Effects of Tip Clearance on Hot Streak Migration in a High-Subsonic Single-Stage Turbine

Dorney, Daniel J.; Sondak, Douglas L.

doi:10.1115/1.1290399

Cited by 23 publications

(4 citation statements)

References 16 publications

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“…They concluded that the local increase in heat transfer was mainly caused by the position of the oblique shock impingement on the blade and by the clocking effects between the hot streak, the blade number, and the relative position. Some experimental and numerical studies concerning the hot spot shape [49], the tip clearance effects Dorney and Sondak [50], and the multistage aspects [51,52] were performed, too.…”

Section: Hot Spot Migration In the High-pressure Turbine Stagementioning

confidence: 99%

Unsteady Flows and Component Interaction in Turbomachinery

Salvadori,

Insinna,

Martelli

2024

IJTPP

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Unsteady component interaction represents a crucial topic in turbomachinery design and analysis. Combustor/turbine interaction is one of the most widely studied topics both using experimental and numerical methods due to the risk of failure of high-pressure turbine blades by unexpected deviation of hot flow trajectory and local heat transfer characteristics. Compressor/combustor interaction is also of interest since it has been demonstrated that, under certain conditions, a non-uniform flow field feeds the primary zone of the combustor where the high-pressure compressor blade passing frequency can be clearly individuated. At the integral scale, the relative motion between vanes and blades in compressor and turbine stages governs the aerothermal performance of the gas turbine, especially in the presence of shocks. At the inertial scale, high turbulence levels generated in the combustion chamber govern wall heat transfer in the high-pressure turbine stage, and wakes generated by low-pressure turbine vanes interact with separation bubbles at low-Reynolds conditions by suppressing them. The necessity to correctly analyze these phenomena obliges the scientific community, the industry, and public funding bodies to cooperate and continuously build new test rigs equipped with highly accurate instrumentation to account for real machine effects. In computational fluid dynamics, researchers developed fast and reliable methods to analyze unsteady blade-row interaction in the case of uneven blade count conditions as well as component interaction by using different closures for turbulence in each domain using high-performance computing. This research effort results in countless publications that contribute to unveiling the actual behavior of turbomachinery flow. However, the great number of publications also results in fragmented information that risks being useless in a practical situation. Therefore, it is useful to collect the most relevant outcomes and derive general conclusions that may help the design of next-gen turbomachines. In fact, the necessity to meet the emission limits defined by the Paris agreement in 2015 obliges the turbomachinery community to consider revolutionary cycles in which component interaction plays a crucial role. In the present paper, the authors try to summarize almost 40 years of experimental and numerical research in the component interaction field, aiming at both providing a comprehensive overview and defining the most relevant conclusions obtained in this demanding research field.

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Section: Hot Spot Migration In the High-pressure Turbine Stagementioning

confidence: 99%

Unsteady Flows and Component Interaction in Turbomachinery

Salvadori,

Insinna,

Martelli

2024

IJTPP

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“…The turbomachinery code used in this research has been extensively validated in the past on a wide variety of configurations [20,26,27]. In particular, the compressor clocking simulations discussed in [20] show that the code can accurately simulate wake interaction.…”

Section: Cfd Validationmentioning

confidence: 99%

CFD Computation of Fan Interaction Noise

Grace

Sondak

Dorney

et al. 2007

Volume 8: Heat Transfer, Fluid Flows, and Thermal Systems, Parts a and B

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In this study, a 3-D, unsteady, Reynolds-averaged Navier-Stokes (RANS) CFD code coupled to an acoustic calculation is used to predict the contribution of the exit guide vanes to tonal fan noise downstream. The configuration investigated is that corresponding to the NASA Source Diagnostic Test (SDT) 22-in fan rig. One configuration from the SDT matrix is considered here: the approach condition, and outlet guide vane count designed for cut-off of the blade passage frequency. In this chosen configuration, there are 22 rotor blades and 54 stator blades. The stators are located 2.5 tip chords downstream of the rotor trailing edge. The RANS computations are used to obtain the spectra of the unsteady surface pressure on the exit guide vanes. The surface pressure at the blade passage frequency and its second harmonic are then integrated together with the Green’s function for an annular duct to obtain the pressure at locations in the duct. Comparison of the computed sound power level at the exhaust plane with experiment show good agreement at the cut-on circumferential mode. The results from this investigation validate the use of the CFD code along with the acoustic model for downstream fan noise predictions. This validation enables future investigations such as the effect of duct variation on the exhaust tonal power level and the validity of using this method for predicting broadband noise levels.

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“…Moreover, the clearance modelling effects are studied comparing resolved clearance simulations with modelled clearance analyses. An accurate resolution of the clearance flows is, in fact, necessary for predicting the correct evolution of HSs as widely described in the literature [20]. All the numerical simulations are validated against a dataset provided by the LFM of the Politecnico di Milano.…”

Section: Introductionmentioning

confidence: 99%

Numerical study of a high-pressure turbine stage with inlet distortions

Bicchi

Pinelli

Marconcini

et al. 2019

Second International Conference on Material Science, Smart Structures and Applications: Icmss-2019

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The study of inlet flow distortion (hot streaks and entropy waves) propagation through high-pressure turbine (HPT) stages is an open topic for aero-engine design, due to their multiple effects on aerodynamics, heat exchange and noise generation. The request to design compact and lightweight systems has recently led to a reduction of the combustorturbine axial gap, making the interaction between the HPT and the combustor extremely critical. For this reason, the main aim of the present work is to numerically study how different clocking positions between temperature distortions and stator vanes can affect the evolution of hot streaks and entropy waves. In order to validate the numerical results, experimental data coming from an un-cooled high-pressure gas turbine stage tested at the Laboratorio di Fluidodinamica delle Macchine (LFM) of the Politecnico di Milano (Italy) has been used. The good agreement between numerical results and experimental data confirms the accuracy of the approach based on the CFD TRAF code and suggests recommendations for the design of the following rows.

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Effects of Tip Clearance on Hot Streak Migration in a High-Subsonic Single-Stage Turbine

Cited by 23 publications

References 16 publications

Unsteady Flows and Component Interaction in Turbomachinery

Unsteady Flows and Component Interaction in Turbomachinery

CFD Computation of Fan Interaction Noise

Numerical study of a high-pressure turbine stage with inlet distortions

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