have little or no effect on the performance of a row of blades, while in others their effects can be significant. This paper shows that blade designs which are most sensitive are those which are susceptible to a distinct switch in the fluid mechanisms responsible for limiting blade performance. To demonstrate this principle, the sensitivity of compressor 2D incidence range to manufacture variations is considered. Only one switch in mechanisms was observed, the onset of flow separation at the leading edge. This switch is only sensitive to geometric variations around the leading edge, 0–3% of the suction surface. The consequence for these manufacture variations was a 10% reduction in the blade's positive incidence range. For this switch, the boundary in the design space is best defined in terms of the blade pressure distribution. Blade designs where the acceleration exceeds a critical value just downstream of the leading edge are shown to be robust to geometric variation. Two historic designs, supercritical blades and blades with sharp leading edges, though superior in design intent, are shown to sit outside this robust region and thus, in practice, perform worse. The improved understanding of the robust, region of the design space is then used to design a blade capable of a robust, 5% increase in operating incidence range.

scholarly journals Beyond analogy: A model of bioinspiration for creative design

2016 ◽  
Vol 30 (2) ◽  
pp. 159-170 ◽  
Author(s):  
Camila Freitas Salgueiredo ◽  
Armand Hatchuel
Keyword(s):  
Design Process ◽  
Design Theory ◽  
Leading Edge ◽  
Knowledge Bases ◽  
Biologically Inspired ◽  
Concept Knowledge ◽  
Bioinspired Design ◽  
Aerodynamic Properties ◽  
Biologically Inspired Design ◽  
The Impact

AbstractIs biologically inspired design only an analogical transfer from biology to engineering? Actually, nature does not always bring “hands-on” solutions that can be analogically applied in classic engineering. Then, what are the different operations that are involved in the bioinspiration process and what are the conditions allowing this process to produce a bioinspired design? In this paper, we model the whole design process in which bioinspiration is only one element. To build this model, we use a general design theory, concept–knowledge theory, because it allows one to capture analogy as well as all other knowledge changes that lead to the design of a bioinspired solution. We ground this model on well-described examples of biologically inspired designs available in the scientific literature. These examples include Flectofin®, a hingeless flapping mechanism conceived for façade shading, and WhalePower technology, the introduction of bumps on the leading edge of airfoils to improve aerodynamic properties. Our modeling disentangles the analogical aspects of the biologically inspired design process, and highlights the expansions occurring in both knowledge bases, scientific (nonbiological) and biological, as well as the impact of these expansions in the generation of new concepts (concept partitioning). This model also shows that bioinspired design requires a special form of collaboration between engineers and biologists. Contrasting with the classic one-way transfer between biology and engineering that is assumed in the literature, the concept–knowledge framework shows that these collaborations must be “mutually inspirational” because both biological and engineering knowledge expansions are needed to reach a novel solution.

Impact of Cavity on Sunroof Buffeting: A Two Dimensional CFD Study

2004 ◽  
Author(s):  
Chang-Fa An ◽  
Seyed Mehdi Alaie ◽  
Michael S. Scislowicz
Keyword(s):  
Fluid Dynamics ◽  
Wind Tunnel ◽  
Three Dimensional ◽  
Leading Edge ◽  
Two Dimensional ◽  
Deep Insight ◽  
Simulation Results ◽  
Dimensional Simulation ◽  
The Impact ◽  
Insight Into

Driven by fluid dynamics principles, the concept for buffeting reduction, a cavity installed at the leading edge of the sunroof opening, is analyzed. The cavity provides a room to hold the vortex, shed from upstream, and prevents the vortex from escaping and from directly intruding into the cabin. The concept has been verified by means of a two dimensional simulation for a production SUV using the CFD software — FLUENT. The simulation results show that the impact of the cavity is crucial to reduce buffeting. It is shown that the buffeting level may be reduced by 3 dB by adding a cavity to the sunroof configuration. Therefore, the cavity could be considered as a means of buffeting reduction, in addition to the three currently-known concepts: wind deflector, sunroof glass comfort position and cabin venting. Thorough understanding of the buffeting mechanism helps explain why and how the cavity works to reduce buffeting. Investigation of the buffeting-related physics provides a deep insight into the flow nature and, therefore, a useful hint to geometry modification for buffeting reduction. The buffeting level may be further reduced by about 4 dB or more by cutting the corners of the sunroof opening into smooth ramps, guided by ideas coming from careful examining the physics of flow. More work including three dimensional simulation and wind tunnel experiment should follow in order to develop more confidence in the functionality of the cavity to hopefully promote this idea to the level that it can be utilized in a feasible way to address sunroof buffeting.

