Design and Testing for Ceramic Matrix Composite Turbine Vane

Abstract

Ceramic matrix composite (CMC) have higher temperature capability and lower density than nickel based alloys which have been used for hot section components of gas turbine engines. These properties are expected to bring many benefits, such as higher turbine inlet temperature (TIT), reduction of cooling air, and reduction of weight, when it is used as the material for hot section components of gas turbine engine. The authors have been developing CMC turbine vane for aircraft engines. In this paper, the authors present the summary of design, manufacturing, and testing, which were conducted from 2010 to 2012. The purpose of this work was to verify that the SiC-SiC CMC which IHI has developed has the applicability to aircraft turbine vanes. The concept was planned for CMC hollow turbine vanes, in which the airfoil and the platform are fabricated in CVI process. As the demonstration of this concept, the first stage turbine vane was designed with CMC for IHI IM270 that is the 2MW-class small industrial gas turbine engine. Bending rig test was conducted at room temperature in order to check the structural feasibility of the airfoil-platform joint. The outer platform of vane was fixed in the same way with the engine parts, and the load simulating the aerodynamic force was applied at the airfoil portion. The fracture load was higher than the load which the vanes receive in the actual engine. Burner rig test was conducted in order to check the durability against thermal cycle. A CMC vane was set between dummy metal vanes, and cyclically heated by gas burner. The maximum airfoil surface temperature was set to 1200 degree C, and the maximum temperature difference between airfoil and platform was about 700 degree C. The minimum airfoil temperature at the interval of heating was about 300 degree C. The time of one thermal cycle was 6 minutes that consisted of 3 minute heating and 3 minute natural cooling. The test was conducted for 1,000 cycles. In post-test inspection there was no defect like a crack. Engine test for CMC vanes was conducted using IHI IM270. The four CMC vanes were mounted into the first stage turbine nozzle assembly in place of the normal metal vanes. The test was conducted for 400 hours. The inlet temperature of CMC vanes were measured by thermocouples installed at the leading edge, and the measured temperature was about 1050 degree C at the steady state. From this work, the applicability of the design concept for the CMC vane to actual engine was verified in which airfoil-platform are fabricated in CVI process.

Degradation of a SiC‐SiC composite in water vapor environments

“…Although their temperature capability falls below those of fibers with compositions closer to stoichiometric SiC, the ZMI fibers are less costly. They are currently candidate reinforcing fibers for composite vanes in low‐pressure turbines of aircraft engines, driven by the reduced cooling air needed for operation with these composites relative to existing metallic alloys . With the expectation that the design stresses will be dictated by the stress at the onset of matrix cracking, the study addresses oxidative degradation at stresses at or slightly above the matrix cracking limit.…”

“…Despite the potential of Tyranno ZMI fibers in engine components, few studies have addressed the fundamental issue of durability of these fibers and the corresponding composites in oxidizing environments (especially in comparison to the profusion of activity focused on the Nicalon TM series of SiC fibers). Two studies are noteworthy.…”

“…They are currently candidate reinforcing fibers for composite vanes in low-pressure turbines of aircraft engines, driven by the reduced cooling air needed for operation with these composites relative to existing metallic alloys. 38,39 With the expectation that the design stresses will be dictated by the stress at the onset of matrix cracking, the study addresses oxidative degradation at stresses at or slightly above the matrix cracking limit. Despite the potential of Tyranno ZMI fibers in engine components, 38,39 few studies have addressed the fundamental issue of durability of these fibers and the corresponding composites in oxidizing environments (especially in comparison to the profusion of activity focused on the Nicalon TM series of SiC fibers).…”

XCT damage evaluation and analysis of SiC/SiC turbine guide vanes after thermal shocks

“…After the duration tests and thermal cycles tests, the porosity and delamination were found at the leading edge. The IHI company designed the SiC/SiC TGV using the Tyranno ZMI fibers with the braided fabric in the airfoil, two‐dimensional (2D) plain‐woven cloth, and 3D orthogonal woven fabric in the platform and fabricated using the CVI and polymer impregnation and pyrolysis methods 10 . The 1000 thermal cycle tests were conducted at T = 1200°C, and the duration for each thermal cycle was t = 6 min.…”

Experimental investigation and multiscale simulation on the bending fatigue of SiCf/SiC composite vanes

“…During the past decades, an enormous amount of experimental studies have been carried out on the fatigue of composite materials, but those researches mainly focus on axial fatigue. [17][18][19][20][21][22][23][24] There are relatively few studies on composite bending fatigue, [25][26][27][28] which is the major failure mode for certain structures served in uneven airflow that triggers vibration, [29][30][31] such as Resin Matrix Composited (RMC) fan blades, 32 Ceramic Matrix Composited (CMC) turbine vanes 33 and exhaust nozzle seals. 34 Thereby, the experimental investigation of bending fatigue is in urgent demand and of great significance.…”