Aircraft Gas Turbine Rotating Compressor Disk Vibration

This paper is concerned with the experimental investigation of vibration in aircraft jet-engine rotating compressor disks of two different configurations. The blades in the first configuration were small, with relatively low mass, and had an insignificant effect on the disk vibration except for centrifugal loading. The second configuration had relatively large blades which resulted in combined blade and disk modes. The test techniques, test results, and examples of some known phenomenon as they occur in lightweight aircraft jet-engine disks are discussed.

Analysis and Testing of Air-Cooled Turbine Rotor and Stator Blades

Advancing turbine engine technology requires air-cooled turbines. Cooling mechanisms applied must be exploited in a practical manner to obtain maximum cooling effectiveness. Cooled turbine stator and rotor blade design requires rigorous analysis supplemented by verifying experimental data. Problem definition, analysis techniques, material application, cascade and engine testing, and correlation of data are presented for air-cooled turbines. Convection, impingement, film, transpiration, and combined cooling mechanisms are reviewed.

Computer Analysis of Flexural Vibrations of a Rotating Disk With an Arbitrary Profile

A collocation method is applied to the differential equation and boundary conditions which govern the flexural vibrations of a rotating thin solid disk with an arbitrary profile, clamped at the inner radius and having a flexible ring carrying masses (turbine blades) at the outer radius. The determinantal equation, from which approximations to the reasonance frequencies and mode shapes are extracted, is derived. The results of sample calculations are compared with theoretical and test results. The treatment of other types of boundary conditions is straightforward. A brief discussion of the convergence of this method is given.

Elimination of Turbine Erosion in the T56 Turboprop Engine

Turbine erosion was encountered in service operation with the T56 turboprop engine. Combustor carboning was suspected to be the cause of the problem. No direct evidence of carboning had been observed during development or in more than one million hours of service operation. An accelerated investigation was initiated to establish a quantitative measure of carbon particles in the combustor exhaust gases. A unique test method was developed to collect carbon particles on a component combustor test rig. Evaluations were conducted with the carbon collector to determine the effects of fuel nozzles, fuel type, operating conditions, and combustor configuration on carbon particle output. The combustor configuration was found to be the most important factor in the control of the problem. Combustor carboning was established as the cause of turbine erosion and a combustion liner modification was developed for service release. Service tests were conducted to correlate development test results and to verify that turbine erosion was eliminated with the modified combustion lines.