Transonic Axial Compressors Loss Correlations: Part II \u2014 Loss Models Validation

2021 ◽  
Author(s):  
Marco Manfredi ◽  
Cedric Babin ◽  
Fabrizio Fontaneto
Keyword(s):  
Axial Compressors ◽  
Loss Models ◽  
Models Validation

Transonic Axial Compressors Loss Correlations: Part II — Loss Models Validation

2020 ◽  
Author(s):  
Marco Manfredi ◽  
Cedric Babin ◽  
Fabrizio Fontaneto
Keyword(s):  
Axial Compressor ◽  
Numerical Data ◽  
Axial Compressors ◽  
Analysis And Design ◽  
Main Driver ◽  
Validity Range ◽  
Loss Models ◽  
Models Validation ◽  
Semi Empirical ◽  
System Designs

Abstract The quest for greener, more efficient aircraft engines is the main driver for the development of innovative compression system designs. Reduced order design tools rely nevertheless on semi-empirical loss models, whose validity range is often not net or in general not verified. The present work aims at defining a set of loss correlations, which could readily be employed in the analysis and design process of modern transonic axial compressors. In Part I, various loss correlations were deeply described and, in some cases, updated to enhance both their generality and their prediction capability. In Part II, the effectiveness of both original and updated models will be tested for one specific low aspect ratio axial compressor stage. Experimental and numerical data will be used at such extent.

Transonic Axial Compressors Loss Correlations: Part I — Analysis and Update of Loss Models

2020 ◽  
Author(s):  
Marco Manfredi ◽  
Fabrizio Fontaneto
Keyword(s):  
Axial Compressor ◽  
Reduced Order ◽  
Axial Compressors ◽  
Analysis And Design ◽  
Main Driver ◽  
Validity Range ◽  
Loss Models ◽  
Generation Mechanisms ◽  
Semi Empirical ◽  
System Designs

Abstract The quest for greener, more efficient aircraft engines is the main driver for the development of innovative compression system designs. Reduced order design tools rely nevertheless on semi-empirical loss models, whose validity range is often not net or in general not verified. The present work aims at defining a set of loss correlations, which could readily be employed in the analysis and design process of modern transonic axial compressors. In part I, the main entropy generation mechanisms are described together with a review of the most commonly employed modelling approaches. Selected loss models are then deeper investigated and updated to increase both their range of validity and the accuracy of their predictions. In Part II, the effectiveness of the investigated models will be tested for one specific low aspect ratio axial compressor stage.

Axial Compressor Performance Prediction Using Improved Streamline Curvature Approach

2018 ◽  
Author(s):  
Tao Li ◽  
Yadong Wu ◽  
Hua Ouyang ◽  
Xiaoqing Qiang
Keyword(s):  
Performance Prediction ◽  
Incidence Angle ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Internal Flow ◽  
Field Calculation ◽  
Axial Compressors ◽  
Streamline Curvature ◽  
Loss Models

This paper presents in detail the improved streamline curvature approach (SLC) to the performance evaluation and internal flow field calculation of subsonic and transonic axial compressors. Based on previous research, the diverse incidence, deviation and total pressure loss models, generally existing in the form of fitting curves and semi-empirical correlations, are discussed respectively. Typically, transonic flow in axial compressor results in the variation of several flow parameters and particularly the appearance of shock waves compared with subsonic flow. In this paper, the revision and improvement of loss models are applied to reach higher accuracy, especially considering the loss component due to actual incidence angle. Several modifications have been made as well considering the influence of three-dimensional flow. For the purpose of validating this approach, two test cases, including a single-stage transonic axial compressor NASA Stage37 and a 3-stage subsonic axial compressor P&W 3S1, are calculated. The overall characteristics and spanwise aerodynamic parameters for blade rows are demonstrated at both design and off-design conditions. Furthermore, the results agree well with both experimental data and computational fluid dynamic (CFD) results. This throughflow method is verified as an applicable and convenient tool for aerodynamic analysis and performance prediction of subsonic and transonic axial compressors.

scholarly journals Simulating Spatio-Temporal Patterns of Bicycle Flows with an Agent-Based Model

