Experimental and Computational Study of the Unsteady Flow in a 1.5 Stage Axial Turbine With Emphasis on the Secondary Flow in the Second Stator

Walraevens, R. E.; Gallus, H. E.; Jung, Alexander; Mayer, Jürgen F.; Stetter, H.

doi:10.1115/98-gt-254

Cited by 28 publications

(10 citation statements)

References 24 publications

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“…INTRODUCTION The need for a better understanding of unsteady effects on the aerodynamics, heat transfer and noise in turbomachinery is increasing as the demand for greater gas turbine efficiency rises. The most significant contribution to the unsteadiness in a turbine is due to the periodic chopping of the wake [1] and secondary flow vortices from the upstream blade row by the downstream blade row [2], [3], [4], [5] . As modern engine design philosophy places emphasis on higher blade loading and smaller engine length, the effects of these interactions become even more important.…”

mentioning

confidence: 99%

Blade-Row Interaction in a High-Pressure Turbine

Chaluvadi

Kalfas

Banieghbal

et al. 2001

Journal of Propulsion and Power

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This paper presents a study of the three-dimensional flow field within the blade rows of a single stage highpressure axial turbine (low-speed, large-scale). Measurements have been performed in the stationary and rotating frames of reference. Time-mean data have been obtained using five-hole pneumatic probes. The transport mechanisms of the stator wake and passage vortices through the rotor blade row have been studied using smoke flow visualisation. Furthermore, unsteady measurements have been carried out using a three axis hot-wire. Steady and unsteady numerical simulations have been performed using a structured threedimensional Navier-Stokes solver to further understand the blade row interactions. The development of the stator exit flow field through the rotor blade row is described. The path of the stator passage vortices is altered by the rotor secondary flow. The rotor passage vortices are also affected by the transport of the stator secondary flow. The predicted flow field was interrogated from the perspective of loss production. The contribution of the unsteady flow to the stage loss has been evaluated using unsteady numerical simulations. The effect of stator viscous flow transport on the rotor flow angles is also discussed in brief. Finally, a simple model is proposed for the transport of the secondary flow vortices in the downstream blade row based on the understanding obtained from the measurements and numerical simulations.

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mentioning

confidence: 99%

Blade-Row Interaction in a High-Pressure Turbine

Chaluvadi

Kalfas

Banieghbal

et al. 2001

Journal of Propulsion and Power

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“…One most important source of unsteadiness is the potential effect in which the pressure field associated with the leading edge of a blade sweeps past the trailing edge of a vane [1]. The other main contributor to unsteadiness is the vanes wakes swept into the blade row due to periodic chopping of wakes [2], added to the secondary flows and vortices convected from an upstream row [3]. Moreover, large variations in the size and strength of the secondary flows and vortices are observed as the rotor blades passages sweep through the flow distortions generated by upstream vanes [4].…”

Section: Introductionmentioning

confidence: 99%

Characterization of Flow Interactions in a One-Stage Shrouded Axial Turbine

Ghenaiet

2018

International Journal of Aerospace Engineering

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The aim of this paper is to characterize the steady and unsteady flow interactions through a one-stage high-pressure (hp) shrouded axial turbine with a tip cavity. The vane and blade passages were reduced based on the scaling technique, and the domains of compromise were identified and used in the flow computations. The flow structures are mainly in the form of vanes’ wakes and vortices inducing circumferential distortions and interacting with the rotor blades. Fast Fourier transform (FFT) of the static pressure fluctuations recorded at the selected points and lines through the turbine stage revealed high unsteadiness characterized by a space-time periodic behavior, and described by the double Fourier decomposition. The vane-rotor interactions (VRI) appeared in the form of a potential flow field about the blades extending both upstream and downstream and correlated with the rotational speed. The other sources of unsteadiness are induced in the rotor blades by the vanes’ wakes and referred to as the wake interaction, in addition to the secondary flows and vortices in endwall regions.

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“…The original Aachen 1-1/2 turbine stage 22 has three rows in order corresponding to the stator, the rotor and the stator and the blade numbers are respectively 36, 41 and 36. For the sake of simplicity and meanwhile not affecting our goals, the last stator is cut down and only the first two rows are simulated.…”

Section: Unsteady Results For a Turbine Stagementioning

confidence: 99%

Numerical Investigations of Two Typical Unsteady Flows in Turbomachinery Using the Multi-Passage Model

Zhou

Guo

et al. 2016

Int. J. Mod. Phys. Conf. Ser.

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In this paper, the research on two types of unsteady flow problems in turbomachinery including blade flutter and rotor-stator interaction is made by means of numerical simulation. For the former, the energy method is often used to predict the aeroelastic stability by calculating the aerodynamic work per vibration cycle. The inter-blade phase angle (IBPA) is an important parameter in computation and may have significant effects on aeroelastic behavior. For the latter, the numbers of blades in each row are usually not equal and the unsteady rotor-stator interactions could be strong. An effective way to perform multi-row calculations is the domain scaling method (DSM). These two cases share a common point that the computational domain has to be extended to multi passages (MP) considering their respective features. The present work is aimed at modeling these two issues with the developed MP model. Computational fluid dynamics (CFD) technique is applied to resolve the unsteady Reynolds-averaged Navier-Stokes (RANS) equations and simulate the flow fields. With the parallel technique, the additional time cost due to modeling more passages can be largely decreased. Results are presented on two test cases including a vibrating rotor blade and a turbine stage.

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Experimental and Computational Study of the Unsteady Flow in a 1.5 Stage Axial Turbine With Emphasis on the Secondary Flow in the Second Stator

Cited by 28 publications

References 24 publications

Blade-Row Interaction in a High-Pressure Turbine

Blade-Row Interaction in a High-Pressure Turbine

Characterization of Flow Interactions in a One-Stage Shrouded Axial Turbine

Numerical Investigations of Two Typical Unsteady Flows in Turbomachinery Using the Multi-Passage Model

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