Application of a Viscous Through-Flow Model to a Modern Axial Low-Pressure Compressor

2021 ◽  
Author(s):  
Arnaud Budo ◽  
Vincent E. Terrapon ◽  
Maarten Arnst ◽  
Koen Hillewaert ◽  
Sophie Mouriaux ◽  
...  

Abstract This paper describes the evaluation of a newly developed viscous time-marching through-flow solver to two test cases to assess the applicability of the method using correlations from the literature to modern blade designs. The test cases are the classic axial compressor stage CME2 and a modern highly loaded multi-stage axial low-pressure compressor developed by Safran Aero Boosters. The through-flow solver is based on the Navier-Stokes equations and uses a pseudo-time marching method. The closure models currently include terms of major importance: the blade forces and the Reynolds stress. The results are compared to higher-fidelity results including three-dimensional RANS simulations to assess their reliability for design and off-design conditions. The main originality of this work is the evaluation of the CFD-based method in the context of a compressor with highly three-dimensional blades, as such an analysis is not commonly found in the literature. The solver gives realistic predictions of loss and deviation for the compressor stage CME2 at both design and off-design operating conditions. Regarding the second test case, the through-flow simulations based on theoretically non-adapted correlations for such a compressor are still in good agreement with RANS simulations, although the results for the 2nd test case are probably not as good as for the first. These results are a promising first step towards the use of this through-flow model for industrial design. Regarding the ongoing closure models development, suggestions to extend the loss models to a larger range of designs are discussed.

Author(s):  
Sebastian Föllner ◽  
Volker Amedick ◽  
Bernhard Bonhoff ◽  
Dieter Brillert ◽  
Friedrich-Karl Benra

Abstract In this paper the development and validation of a new meridional throughflow solver for the analysis of multistage axial turbines is presented. The quasi-three-dimensional finite-volume solver named tFlow is based on the inviscid Euler equations. To treat transonic flows with shocks the approximate Riemann solver of Roe for the computation of the inviscid fluxes in combination with the MUSCL approach are used. In the meridional plane turbine blades are numerically modeled by introducing two volume source terms for blade blockage and blade deviation effects. In this contribution four different validation test-cases are discussed. The general fluid solver is validated by analytical solutions of the established Ringleb flow and the simulation of a two-dimensional transonic nozzle flow. In contrast to prior publications [1–3] tFlow uses a different formulation of the blockage effect which is tested using the blockage data of a general convergent-divergent nozzle. Blade deviation effects are validated by comparison with three-dimensional results obtained from the commercial flow solver CFX. The results of tFlow are consistent with the analytical solutions and in case of the blade deviation test-case in good agreement to the three-dimensional results. Compared to fully three-dimensional simulations the developed solver enables faster analyses of multistage axial turbines to evaluate the performance characteristic.


1977 ◽  
Vol 99 (1) ◽  
pp. 53-62 ◽  
Author(s):  
Jean-Pierre Veuillot

The equations of the through flow are obtained by an asymptotic theory valid when the blade pitch is small. An iterative method determines the meridian stream function, the circulation, and the density. The various equations are discretized in an orthogonal mesh and solved by classical finite difference techniques. The calculation of the steady transonic blade-to-blade flow is achieved by a time marching method using the MacCormack scheme. The space discretization is obtained either by a finite difference approach or by a finite volume approach. Numerical applications are presented.


2003 ◽  
Vol 125 (1) ◽  
pp. 25-32 ◽  
Author(s):  
W. Ning ◽  
Y. S. Li ◽  
R. G. Wells

A multistage frequency domain (time-linearized/nonlinear harmonic) Navier-Stokes unsteady flow solver has been developed for predicting unsteady flows induced by bladerow interactions. In this paper, the time-linearized option of the solver has been used to analyze unsteady flows in a subsonic turbine test stage and the DLR transonic counter-rotating shrouded propfan. The numerical accuracy and computational efficiency of the time-linearized viscous methods have been demonstrated by comparing predictions with test data and nonlinear time-marching solutions for these two test cases. It is concluded that the development of efficient frequency domain approaches enables unsteady flow predictions to be used in the design cycles to tackle aeromechanics problems.


