The Effects of Coolant Pipe Geometry and Flow Conditions on Turbine Blade Film Cooling

Akbar, Muhammad

doi:10.18186/journal-of-thermal-engineering.314165

Cited by 3 publications

(3 citation statements)

References 22 publications

(50 reference statements)

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“…The lower kinetic energy at the jet centerline of the second modified irregular nozzle indicates that the jet divergence started from inside the coolant nozzle. The smaller inclination angle and the lateral divergence of the jet are attributes of the second modified irregular nozzle as observed in Figure 15b; both attributes have been shown to have a positive effect on film cooling performance (Goldstein et al, 1974;Akbar et al, 2017).…”

Section: Aerothermal Analysismentioning

confidence: 91%

“…One of the most significant aerodynamic features in film cooling is the formation of the Counter Rotating Vortex Pair (CRVP). The size and position of the CRVP influence the jet attachment/detachment and the film cooling effect (Akbar et al, 2017). Eliminating or reducing the strength of the CRVP is desired to mitigate its adverse effect (Hossain, 2020).…”

Section: Aerothermal Analysismentioning

confidence: 99%

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Numerical optimization study for the geometry of film cooling nozzle

Alshehaby

El-Gabry

2022

J. Glob. Power Propuls. Soc.

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Film cooling is one of the essential approaches developed to protect gas turbine blades and vanes from high temperature gases. It does so by covering the surface with a film of coolant air. Experimental and numerical studies have identified the parameters affecting film cooling aerodynamic and thermal behaviours; one of the most important is the coolant nozzle geometry. In this study, the nozzle geometry is optimized to enhance film effectiveness and heat transfer while keeping the inlet area and pitch-to-hole-width ratio fixed. A Reynolds-Averaged Navier Stokes (RANS) model, developed and validated against experimental data, served as the baseline for further optimization. The model was used to design a “racetrack slot” which is rectangular slot with semi-circular lateral edges. The aspect ratio of the slot was varied and an aspect ratio of seven was found to have the best cooling performance. As such, it served as the starting point for further, irregular, shape optimization of the coolant nozzle utilizing the ANSYS Fluent Adjoint solver. This solver allows mesh morphing within specified constraints and yielded a highly irregular coolant hole which taps into the potential of using additive manufacturing to produce cooled parts. The irregular shape optimization increased adiabatic film effectiveness over the test surface from 0.24 (for optimum racetrack coolant hole) to 0.34 (for optimum, irregular, coolant nozzle geometry). The enhancement is remarkable, especially when compared to 0.1; the value for the round coolant hole under the same conditions.

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Section: Aerothermal Analysismentioning

confidence: 91%

Section: Aerothermal Analysismentioning

confidence: 99%

Numerical optimization study for the geometry of film cooling nozzle

Alshehaby

El-Gabry

2022

J. Glob. Power Propuls. Soc.

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“…However, most previous uncertainty quantification studies are conducted based on conventional and inefficient Polynomial Chaos Expansion (PCE) models. Akbar et al (13) surveyed seven uncertainty parameters in total and performed the uncertainty quantification analysis by the PCE method for film cooling. Shi et al (14) used a PCE method to evaluate the uncertain effect of the conical angles etc.…”

Section: Introductionmentioning

confidence: 99%

Deep‐Learning-Based Uncertainty Analysis of Flat Plate Film Cooling With Application to Gas Turbine

Wang

Qiu

Qian

et al. 2023

Aerosp. Res. Commun.

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Nowadays, gas turbines intake jet air at high temperatures to improve the power output as much as possible. However, the excessive temperature typically puts the blade in the face of unpredictable damage. Film cooling is one of the prevailing methods applied in engineering scenarios, with the advantages of a simple structure and high cooling efficiency. This study aims to assess the uncertain effect that the three major film cooling parameters exert on the global and fixed-cord-averaged film cooling effectiveness under low, medium, and high blowing ratios br. The three input parameters include coolant hole diameter d, coolant tube inclination angle θ, and density ratio dr. The training dataset is obtained by Computational Fluid Dynamics (CFD). Moreover, a seven-layer artificial neural network (ANN) algorithm is applied to explore the complex non-linear mapping between the input flat film cooling parameters and the output fixed-cord-averaged film cooling effectiveness on the external turbine blade surface. The sensitivity experiment conducted using Monte Carlo (MC) simulation shows that the d and θ are the two most sensitive parameters in the low-blowing-ratio cases. The θ comes to be the only leading factor of sensitivity in larger blowing ratio cases. As the blowing ratio rises, the uncertainty of the three parameters d, θ, and dr all decrease. The combined effect of the three parameters is also dissected and shows that it has a more significant influence on the general cooling effectiveness than any single effect. The d has the widest variation of uncertainty interval at three blowing ratios, while the θ has the largest uncertain influence on the general cooling effectiveness. With the aforementioned results, the cooling effectiveness of the gas turbine can be furthermore enhanced.

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Simultaneous estimation of reference temperature and heat transfer coefficient in transient film cooling problems

ADEMANE

Kadoli

Hindasageri³

2023

Journal of Thermal Engineering

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This paper aims to simultaneously estimate the reference temperature and heat transfer coefficient in film cooling situations from transient temperature measurements. The exist-ing steady-state technique is a tedious process and employs distinct boundary conditions to evaluate each parameters of the film cooling. Applying different boundary conditions may lead to errors in the estimated parameters due to differences in aerodynamic condi-tions. On the other hand, a transient technique can estimate both parameters in a single test by utilizing short-duration transient temperature data. Hence, the present study uses a novel approach for solving transient film cooling problems based on the inverse heat con-duction approach, which can simultaneously estimate heat transfer coefficient and refer-ence temperature. The present method employs an optimization technique known as the Levenberg-Marquardt Algorithm. The objective function for the inverse algorithm is con-structed using the analytical solution of a transient one-dimensional semi-infinite body. The transient surface temperature data required for the present analysis is obtained through a numerical simulation of film cooling arrangement over a flat surface. Laterally averaged effectiveness and heat transfer coefficient for blowing ratios of 0.5, 0.8, and 1.0 are analyzed using the present technique and compared against the steady-state simulation results to demonstrate the methodology. An average deviation of around 7% for the estimated effec-tiveness and 4% for the heat transfer coefficient values are observed between the present IHCP method and the steady state simulation results. The deviation in heat transfer coeffi-cient predominately occurred near the film hole exit of x/d < 5, which might have occurred due to the conjugate solution employed in the present work.

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The Effects of Coolant Pipe Geometry and Flow Conditions on Turbine Blade Film Cooling

Cited by 3 publications

References 22 publications

Numerical optimization study for the geometry of film cooling nozzle

Numerical optimization study for the geometry of film cooling nozzle

Deep‐Learning-Based Uncertainty Analysis of Flat Plate Film Cooling With Application to Gas Turbine

Simultaneous estimation of reference temperature and heat transfer coefficient in transient film cooling problems

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