A Comprehensive Analytical Shock Loss Model for Axial Compressor Cascades

2021 ◽  
Author(s):  
Milan Banjac ◽  
Teodora Savanovic ◽  
Djordje Petkovic ◽  
Milan V. Petrovic
Keyword(s):  
Numerical Test ◽  
Axial Compressor ◽  
Test Cases ◽  
Research Papers ◽  
Loss Model ◽  
Precise Prediction ◽  
Model Compressor ◽  
And Performance ◽  
Operating Regimes ◽  
Shock Loss

Abstract The approach applied in various research papers that model compressor shock losses is valid only for certain types of airfoil cascades operating in a narrow range of working conditions. Lately, more general shock loss models have been established that cover a wider variety of airfoils and operating regimes. However, owing to the complexity of the studied matter, the majority of such models are, to a certain extent, presented only in a descriptive manner. The lack of specific details can affect the end results when such a model is utilized since improvisation cannot be avoided. Some models also apply complex numerical procedures that can slow the calculations and be a source of computational instability. In this research, an attempt has been made to produce an analytical shock loss model that is simple enough to be described in detail while being universal and robust enough to find wide application in the fields of design and performance analysis of transonic compressors and fans. The flexible description of airfoil geometry encompasses a variety of blade shapes. Both unchoked and choked operating regimes are covered, including a precise prediction of choke occurrence. The model was validated using a number of numerical test cases.

Aero-Thermodynamic Loss Analysis in Cases of Normal Shock Wave-Turbulent Shear Layer Interaction

1997 ◽  
Vol 119 (2) ◽  
pp. 297-303 ◽  
Author(s):  
J. K. Kaldellis
Keyword(s):  
Shear Layer ◽  
Practical Interest ◽  
Flow Simulation ◽  
Strong Shock ◽  
Turbulent Shear ◽  
Complex Flow ◽  
Loss Model ◽  
Layer Interaction ◽  
Loss Analysis ◽  
Shock Loss

Transonic-supersonic decelerating flow cases appearing in modern turbomachines are some of the most complex flow cases in fluid mechanics which also present practical interest. In the present work, a closed and coherent shock loss model is proposed based on the complete viscous flow simulation using some fast and reliable computational tools. The resulting model describes accurately the entropy rise and the total pressure loss in cases of strong shock-shear layer interaction and cancels the need to use low speed correlations modified for compressibility effects and extrapolated to transonic-supersonic flow cases. The accuracy and the reliability of the proposed shock-loss model are verified using detailed experimental data concerning various flow cases which present either flow separation or industrial interest.

scholarly journals A Three-Dimensional Shock Loss Model Applied to an Aft-Swept, Transonic Compressor Rotor

1996 ◽  
Author(s):  
Steven L. Puterbaugh ◽  
William W. Copenhaver ◽  
Chunill Hah ◽  
Arthur J. Wennerstrom
Keyword(s):  
Flow Rate ◽  
Pressure Ratio ◽  
Three Dimensional ◽  
Numerical Results ◽  
Design Flow ◽  
Design System ◽  
Loss Model ◽  
Transonic Compressor ◽  
Compressor Rotor ◽  
Shock Loss

An analysis of the effectiveness of a three-dimensional shock loss model used in transonic compressor rotor design is presented. The model was used during the design of an aft-swept, transonic compressor rotor. The demonstrated performance of the swept rotor, in combination with numerical results, is used to determine the strengths and weaknesses of the model. The numerical results were obtained from a fully three-dimensional Navier-Stokes solver. The shock loss model was developed to account for the benefit gained with three-dimensional shock sweep. Comparisons with the experimental and numerical results demonstrated that shock loss reductions predicted by the model due to the swept shock induced by the swept leading edge of the rotor were exceeded. However, near the tip the loss model under-predicts the loss because the shock geometry assumed by the model remains swept in this region while the numerical results show a more normal shock orientation. The design methods and the demonstrated performance of the swept rotor is also presented. Comparisons are made between the design intent and measured performance parameters. The aft-swept rotor was designed using an inviscid axisymmetric streamline curvature design system utilizing arbitrary airfoil blading geometry. The design goal specific flow rate was 214.7 kg/sec/m2 (43.98 lbm/sec/ft2), the design pressure ratio goal was 2.042, and the predicted design point efficiency was 94.0. The rotor tip sped was 457.2 m/sec (1500 ft/sec). The design flow rate was achieved while the pressure ratio fell short by 0.07. Efficiency was 3 points below prediction, though at a very high 91 percent. At this operating condition the stall margin was 11 percent.

