Analysis of the Interrow Flow Field Within a Transonic Axial Compressor: Part 2—Unsteady Flow Analysis

ABSTRACT An analysis of the experimental data, obtained by laser two-focus anemometry in the IGV-rotor inter-row region of a transonic axial compressor, is presented with the aim of improving the understanding of the unsteady flow phenomena. A study of the IGV wakes and of the shock waves emanating from the leading edge of the rotor blades is proposed. Their interaction reveals the increase in magnitude of the wake passing through the moving shock. This result is highlighted by the streamwise evolution of the wake vorticity. Moreover, the results are analyzed in terms of a time averaging procedure and the purely time-dependent velocity fluctuations which occur are quantified. It may be concluded that they are of the same order of magnitude as the spatial terms for the inlet rotor flow field. That shows that the temporal fluctuations should be considered for the 3D rotor time-averaged simulations. NOMENCLATURE Symbols M R = relative Mach number N = number of blades P = measurement point location T = temporal period r U , U = rotor velocity vector, modulus V r , V = velocity vector, modulus X = some flow parameter or other r f = external forces n = co-ordinate normal to the shock p = pressure r = radial co-ordinate t = time z = axial co-ordinate r Ω , Ω = vorticity vector, modulus Θ = angular blade pitch α = absolute velocity angle ϕ = phase shift ω = rotation speed (radian/s) θ = azimuthal co-ordinate ρ = fluid density τ = turbulent and viscous stress tensor τ = co-ordinate tangent to the shock Superscripts -= time averaged valuẽ = spatial averaged value ' = time fluctuating value in the absolute frame * = spatial fluctuating value " = purely time-dependent fluctuating value Subscripts R = relative to the rotor n = component normal to the shock r = radial component r = rotor red = reduced value ref = reference value rel = relative to the rotor (for a time averaged process) s = stator θ = azimuthal co-ordinate τ = component tangent to the shock 1 = rotor inlet conditions INTRODUCTION A critical issue for the turbomachinery industry remains the timeaveraged simulation of multi-stage turbomachinery. Classical 3D multi-blade row simulation methods consist in connecting results of stationary calculations applied to isolated adjacent blade rows, the information between the rows usually being exchanged throug

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Les redresseurs de compresseur de turbomachine axiale sont soumis à de la fatigue vibratoire. Or leur réalisation par assemblage de secteurs monobloc rend leur modélisation difficile (absence de symétrie cyclique, sensibilité au désaccordage). Le but est de présenter une stratégie de calcul robuste basée sur une modélisation stochastique de la structure et sur un calcul instationnaire tridimensionnel du chargement fluide. Des essais réalisés sur le compresseur HP multiétages CREATE permettent d'évaluer les niveaux de vibration sur un secteur de redresseur instrumenté pour valider le modèl

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Analysis of the Interrow Flow Field Within a Transonic Axial Compressor: Part 1—Experimental Investigation

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Analysis of the Interrow Flow Field Within a Transonic Axial Compressor: Part 2—Unsteady Flow Analysis

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