Assessment of modelling strategies for film cooling

Abstract

Purpose Effusion cooling represents one the most innovative techniques for the thermal management of aero-engine combustors liners. The huge amount of micro-perforations implies a significant computational cost if cooling holes are included in computational fluid dynamics (CFD) simulations; therefore, many efforts are reported in literature to develop lower-order approaches aiming at limiting the number of mesh elements. This paper aims to report a numerical investigation for validating two approaches for modelling film cooling, distinguished according to the way coolant is injected (i.e. through either point or distributed mass sources). Design/methodology/approach The approaches are validated against experimental data in terms of adiabatic effectiveness and heat transfer coefficient distributions obtained for effusion cooled flat plates. Additional reynolds-averaged naver stokes (RANS) simulations were performed meshing also the perforation, so as to distinguish the contribution of injection modelling with respect to intrinsic limitations of turbulence model modelling. Findings Despite the simplified strategies for coolant injection, this work clearly shows the feasibility of obtaining a sufficiently accurate reproduction of coolant protection in conjunction with a significant saving in terms of computational cost. Practical/implications The proposed methodologies allow to take into account the presence of film cooling in simulations of devices characterized by a huge number of holes. Originality/value This activity represents the first thorough and quantitative comparison between two approaches for film cooling modelling, highlighting the advantages involved in their application.

Low order modeling method for assessing the temperature of multi-perforated plates

“…15. The experimental values are presented together with the numerical data of Mazzei et al [47] as well as the present results obtained for different estimators of the adiabatic temperature. For the adiabatic estimator of the temperature, the integration length was taken as 99% of the thermal thickness on each position, and has been extracted from the simulation.…”

“…The reference temperature estimator is now applied to the KIAI (Knowledge for Ignition, Acoustics and Instabilities) setup developed during a EU funded Research Project. This configuration has been studied and detailed in [47,2,3,9]. For the present study, the blowing and density ratios are M ¼ 3 and D R ¼ 1 respectively.…”

“…For the present study, the blowing and density ratios are M ¼ 3 and D R ¼ 1 respectively. The geometry denoted G2 in [47,2,3,9] has been retained. It consists in a multi-perforated plate similar to the one considered in Section 6.…”

“…15. Adiabatic efficiency for one of the configuration described in [47]. Experimental and hole resolved CFD results are extracted from Mazzei et al [47].…”

“…Adiabatic efficiency for one of the configuration described in [47]. Experimental and hole resolved CFD results are extracted from Mazzei et al [47]. TFN and Tmix correspond to the results obtained using either the first node value or the mixing temperature to estimate the adiabatic temperature, respectively.…”