Advanced Flow Control for Supersonic Blowdown Wind Tunnel Using Extended Kalman Filter

Xi, Jiaqi; Zhang, Qiang; Li, Mian; Wang, Zhaoguang

doi:10.1115/gt2013-95281

Cited by 5 publications

(3 citation statements)

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“…To adjust total pressure at the inlet of test section, a Fisher valve (EWT Body with 667 actuator and Fieldvue DVC6000 controller) controlled through an extended Karman filter algorithm as described in Refs. [37,38] was used. Airflow is homogenized by honeycomb screens and flow straightening Transactions of the ASME devices and heated by a fine mesh (aperture size of 0.08 mm and filament diameter of 0.05 mm) powered by a 100 kW DC supply.…”

Section: Experimental Setup and Methodologymentioning

confidence: 99%

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

Zeng

Jiang

et al. 2021

Journal of Turbomachinery

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Cooling design of highly-loaded turbine blade tips is challenged by the scarcity of experimental data and the lack of physical understanding in cooling and over-tip leakage (OTL) interaction under transonic conditions. To address these issues, this paper carried out transient thermal measurements through infrared thermography on a transonic flat tip with and without cooling injection. Experimental data of Nusselt number and cooling effectiveness were obtained and compared with computational fluid dynamics results for numerical validation. Both experimental data and simulation results show that cooling injection drastically augments tip Nusselt number near pressure side which is upstream of ejection, and in areas around coolant holes. Moreover, a strikingly low Nusselt number stripe is observed downstream of cooling injection from one of the holes in aft portion of blade. The strip is directed transverse to local OTL streamline flowing from pressure to suction side and sprawls to adjacent coolant wakes. Further numerical analyses concluded that cooling injection changes tip aerodynamics and overtip shock wave structure fundamentally. Oblique shock waves across uncooled flat tip are replaced by a confined shock train downstream of cooling injection and between cooling holes, which is constituted by two shocks normal to local OTL flow coming from pressure side. Across the first shock, density and pressure increases abruptly, contributing to thickening of tip boundary layer and the plummet of skin friction on tip surface, which is responsible for the sharp decline of tip Nusselt number and therefore, formation of low heat transfer stripe downstream cooling injection.

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Section: Experimental Setup and Methodologymentioning

confidence: 99%

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

Zeng

Jiang

et al. 2021

Journal of Turbomachinery

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“…A pitot tube and a fast response thermocouple are mounted to monitor the real-time inlet parameters, as plotted in Figure 4. Inlet total pressure P 0,i is regulated by a control valve based on Karman filter algorithm(Xi et al 24 and Zheng et al 25 ) at 180 kPa. A heater mesh is placed to heat the mainstream flow.…”

Section: Experimental Validationmentioning

confidence: 99%

“…Inlet total pressure P 0,i is regulated by a control valve based on Karman filter algorithm(Xi et al. 24 and Zheng et al. 25 ) at 180 kPa.…”

Section: Experimental Validationmentioning

confidence: 99%

Influence of tip clearance and cavity depth on heat transfer in a cutback squealer tip

Wang

Jiang

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part G:

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Numerical simulations are conducted to present the aerothermal performance of a turbine blade tip with cutback squealer rim. Two different tip clearance heights (0.5%, 1.0% of the blade span) and three different cavity depths (2.0%, 3.0%, and 6.0% of the blade span) are investigated. The results show that a high heat transfer coefficient (HTC) strip on the cavity floor appears near the suction side. It extends with the increase of tip clearance height and moves towards the suction side with the increase of cavity depth. The cutback region near the trailing edge has a high HTC value due to the flush of over-tip leakage flow. High HTC region shrinks to the trailing edge with the increase of cavity depth since there is more accumulated flow in the cavity for larger cavity depth. For small tip clearance cases, high HTC distribution appears on the pressure side rim. However, high HTC distribution is observed on suction side rim for large tip clearance height. This is mainly caused by the flow separation and reattachment on the squealer rims.

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Cooling Injection Effect on a Transonic Squealer Tip—Part I: Experimental Heat Transfer Results and CFD Validation

Zhang

et al. 2017

Journal of Engineering for Gas Turbines and Power

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Recent studies have demonstrated that the aerothermal characteristics of turbine rotor blade tip under a transonic condition are qualitatively different from those under a low-speed subsonic condition. The cooling injection adds further complexity to the over-tip-leakage (OTL) transonic flow behavior and aerothermal performance, particularly for commonly studied shroudless tip configurations such as a squealer tip. However there has been no published experimental study of a cooled transonic squealer. The present study investigates the effect of cooling injection on a transonic squealer through a closely combined experimental and CFD effort. Part I of this two-part paper presents the first of the kind tip cooling experimental data obtained in a transonic linear cascade environment (exit Mach number 0.95). Transient thermal measurements are carried out for an uncooled squealer tip and six cooling configurations with different locations and numbers of discrete holes. High-resolution distributions of heat transfer coefficient and cooling effectiveness are obtained. ansysFluent is employed to perform numerical simulations for all the experimental cases. The mesh and turbulence modeling dependence is first evaluated before further computational studies are carried out. Both the experimental and computational results consistently illustrate strong interactions between the OTL flow and cooling injection. When the cooling injection (even with a relatively small amount) is introduced, distinctive series of stripes in surface heat transfer coefficient are observed with an opposite trend in the chordwise variations on the squealer cavity floor and on the suction surface rim. Both experimental and CFD results have also consistently shown interesting signatures of the strong OTL flow–cooling interactions in terms of the net heat flux reduction distribution in areas seemingly unreachable by the coolant. Further examinations and analyses of the related flow physics and underlining vortical flow structures will be presented in Part II.

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Advanced Flow Control for Supersonic Blowdown Wind Tunnel Using Extended Kalman Filter

Cited by 5 publications

References 0 publications

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

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

Influence of tip clearance and cavity depth on heat transfer in a cutback squealer tip

Cooling Injection Effect on a Transonic Squealer Tip—Part I: Experimental Heat Transfer Results and CFD Validation

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