2021 ◽  
Vol 10 (2) ◽  
pp. 88
Author(s):  
Dana Kaziyeva ◽  
Martin Loidl ◽  
Gudrun Wallentin
Keyword(s):  
Regional Scale ◽  
Evidence Base ◽  
Wide Field ◽  
Traffic Patterns ◽  
Agent Based Model ◽  
Validation Data ◽  
Agent Based ◽  
Mobility Behavior ◽  
Spatio Temporal ◽  
Models Validation

Transport planning strategies regard cycling promotion as a suitable means for tackling problems connected with motorized traffic such as limited space, congestion, and pollution. However, the evidence base for optimizing cycling promotion is weak in most cases, and information on bicycle patterns at a sufficient resolution is largely lacking. In this paper, we propose agent-based modeling to simulate bicycle traffic flows at a regional scale level for an entire day. The feasibility of the model is demonstrated in a use case in the Salzburg region, Austria. The simulation results in distinct spatio-temporal bicycle traffic patterns at high spatial (road segments) and temporal (minute) resolution. Scenario analysis positively assesses the model’s level of complexity, where the demographically parametrized behavior of cyclists outperforms stochastic null models. Validation with reference data from three sources shows a high correlation between simulated and observed bicycle traffic, where the predictive power is primarily related to the quality of the input and validation data. In conclusion, the implemented agent-based model successfully simulates bicycle patterns of 186,000 inhabitants within a reasonable time. This spatially explicit approach of modeling individual mobility behavior opens new opportunities for evidence-based planning and decision making in the wide field of cycling promotion

scholarly journals Analysis of Radial Inflow Turbine Losses Operating with Supercritical Carbon Dioxide

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3561
Author(s):  
Antti Uusitalo ◽  
Aki Grönman
Keyword(s):  
Fluid Dynamic ◽  
Dynamic Simulations ◽  
Average Deviation ◽  
Loss Analysis ◽  
Specific Speed ◽  
Loss Models ◽  
Rotor Losses ◽  
Radial Turbines ◽  
Design Power ◽  
Good Agreement

The losses of supercritical CO2 radial turbines with design power scales of about 1 MW were investigated by using computational fluid dynamic simulations. The simulation results were compared with loss predictions from enthalpy loss correlations. The aim of the study was to investigate how the expansion losses are divided between the stator and rotor as well as to compare the loss predictions obtained with the different methods for turbine designs with varying specific speeds. It was observed that a reasonably good agreement between the 1D loss correlations and computational fluid dynamics results can be obtained by using a suitable set of loss correlations. The use of different passage loss models led to high deviations in the predicted rotor losses, especially with turbine designs having the highest or lowest specific speeds. The best agreement in respect to CFD results with the average deviation of less than 10% was found when using the CETI passage loss model. In addition, the other investigated passage loss models provided relatively good agreement for some of the analyzed turbine designs, but the deviations were higher when considering the full specific speed range that was investigated. The stator loss analysis revealed that despite some differences in the predicted losses between the methods, a similar trend in the development of the losses was observed as the turbine specific speed was changed.

Tests Design and Models Validation for the Acceleration Grid Power Supply Conversion System of the MITICA Test Facility

2020 ◽  
Vol 48 (6) ◽  
pp. 1681-1687
Author(s):  
Mattia Dan ◽  
Loris Zanotto ◽  
Claudio Finotti ◽  
Mauro Perna ◽  
Hans Decamps ◽  
...  
Keyword(s):  
Power Supply ◽  
Test Facility ◽  
Conversion System ◽  
Models Validation

Validation of Inductor Analytical Loss Models under Saturation Conditions for PWM inverter

2019 ◽  
Author(s):  
Adrien Voldoire ◽  
Jean-Paul Ferrieux ◽  
Jean-Luc Schanen ◽  
Corentin Rizet ◽  
Cyrille Gautier ◽  
...  
Keyword(s):  
Pwm Inverter ◽  
Loss Models

scholarly journals Probabilistic Flood Loss Models for Companies

2020 ◽  
Vol 56 (9) ◽  
Author(s):  
Lukas Schoppa ◽  
Tobias Sieg ◽  
Kristin Vogel ◽  
Gert Zöller ◽  
Heidi Kreibich
Keyword(s):  
Flood Loss ◽  
Loss Models
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