Impact of Cooling Injection on Shock Wave Over a Flat Tip in High Pressure Turbine

Ma, Haiteng; Zeng, Wei; Jiang, Hongmei; Hong, Jun

doi:10.1115/1.4052135

Cited by 3 publications

(2 citation statements)

References 52 publications

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“…Moreover, the cooling injection alters the effective flow characteristic and shock wave position. [30][31][32] It is to be noted that the TLF characteristics are expected to significantly differ for the transonic condition compared to the subsonic condition. This is due to phenomena like flow choking, shock waves, SBLI, and supersonic reattachment, which are not seen at subsonic speeds.…”

Section: Introductionmentioning

confidence: 99%

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Blade tip leakage flow and heat transfer characteristics over a gas turbine blade at subsonic and transonic exit conditions

Dipendrasingh,

MVV,

2023

Proceedings of the Institution of Mechanical Engineers, Part G:

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The present study numerically investigates the blade tip leakage flow (TLF) over a gas turbine blade cascade at low speed ( M ex = 0.1) and transonic ( M ex = 0.92) blade exit Mach numbers, with and without shroud motion. Various blade tip flow phenomena like flow separation and reattachment, flow choking, shock-boundary layer interaction (SBLI), and tip leakage vortex (TLV) are studied, and their influence on the heat transfer coefficient (HTC) distributions over the blade tip and near tip blade suction surface is investigated. The study has found some new zones of heat transfer due to the interaction of horseshoe vortices (HSV) with the blade tip. In addition to the primary TLV, a secondary TLV is formed, which increases near tip blade suction surface heat transfer. The flow transitions to supersonic speed in the aft portion of the blade tip for the transonic case resulting in complex heat transfer distribution due to SBLI, compared to near-uniform distribution for the low speed case. This supersonic flow results in a smaller flow separation zone near the aft portion of the pressure side tip edge for the transonic case compared to the low speed case. The qualitative nature of HTC near the leading edge of the blade tip resembles for low speed and transonic cases. However, near the trailing edge of the blade tip, the qualitative nature of HTC for the transonic case shows a substantial difference due to supersonic flow compared to the low speed case.

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Section: Introductionmentioning

confidence: 99%

“…Moreover, the cooling injection alters the effective flow characteristic and shock wave position. 30–32…”

Section: Introductionmentioning

confidence: 99%

Blade tip leakage flow and heat transfer characteristics over a gas turbine blade at subsonic and transonic exit conditions

Dipendrasingh,

MVV,

2023

Proceedings of the Institution of Mechanical Engineers, Part G:

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Sensitivity of Adiabatic Cooling Effectiveness to Mainstream and Coolant Temperatures in Transonic Flow Over an Idealized Blade Tip Model

Zeng

Dai

et al. 2022

Journal of Turbomachinery

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Film cooling has been studied profusely in subsonic flows, but in transonic flow, the determination of adiabatic cooling effectiveness faces a dilemma in the state of the art. Specifically, derivation of reference temperature, or local recovery temperature, in adiabatic effectiveness is disputable. Some researchers designate it to be the adiabatic wall temperature for the uncooled model (linear regression method, LRM), but others calculate it from an iterative procedure based on a pair of cooling tests which only differs in coolant temperature (dual linear regression technique, DLRT). As the first of the kind effort to explore this dilemma, this paper carried out transient thermal measurements by infrared thermography, for transonic flow over an idealized blade tip model. Heat transfer experiments were conducted for the uncooled and cooled cases, at two mainstream temperatures (340K and 325K), and two coolant temperatures (276K and 287K). Data from these six experiments were processed by LRM and DLRT respectively. It is found that heat transfer coefficient is insensitive to temperature boundary conditions and data reduction methods, as expected. However, for adiabatic effectiveness, LRM results are sensitive to the 11K decrease of coolant temperature in areas confined to the upstream of cooling injection, and much less so to the 15K rise in mainstream temperature. DLRT result reduces globally and conspicuously with 15K increase in mainstream temperature. Furthermore, adiabatic effectiveness obtained by LRM is qualitatively different to that by DLRT, which is attributed to the large discrepancy of reference temperature between the two methods.

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Aerodynamic Performance and Leakage Flow in Turbine Cascades With Sweeping Jet Actuators

Chen¹,

Yang³

et al. 2023

Journal of Turbomachinery

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In recent years, unsteady flow-control technology has been considered as more promising for reducing secondary flow loss in turbines. In particular, because of their large sweeping range, sweeping jet actuators (SJAs) have gradually been applied to turbomachinery to reduce loss. However, most of the preliminary studies were focused mainly on computational fluid dynamics (CFD) calculations, with very few on wind-tunnel experiments to verify the flow-control effectiveness. To fill this gap, an innovative attempt to investigate experimentally the influences of SJAs on the aerodynamic performance and leakage flow is presented in a high-pressure turbine cascade. By comparing SJAs and hole-style steady jet actuators (HSJAs), the influence on the tip leakage flow and the loss characteristics with different incidences and injection frequencies are discussed in detail. The results indicate that the SJAs effectively reduce the magnitude and extension of the leakage vortex and the passage vortex, and weaken the interactions between them. When the jet flow of an SJA is 0.2% of the inlet flow, the loss at the cascade outlet decreases by up to 10.3%, which is significantly better than that with an HSJA (6.3%).

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Impact of Cooling Injection on Shock Wave Over a Flat Tip in High Pressure Turbine

Cited by 3 publications

References 52 publications

Blade tip leakage flow and heat transfer characteristics over a gas turbine blade at subsonic and transonic exit conditions

Blade tip leakage flow and heat transfer characteristics over a gas turbine blade at subsonic and transonic exit conditions

Sensitivity of Adiabatic Cooling Effectiveness to Mainstream and Coolant Temperatures in Transonic Flow Over an Idealized Blade Tip Model

Aerodynamic Performance and Leakage Flow in Turbine Cascades With Sweeping Jet Actuators

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