Three-Dimensional Relief in Turbomachinery Blading

1990 ◽  
Vol 112 (4) ◽  
pp. 587-596 ◽  
Author(s):  
A. R. Wadia ◽  
B. F. Beacher
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Axial Flow ◽  
Leading Edge ◽  
Two Dimensional ◽  
Suction Surface ◽  
Airfoil Surface ◽  
Flow Angle ◽  
Edge Loading ◽  
Cascade Analysis

The leading edge region of turbomachinery blading in the vicinity of the endwalls is typically characterized by an abrupt increase in the inlet flow angle and a reduction in total pressure associated with endwall boundary layer flow. Conventional two-dimensional cascade analysis of the airfoil sections at the endwalls indicates large leading edge loadings, which are apparently detrimental to the performance. However, experimental data exist that suggest that cascade leading edge loading conditions are not nearly as severe as those indicated by a two-dimensional cascade analysis. This discrepancy between two-dimensional cascade analyses and experimental measurements has generally been attributed to inviscid three-dimensional effects. This article reports on two and three-dimensional calculations of the flow within two axial-flow compressor stators operating near their design points. The computational results of the three-dimensional analysis reveal a significant three-dimensional relief near the casing endwall that is absent in the two-dimensional calculations. The calculated inviscid three-dimensional relief at the endwall is substantiated by airfoil surface static pressure measurements on low-speed research compressor blading designed to model the flow in the high-speed compressor. A strong spanwise flow toward the endwall along the leading edge on the suction surface of the airfoil is responsible for the relief in the leading edge loading at the endwall. This radial migration of flow results in a more uniform spanwise loading compared to that predicted by two-dimensional calculations.

The Impact of Real Geometries on Three-Dimensional Separations in Compressors

2011 ◽  
Vol 134 (2) ◽  
Author(s):  
Martin N. Goodhand ◽  
Robert J. Miller
Keyword(s):  
Three Dimensional ◽  
Leading Edge ◽  
Suction Surface ◽  
Blade Loading ◽  
Flow Parameters ◽  
Surface Transition ◽  
Edge Roughness ◽  
Large Growth ◽  
Edge Quality ◽  
The Impact

This paper considers the effect of small variations in leading edge geometry, leading edge roughness, leading edge fillet, and blade fillet geometry on the three-dimensional separations found in compressor blade rows. The detrimental effects of these separations have historically been predicted by correlations based on global flow parameters, such as blade loading, inlet boundary layer skew, etc., and thus ignoring small deviations such as those highlighted above. In this paper it is shown that this may not be the case and that certain, engine representative geometry deviations can have an effect equivalent to an increase in blade loading of 10%. Experiments were performed at the stator hub of a low-speed, single-stage compressor. The results show that any deviation which causes suction surface transition to move to the leading edge over the first 30% of span will cause a large growth in the size of the hub separation, doubling its impact on loss. The geometry deviations that caused this, and are thus of greatest concern to a designer, are changes in leading edge quality and roughness around the leading edge, which are characteristic of an eroded blade.

