Towards Structural Topology Optimization of Rotor Blisks

Abstract

The current trend in turbomachinery is pushing forward more and more efficient machines, increasing speeds, reducing components mass and improving their vibrational behaviour. Structural topology optimization is a challenging and promising approach to satisfy all these demands, with a very remarkable economic impact. This approach enables the creation of structures characterized by complex three-dimensional geometries, which are usually difficult or impossible to be produced using traditional manufacturing processes. However, thanks to innovative technologies, as new additive manufacturing techniques, it is now possible to effectively exploit topology optimization to develop innovative components. The aim of this work is to demonstrate the applicability of structural topology optimization techniques in turbomachinery, to improve the dynamic performances and vibrational behaviour of critical components. A 3D mock-up blade geometry based on T106 profile has been designed to reproduce a typical rotor blade in design conditions. The blade has been mounted on a rough disk model, to obtain a rotor blisk in order to ensure a wide design space for the optimization. The optimization has been carried out by applying mean and fluctuating loads coming from a 3D unsteady computation of 1.5stage (stator-rotor-stator) together with the centrifugal stresses. The unsteady loads acting on the rotor skin are due to the wake of the upstream stator and the potential field generated by the downstream stator. A new concept design for the blisk has been developed and the optimized geometry has been compared to the original one to highlight the improvements in terms of mass reduction and improved dynamic behaviour. This paper will confirm the suitability of this approach to turbomachinery components and a prototype of optimized geometry will be ready to be manufactured through innovative additive manufacturing techniques for high resistance alloys.

Topological Optimisation and 3d Printing of a Bladed Disc

“…So a reduction of the density far from the axis of rotation decreases the compliance. Similar results are obtained in [8], which gives confidence in the results here. Moreover, one can see that at the bottom of the blades, intermediary densities are present.…”

“…Even though the geometry was simplified, results were promising. Then in [8], topology optimisation was considered for a full bladed disc for a static loading and a dynamic loading, both obtained from CFD simulations. However, no work has been dedicated to the optimisation of a full bladed disc with regard to (w.r.t.)…”

A preliminary design method for axisymmetric turbomachinery disks based on topology optimization

“…17 The cooling channels in turbine blades were optimized in Ghosh et al. 18 Topology optimizations of turbomachinery disks were conducted in Shen et al., 19 Ngim et al., 20 Boccini et al., 21 , 22 and Rindi et al. 23 In these literatures about the optimization of disks, the optimal results tended to contain enclosed holes 19 which may challenge the manufacturing processes.…”

“…10 It has also been playing a more and more important role in designing turbomachinery components. For example, two impellers were optimized and additive manufactured in Meli et al 11,12 A low-pressure turbine guide vane was optimized in Sepp€ al€ a et al 13 Novel turbine blade designs were obtained by topology optimization in Magerramova et al, 14 Alkebsi et al, 15 and Amedei et al 16 Innovative lattice-infilled components were obtained in Boccini et al 17 The cooling channels in turbine blades were optimized in Ghosh et al 18 Topology optimizations of turbomachinery disks were conducted in Shen et al, 19 Ngim et al, 20 Boccini et al, 21,22 and Rindi et al 23 In these literatures about the optimization of disks, the optimal results tended to contain enclosed holes 19 which may challenge the manufacturing processes. 20 Besides, as observed in Rindi et al, 23 the optimal results tended to have indistinct solid-void interface.…”