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DOI number:10.1016/j.ijheatmasstransfer.2025.127046
Journal:International Journal of Heat and Mass Transfer
Key Words:Film cooling, Impingement, Active subspace, Uncertainty quantification, Gas turbine
Abstract:Within the context of exploiting efficient cooling methods for advanced gas turbine combustors, understanding the fundamental physics for impinging-film cooling under various operational conditions is of significance. In this paper, impacts of different interaction modes between coolant and hot mainstream on the impinging-film cooling are quantitatively evaluated via active subspace (AS) method. Three interaction modes are considered, i.e., a transitional flow (TF), a turbulent boundary layer (TBL) and a wall jet (WJ). Sensitivities and uncertainties of cooling effectiveness η with respect to coolant mass flow rate M_c and model parameters (C_μ,C_ε1,C_ε2,〖Pr〗_tw) are estimated. Results show that 1-D active subspaces are sufficient to map η in TF and TBL modes while high-dimensional active subspaces are warranted for WJ mode, indicating its more complicated interaction between cold and hot flows. η is the most sensitive to and dominated by M_c especially in the slot and far fields, and turbulent effects are more significant in the near field than other places. Specifically, an increase in M_c or a decrease in turbulent level monotonously improves η in TF and TBL modes while initially increases η then reduces it for WJ mode. Further analysis of flow characteristics of WJ mode demonstrates that the reduction in η results from the strengthened impingement-induced streamwise vortexes and thereby, enhanced mixing between the coolant and mainstream. The propagation of the input uncertainty to η is space- and operational condition-dependent, consistent with the evolution of active subspaces.
Indexed by:Journal paper
Document Code:127046
Discipline:Engineering
Document Type:J
Volume:245
Page Number:127046
Translation or Not:no
Date of Publication:2025-07-30
Included Journals:SCI
Co-author:Wang Nana,Zhang Jingyu,He Xiaomin
First Author:Wei Jieli