In English

Multidisciplinary Conceptual Design of a Transonic High Pressure Compressor

Funda Ersavas
Göteborg : Chalmers tekniska högskola, 2011. Diploma work - Department of Applied Mechanics, Chalmers University of Technology, Göteborg, Sweden, ISSN 1652-8557; 2011:56, 2011.
[Examensarbete på avancerad nivå]

The aim of this work is to develop a systematic approach for multidisciplinary high pressure transonic axial compressor conceptual design. Several aspects have to be taken into account when establishing a new compressor design. Apart from developing a successful aerodynamic design that provides high efficiency and maintaining a design that allows manufacturing at a reasonable cost, structural dynamics and rotor dynamic considerations have to be taken to ensure a mechanically stable operation. It is quite common that a seemingly well designed compressor exhibits rotor dynamic instability at some rotational speed and that this requires redesigning the machine. This report presents the initial results of a multidisciplinary conceptual design of a five stage transonic high pressure compressor that has an overall pressure ratio of 4.46, an inlet temperature of 401.4K an inlet pressure of 132.9 kPa and a mass flow of 14.18 kg/s. Basic parameters such as blade masses, disc stress calculations and conceptual disc design were carried out using existing tools and analytical techniques. The work consists of setting up a basic Finite Element (FE) model using the ANSYS software and subsequently a basic rotor dynamic model in the DyRoBeS tool. In order to evaluate these parameters, basic aerodynamic theory of the axial flow compressor was used. The work starts with a brief introduction to the fundamentals of gas turbine theory and results in a basic aerodynamics design. The aerodynamic theory of axial flow compressors is used to calculate design parameters such as temperatures and pressures for all stages, geometrical parameters, velocity triangles, etc. After the aerodynamic calculation, weight and stress calculation for the compressor disks follows. Since weight is one of the most important parameters when designing a gas turbine engine, an accurate weight estimation method is desired. In the beginning of the design process, several different approaches can be used in order to achieve the same functionality. In this report, an approach similar to the weight estimation method WATE (Weight Analysis of Turbine Engines) was used to calculate rotor and stator blade weights. Subsequent steps are comprised of modelling the disks. A preliminary design calculation is carried out in such a way that the whole disk is approximated as a superposition of several coupled elementary parts: a ring disc, a section with hyperbolic shape and a section with a linearly varying thickness. This basic non-linear analytic procedure is followed by creating the basic FE model using the ANSYS software to determine best shape of the bladed disc (blisc) and vibrational characteristics of the blisc geometries. After this step, a basic rotor dynamic model in the DyRoBeS tool is established to correctly continue the analysis and to learn the behaviour of the compressor during operation at high speed.

Nyckelord: Transonic compressor, conceptual aerodynamic design, gas turbine rotor

Publikationen registrerades 2011-11-10. Den ändrades senast 2013-04-04

CPL ID: 148353

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