Correlating Cavity Sealing Effectiveness to Time-Resolved Rim Seal Events in the Presence of Vane Trailing Edge Flow

Siroka, Shawn; Monge-Concepción, Iván; Berdanier, Reid A.; Barringer, M. D.; Thole, Karen A.; Robak, Christopher

doi:10.1115/gt2021-59285

Cited by 7 publications

(2 citation statements)

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“…Table 1 also details the material choices and thermal properties for the study. The thermal properties for the substrate come from previous tests conducted for the same material [14], while the manufacturer specifications were used for the parylene-F coating properties [15]. These materials and thicknesses were…”

Section: Gauge Designmentioning

confidence: 99%

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Development of coated heat flux gauges for fast responding measurements

Siroka¹,

Berdanier²,

Thole³

2022

Meas. Sci. Technol.

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Thermal systems often exhibit transient behaviors that have important implications for the operation of the system and can be difficult to predict. For these reasons, experimental testing is often required to ensure system durability requirements are achieved. One important parameter governing the survivability of components in hot, high-stress environments is the heat flux into the part that dictates the temperature distribution for the component. However, sensors required to experimentally characterize heat fluxes in extreme environments must also be resilient. This study presents the development of coated heat transfer gauges capable of robust, high-frequency measurements in turbine research facilities. The addition of a protective coating increases the durability of the gauge, but inherent of that coating is the attenuation of high-frequency temperature penetrations. As a result, this study first outlines the use of analytical solutions to define a gauge design for a specific frequency range and heat transfer, ensuring that subsurface signals can be rectified to surface conditions through inverse methods. Then, the fabrication of polyimide substrate sensors with a parylene-F coating is described. Micro surface heaters added to the custom sensors were used to determine important geometric and thermal properties necessary to calculate accurate surface heat flux. Ultimately, this work shows increased sensor robustness in a turbine test bed and experimentally validates that the frequency response of the fabricated sensors meet the design intent.

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Section: Gauge Designmentioning

confidence: 99%

“…(rad s −1 ) Polyimide [14] (ρscsks) 0.5 501 (J K −1 m −2 s −0.5 ) ks 0.19 (W m −1 K −1 ) ds 50E-6 (m) Parylene-F [15] (ρccckc) 0.5 407…”

Section: Gauge Designmentioning

confidence: 99%

Development of coated heat flux gauges for fast responding measurements

Siroka¹,

Berdanier²,

Thole³

2022

Meas. Sci. Technol.

Self Cite

View full text Add to dashboard Cite

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Correlating Time-Resolved Pressure Measurements With Rim Sealing Effectiveness for Real-Time Turbine Health Monitoring

DeShong

Peters

Berdanier

et al. 2022

Journal of Turbomachinery

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Purge flow is bled from the upstream compressor and supplied to the under-platform region to prevent hot main gas path ingress that damages vulnerable under-platform hardware components. A majority of turbine rim seal research has sought to identify methods of improving sealing technologies and understanding the physical mechanisms that drive ingress. While these studies directly support the design and analysis of advanced rim seal geometries and purge flow systems, the studies are limited in their applicability to real-time monitoring required for condition-based operation and maintenance. As operational hours increase for in-service engines, this lack of rim seal performance feedback results in progressive degradation of sealing effectiveness, thereby leading to reduced hardware life. To address this need for rim seal performance monitoring, the present study utilizes measurements from a one-stage turbine research facility operating with true-scale engine hardware at engine-relevant conditions. Time-resolved pressure measurements collected from the rim seal region are regressed with sealing effectiveness through the use of common machine learning techniques to provide real-time feedback of sealing effectiveness. Two modelling approaches are presented that use a single sensor to predict sealing effectiveness accurately over a range of two turbine operating conditions. Results show that an initial purely data-driven model can be further improved using domain knowledge of relevant turbine operations, which yields sealing effectiveness predictions within three percent of measured values.

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Influence of Vane Trailing Edge Flow on the Formation of Cavity Cells and Rim Sealing

Monge-Concepción

Siroka

Berdanier

et al. 2022

Journal of Turbomachinery

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Hot gas ingestion into turbine rim seal cavities is an important concern for engine designers. To prevent ingestion, rim seals use high pressure purge flow; however, the penalty is excessive use of purge flow decreases engine thermal efficiency. In this paper, a one-stage turbine operating at engine representative conditions was used to study the effect of steady and time-resolved under-platform cavity temperatures and pressures across a range of coolant flow rates in the presence of vane trailing edge (VTE) flow. This study correlates time-resolved pressure with time-resolved temperature to identify primary frequencies driving ingestion. At certain flow rates, time-resolved pressures are out of phase with temperatures, indicating ingestion. Measurements from high-frequency response pressure sensors in the rim seal and vane platform were used to determine rotational speed and quantity of large-scale structures (cells). A computational model using Unsteady Reynolds-averaged Navier-Stokes (URANS) was applied to determine swirl ratio in the rim seal cavity and time-resolved rim sealing effectiveness. Experimental results confirm at low purge flow rates, VTE flow influences the unsteady flow field by decreasing pressure unsteadiness in the rim seal cavity. Results show an increase in purge flow increases the number of unsteady cells and decreases their rotational speed. However, VTE flow was shown to not significantly change cell speed and count. Simulations point to the importance of the large-scale cell structures in influencing rim sealing unsteadiness, which is not captured in current rim sealing predictive models.

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Correlating Cavity Sealing Effectiveness to Time-Resolved Rim Seal Events in the Presence of Vane Trailing Edge Flow

Cited by 7 publications

References 0 publications

Development of coated heat flux gauges for fast responding measurements

Development of coated heat flux gauges for fast responding measurements

Correlating Time-Resolved Pressure Measurements With Rim Sealing Effectiveness for Real-Time Turbine Health Monitoring

Influence of Vane Trailing Edge Flow on the Formation of Cavity Cells and Rim Sealing

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