Film Cooling Effectiveness Aided  with Increased Turbulence in the  Coolant Flow

F.Z. Sierra-Espinosa

doi:10 .4172/2327-4581.1000411

Commentary, J Nucl Ene Sci Power Generat Techno Vol: 14 Issue: 2

Film Cooling Effectiveness Aided with Increased Turbulence in the Coolant Flow

F.Z. Sierra-Espinosa^*

Department of Applied Sciences and Engineering, Autonomuos University of Morelos State, Av. Universidad 1001, Cuernavaca, Morelos, 62209, México

*Corresponding Author: F.Z. Sierra-EspinosaDepartment of Applied Sciences and Engineering, Autonomuos University of Morelos State, Av. Universidad 1001, Cuernavaca, Morelos, 62209, México; E-mail:fse@uaem.mx

Received date: 13 June, 2024, Manuscript No. JNPGT-24-138856;
Editor assigned date: 17 June, 2024, PreQC No. JNPGT-24-138856 (PQ);
Reviewed date: 02 July, 2024, QC No. JNPGT-24-138856;
Revised date: 08 March, 2025, Manuscript No. JNPGT-24-138856 (R);
Published date: 15 March, 2025, DOI: 10.4172/2325-9809.1000438.

Citation: Sierra-Espinosa FZ (2025) Film Cooling Effectiveness Aided with Increased Turbulence in the Coolant Flow. J Nucl Ene Sci Power Generat Technol 14:2.

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Description

The cooling of blades in gas turbines is needed and it continues to be a challenge as higher and higher operation temperatures represent a constant demand for increasing the efficiency of the engine. Such a demand means more severe environment. For solving the problem, researchers are orienting the attention to complex but promising methods. Recent advances point out that film cooling is one the most accepted techniques for facing this demand. This is because the development of novel approaches make film cooling continuously improving. One of these novelties is presented in Enhanced film cooling effectiveness using turbulence promoter in cooling hole [1]. Film cooling effectiveness n is a function of several variables like temperature of the mainstream Tm, adiabatic wall, Taw, and coolant, Tc , as observed in its formulation: n=(Tm-Taw)/(Tm-Tc) therefore, its numerical simulation represents a first step into deep analysis [2]. The film cooling develops on the blade surface in interaction with the mainstream of hot gases, such that heat transfer rate becomes the focus of attention, although mass transfer is important too, as observed in another parameter that describes its performance, the blowing ratio: M=ρc−Uc /ρm−Um [2]. In this expression ρc is the density of coolant, ρm is the density of mainstream, while Uc , and Um are the corresponding velocities, respectively. The novelty [1] introduces the idea that a coolant flow with increased turbulence conditions in the discharge from the cooling hole would improve the film cooling effectiveness and would have an impact on the film distribution. In this ambitious and recently published study, the authors consider that there is a chance of modifying the turbulence level of coolant flow in benefit of film cooling effectiveness. The goal is to obtain a film cooling process aided with a coolant discharge that was previously modified with higher turbulent kinetic energy and its dissipation rate [1,3]. The authors were inspired by a research on a turbulent boundary layer that develops in presence of a series of transversal obstacles simulating the roughness of a flat plate [3]. It was observed that the boundary layer changes its structure under these conditions, with special interest its turbulent kinetic energy, and its dissipation rate of this energy. The use of turbulators has been proposed many years ago for other purposes [4], while no studies attended the concept for using it in film cooling through the coolant hole. In fact, several studies proposed turbulators as part of modified film cooling configurations [5-6]. But using a barrier of spiral shape inside the cooling hole to modify the coolant conditions constitutes a novel approach, where authors found a definitive increased film cooling effectiveness of 13% compared to the case of no barrier. On the other hand, the coverage of film cooling increases 14.4% which may have an impact on the number of holes needed in a turbine blade. A computational simulation of the process obtained with a second order turbulence model [1,7], showed that the turbulent kinetic energy dissipation rate increased 24% with this method. The results are encouraging for gas turbines and with potential of application to other systems where cooling film may succeed.