Experimental study of multi-hole cooling for integrally-woven, ceramic matrix composite walls for gas turbine applications

Abstract

a b s t r a c tIn this paper, multi-hole cooling is studied for an oxide/oxide ceramic specimen with normal injection holes and for a SiC/SiC ceramic specimen with oblique injection holes. A special purpose heat transfer tunnel was designed and built, which can provide a wide range of Reynolds numbers (10 5 $ 10 7 ) and a large temperature ratio of the primary flow to the coolant (up to 2.5). Cooling effectiveness determined by the measured surface temperature for the two types of ceramic specimens is investigated. It is found that the multi-hole cooling system for both specimens has a high cooling efficiency and it is higher for the SiC/SiC specimen than for the oxide/oxide specimen. Effects on the cooling effectiveness of parameters including blowing ratio, Reynolds number and temperature ratio, are studied. In addition, profiles of the mean velocity and temperature above the cooling surface are measured to provide further understanding of the cooling process. Duplication of the key parameters for multi-hole cooling, for a representative combustor flow condition (without radiation effects), is achieved with parameter scaling and the results show the high efficiency of multi-hole cooling for the oblique hole, SiC/SiC specimen.

Investigation of the film cooling performance of ceramic matrix composites plate with different braided structures

“…For example, NASA [10] applied gas film cooling technology to CMC material blades, successfully passing 50h steady state and 102 thermal cycling tests from 1173K to 1713K. Zhong et al [11] showed through experiments that opening air film pores in CMC materials has high cooling efficiency.…”

To drill or not to drill? Creep of an oxide‐oxide composite with diamond‐drilled effusion holes at elevated temperature

“…Obviously, the film cooling technique requires that component surface be perforated with multiple small holes. Still only a few studies focused on experimental investigation of film cooling for CMC combustor liners 14–16 …”

“…Still only a few studies focused on experimental investigation of film cooling for CMC combustor liners. [14][15][16] Flaw tolerant behavior of oxide/oxide CMC is enabled by their porous matrix. 10 Hence, it is reasonable to expect that these materials would be relatively insensitive to the presence of small holes or notches.…”

Evaluation of preparation and combustion rig tests of an effusive cooled SiC/SiCN panel

“…Only few experimental evaluations of film cooling hole for SiC/SiC combustor liners are reported in the literature. 7,25 Cooling effectiveness of 3D woven SiC/SiC structures was experimentally analyzed by Zhong et al 25 and numerically by Mehta et al 26 Many cooling investigations are conducted under non-reacting conditions like in the grouping of test rigs in Ref. 25 These investigations typically lack a realistic swirling and highly turbulent hot gas flow.…”

“…7,25 Cooling effectiveness of 3D woven SiC/SiC structures was experimentally analyzed by Zhong et al 25 and numerically by Mehta et al 26 Many cooling investigations are conducted under non-reacting conditions like in the grouping of test rigs in Ref. 25 These investigations typically lack a realistic swirling and highly turbulent hot gas flow. The cooling effectiveness of 2D laminated SiC/SiCN component under realistic hot gas flow is investigated in this paper and fills in the scientific literature.…”