Influence of Secondary Inertia Terms on Natural Frequencies of Rotating Beams

1955 ◽  
Vol 22 (4) ◽  
pp. 587-591
Author(s):  
J. L. Bogdanoff

Abstract The equations of small motion of a straight cantilever beam attached to the rim of a rotating disk are determined assuming the Bernoulli-Euler theory of bending and the Saint Venant theory of torsion are valid, the mass and elastic axes coinciding and retaining all inertia terms. Influence of the secondary inertia terms on the fundamental torsional and lateral frequencies is then examined at two angular settings for a uniform beam having a length to disk-radius ratio in the range usually encountered in gas-turbine buckets and axial-flow compressor blades.

2020 ◽  
Vol 23 (5) ◽  
pp. 39-53
Author(s):  
V. A. Potapov ◽  
A. A. Sanko

The construction and useful practice of gas-turbine engine diagnosis systems depend largely on the availability of the engine mathematical models and its certain components in their structure. Utilization of multi-stage axial flow compressor performance with account for erosive wear of its parts during the operation fundamentally raises possibilities of such systems as erosive wear of flow channel, blade rings of impellers and vane rings of multi-stage compressor is a common cause of preschedule gas-turbine engine detaching from an aircraft. As evidenced by various contributions presented in the article, special emphasis on abrasive wear impact assessment on axial flow compressor performance is placed upon rotor-wing turbo-shaft engine due to their particular operating conditions. One of the main tasks in the process of mathematic simulation of an axial flow compressor blade ring is consideration of its wear type that again has a nonlinear distribution along the level of the blade. In addition, wear rate at entry and exit blade edges often have different principles. Detecting of these principles and their consideration when constructing the compressor mathematical model is a crucial task in diagnostic assessment and integrity monitoring of rotor-wing turbo-shaft engine in operation. The article represents a concept to an estimate nonlinear erosive wear effect of axial flow compressor blades on its performance based on the three-dimensional flow approach in the gas-air flow duct of compressor with a formulation of the blade rings. This approach renders possible to take into account the nonlinearity of the compressor blades wear during their operation. Through the example of the inlet compressor stage of a rotor-wing aircraft gas-turbine engine, the engine pump properties predictions with different kind of rotor blade wear have been presented.


Author(s):  
I. N. Egorov ◽  
G. V. Kreitinin

A numerical method has been preposed to determine optimum laws to control gas turbine engine (CTE) variable components, including an independent control of blade rows in a multistage axial flow compressor under strong non-stationary flow disturbances at the inlet, optimum laws to control a turbofan under non-stationary thermal effects at the inlet have been obtained using mathematical models with various degree of filling in detail the flow in an engine flow path. There is shown a possibility to considerably increase a range of the CTE stable operation through the use of dynamic control of stator blades in a multistage axial flow compressor, also possibilities of practical use of optimum laws to control engine variable components in the system of preventing an unstable operation are being discussed.


Author(s):  
W. Tabakoff

Turbines and compressors operating in polluted atmosphere with solid particles are subjected to performance deterioration. This paper presents an investigation carried out on two-stage gas turbine with blunt leading edge blades and on a single-stage axial flow compressor to study the effects of particulates and erosion on performance deterioration.


Author(s):  
Y. Kashiwabara ◽  
Y. Katoh ◽  
H. Ishii ◽  
T. Hattori ◽  
Y. Matsuura ◽  
...  

In this paper, the development leading to a 17-stage axial flow compressor (pressure ratio 14.7) for the 25 MW class heavy duty gas turbine H-25 is described. In the course of developing the H-25’s compressor, extensive measurements were carried out on models. Experimental results are compared with predicted values. Aerodynamic experiments covered the measurements of unsteady flows such as rotating stall and surge as well as the steady-state performance of the compressor. Based on the results of these tests, the aerodynamic and mechanical design parameters of the full scale H-25 compressor were finalized on the basis of two model compressors. Detailed measurements of the first unit of the H-25 gas turbine were carried out. Test results on the compressor are presented and show the achievement of the expected design targets.


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