Clocking In Turbines: Remarks On Physical Nature And Geometric Requirements

Świrydczuk, J.

doi:10.1515/pomr-2015-0018

Cited by 6 publications

(3 citation statements)

References 29 publications

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“…Opting for this slight modification, the simulation of 1/8 sector of the whole geometry allowed satisfying the same periodicity of the rotating and stationary parts. The angular position of the first stage vanes and rotor blades was varied over the five equal distances within the angular interval a clock as proposed by Swirydczuk (2015)…”

Section: Clocking Effectsmentioning

confidence: 99%

Blade stacking and clocking effects in two-stage high-pressure axial turbine

Touil

Ghenaiet

2019

AEAT

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Purpose The purpose of this paper is to characterize the blade–row interaction and investigate the effects of axial spacing and clocking in a two-stage high-pressure axial turbine. Design/methodology/approach Flow simulations were performed by means of Ansys-CFX code. First, the effects of blade–row stacking on the expansion performance were investigated by considering the stage interface. Second the axial spacing and the clocking positions between successive blade–rows were varied, the flow field considering the frozen interface was solved, and the flow interaction was assessed. Findings The axial spacing seems affecting the turbine isentropic efficiency in both design and off-design operating conditions. Besides, there are differences in aerodynamic loading and isentropic efficiency between the maximum efficiency clocking positions where the wakes of the first-stage vanes impinge around the leading edge of the second-stage vanes, compared to the clocking position of minimum efficiency where the ingested wakes pass halfway of the second-stage vanes. Research limitations/implications Research implications include understanding the effects of stacking, axial spacing and clocking in axial turbine stages, improving the expansion properties by determining the adequate spacing and locating the leading edge of vanes and blades in both first and second stages with respect to the maximum efficiency clocking positions. Practical implications Practical implications include improving the aerodynamic design of high-pressure axial turbine stages. Originality/value The expansion process in a two-stage high-pressure axial turbine and the effects of blade–row spacing and clocking are elucidated thoroughly.

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Section: Clocking Effectsmentioning

confidence: 99%

Blade stacking and clocking effects in two-stage high-pressure axial turbine

Touil

Ghenaiet

2019

AEAT

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“…Using potential flow formulation, Swirydczuk concluded that under an optimum clocking position, a special form of upstream wake vortices is shed within the blades passage which increases dynamic pressure and consequently outlet total pressure at blade throat. 22 Other wake tracking analyses can be referred to some researchers like Hodson, 23 Jouini et al, 24 Gombert et al, 25 and Arndt. 26 These researchers reported that the blade-wake interactions can be controlled by clocking mechanism to influence the aerodynamic performance of axial turbines, including turbine efficiency, profile loss, boundary layer transition, and development of the secondary flows.…”

Section: Introductionmentioning

confidence: 99%

Clocking effects on aerodynamics of a gas turbine low pressure axial turbine, part 2: Unsteady simulation

Taghavi Zenouz,

Abiri

2023

Proceedings of the Institution of Mechanical Engineers, Part G:

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Unsteady, viscous compressible flow is numerically simulated within first two stages of a low pressure turbine of a gas turbine engine under different clocking of its stator blades rows. Zonal DES turbulence modeling has been used for flow simulations. Time-dependent wake flow trajectory is modeled and visualized within the blades passages. All characteristics of the passage wake flow, including its V-shape motion, re-orientation, elongation, expansion, and stretching, are properly simulated. Unsteady flow field results together with those of general aerodynamic performance of the optimum and worst clocking cases are presented and compared with each other. Analyses of the flow simulation results showed that the optimum clocking of the blades rows occurs while the upstream wake flow impinges on the downstream stator blade leading edge region. Final results demonstrated that under the optimum clocking of the second stator, the inlet total pressure of the second rotor blades row and its output power increase by 0.1% and 0.336%, respectively. Consequently, efficiency of the second stage increases by 0.35%. In addition, total output power of the whole two stages increases by 0.237%.

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“…Additionally, all over the world new trends were introduced. Flow channels, machines geometries (especially those of vanes and blades), and flow conducting solutions started to be redesigned since new machines should be as compact as possible, be characterized by low energy losses and the use of new materials and technologies is involved (Saren et al, 2000;Rzadkowski et al, 2003;Liptak, 2009;Balicki et al, 2010;Kang, 2014;Swirydczuk, 2015). To solve these problems rarely completely new unconventional methods are proposed, basing mostly on numerical methods (Marczyk, 1999;Sondak, Dorney, 2000;Bennett, 2005;Button, 2015;Manoha, 2017), sometimes also using neural networks (Gluch et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Experimental research of noise reduction possibilities of an axial fan with an additional contra-rotor

Błaszczak

Kryłłowicz

2019

European Conference on Turbomachinery Fluid Dynamics and Hermodynamics

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This work refers to investigations of the noise propagation of a fan with an inlet contrarotating rotor. The main goal was to find if there were regions of rotational frequency where the noise levels emitted by the system may be lower than expected. The measurements were performed at Lodz University of Technology in the aeroacoustic anechoic chamber. Constant rotational speed of the first rod-rotor was set-up as constant with varying rotational speed of the second rotor (the fan). The system was similar to one of the NASA earlier experiments. The analysis showed correlations between the emitted noise levels and the rotational speeds of the rotors. Next, the noise emitted only by the second rotor (the fan) was compared with the noise of two co-operating rotors. Some regions, where the noise of the fan was reduced due to the presence of the second contra-rotating rotor at the inlet, gave a base for future investigations. The issue is important especially in cases where quiet electric drives can be used and the aerodynamic noise is crucial. The presented results can be used in similar systems in modern flow machinery, aeroengines configurations, double -rotor drones, as well as, due to the simplicity of the system and its geometry, for verification of numerical methods. KEYWORDSFAN, CONTRA-ROTATING ROTORS, NOISE REDUCTION NOMENCLATURE BPF [-] blade passing frequency = 8•n P [W] power of the drive c [m/s] flow velocity P 0 [W] power of the fan drive for n = n 0 c 0 [m/s] flow velocity for n = n 0 RPF [-] rod passing frequency = 3•n 0 L [dB] sound pressure level Tu [-] turbulence level n [Hz] fan rotational speed Tu 0 [-] turbulence level for n = n 0 n 0 [Hz] rod-rotor rotational speed Δp [Pa] dynamic pressure fluctuation p ref [Pa] ref. sound pressure: 20 μPa Δp 0 [Pa] dyn. press. fluctuation for n = n 0

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Clocking In Turbines: Remarks On Physical Nature And Geometric Requirements

Cited by 6 publications

References 29 publications

Blade stacking and clocking effects in two-stage high-pressure axial turbine

Blade stacking and clocking effects in two-stage high-pressure axial turbine

Clocking effects on aerodynamics of a gas turbine low pressure axial turbine, part 2: Unsteady simulation

Experimental research of noise reduction possibilities of an axial fan with an additional contra-rotor

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