Infrared thermography to study endwall cooling and heat transfer in turbine stator vane passages using the auxiliary wall method and comparison to numerical simulations

Werschnik, Holger; Ostrowski, Tom; Hilgert, Jonathan; Schneider, Marius; Schiffer, Heinz-Peter

doi:10.1080/17686733.2015.1066135

Cited by 9 publications

(4 citation statements)

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“…The experimental and numerical results of endwall heat transfer and film-cooling effectiveness in Refs. [1][2][3] are obtained with the cylindrical film-cooling holes either in a single or two-row arrangements in the upstream endwall. The results in…”

Section: Introductionmentioning

confidence: 99%

“…Refs. [1][2][3] are affected as the film-cooling flow interacts with the endwall region flows and migrates away from the endwall and pressure side of the cascade passage. Wang et al [4] employs two rows of cylindrical holes at the upstream-endwall as well as at the downstream of mid-passage locations in the cascade endwall to show the upstream holes are the most effective in the film-cooling coverage and higher adiabatic effectiveness.…”

Section: Introductionmentioning

confidence: 99%

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Upstream Endwall Film-Cooing in a Vane Cascade with Cylindrical Shape Holes

Huyssen

Shote

Mahmood

2023

Journal of Thermophysics and Heat Transfer

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To overcome the disadvantages of cylindrical holes in film cooling, complex geometries of the fan-shaped diffused holes are employed in cascade investigations. The present experiment employs a new design of a diffused hole for film cooling that is formed by diffusing a cylindrical hole smoothly and only in the forward direction. The aerothermal performances in a linear vane cascade are compared between an array of simple cylindrical holes and an array of diffused-cylindrical holes by employing them in the cascade upstream endwall. The objectives are to increase the aerothermal performance of the cylindrical holes in the gas-turbine passage film cooling. The measurements of the temperature, velocity, flow angle, and total-pressure losses are obtained at the inlet Reynolds number of [Formula: see text], as well as the coolant-to-mainstream density ratio of 1.0 and temperature ratios between 0.94 and 1.0. Four inlet blowing ratios of film-cooling flow are tested. The results show less coolant migration into the boundary layer and passage vortex for the diffused holes than for the cylindrical holes. The passage vortex becomes weaker, and the overall total-pressure losses at the passage exit are lower for the diffused holes. The local and average adiabatic film-cooling effectivenesses along the endwall are always higher for the diffused holes.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Upstream Endwall Film-Cooing in a Vane Cascade with Cylindrical Shape Holes

Huyssen

Shote

Mahmood

2023

Journal of Thermophysics and Heat Transfer

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“…Another stationary high-resolution heat transfer study is presented in Laveau et al [3]. Laveau's concept to simultaneously derive the heat transfer coefficient and the adiabatic wall temperature served as one reference for the study presented in Werschnik et al [4]. The work of Schuler [5] represents a comprehensive experimental aero-thermal study on the effect of rim seal purge flow to the hub side endwall region.…”

Section: Introductionmentioning

confidence: 99%

“…As published in Werschnik et al [19], the heat transfer measurement technique as applied in the linear cascade [4] was adopted to the first stator endwall of the Large Scale Turbine Rig (LSTR), a large scale low Mach number turbine test facility operated by the Institute of Gas Turbines and Aerospace Propulsion at Technische Universität Darmstadt. For the work presented in this paper, the aforementioned setup was adapted and enhanced to be applicable to the rotor hub side endwall at the LSTR.…”

Section: Introductionmentioning

confidence: 99%

High-resolution heat transfer measurements on a rotating turbine endwall with infrared thermography

Ostrowski

Schiffer

2021

Meas. Sci. Technol.

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Computational thermo-fluid dynamics in the field of turbo machinery research tend to account for transient interaction mechanisms to predict the convective heat transfer within the hot gas path. In this context, the rotor hub side endwall region of the high pressure turbine depicts an object of interest as the near wall flow field may be dominated by rotating flow structures emerging from the disc space cavities. The validation of the applied numerical tools rely on experimental heat transfer setups reproducing such transient boundary conditions. This paper describes an experimental approach to quantify the heat transfer coefficient and the adiabatic wall temperature on the rotating endwall of a large scale test turbine. The wall heat flux distribution in a thin film isolator coated to a well conducting support structure is quantified for a series of quasi-isothermal boundary conditions. A high-resolution infrared camera is used to capture triggered thermograms of the rotating surface. Distributed thermocouples in the base body serve as reference points for camera calibration and to deduce the temperature distribution at the interface to the isolator. The calibration is in-situ and includes the pixel-wise quantification of uncertainties in the surface temperatures. An advanced linear fit approach is applied to derive the unknown adiabatic quantities and their uncertainties. For the examined operating point with a rim seal purge flow rate of 1% the random part of the relative measurement uncertainty is clearly below 10% for the heat transfer coefficient and below 5% for the adiabatic wall temperature. As the evaluation algorithm is designed to consider covariances between the thermocouple and infrared readings, the surface wall heat flux can be evaluated for every single infrared image.

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