Numerical Simulation of the Effects of Manufacturing Deviations in Compressor Wheel Geometry on Performance

2019 ◽  
Author(s):  
Dhinagaran Ramachandran ◽  
Balamurugan Mayandi ◽  
Subramani Dasappagoundenpudur Arthanarisamy ◽  
Vanamurthy Murugan ◽  
Saravanan Boolingam ◽  
...  
Keyword(s):  
Axial Length ◽  
Thickness Distribution ◽  
Pressure Ratio ◽  
Angle Distribution ◽  
Performance Impact ◽  
Compressor Wheel ◽  
Systematic Analysis ◽  
Blade Thickness ◽  
Real Geometry ◽  
The Impact

Abstract Increasingly stringent emission norms place tougher challenges on the efficiencies of a turbocharger. Higher efficiency requirement on turbocharger translates into tighter tolerances on the various geometrical dimensions. While this is applicable for all the components, in this study, the focus is on the compressor wheel. Compressor wheels are either cast or milled and variations are possible in either of the processes. Even small changes in the dimensions of compressor wheel (like diameter, angle distribution, thickness distribution, axial length and blade width etc.), cause the performance losses in Turbo charger. Loss in Performance of turbocharger affects Low-end torque, power rating, fuel economy as well as increasing compressor exit temperature. It is therefore important to understand and quantify the impact of the variation in blade geometry on pressure ratio, choke flow and efficiency. In this paper, a few case studies of manufacturing variations in blade thickness, blade height and axial length are shown based on gas stand tests as well as 3D CFD simulations. A process for extracting real geometry from white light scan data obtained from the manufactured wheel is shown which helps to compare the differences with the design intent geometry. Flow simulations with the real geometry show the impact on performance. Subsequently a systematic analysis of the variations is carried out to quantify the performance impact.

Optimization and Investigation on the Impact of Centrifugal Impeller Blade Thickness Distribution on Hydro-Induced Vibration

2018 ◽  
Author(s):  
B. Qian ◽  
D. Z. Wu
Keyword(s):  
Secondary Flow ◽  
Thickness Distribution ◽  
Suction Side ◽  
Centrifugal Impeller ◽  
Impeller Blade ◽  
Streamwise Location ◽  
Unbalanced Rotor ◽  
Blade Thickness ◽  
Vibration Performance ◽  
The Impact

The vibration performance of centrifugal impellers is of great importance for pumps in some application areas such as automobiles and ships. Apart from mechanical excitations for instance, unbalanced rotor and misalignment, attentions should be concentrated on the hydraulic excitations. The complex internal secondary flow in the centrifugal impeller brings degradation on both hydraulic and vibration performances. On the purpose of repressing the internal secondary flow and alleviating vibration, an attempt of optimization by controlling the thickness distribution of centrifugal impeller blade is given. The vibration performances of the impellers are investigated numerically and experimentally. Meanwhile, further study on the mechanism of the influence of the thickness distribution optimization on vibration is conducted. There is a relative velocity gradient from suction side (SS) to pressure side (PS) due to the Coriolis force, which causes non-uniformity of energy distribution. By means of thickness distribution optimization, the impeller blade angle on the PS and SS along the blade-aligned (BA) streamwise location is respectively modified and therefore the flow field can be improved.

Redesigning Annular Turbine Blade Rows Using a Viscous-Inviscid Inverse Design Method

2008 ◽  
Author(s):  
J. C. Pa´scoa ◽  
A. C. Mendes ◽  
L. M. C. Gato
Keyword(s):  
Turbine Blade ◽  
Design Method ◽  
Thickness Distribution ◽  
Tangential Velocity ◽  
Inverse Design ◽  
Angle Distribution ◽  
Flow Angle ◽  
Design Algorithm ◽  
Blade Thickness ◽  
Inverse Design Method

