Unsteady Flow Calculation in Cascades

Fourmaux, A.

doi:10.1115/86-gt-178

Cited by 15 publications

(4 citation statements)

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“…In the last seven years there have been several research groups working on the development of methods for the calculation of unsteady flows in turbomachinery (Hodson, 1984;Koya and Kotake, 1985;Rai, 1987aRai, , 1987bFourmaux, 1986;Lewis et al, 1987;Gibeling et al, 1988). At MIT we have also been working on unsteady flow calculation methods for the last five years, starting initially with an inviscid wake/rotor interaction program (Giles, 1988a).…”

Section: Introductionmentioning

confidence: 99%

Validation of a Numerical Method for Unsteady Flow Calculations

Giles

Haimes

1991

Volume 1: Turbomachinery

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This paper describes and validates a numerical method for the calculation of unsteady inviscid and viscous flows. A companion paper compares experimental measurements of unsteady heat transfer on a transonic rotor with the corresponding computational results. The mathematical model is the Reynolds-averaged unsteady Navier-Stokes equations for a compressible ideal gas. Quasi-three-dimensionality is included through the use of a variable streamtube thickness. The numerical algorithm is unusual in two respects: a) for reasons of efficiency and flexibility it uses a hybrid Navier-Stokes/Euler method, and b) to allow for the computation of stator/rotor combinations with arbitrary pitch ratio a novel space-time coordinate transformation is used.Several test cases are presented to validate the performance of the computer program, UNSFLO. These include: a) unsteady, inviscid flat plate cascade flows, b) steady and unsteady, viscous flat plate cascade flows, c) steady turbine heat transfer and loss prediction. In the first two sets of cases comparisons are made with theory, and in the third the comparison is with experimental data.

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Section: Introductionmentioning

confidence: 99%

Validation of a Numerical Method for Unsteady Flow Calculations

Giles

Haimes

1991

Volume 1: Turbomachinery

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“…Computational investigations of vane/blade interactions reported in the past concentrated on the aerodynamics of the blades and/or vanes, eg. Erdos et al (1977), Hodson (1985), Koya and Kotake (1985), Fourmeau (1986) Lewis et al (1987), Giles (1988), Rai (1987), Jorgenson and Chima (1989) and Richardson (1990). With the exception of the last three methods, which solved the aver-aged Navier-Stokes equations, other methods cited above do not have the capability to calculate the surface heat transfer.…”

Section: Introductionmentioning

confidence: 99%

Prediction of Unsteady Rotor-Surface Pressure and Heat Transfer From Wake Passings

Tran¹,

Taulbee

1991

Volume 4: Heat Transfer; Electric Power; Industrial and Cogeneration

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The research described in this paper is a numerical investigation of the effects of unsteady flow on gas turbine heat transfer, particularly on a rotor blade surface. The unsteady flow in a rotor blade passage and the unsteady heat transfer on the blade surface as a result of wake/blade interaction are modeled by the inviscid flow/boundary layer approach. The Euler equations which govern the inviscid flow are solved using a time accurate marching scheme. The unsteady flow in the blade passage is induced by periodically moving a wake model across the passage inlet. Unsteady flow solutions in the passage provide pressure gradients and boundary conditions for the boundary-layer equations which govern the viscous flow adjacent to the blade surface. Numerical solutions of the unsteady turbulent boundary layer yield surface heat flux values which can then be compared to experimental data. Comparisons with experimental data show that unsteady heat flux on the blade suction surface is well predicted, but the predictions of unsteady heat flux on the blade pressure surface do not agree.

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“…The order of the coefficient matrix of equations (A9) is four, consequently, one independent variable is arbitrary, take α 5 =1, others are:Brought to you by | University of Arizona Authenticated Download Date | 5/26/15 6:06 PM Hence, the two solutions are obtained for d=d4 …”

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confidence: 99%

A New Model for Describing Inherent Unsteady Flow in Turbomachinery

Zhang¹,

Zhou²,

Liang³

2001

International Journal of Turbo and Jet Engines

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Λ new model for numerical simulation of unsteady flow in turbomachines is presented in this paper. Most turbomachinery analyses assume periodicity from blade to blade. This makes it possible to analyze one blade only. The turbomachinery is designed with unequal number of blades to avoid forced vibration problems, the asymmetry boundary condition due to unequal number of blades is one of the major difficulty in simulation rotor-stator flow with the relative motion of rotor and Stator rows. As soon as there are more than one stage in the computational domain, which is an unavoidable problem for multistage turbomachines, ultimately, the only correct nonlinear time-accurate simulation is to analyze the entire annulus in each blade row. This is simply too computationally expensive to consider for engineering application. The new model can handle this problem effectively, which divide computational domains into blade row domains and volume domains between the blade rows. The volume computational domains are the full annulus that can eliminate the periodic boundary condition limitation, the three-dimensional characteristic compatibility equations are used as complementary condition to determine the boundary conditions between the blade rows and the volumes, The asymmetry of characteristic compatibility equations represent important turbomachinery unsteady flow mechanism. The results of the 3D unsteady Euler equations numerical simulation for a two stage transonic fan is presented. The new model has proven to be effective in analysis details of unsteady rotor-stator interactions in multistage turbomachines, and encourages future investigations. The model is not only usable for numerical simulation, but maybe also beneficial to experimental measurements and analysis.

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Unsteady Flow Calculation in Cascades

Cited by 15 publications

References 0 publications

Validation of a Numerical Method for Unsteady Flow Calculations

Validation of a Numerical Method for Unsteady Flow Calculations

Prediction of Unsteady Rotor-Surface Pressure and Heat Transfer From Wake Passings

A New Model for Describing Inherent Unsteady Flow in Turbomachinery

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