Numerical Characterisation of a HP Compressor Stage Equipped with a Closed Shrouded Stator Cavity

2021 ◽  
pp. 1-27
Author(s):  
Cedric Babin ◽  
Michel Dumas ◽  
Xavier Ottavy ◽  
Fabrizio Fontaneto
Keyword(s):  
Axial Compressor ◽  
Second Phase ◽  
Cavity Flows ◽  
Flow Topology ◽  
Closed Cavity ◽  
Axial Compressors ◽  
Performance Effects ◽  
Cavity Configuration ◽  
And Performance ◽  
Final Extent

Abstract In axial compressors, shrouded stator cavity flows are responsible for performance degradation due to their interaction with the power stream. The present paper aims at exploring the possibility of employing a single stage high pressure axial compressor as a test vehicle for cavity flows investigations. In a first step, the robustness of the adopted RANS approach is tested against experimental data on the closed-cavity baseline configuration (i.e. no downstream-to-upstream recirculation). In a second phase, the effect of different hub cavities layouts of different levels of realism is numerically investigated. The focus is set on the representativeness of a closed cavity configuration with injection. The cavity flow topology and impact on the overall performance are considered in the analysis. At its final extent, this paper provides numerical and experimental guidelines for the robust assessment of cavity flows topology and performance effects.

Numerical Characterization of a HP Compressor Stage Equipped With a Closed Shrouded Stator Cavity

2020 ◽  
Author(s):  
Cedric Babin ◽  
Michel Dumas ◽  
Xavier Ottavy ◽  
Fabrizio Fontaneto
Keyword(s):  
Axial Compressor ◽  
Second Phase ◽  
Cavity Flows ◽  
Flow Topology ◽  
Closed Cavity ◽  
Axial Compressors ◽  
Numerical Characterization ◽  
Performance Effects ◽  
And Performance ◽  
Final Extent

Abstract In axial compressors, shrouded stator cavity flows are responsible for performance degradation due to their interaction with the power stream. The present paper aims at exploring the possibility of employing a single stage high pressure axial compressor as a test vehicle for cavity flows investigations. In a first step, the robustness of the adopted RANS approach is tested against experimental data on the closed-cavity baseline configuration (i.e. no downstream-to-upstream recirculation). In a second phase, the effect of different hub cavities layouts of different levels of realism is numerically investigated. The focus is set on the representativeness of a closed cavity configuration with injection. The cavity flow topology and impact on the overall performance are considered in the analysis. At its final extent, this paper provides numerical and experimental guidelines for the robust assessment of cavity flows topology and performance effects.

scholarly journals Simplified Method for Flow Analysis and Performance Calculation Through an Axial Compressor

1984 ◽  
Author(s):  
Hubert Miton ◽  
Youssef Doumandji ◽  
Jacques Chauvin
Keyword(s):  
Equations Of Motion ◽  
Computing Time ◽  
Flow Analysis ◽  
Axial Compressor ◽  
Computation Method ◽  
Duct Flow ◽  
Axial Compressors ◽  
Flow Through ◽  
And Performance ◽  
Performance Calculation

This paper describes a fast computation method of the flow through multistage axial compressors of the industrial type. The flow is assumed to be axisymmetric between the blade rows which are represented by actuator disks. Blade row losses and turning are calculated by means of correlations. The equations of motion are linearized with respect to the log of static pressure, whose variation along the radius is usually of limited extent for the type of machines for which the method has been developed. In each computing plane (i.e. between the blade rows) two flows are combined: a basic flow with constant pressure satisfying the mass flow requirements and a perturbation flow fulfilling the radial equilibrium condition. The results of a few sample calculations are given. They show a satisfactory agreement with a classical duct flow method although the computing time is reduced by a factor five. The method has also been coupled with a surge line prediction calculation.

scholarly journals Design optimization of a multi-stage axial compressor using throughflow and a database of optimal airfoils

2018 ◽  
Vol 2 ◽  
pp. W5N91I ◽  
Author(s):  
Markus Schnoes ◽  
Christian Voß ◽  
Eberhard Nicke
Keyword(s):  
Axial Compressor ◽  
Axial Compressors ◽  
New Class ◽  
Multi Stage ◽  
Blade Row ◽  
Wall Flow ◽  
Tool Set ◽  
And Performance ◽  
Gas Turbine Compressor ◽  
End Wall

The basic tool set to design multi-stage axial compressors consists of fast codes for throughflow and blade-to-blade analysis. Detailed blade row design is conducted with 3D CFD, mainly to control the end wall flow. This work focuses on the interaction between throughflow and blade-to-blade design and the transition to 3D CFD. A design strategy is presented that is based on a versatile airfoil family. The new class of airfoils is generated by optimizing a large number of airfoil shapes for varying design requirements. Each airfoil geometry satisfies the need for a wide working range as well as low losses. Based on this data, machine learning is applied to estimate optimal airfoil shape and performance. The performance prediction is incorporated into the throughflow code. Based on a throughflow design, the airfoils can be stacked automatically to generate 3D blades. On this basis, a 3D CFD setup can be derived. This strategy is applied to study upgrade options for a 15-stage stationary gas turbine compressor test rig. At first, the behavior of the new airfoils is studied in detail. Afterwards, the design is optimized for mass flow rate as well as efficiency. Selected configurations from the Pareto-front are evaluated with 3D CFD.