This paper presents the results of the aerodynamic redesign of an annular turbine blade row. The inverse method herein applied is an extension to 3D of an iterative inverse design method based on the imposition of the blade load, thickness distribution and stacking line. We define a mass-averaged mean tangential velocity over one blade pitch, ru¯θ, as the main design variable, since its derivative is related to the aerodynamic load. A time-lagged formulation for the 3D camber surface generator is given in order to include the blade thickness distribution into the design algorithm. The hybrid viscous-inviscid design code comprises three main components: the blade update algorithm; a fast inviscid 3D Euler code; and a viscous analysis code. The blade geometry and flow conditions are typical of LP turbine nozzle guide vanes. The design method will demonstrate its ability to redesign blade rows that achieve lower flow losses and a more uniform exit flow angle distribution. The performance of the new blades is checked by means of a Navier-Stokes computation using the κ–ε turbulence model. The presented results show a minor decrease in the losses and a better redistribution of the exit flow angle.

Exile, Diaspora, and Return

2017 ◽  
Author(s):  
Luis Roniger ◽  
Leonardo Senkman ◽  
Saúl Sosnowski ◽  
Mario Sznajder
Keyword(s):  
Systematic Analysis ◽  
The Arts ◽  
Scientific Disciplines ◽  
Early Twenty ◽  
Transnational Connections ◽  
Late Twentieth ◽  
Institutional Impact ◽  
Global Arena ◽  
Education Science ◽  
The Impact

This book explores how Argentina, Chile, Paraguay, and Uruguay have been affected by postexilic relocations, transnational migrant displacements, and diasporas. It provides a systematic analysis of the formation of exile communities and diaspora politics, the politics of return, and the agenda of democratization in the late twentieth and early twenty-first centuries, focusing on the impact of intellectuals, academics, activists, and public figures who had experienced exile on the reconstitution and transformation of their societies following democratization. Readers are offered a kaleidoscope of intellectual itineraries, debates, and contributions held in the public domain by individuals who confronted and fought authoritarian rule. The book covers their contributions to the restructuring and transformation of scientific disciplines and of the humanities and the arts, as well as their collective institutional impact on higher education, science and technology, and public institutions. Bringing together sociopolitical, cultural, and policy analysis with the testimonies of dozens of intellectuals, academics, political activists, and policymakers, the book addresses the impact of exile on people’s lives and on their fractured experiences, the debates and prospects of return, the challenges of dis-exile and postexilic trends, and, finally, the ways in which those who experienced exile impacted democratized institutions, public culture, and discourse. It also follows some crucial shifts in the frontiers of citizenship, moving analysis to transnational connections and permanent diasporas, including the diasporas of knowledge that increasingly changed the very meaning of being national and transnational, while connecting those countries to the global arena.

scholarly journals University students’ representations of Europe and self-identification as Europeans: a synthesis of qualitative evidence for future policy formulation

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Esther Cores-Bilbao ◽  
María del Carmen Méndez-García ◽  
M. Carmen Fonseca-Mora
Keyword(s):  
University Students ◽  
Evidence Synthesis ◽  
Foreign Language Learning ◽  
Educational Interventions ◽  
Policy Formulation ◽  
Qualitative Evidence Synthesis ◽  
The European Union ◽  
Systematic Analysis ◽  
Qualitative Evidence ◽  
The Impact

AbstractThe current European context is characterised by the emergence of socio-political tensions that threaten to derail the cohesion objectives traditionally promoted by the authorities of the European Union. With EU citizenship in the shadow of Brexit, the fear of dismemberment of the current Europe of the 28 looms over a renewed debate on concepts like European identity, European citizenship or EU legitimacy and the involvement of its constituents in European affairs, as well as the role of education for promoting democratic awareness among young Europeans. This work aims to collect, appraise and synthesise qualitative evidence obtained in primary research exploring the perceptions of European university students about their civic and cultural identity. This systematic analysis sets out to identify predictors of positive self-identification with the EU and its institutions, focusing on the impact that different educational interventions have had on the attitudes and perceptions expressed by university students, and the importance of foreign language learning in the results obtained. The authors report their assessment of quality of the findings in a Cochrane-style qualitative evidence synthesis (QES), based on the GRADE-CERQual (Confidence in Evidence from Reviews of Qualitative research) method. The 12 informed findings described in this study support decision-making in future education policy formulation.