2012 ◽  
Vol 212-213 ◽  
pp. 1098-1102
Author(s):  
Bin Deng ◽  
Chang Bo Jiang ◽  
Zhi Xin Guan ◽  
Chao Shen

The numerical calculation and simulation of gas-liquid two-phase flows with interfacial deformations have nowadays become more and more popular issues in various scientific and industrial fields. In this study, a three-dimensional gas-liquid two-phase flow numerical model is presented for investigating interfacial flows. The finite volume method was used to discretize the governing equations. A High-resolution scheme of VOF method (STACS) is applied to capture the free surface. The paper outlines the methodology of STACS and its validation against three typical test cases used to verify its accuracy. The results show the STACS-VOF gives very satisfactory results for three-dimensional two-phase interfacial flows problem, and this scheme performs more accurate and less diffusive preserving interface sharpness and boundedness.


1992 ◽  
Author(s):  
William W. Copenhaver ◽  
Chunill Hah ◽  
Steven L. Puterbaugh

A detailed aerodynamic study of a transonic, high-through-flow, single stage compressor is presented. The compressor stage was comprised of a low-aspect-ratio rotor combined alternately with two different stator designs. Both experimental and numerical studies are conducted to understand the details of the complex flow field present in this stage. Aerodynamic measurements using high-frequency, Kulite pressure transducers and conventional probes are compared with results from a three-dimensional viscous flow analysis. A steady multiple blade row approach is used in the numerical technique to examine the detailed flow structure inside the rotor and the stator passages. The comparisons indicate that many flow field features are correctly captured by viscous flow analysis, and therefore unmeasured phenomena can be studied with some level of confidence.


Author(s):  
W. Ning ◽  
Y. S. Li ◽  
R. G. Wells

A multistage frequency domain (time-linearized/nonlinear harmonic) Navier-Stokes unsteady flow solver has been developed for predicting unsteady flows induced by bladerow interactions. In this paper, the time-linearized option of the solver has been used to analyze unsteady flows in a subsonic turbine test stage and the DLR transonic counter-rotating shrouded propfan. The numerical accuracy and computational efficiency of the time-linearized viscous methods have been demonstrated by comparing predictions with test data and nonlinear time-marching solutions for these two test cases. It is concluded that the development of efficient frequency domain approaches enables unsteady flow predictions to be used in the design cycles to tackle aeromechanics problems.


Author(s):  
Kevin Schillo ◽  
Jason Cassibry ◽  
Mitchell Rodriguez ◽  
Seth Thompson

Three-dimensional (3D) modeling of magneto-inertial fusion (MIF) is at a nascent stage of development. A suite of test cases relevant to plasma liner formation and implosion is presented to present the community with some exact solutions for verification of hydrocodes pertaining to MIF confinement concepts. MIF is of particular interest to fusion research, as it may lead to the development of smaller and more economical reactor designs for power and propulsion. The authors present simulated test cases using a new smoothed particle hydrodynamic (SPH) code called SPFMax. These test cases consist of a total of six problems with analytical solutions that incorporate the physics of radiation cooling, heat transfer, oblique-shock capturing, angular-momentum conservation, and viscosity effects. These physics are pertinent to plasma liner formation and implosion by merging of a spherical array of plasma jets as a candidate standoff driver for MIF. An L2 norm analysis was conducted for each test case. Each test case was found to converge to the analytical solution with increasing resolution, and the convergence rate was on the order of what has been reported by other SPH studies.