Design of Industrial Axial Compressor Blade Sections for Optimal Range and Performance

2003 ◽  
Author(s):  
Frank Sieverding ◽  
Beat Ribi ◽  
Michael Casey ◽  
Michael Meyer
Keyword(s):  
Genetic Algorithm ◽  
Fitness Function ◽  
Optimization Technique ◽  
Axial Compressor ◽  
Design System ◽  
Flow Solver ◽  
Axial Compressors ◽  
Mechanical Constraints ◽  
And Performance ◽  
Operating Points

A design system for the blade sections of industrial axial compressors has been developed. The method combines a parametric geometry definition method, a powerful blade-to-blade flow solver (MISES) and an optimization technique (breeder genetic algorithm) with an appropriate fitness function. Particular effort has been devoted to the design of the fitness function for this application which includes non-dimensional terms related to the required performance at design and off-design operating points. It has been found that essential aspects of the design (such as the required flow turning, or mechanical constraints) should not be part of the fitness function, but need to be treated as so-called “killer” criteria in the genetic algorithm. Finally, it has been found worthwhile to examine the effect of the weighting factors of the fitness function to identify how these affect the performance of the sections. The system has been tested on the design of a repeating stage for the middle stages of an industrial axial compressor. The resulting profiles show an increased operating range compared to an earlier design using NACA65 profiles.

scholarly journals SWIPT in mMIMO system with non-linear energy-harvesting terminals: protocol design and performance optimization

2019 ◽  
Vol 2019 (1) ◽  
Author(s):  
Kui Xu ◽  
Ming Zhang ◽  
Jie Liu ◽  
Nan Sha ◽  
Wei Xie ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Performance Optimization ◽  
Power Transmission ◽  
Base Station ◽  
Second Phase ◽  
Wireless Power ◽  
Half Duplex ◽  
Non Linear ◽  
Two Phases ◽  
And Performance

Abstract In this paper, we design the simultaneous wireless information and power transfer (SWIPT) protocol for massive multi-input multi-output (mMIMO) system with non-linear energy-harvesting (EH) terminals. In this system, the base station (BS) serves a set of uplink fixed half-duplex (HD) terminals with non-linear energy harvester. Considering the non-linearity of practical energy-harvesting circuits, we adopt the realistic non-linear EH model rather than the idealistic linear EH model. The proposed SWIPT protocol can be divided into two phases. The first phase is designed for terminals EH and downlink training. A beam domain energy beamforming method is employed for the wireless power transmission. In the second phase, the BS forms the two-layer receive beamformers for the reception of signals transmitted by terminals. In order to improve the spectral efficiency (SE) of the system, the BS transmit power- and time-switching ratios are optimized. Simulation results show the superiority of the proposed beam-domain SWIPT protocol on SE performance compared with the conventional mMIMO SWIPT protocols.

How do resources and diversification strategy explain the performance consequences of internationalization?

2014 ◽  
Vol 52 (5) ◽  
pp. 897-915 ◽  
Author(s):  
Yan Chen ◽  
Yiwei Jiang ◽  
Chengqi Wang ◽  
Wen Chung Hsu
Keyword(s):  
Emerging Market ◽  
Product Diversification ◽  
Firm Resources ◽  
Diversification Strategy ◽  
Data Set ◽  
Content Type ◽  
Listed Firms ◽  
Performance Consequences ◽  
Performance Effects ◽  
And Performance

Purpose – The purpose of this paper is to examine how firm resources and diversification strategy explain the performance consequences of internationalization of emerging market enterprises. Design/methodology/approach – The paper conducts a regression analysis by using a novel panel data set comprising of 685 listed Chinese firms over the period of 2008-2011. Findings – The results show that the relationship between internationalization and performance is inverse U-shaped. Further, marketing resources play a greater role in enhancing the performance effects of internationalization than technological resources do. Related product diversification enhances the performance effects, while unrelated product diversification does the contrary. Research limitations/implications – The study focusses on listed firms in one country, and as a result, the findings cannot be generalized to non-listed firms and firms in other countries. Practical implications – This paper offers guidelines for international managers to improve performance of internationalization by developing a particular type of resources and diversification strategy. Originality/value – This paper extends the literature on the functional form of the internationalization-performance relationship, and further suggests that the analysis of the performance consequences of internationalization should go beyond the nexus between internationalization and performance, and focusses on firm-specific resources and strategies that may facilitate or constrain the performance effects of internationalization.

A Driving Simulator Study of the Performance Effects of Low Blood Alcohol Concentration

1996 ◽  
Vol 40 (18) ◽  
pp. 943-946 ◽  
Author(s):  
R. Wade Allen ◽  
Zareh Parseghian ◽  
Anthony C. Stein
Keyword(s):  
Divided Attention ◽  
Driving Simulator ◽  
Blood Alcohol Concentration ◽  
Large Body ◽  
Alcohol Concentration ◽  
Blood Alcohol ◽  
Performance Effects ◽  
Driving Task ◽  
Simulator Study ◽  
And Performance

There is a large body of research that documents the impairing effect of alcohol on driving behavior and performance. Some of the most significant alcohol influence seems to occur in divided attention situations when the driver must simultaneously attend to several aspects of the driving task. This paper describes a driving simulator study of the effect of a low alcohol dose, .055 BAC (blood alcohol concentration %/wt), on divided attention performance. The simulation was mechanized on a PC and presented visual and auditory feedback in a truck cab surround. Subjects were required to control speed and steering on a rural two lane road while attending to a peripheral secondary task. The subject population was composed of 33 heavy equipment operators who were tested during both placebo and drinking sessions. Multivariate Analysis of Variance showed a significant and practical alcohol effect on a range of variables in the divided attention driving task.

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