Development of a Method for Calculating the Working Blade Stress Profile of the Aviation Gas Turbine Engine for Student Training

Abstract

The paper presents a method of calculation gas turbine engine compressor or low-pressure turbine working blade profile for student training. This method of calculation was prepared for working blades with and without shroud shelves. This method provides a calculation technique to reduce the load on blade root part and the determination of blade profile stress distribution and the comparison before and after reduction of load.

Turbine Blade of Gas Turbine Engine Additional Unloading by Changing the Layout of the Gravity Centre of the Shroud Shelf

“…The centrifugal force created by the shroud shelf was concentrated at the end of the blade. It changes the force, thus also the moment, the balance along the length of the blade [1]. The shroud shelf also changes the bending stress marks.…”

“…The initial data corresponds to a classic calculation case, which were: rotor rotation speed, blade material density, rotor diameter, geometrical dimensions of the blade, and degree gas dynamic values of the rotor stage [1].…”

“…2 The distribution of the bending (a) and the total (b) stresses along the blade length before stress reduction of the root part of the blade considering the impact of the shroud shelf; σA σB and σC,bending stresses in profile points A, B and C accordingly; σsumA, σsumB and σsumCbending and circumferential total stresses in profile points A, B and C accordingly; σcfcircumferential force created stresses. The further calculations related to the shroud shelf on the results obtained by the methodology are described at work [1]. Fig.…”

“…For the simplification of the given calculation the coefficient ξ = 1 is accepted (assume that the calculation was carried out directly for the cruising mode). After the blade load reduction calculation [1] the stresses dependencies shown in Fig. 3 were derived.…”

“…Shroud shelves increase the rigidity of blades and ensure gas flow sealing. But an increased load of the blade resulting from additional mass within the maximum radius of the rotor may be mentioned as a deficiency [1]- [3]. The additional centrifugal forces increase the stress level in the aerodynamically profiled part of the blade including its profile root part.…”