2013 ◽  
Vol 58 (3) ◽  
pp. 1-9 ◽  
Author(s):  
A. D. Gardner ◽  
K. Richter

A computational investigation of the effect of rotation on two-dimensional (2D) deep dynamic stall has been undertaken, showing that the effect of rotation is to reduce the severity of the pitching moment peak and cause earlier reattachment of the flow. A generic single blade rotor geometry was investigated, which had a pitching oscillation around the quarter-chord axis while in hover, causing angle-driven dynamic stall. The results at the midpoint of the blade have the same Mach number (0.31), Reynolds number (1.15 × 106), and pitching motion (α = 13° ± 7°) as a dynamic stall test case for which significant experimental wind tunnel data and 2D computations exist. The rotating blade is compared with 2D computations and computations using the same blade without rotation at Mach 0.31 and with the same pitching motion. All test cases involve geometries propagating into undisturbed flow with no downwash. The three-dimensional (3D) grid computed without rotation had lower lift at the reference section than for a 2D computation with the same geometric angle of attack time history, and the lift overshoot classically observed for Spalart–Allmaras turbulence models during 2D dynamic stall was significantly reduced in the 3D case. Rotation reduced the strength of the dynamic stall vortex, which reduced the accompanying pitching moment peak by 25%.


Author(s):  
A. L. de Wet ◽  
T. W. von Backström ◽  
S. J. van der Spuy

The compressor section of a diesel locomotive turbocharger was re-designed to increase its maximum total-to-total pressure ratio and efficiency. Tests conducted on the prototype compressor showed possible rotating stall in the diffuser section before the designed higher pressure ratio could be achieved. It was decided to simulate the prototype compressor’s operation by using one-dimensional theory [1], followed by a three-dimensional CFD analysis of the compressor. This publication focuses on implementation of the impeller, vaneless annular passage and vaned diffuser one-dimensional theories. A verification process was followed to show the accuracy of the one- and three-dimensional modelling methods using two well-known centrifugal compressor test cases found in the literature [2–5]. Comparing the test case modelling results to available experimental results indicated sufficient accuracy to investigate the prototype compressor’s impeller and diffuser. Conclusions drawn on the prototype compressor’s performance using the one- and three-dimensional modelling methods led to a recommendation to redesign the impeller and diffuser of the prototype compressor.


Author(s):  
Mark R. Anderson ◽  
Daryl L. Bonhaus

Through-flow solvers have historically played a very prominent role in the design and analysis of axial turbomachinery. While three-dimensional, Full Navier-Stokes (FNS) CFD is taking an increasing larger role, quasi-3D through-flow methods are still widely used. Automated optimization techniques that search over a wide design space, involving many possible variables, are particularly suitable for the computationally efficient through-flow solver. Pressure-based methods derived from CFD solution techniques have gradually replaced older streamline curvature methods, due to their ability to capture flow across a wide range of Mach numbers, particularly the transonic and supersonic regimes. The through-flow approach allows for the solution of the three-dimensional problem with the computational efficiency of a two-dimensional solution. Since the losses are explicitly calculated through empirically based models, the need for detailed grid resolution to capture tiny flow entities (such as wakes and boundary layers) is also greatly reduced. The combined savings can result in computational costs as much as two orders of magnitude lower than full 3D CFD methods. A state-of-the-art through-flow solver has several features that are crucial in the design process. One of these is the ability to run in both a design and an analysis mode. Also important, is the ability to generate solutions where critical components are solved using 3D FNS, while others are run using a through-flow method. Other desirable features in a through-flow solver are: an advanced equation of state, injection and extraction ability, the handling of arbitrary (non-axial) shapes, and a link to a capable geometry generation engine. Through-flow solvers represent a unique mix of higher order numerical methods (increasingly CFD-based) coupled with empirically derived models (generally meanline based). The combination of these two methods in one solver creates a particularly challenging programming problem. This paper details the techniques required to effectively generate through-flow solutions. Special attention is given to an improved off-design loss model for compressors, as well as a transonic loss model needed for high-speed compressor and turbine flows. Validation with recognized test data along with corresponding 3D FNS CFD results are presented.


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