Analyses of Centrifugal Compressor Performance Impacts on Volute and Scroll

2010 ◽  
Author(s):  
C. Xu ◽  
R. S. Amano
Keyword(s):  
Static Pressure ◽  
Stokes Equations ◽  
Single Stage ◽  
Navier Stokes ◽  
Performance Tests ◽  
Peak Efficiency ◽  
Navier Stokes Equations ◽  
Flow Simulations ◽  
Compressor Performance ◽  
Compressor Efficiency

Volute is used to collect and transport swirling gas produced by impeller or diffuser. Design of the volute not only impacts compressor efficiency but also influences the operating ranges of the compressor. In this study, Navier-Stokes equations combined with an algebra turbulence model were used to simulate flows inside a single stage compressor. Detailed flow simulations for a large cut back tongue volute are presented and discussed. A rounded tongue volute was tested in a single stage test rig. The compressor stage performance tests were conducted in the test lab and static pressure taps were used to measure static pressures at volute internal walls at locations of θ = 240° and 360°. Thermal couples and other static pressure probes were instrumented at inlet and outlet of the compressor for performance tests. The numerical results were compared with experiments and good agreements are found. Studies showed that a large cut back rounded tongue volute provided good operating range without dramatically dropping compressor peak efficiency.

Investigation of the Flow in Centrifugal Compressor Volute

2008 ◽  
Author(s):  
C. Xu ◽  
R. S. Amano
Keyword(s):  
Static Pressure ◽  
Stokes Equations ◽  
Single Stage ◽  
Navier Stokes ◽  
Performance Tests ◽  
Test Rig ◽  
Peak Efficiency ◽  
Navier Stokes Equations ◽  
Flow Simulations ◽  
Compressor Efficiency

Volute is used to collect and transport swirling gas produced by impeller or diffuser. Design of the volute not only impacts compressor efficiency but also influences the operating ranges of the compressor. In this study, Navier-Stokes equations combined with an algebra turbulence model were used to simulate flows inside a single stage compressor. Detailed flow simulations for a large cut back tongue volute are presented and discussed. A rounded tongue volute was tested in a single stage test rig. The compressor stage performance tests were conducted in the test lab and static pressure taps were used to measure static pressures at volute internal walls at locations of θ = 240° and 360°. Thermal couples and other static pressure probes were instrumented at inlet and outlet of the compressor for performance tests. The numerical results were compared with experiments and good agreements are found. Studies showed that a large cut back rounded tongue volute provided good operating range without dramatically dropping compressor peak efficiency.

Computational Analysis of Scroll Tongue Shapes to Compressor Performance by Using Different Turbulence Models

2007 ◽  
Author(s):  
Cheng Xu ◽  
R. S. Amano
Keyword(s):  
Turbulence Model ◽  
Stokes Equations ◽  
Turbulence Models ◽  
Equation Model ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Operating Range ◽  
Performance Predictions ◽  
Compressor Performance ◽  
Compressor Efficiency

A scroll is used to collect and transport swirling fluid produced by impeller or diffuser. Scroll or volute is one of the key components of centrifugal compressors. Design of the scroll not only impacts compressor efficiency but also influences operating range of the compressor. In this study, navier-stokes equations combined with both an zero-equation turbulence model and the k-ε turbulence model were used to simulate the flows inside a single stage compressor. Detailed flow simulations for a large cut back tongue scroll were presented and discussed. Studies showed that a large cut back rounded tongue scroll provided good operating range without dropping compressor peak efficiency dramatically. The turbulence model influences to the calculation were discussed and some suggestions for scroll flow modeling were made. The numerical results obtained using two turbulence models were compared and showed agreement reasonably well with experiments. Although the k-ε model behaves well inside the boundary layer, it was not decisively better than the zero-equation model for the performance predictions.

Effects of stator splitter blades on aerodynamic performance of a single-stage transonic axial compressor

2020 ◽  
Vol 14 (4) ◽  
pp. 7369-7378
Author(s):  
Ky-Quang Pham ◽  
Xuan-Truong Le ◽  
Cong-Truong Dinh
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Aerodynamic Performance ◽  
Numerical Results ◽  
Single Stage ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Operating Stability ◽  
Length Coverage

Splitter blades located between stator blades in a single-stage axial compressor were proposed and investigated in this work to find their effects on aerodynamic performance and operating stability. Aerodynamic performance of the compressor was evaluated using three-dimensional Reynolds-averaged Navier-Stokes equations using the k-e turbulence model with a scalable wall function. The numerical results for the typical performance parameters without stator splitter blades were validated in comparison with experimental data. The numerical results of a parametric study using four geometric parameters (chord length, coverage angle, height and position) of the stator splitter blades showed that the operational stability of the single-stage axial compressor enhances remarkably using the stator splitter blades. The splitters were effective in suppressing flow separation in the stator domain of the compressor at near-stall condition which affects considerably the aerodynamic performance of the compressor.