Reconfigurable manufacturing system: a systematic review, meta-analysis and future research directions

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Rajesh Pansare ◽  
Gunjan Yadav ◽  
Madhukar R. Nagare
Keyword(s):  
Manufacturing System ◽  
Meta Analysis ◽  
Future Research ◽  
Future Trends ◽  
Reconfigurable Manufacturing ◽  
Research Papers ◽  
Reconfigurable Manufacturing System ◽  
Content Type ◽  
Related Research ◽  
And Performance

Purpose Uncertainties in manufacturing and changing customer demands force manufacturing industries to adopt new strategies, such as the reconfigurable manufacturing system (RMS). To improve the implementation and performance of RMS, it is necessary to review the available literature and identify future trends in this field. This paper aims to analyze existing literature and to see trends in RMS-related research. Design/methodology/approach The systematic literature review and analysis of RMS-related research papers from 1999 to 2020 is carried out in this literature. The selected studies are analyzed based on the year of publication, journals, publishers, active authors, research design, countries, enablers, barriers, performance evaluation parameters and universities. Findings After the analysis of selected RMS-related research papers, the top countries, universities, journals, publishers and authors are identified in this domain. Research themes and trends in research are identified in this study. Besides, it has been noted that there is a need for further research in this domain and for the creation of a generalized framework that can guide researchers and practitioners to increase RMS adoption. Practical implications Research insights, guidance and observations from this paper are provided to RMS-related researchers and practitioners. Important research gaps are identified in this study, which can provide direction for future research and trends in RMS research. Originality/value The study presented focuses mainly on the method of collecting, organizing, capturing, interpreting and analyzing data to provide more insight into RMS to identify future trends in research.

Loss Generation in Transonic Turbine Blading

2017 ◽  
Author(s):  
Penghao Duan ◽  
Choon S. Tan ◽  
Andrew Scribner ◽  
Anthony Malandra
Keyword(s):  
Experimental Data ◽  
Boundary Layer ◽  
Mach Number ◽  
High Speed ◽  
Turbine Blades ◽  
Surface Boundary ◽  
Loss Model ◽  
Exit Mach Number ◽  
Loss Characteristic ◽  
Shock Loss

The measured loss characteristic in a high-speed cascade tunnel of two turbine blades of different designs showed distinctly different trend with exit Mach number ranging from 0.8 to 1.4. Assessments using steady RANS computation of the flow in the two turbine blades, complemented with control volume analyses and loss modelling, elucidate why the measured loss characteristic looks the way it is. The loss model categorizes the total loss in terms of boundary layer loss, trailing edge loss and shock loss; it yields results in good agreement with the experimental data as well as steady RANS computed results. Thus RANS is an adequate tool for determining the loss variations with exit isentropic Mach number and the loss model serves as an effective tool to interpret both the computational and experimental data. The measured loss plateau in Blade 1 for exit Mach number of 1 to 1.4 is due to a balance between a decrease of blade surface boundary layer loss and an increase in the attendant shock loss with Mach number; this plateau is absent in Blade 2 due to a greater rate in shock loss increase than the corresponding decrease in boundary layer loss. For exit Mach number from 0.85 to 1, the higher loss associated with shock system in Blade 1 is due to the larger divergent angle downstream of the throat than that in Blade 2. However when exit Mach number is between 1.00 and 1.30, Blade 2 has higher shock loss. For exit Mach number above around 1.4, the shock loss for the two blades is similar as the flow downstream of the throat is completely supersonic. In the transonic to supersonic flow regime, the turbine design can be tailored to yield a shock pattern the loss of which can be mitigated in near equal amount of that from the boundary layer with increasing exit Mach number, hence yielding a loss plateau in transonic-supersonic regime.

