Hot Streak Evolution in an Axial HP Turbine Stage

Gaetani, Paolo; Persico, Giacomo

doi:10.3390/ijtpp2020006

Cited by 20 publications

(7 citation statements)

References 24 publications

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“…The temperature inhomogeneity was found to decrease the acoustic noise compared to the homogeneous reference case. Gaetani and Persico [17] showed experimentally that steady hot streaks are significantly attenuated over the nozzle guide vanes, while the vorticity field is highly altered.…”

Section: Introductionmentioning

confidence: 99%

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Entropy and Vorticity Wave Generation in Realistic Gas Turbine Combustors

Semlitsch¹,

Hynes²,

Langella

et al. 2019

Journal of Propulsion and Power

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Understanding the nature of the unsteady flow at the combustor exit is required to accurately simulate time dependent phenomena in the turbine entry, such as indirect noise generation. Using Large Eddy Simulations of the combustion process in a realistic geometry, we analyse the flow at its exit. Two realistic, near-ground certification operating conditions are considered. Different mechanisms for large-scale flow and thermal structure generation are described, which are ejected into the turbine. Modal decomposition methods are used to extract the spatial and temporal scales at the turbine entry. We find that, depending on the operating condition, the entropy waves convect as elongated streaks in the core of the combustor annulus or the proximity of the walls. The dominant unsteady character of the fluctuations exhibits different spectral properties, i.e. low-frequency in the core and high-frequency towards walls. At the combustor exit, the vortical field is dominated by the swirl in the air inlet, which is found to have little influence on the entropy perturbations. Further, the importance of considering the interaction of multiple fuel injectors and combustion zones in an annular combustor is investigated. It is shown that pulsating circumferential vorticity modes can occur in multi-sector annular combustors but these, however, do not affect the entropy wave distribution.

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Section: Introductionmentioning

confidence: 99%

“…All investigations employed idealised entropy wave shapes, i.e. spots [15,17] or plane waves [9]. Further, investigation treated vorticity and entropy waves separately.…”

Section: Introductionmentioning

confidence: 99%

Entropy and Vorticity Wave Generation in Realistic Gas Turbine Combustors

Semlitsch¹,

Hynes²,

Langella

et al. 2019

Journal of Propulsion and Power

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“…Their results demonstrated the effects on the flow path near wall due to the behavior of cavity-main flow interaction. Gaetani et al [9] studied the hot streak injection with respect to the stator blade. Measurements conducted upstream and downstream of the stage showed a severe attenuation of the streaks within the stator cascade and an enhancement of the rotor secondary flows by the streaks.…”

Section: Introductionmentioning

confidence: 99%

Particle Image Velocimetry (PIV) Investigation of Blade and Purge Flow Impacts on Inter-Stage Flow Field in a Research Turbine

Zhang

2019

Energies

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Flow field in the inter-stage is of great importance to jet engine turbine performance and efficiency. Investigation of flow fields is limited by the complex geometrical structure. Traditional measurement techniques, such as hot wire, pressure probe and laser Doppler velocimetry (LDV) can hardly obtain a planar information of the flow field simultaneously. To overcome this difficulty, an instantaneous planar velocimetry technique, the particle image velocimetry (PIV) technique is widely employed. However, there is no publication that studied the detailed flow field by PIV in a turbine inter-stage with the consideration of the influence of rotor blade and purge flow. This paper presents a quasi-three dimensional perspective of flow field between inlet guide vane (IGV) and rotor blade in a research turbine inter-stage by using a 2D PIV system. Coherent structures in the flow field are extracted by the proper orthogonal decomposition (POD) method. Time-averaged results show the ellipsoid structures caused by secondary flow in the inter-stage. Rotor blade influence to axial and radial flow is evaluated by time-averaged data and the first order POD mode. Egress of purge flow (9.4% of main annulus flow rate) leads to a domain with 60% axial velocity loss near hub and a growth over three times in radial velocity. POD analysis of purge flow shows detailed flow migration in the whole measurement plane.

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“…Adjusting the hot spot positions relative to the nozzle blades can be used to control the blade temperatures in gas turbines. It was shown [3][4][5][6][7][8][9] that the clocking effect when the hot spot is directed to the inlet edge of the nozzle blade reduces the effect of hot spots on the subsequent impeller. This can be explained by increased braking and increased mixing of the hot spot with the trace of the nozzle apparatus.…”

Section: Introductionmentioning

confidence: 99%

Simulation of the joint effect of rotor-stator interaction and circumferential temperature unevenness on losses in the turbine stage

Kortikov

2018

MATEC Web Conf.

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The article devotes to problems of unsteady interaction of the hot streams downstream of the combustion chamber with the rotating blades of the rotor wheel. The hot streams downstream of the combustion chamber are caused by discrete circumferentially located fuel nozzles and openings for air supply to the combustion chamber mixing zone. Unsteady interaction of the hot streams with the rotating blades of the rotor wheel leads to local redistribution of the time average gas flow temperature which has effect on the blade – “temperature segregation”.

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Hot Streak Evolution in an Axial HP Turbine Stage

Cited by 20 publications

References 24 publications

Entropy and Vorticity Wave Generation in Realistic Gas Turbine Combustors

Entropy and Vorticity Wave Generation in Realistic Gas Turbine Combustors

Particle Image Velocimetry (PIV) Investigation of Blade and Purge Flow Impacts on Inter-Stage Flow Field in a Research Turbine

Simulation of the joint effect of rotor-stator interaction and circumferential temperature unevenness on losses in the turbine stage

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