Altitude Effects on the Performance of Small Radial Turbomachinery: Part I — Compressor Impellers

2016 ◽  
Author(s):  
Dries Verstraete ◽  
Kjersti Lunnan
Keyword(s):  
Reynolds Number ◽  
Performance Analysis ◽  
Rotational Speed ◽  
Pressure Ratio ◽  
Unmanned Aircraft ◽  
Good Match ◽  
One Dimensional ◽  
Design Changes ◽  
Current Article ◽  
The Impact

Small unmanned aircraft are currently limited to flight ceilings below 20,000 ft due to the lack of an appropriate propulsion system. One of the most critical technological hurdles for an increased flight ceiling of small platforms is the impact of reduced Reynolds number conditions at altitude on the performance of small radial turbomachinery. The current article investigates the influence of Reynolds number on the efficiency and pressure ratio of two small centrifugal compressor impellers using a one-dimensional meanline performance analysis code. The results show that the efficiency and pressure ratio of the 60 mm baseline compressor at the design rotational speed drops with 6–9% from sea-level to 70,000 ft. The impact on the smaller 20 mm compressor is slightly more pronounced and amounts to 6–10%. Off-design changes at low rotational speeds are significantly higher and can amount to up to 15%. Whereas existing correlations show a good match for the efficiency drop at the design rotational speed, they fail to predict efficiency changes with rotational speed. A modified version is therefore proposed.

Abstract P163: Global and Regional Consumption of Specific Dietary Fats and Dietary Cholesterol in 1990 and 2005: Systematic Analysis of Country-Specific Nutrition Surveys Worldwide

Circulation ◽  
2012 ◽  
Vol 125 (suppl_10) ◽  
Author(s):  
Renata Micha ◽  
Shahab Khatibzadeh ◽  
Edward Giovannucci ◽  
John Powles ◽  
Peilin Shi ◽  
...  
Keyword(s):  
Chronic Diseases ◽  
Dietary Habits ◽  
Dietary Cholesterol ◽  
Assessment Method ◽  
Dietary Fats ◽  
Systematic Analysis ◽  
Diet Surveys ◽  
Nationally Representative ◽  
The Impact ◽  
Age And Sex

Background. Assessing the impact of diet on chronic diseases worldwide has been limited by availability only of food disappearance data rather than reliable and systematically assessed consumption data on dietary habits globally. Objective. To review and access published and unpublished national diet surveys worldwide in a systematic and consistent way to produce comprehensive intake data of specific dietary fats and their uncertainties by country, region, age, and sex in 1990 and 2005. Methods. We developed methods to identify, assess, and obtain exposure data (mean, SD) from nationally representative diet surveys worldwide on saturated, n-6, n-3 and trans fats, and dietary cholesterol. To address missing data and estimate mean intake, we developed and applied a multi-level hierarchical Bayesian model that accounted for country- and region-level data, measurement comparability, study representativeness, and diet assessment method. Time-varying country-level covariates were used to inform the estimates, including FAO food availability data, population, GDP, latitude, metabolic risks, and other diet covariates. Uncertainty of the estimates accounted for uncertainty from sampling and statistical modeling. Results. We obtained relevant data (85% by direct author contact) from 76 nationally representative and 15 large regional surveys from 49 countries in 15 regions, covering 75% of the world’s population. Several countries and regions lacked representative data. Data were most frequently available for saturated fat and dietary cholesterol (Figure). Results for other fats will be presented at the meeting. Conclusions. These new methods developed to systematically assess, compile and estimate the exposure distribution of specific dietary fats and cholesterol in a uniform fashion globally allow, for the first time, characterization of consumption habits and trends by country, region, age and sex. Such global assessment is imperative for estimating the impact of dietary fats on chronic diseases worldwide.