The Impact of Real Geometries on Three-Dimensional Separations in Compressors

2010 ◽  
Author(s):  
Martin N. Goodhand ◽  
Robert J. Miller
Keyword(s):  
Three Dimensional ◽  
Leading Edge ◽  
Suction Surface ◽  
Blade Loading ◽  
Flow Parameters ◽  
Surface Transition ◽  
Edge Roughness ◽  
Large Growth ◽  
Edge Quality ◽  
The Impact

This paper considers the effect of small variations in leading edge geometry, leading edge roughness, leading edge fillet and blade fillet geometry on the three dimensional separations found in compressor blade rows. The detrimental effects of these separations have historically been predicted by correlations based on global flow parameters, such as blade loading, inlet boundary layer skew etc, and thus ignoring small deviations such as those highlighted above. In this paper it is shown that this may not to be the case and that certain, engine representative geometry deviations can have an effect equivalent to an increase in blade loading of 10%. Experiments were performed at the stator hub of a low-speed, single-stage compressor. The results show that any deviation which causes suction surface transition to move to the leading edge over the first 30% of span will cause a large growth in the size of the hub separation, doubling its impact on loss. The geometry deviations that caused this, and are thus of greatest concern to a designer, are changes in leading edge quality and roughness around the leading edge, characteristic of an eroded blade.

Three-Dimensional Relief in Turbomachinery Blading

1989 ◽  
Author(s):  
A. R. Wadia ◽  
B. F. Beacher
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Axial Flow ◽  
Leading Edge ◽  
Two Dimensional ◽  
Suction Surface ◽  
Airfoil Surface ◽  
Flow Angle ◽  
Edge Loading ◽  
Cascade Analysis

The leading edge region of turbomachinery blading in the vicinity of the endwalls is typically characterized by an abrupt increase in the inlet flow angle and a reduction in total pressure associated with endwall boundary layer flow. Conventional two-dimensional cascade analysis of the airfoil sections at the endwalls indicates large leading edge loadings, apparently detrimental to the performance. However, experimental data exist that suggest that cascade leading edge loading conditions are not nearly as severe as those indicated by a two-dimensional cascade analysis. This discrepancy between two-dimensional cascade analyses and experimental measurements has generally been attributed to inviscid three-dimensional effects. This article reports on two- and three-dimensional calculations of the flow within two axial flow compressor Stators operating near their design points. The computational results of the three-dimensional analysis reveal a significant three-dimensional relief near the casing endwall absent in the two-dimensional calculations. The calculated inviscid three-dimensional relief at the endwall is substantiated by airfoil surface static pressure measurements on low speed research compressor blading designed to model the flow in the high speed compressor. A strong spanwise flow towards the endwall along the leading edge on the suction surface of the airfoil is responsible for the relief in the leading edge loading at the endwall. This radial migration of flow results in a more uniform spanwise loading compared to that predicted by two-dimensional calculations.

The Impact of Manufacturing Variations on Performance of a Transonic Axial Compressor Rotor

2020 ◽  
Vol 142 (8) ◽  
Author(s):  
Marcus Lejon ◽  
Niklas Andersson ◽  
Lars Ellbrant ◽  
Hans Mårtensson
Keyword(s):  
Flow Field ◽  
Geometric Mean ◽  
Pressure Ratio ◽  
Axial Compressor ◽  
Leading Edge ◽  
Mean Deviation ◽  
Design Intent ◽  
Compressor Rotor ◽  
The Mean ◽  
The Impact

Abstract In this paper, the impact of manufacturing variations on performance of an axial compressor rotor is evaluated at design rotational speed. The geometric variations from the design intent obtained from measurements were used to evaluate the impact of manufacturing variations on performance and the flow field in the rotor. The complete blisk is simulated using 3D computational fluid dynamics calculations, allowing for a detailed analysis of the impact of geometric variations on the flow. It is shown that the mean shift of the geometry from the design intent is responsible for the majority of the change in performance in terms of mass flow and total pressure ratio for this specific blisk. In terms of polytropic efficiency, the measured geometric scatter is shown to have a higher influence than the geometric mean deviation. The geometric scatter around the mean is shown to impact the pressure along the leading edge and the shock position. Furthermore, a blisk is analyzed with one blade deviating substantially from the design intent. It is shown that the impact of this blade on the flow is largely limited to the blade passages that it is directly a part of. It is also shown that the impact of this blade on the flow field can be represented by a simulation including three blade passages. In terms of loss, using five blade passages is shown to give a close estimate for the relative change in loss for the blade deviating substantially from the design intent and for the neighboring blades.