Luminosity calculation of meteor entry based on detailed flow simulations in the continuum regime

2020 ◽  
Vol 635 ◽  
pp. A184 ◽  
Author(s):  
B. Dias ◽  
J. B. Scoggins ◽  
T. E. Magin
Keyword(s):  
Radiation Effects ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Transfer Coefficients ◽  
Coupled Flow ◽  
Navier Stokes Equations ◽  
Lost City ◽  
Flow Simulations ◽  
Chemical Models ◽  
The Continuum

Context. Composition, mass, and trajectory parameters of meteors can be derived by combining observations with the meteor physics equations. The fidelity of these equations, which rely on heuristic coefficients, significantly affects the accuracy of the properties inferred. Aims. Our objective is to present a methodology that can be used to compute the luminosity of meteor entry based on detailed flow simulations in the continuum regime. Methods. The methodology consists in solving the Navier–Stokes equations using state-of-the-art physico-chemical models for hypersonic flows. It includes accurate boundary conditions to simulate the surface evaporation of the molten material and coupled flow-radiation effects. Such detailed simulations allow for the calculation of heat-transfer coefficients and luminous efficiency, which can be incorporated into the meteor physics equations. Finally, we integrate the radiative transfer equation over a line of sight from the ground to the meteor to derive the luminosity magnitude. Results. We use the developed methodology to simulate the Lost City bolide and to derive the luminosity magnitude, obtaining good agreement between numerical results and observations. The computed color index is more prominent than the observations. This is attributed to a lack of refractory elements such as Ca in the modeled flow that might originate from the vaporization of droplets in the trail, a phenomenon currently not included in the model.

scholarly journals Instability of transonic flow past flattened airfoils

2013 ◽  
Vol 3 (4) ◽  
Author(s):  
Alexander Kuzmin
Keyword(s):  
Numerical Modeling ◽  
Transonic Flow ◽  
Stokes Equations ◽  
Lift Coefficient ◽  
Reynolds Numbers ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Flow Simulations ◽  
Flow Past ◽  
Coefficient Versus

AbstractTransonic flow past a Whitcomb airfoil and two modifications of it at Reynolds numbers of the order of ten millions is studied. The numerical modeling is based on the system of Reynolds-averaged Navier-Stokes equations. The flow simulations show that variations of the lift coefficient versus the angle of attack become more abrupt with decreasing curvature of the airfoil in the midchord region. This is caused by an instability of closely spaced local supersonic regions on the upper surface of the airfoil.

On the limitation of imposed velocity field strategy for Coulomb-driven electroconvection flow simulations

2013 ◽  
Vol 727 ◽  
Author(s):  
Philippe Traoré ◽  
Jian Wu
Keyword(s):  
Velocity Field ◽  
Stokes Equations ◽  
Numerical Study ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Flow Simulations ◽  
Mobility Parameter ◽  
The Rich ◽  
Strong Injection ◽  
Unipolar Injection

AbstractThis study refers to the article of Chicón, Castellanos & Martion (J. Fluid Mech., vol. 344, 1997, pp. 43–66), who presented a numerical study of electroconvection in a layer of dielectric liquid induced by unipolar injection. An important characteristic of the numerical strategy proposed by Chicón et al. lies in the fact that the Navier–Stokes equations are never solved to obtain the velocity field, which is subsequently needed in the charge density transport equation. Instead, the velocity field is explicitly provided by an expression obtained with some assumptions about the flow structure and related to the electric field (the imposed velocity field approach; IVF). The validity of the above simplification is examined through a direct comparison of the solutions obtained by solving the Navier–Stokes equations (the Navier–Stokes computation approach; NSC). It is clearly demonstrated that, even in the strong injection regime ($C= 10$), the results look very similar for a given range of the mobility parameter $M$; however, in the weak injection regime ($C= 0. 1$), significant discrepancies are observed. The rich flow structures obtained with the NSC approach invalidate the use of the IVF approach in the weak injection regime.

The Interaction Between the Impeller and Casing in a Small-Size Turbo-Compressor

2002 ◽  
Author(s):  
D.-W. Kim ◽  
Youn J. Kim
Keyword(s):  
Static Pressure ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Reference Method ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Pressure Distributions ◽  
Loss Coefficients ◽  
Compressible Turbulent Flow ◽  
Turbo Compressor

The effects of casing shape on the performance and the interaction between the impeller and casing in a small-size turbo-compressor are investigated. Numerical analysis is conducted for the compressor with circular and single volute casings from inlet to discharge nozzle. In order to predict the flow pattern inside the entire impeller, vaneless diffuer and casing, calculations with multiple frames of reference method between the rotating and stationery parts of the domain are carried out. For compressible turbulent flow fields, the continuity and three-dimensional time-averaged Navier-Stokes equations are employed. To evaluate the performance of two types of casings, the static pressure and loss coefficients are obtained with various flow rates. Also, static pressure distributions around casings are studied for different casing shapes, which are very important to predict the distribution of radial load. To prove the accuracy of numerical results, measurements of static pressure around casing and pressure difference between the inlet and outlet of the compressor are performed for the circular casing. Comparison of these results between the experimental and numerical analyses are conducted, and reasonable agreement is obtained.

Simulation of Surge Inception and Performance of Axial Multistage Compressor

2006 ◽  
Author(s):  
Nicolas Tauveron ◽  
Pascal Ferrand ◽  
Francis Leboeuf
Keyword(s):  
Stokes Equations ◽  
Point Of View ◽  
Navier Stokes ◽  
Deterministic Approach ◽  
Disk Model ◽  
Navier Stokes Equations ◽  
1D Model ◽  
Compressor Performance ◽  
Multistage Compressor ◽  
And Performance

This work concerns transient multistage turbomachine modeling. The main application is the simulation of off-design regimes and unstable situations (essentially surge). Two specific approaches are developed: the first is a simple and fast model, based on a simplification of actuator disk model (0D). The second approach is based on 1D axisymmetric Navier-Stokes equations at the scale of the row. The models are tested on open literature cases of the gas turbine aircraft community. The numerical results compare favorably with these data from a qualitative point of view. The description of deep surge occurrence and the prediction of quantitative elements of compressor performance during surge are satisfactory provided few steady-state parameters are correctly determined. Otherwise the fully deterministic approach gives approximate, but acceptable results for a 0D or 1D model.

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