The benefit of high-conductivity materials in film cooled turbine nozzles

Montomoli, Francesco; Massini, Michela; Yang, Haiyuan; Han, Je-Chin

doi:10.1016/j.ijheatfluidflow.2011.12.005

Cited by 34 publications

(9 citation statements)

References 26 publications

(36 reference statements)

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“…The main goal is increasing heat transfer while reducing thermal gradients across the blades and minimize the energy used for coolant purpose (Saha and Acharja 2014). Temperature uniformity is strongly required to avoid cracks and ensure high level of reliability; this aspect is still considered one of the greatest challenges in gas turbine production (Bunker 2007;Montomoli et al 2012). In order to predict the metal temperature accurately, it is important to carry out a conjugate heat transfer (CHT) method, where the thermal field in the fluid and the solid are solved at the same time.…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional fluid topology optimization for heat transfer

Pietropaoli¹,

Montomoli²,

Gaymann³

2018

Struct Multidisc Optim

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In this work, an in house topology optimization (TO) solver is developed to optimize a conjugate heat transfer problem: realizing more complex and efficient coolant systems by minimizing pressure losses and maximizing the heat transfer. The TO method consists in an idealized sedimentation process in which a design variable, in this case impermeability, is iteratively updated across the domain. The optimal solution is the solidified region uniquely defined by the final distribution of impermeability. Due to the geometrical complexity of the optimal solutions obtained, this design method is not always suitable for classic manufacturing methods (molding, stamping....) On the contrary, it can be thought as an approach to better and fully exploit the flexibility offered by additive manufacturing (AM), still often used on old and less efficient design techniques. In the present article, the proposed method is developed using a Lagrangian optimization approach to minimize stagnation pressure dissipation while maximizing heat transfer between fluid and solid region. An impermeability dependent thermal conductivity is included and a smoother operator is adopted to bound thermal diffusivity gradients across solid and fluid. Simulations are performed on a straight squared duct domain. The variability of the results is shown on the basis of different weights of the objective functions. The solver builds automatically three-dimensional structures enhancing the heat transfer level between the walls and the flow through the generation of pairs of counter rotating vortices. This is consistent to solution proposed in literature like v-shaped ribs, even if the geometry generated is more complex and more efficient. It is possible to define the desired level of heat transfer and losses and obtain the closest optimal solution. It is the first time that a conjugate heat transfer optimization problem, with these constraints, has been tackled with this approach for three-dimensional geometries.

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Section: Introductionmentioning

confidence: 99%

Three-dimensional fluid topology optimization for heat transfer

Pietropaoli¹,

Montomoli²,

Gaymann³

2018

Struct Multidisc Optim

Self Cite

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“…Lee investigated on a key vortical structure in film cooling flow, which is called counter-rotating vortex pair (CRVP) in order to increase the effectiveness during film cooling on turbine blades. Montomoli (2012) conducted numerical as well as experimental investigation to study the effect of higher conductivity materials in HP turbine nozzles. They concluded that using nickelaluminide alloys in nozzles reduce the thermal gradients from 3 to 4 times.…”

Section: Literature Reviewmentioning

confidence: 99%

Computational Study on Pressure Side Film Cooling and Flow Structure

Dhanasegaran¹,

Venkatachalapathy²,

Gnanasekaran³

2013

ASME 2013 Gas Turbine India Conference

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a Final year Student BE Mechanical Engineering, b Associate Professor SSN College of Engineering Chennai, TamilNadu, India ABSTRACTA computational investigation is carried out to understand the film cooling performance and flow phenomenon on a pressure side of gas turbine airfoil. A specific geometry with multiple rows of cylindrical holes is considered on the pressure surface and opposite to which a flat surface is kept so as to avoid effect of imposed flow conditions. Meshing of the present model is done by using GAMBIT. Computations are carried out with К-epsilon Realizable model available in the commercial code FLUENT. The film cooling performance is discussed with flow structure followed by the effectiveness distribution on the pressure surface. The blowing ratio is varied from 0.4-2.4 and it is found that, at very low blowing ratio cases in the initial part of the pressure surface higher effectiveness values are observed but at higher blowing ratio these values become very low whereas close to the trailing edge side the effectiveness distribution is just the reverse. It was found that the optimum blowing ratio was close to unity where better flow and temperature distribution were observed.

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“…However, it is a large challenge for the design of turbine devices, especially NGV, owing to the non-uniform temperature profiles of turbine inlet (combustor outlet). To investigate the interacting influences between total pressure and temperature radial gradients on heat transfer performance of a high-pressure turbine vane, Barringer et al [5,6] developed a combustor simulator and revealed pressure gradient seriously influencing vane heat transfer [7]; Povey et al [8] also simulated the engine combustor exit realistic temperature profiles. The subsequent studies revealed the influences of hot spot on the heat transfer of both NGV and intermediate pressure vanes [9].…”

Section: Introductionmentioning

confidence: 99%

An Enhanced Flow-Thermo-Structural Modeling and Validation for the Integrated Analysis of a Film Cooling Nozzle Guide Vane

Guan

Fei

2019

Energies

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The target of this paper is to develop an enhanced flow-thermo-structural (FTS) model with high computational accuracy, to perform the integrated analysis of film cooling nozzle guide vane (NGV). An efficient turbulence model and weak spring approach are utilized in the enhanced FTS model. In respect of the power balance principle of aeroengine rotor shaft and temperature test of a typical combustor, the mean temperature inlet and five normalization temperature curves were confirmed, respectively. The temperature-sensitive paint (TSP) technology was used to verify the numerical simulation. From this study, we find that the predicted temperature caters for the TSP test well, between which the maximum error is less than 6%, and the maximum thermal stress is 758 MPa around the hole edges and the location of stress concentration keeps the consistency with that of the cracks. The maximum thermal stress increases by 10% with the increasing inlet temperature and reduces by about 16% with the shifting of flame peak from the outer to inner hub. The prediction provides general information on the initiation of cracks on a vane segment. The developed enhanced FTS model is validated to be workable and precise in the integrated analysis of film cooling NGV. The efforts of this study provide an integrated analysis approach of film cooling NGV and are promising to provide guidance for the integrated design of film cooling components besides NGV.

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The benefit of high-conductivity materials in film cooled turbine nozzles

Cited by 34 publications

References 26 publications

Three-dimensional fluid topology optimization for heat transfer

Three-dimensional fluid topology optimization for heat transfer

Computational Study on Pressure Side Film Cooling and Flow Structure

An Enhanced Flow-Thermo-Structural Modeling and Validation for the Integrated Analysis of a Film Cooling Nozzle Guide Vane

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