Introduction of a Novel Parameter Model to Analyze the Geometric Variation of Airfoil Edges of Ex-In-Service Compressor Airfoils

2020 ◽  
Author(s):  
Paul Voigt ◽  
Matthias Voigt ◽  
Ronald Mailach ◽  
Kimon Abu-Taa ◽  
Mirco Rostamian
Keyword(s):  
Relevant Literature ◽  
Quantitative Description ◽  
Leading Edge ◽  
Parametric Model ◽  
Scanning System ◽  
Design Intent ◽  
Operational Conditions ◽  
Shape Characteristics ◽  
Future Work ◽  
Geometric Variation

Abstract The leading and trailing edge shapes of high pressure compressor (HPC) airfoils have a high impact on their aerodynamic performance. Typically, the shape of these airfoil edges are designed symmetrically as half circles or half ellipses. Due to manufacturing scatter and operational effects, the edges of real HPC airfoils deviate from the design intent. Especially the change in shape of the airfoil edges due to erosion can lead to a reduction of the aerodynamic efficiency and operability range. This paper introduces a novel and intuitive parametrization approach to describe the occurring airfoil edge shapes. The introduced parametric model has been applied to a set of postservice airfoils with a variety of airfoil edge shapes. For this purpose, just above 1000 of used HPC airfoils from different engines with different operational conditions and runtimes were digitized by means of a structured light 3D scanner. The high precision of the scanning system enables accurate capturing of the sensitive airfoil edge shapes. Subsequently, the extracted parameters were used for a statistical evaluation of the leading edge (LE) shape geometry. It turned out that the LEs of the investigated post-service compressor airfoils exhibit a thinner LE shape characteristics compared to the design intent LE shape. Furthermore, in nearly all cases, more material is missing on the suction sided LE of the investigated airfoils. This result is rather contrary compared to the findings of relevant literature, where the LE pressure side is missing more material due to erosion. Nevertheless, the generated results suggest that the developed method is suitable for a sufficient qualitative and quantitative description of HPC LE shapes. In future work, the introduced parametric model can be used as the basis of a prospective evaluation of the correlation between the geometric variation of airfoil edges and manufacturing scatter as well as engine operational condition.

Students As Sequential Decision-Makers: Quantifying the Impact of Problem Knowledge and Process Deviation on the Achievement of Their Design Problem Objective

2018 ◽  
Author(s):  
Murtuza Shergadwala ◽  
Ilias Bilionis ◽  
Jitesh H. Panchal
Keyword(s):  
Decision Making ◽  
Design Process ◽  
Design Problem ◽  
Design Space ◽  
Research Question ◽  
Decision Makers ◽  
Sequential Decision ◽  
Sequential Decisions ◽  
Decision Making Model ◽  
The Impact

Factors such as a student’s knowledge of the design problem and their deviation from a design process impact the achievement of their design problem objective. Typically, an instructor provides students with qualitative assessments of such factors. To provide accurate assessments, there is a need to quantify the impact of such factors in a design process. Moreover, design processes are iterative in nature. Therefore, the research question addressed in this study is, How can we quantify the impact of a student’s problem knowledge and their deviation from a design process, on the achievement of their design problem objective, in successive design iterations? We illustrate an approach in the context of a decision-making scenario. In the scenario, a student makes sequential decisions to optimize a mathematically unknown design objective with given constraints. Consequently, we utilize a decision-making model to abstract their design process. Their problem knowledge is quantified as their belief about the feasibility of the design space via a probability distribution. Their deviation from the decision-making model is quantified by introducing uncertainty in the model. We simulate cases where they have a combination of high (or low) knowledge of the design problem and high (or low) deviation in their design process. The results of our simulation study indicate that if students have a high (low) deviation from the modeled design process then we cannot (can) infer their knowledge of the design problem based on their problem objective achievement.

The impact of design space constraints on the noise and emissions from derivative engines for civil supersonic aircraft

2021 ◽  
Author(s):  
Laurens Voet ◽  
Prakash Prashanth ◽  
Raymond Speth ◽  
Jayant Sabnis ◽  
Choon Tan ◽  
...  
Keyword(s):  
Design Space ◽  
Supersonic Aircraft ◽  
The Impact
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