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

2018 ◽  
Author(s):  
Marcus Lejon ◽  
Niklas Andersson ◽  
Lars Ellbrant ◽  
Hans Mårtensson
Keyword(s):  
Flow Field ◽  
Geometric Mean ◽  
Pressure Ratio ◽  
Axial Compressor ◽  
Mean Deviation ◽  
Design Intent ◽  
Compressor Rotor ◽  
Measuring Machine ◽  
The Mean ◽  
The Impact

In this paper, the impact of manufacturing variations on performance of an axial compressor rotor are evaluated at design rotational speed. The geometric variations from the design intent were obtained from an optical coordinate measuring machine and used to evaluate the impact of manufacturing variations on performance and the flow field in the rotor. The complete blisk is simulated using 3D CFD 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 distribution along the leading edge and the shock position. Furthermore, a blisk is analyzed with one blade deviating substantially from the design intent, denoted as blade 0. It is shown that the impact of blade 0 on the flow is largely limited to the blade passages that it is directly a part of. The results presented in this paper also show that the impact of this blade on the flow field can be represented by a simulation including 3 blade passages. In terms of loss, using 5 blade passages is shown to give a close estimate for the relative change in loss for blade 0 and neighboring blades.

Map Width Enhancement Technique for a Turbocharger Compressor

2013 ◽  
Vol 136 (6) ◽  
Author(s):  
Subenuka Sivagnanasundaram ◽  
Stephen Spence ◽  
Juliana Early
Keyword(s):  
Performance Improvement ◽  
Peak Pressure ◽  
Pressure Ratio ◽  
Comparison Study ◽  
Heavy Duty ◽  
Recirculating Flow ◽  
Heavy Duty Diesel ◽  
And Performance ◽  
The Stability ◽  
The Impact

This paper presents an investigation of map width enhancement and the performance improvement of a turbocharger compressor using a series of static vanes in the annular cavity of a classical bleed slot system. The investigation has been carried out using both experimental and numerical analysis. The compressor stage used for this study is from a turbocharger unit used in heavy duty diesel engines of approximately 300 kW. Two types of vanes were designed and added to the annular cavity of the baseline classical bleed slot system. The purpose of the annular cavity vane technique is to remove some of the swirl that can be carried through the bleed slot system, which would influence the pressure ratio. In addition to this, the series of cavity vanes provides a better guidance to the slot recirculating flow before it mixes with the impeller main inlet flow. Better guidance of the flow improves the mixing at the inducer inlet in the circumferential direction. As a consequence, the stability of the compressor is improved at lower flow rates and a wider map can be achieved. The impact of two cavity vane designs on the map width and performance of the compressor was highlighted through a detailed analysis of the impeller flow field. The numerical and experimental study revealed that an effective vane design can improve the map width and pressure ratio characteristic without an efficiency penalty compared to the classical bleed slot system without vanes. The comparison study between the cavity vane and noncavity vane configurations presented in this paper showed that the map width was improved by 14.3% due to a significant reduction in surge flow and the peak pressure ratio was improved by 2.25% with the addition of a series of cavity vanes in the annular cavity of the bleed slot system.

STAEBL/General Composites With Hygrothermal Effects (STAEBL/GENCOM)

1988 ◽  
Vol 110 (2) ◽  
pp. 301-305
Author(s):  
R. Rubinstein
Keyword(s):  
Composite Laminates ◽  
Fiber Composite ◽  
Thickness Distribution ◽  
Turbine Blades ◽  
Material Design ◽  
Computer Code ◽  
Forced Response ◽  
General Description ◽  
Blade Thickness ◽  
Design Variables

A computer code has been developed to perform structural optimization of turbine blades made from angle ply fiber composite laminates. Design variables available for optimization include geometric parameters such as blade thickness distribution and root chord, and composite material parameters such as ply angles and numbers of plies of each constituent material. Design constraints include resonance margins, forced response margins, maximum stress, and maximum ply combined stress. A general description of this code is given. Design optimization studies for typical blades are presented.

Sign in / Sign up

Export Citation Format

Share Document