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.

Agglomeration-based physical frame dG discretizations: An attempt to be mesh free

2014 ◽  
Vol 24 (08) ◽  
pp. 1495-1539 ◽  
Author(s):  
Francesco Bassi ◽  
Lorenzo Botti ◽  
Alessandro Colombo
Keyword(s):  
Finite Element ◽  
Convergence Rates ◽  
Numerical Test ◽  
High Order ◽  
Test Cases ◽  
Computational Domain ◽  
Element Discretization ◽  
Mesh Free ◽  
Domain Boundaries ◽  
Coarse Grids

In this work we consider agglomeration-based physical frame discontinuous Galerkin (dG) discretization as an effective way to increase the flexibility of high-order finite element methods. The mesh free concept is pursued in the following (broad) sense: the computational domain is still discretized using a mesh but the computational grid should not be a constraint for the finite element discretization. In particular the discrete space choice, its convergence properties, and even the complexity of solving the global system of equations resulting from the dG discretization should not be influenced by the grid choice. Physical frame dG discretization allows to obtain mesh-independent h-convergence rates. Thanks to mesh agglomeration, high-order accurate discretizations can be performed on arbitrarily coarse grids, without resorting to very high-order approximations of domain boundaries. Agglomeration-based h-multigrid techniques are the obvious choice to obtain fast and grid-independent solvers. These features (attractive for any mesh free discretization) are demonstrated in practice with numerical test cases.

The wave finite element method for uncertain systems with model uncertainty

2015 ◽  
Vol 230 (6) ◽  
pp. 974-985 ◽  
Author(s):  
MA Ben Souf ◽  
O Bareille ◽  
M Ichchou ◽  
M Haddar
Keyword(s):  
Finite Element ◽  
Dynamic Systems ◽  
Periodic Structures ◽  
Probabilistic Approach ◽  
Numerical Test ◽  
Maximum Entropy Principle ◽  
Nonparametric Model ◽  
Test Cases ◽  
Entropy Principle ◽  
Random Uncertainties

The random dynamic response of periodic structures with model uncertainties is here studied. For that purpose, a nonparametric model of random uncertainties is used. The present approach is based on the maximum entropy principle optimization and is developed to identify the response of linear and nonlinear dynamic systems. This non-parametric probabilistic approach is implemented in combination with the Wave Finite Element. Numerical test cases are used as examples and for validation purpose.

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.

New Supersonic Loss Model for the Preliminary Design of Transonic Turbine Blades and the Influence of Pitch

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Luis Teia
Keyword(s):  
Mach Number ◽  
Turbine Blades ◽  
Turbine Rotor ◽  
Published Data ◽  
Efficient Design ◽  
Operational Parameters ◽  
Loss Model ◽  
Shock System ◽  
Transonic Turbine ◽  
Shock Loss

Abstract In order to produce a more efficient design of a compact turbine driving a cryogenic engine turbo-pump for a satellite delivering rocket, a new supersonic loss model is proposed. The new model was constructed based on high-quality published data, composed of Schlieren photographs and experimental measurements, that combined provided a unique insight into the mechanisms driving supersonic losses. Using this as a cornerstone, model equations were formulated that predict the critical Mach number and shock loss and shock-induced mixing loss as functions of geometrical (i.e., blade outlet and uncovered turning angle and trailing edge thickness) and operational parameters (i.e., exit Mach number). A series of highly resolved CFD numerical simulations were conducted on an in-house designed state-of-the-art transonic turbine rotor row (around unity aspect ratio (AR)) to better understand changes in the shock system for varying parameters. The main outcome showed that pitch to chord ratio has a powerful impact on the shock system, and thus on the manner by which shock loss and shock-induced mixing loss is distributed to compose the overall supersonic losses. The numerical loss estimates for two pitch to chord ratios—t⁄c = 0.70 and t⁄c = 0.98—were compared with absolute loss data of a previously published similar blade with satisfactory agreement. Calibrated equations are provided to allow hands-on integration into existing overall turbine loss models, where supersonic losses play a key role, for further enhancement of preliminary turbine design.

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