Topology optimization of unsteady and compressible fluid flows

Abstract

Global warming is amongst the major challenges of the century with dire consequences. In order to counteract CO2 emissions, Carbon Capture and Storage (CCS) and Utilisation (CCU) offer viable means to contribute toward this goal. Processes of CCS converge to the compression stage, responsible for 50% of the performance of the process (Rodriguez, 2022). Currently, the dissemination of the CCS technology relies largely on the improvement of the compressor. One-dimensional, parametric and shape optimization are incapable of handling the extenuating number of parameters associated with the compressor operation. To overcome these difficulties, topology optimization is suggested here. It is a more generalist approach, independent of the initial design. A formulation to treat steady-state flow cases has already been developed. Nevertheless, despite previous efforts, there is still no methodology to evaluate compressible, turbulent and unsteady fluid flows in topology optimization. Unsteadiness is intrinsically related with the vortex dynamics that leads to surge and stall phenomena, which affect compressor performance, and therefore motivates this study. We principally envision to formulate the topology optimization problem, develop the adequate methodology and optimize the rotor design to attain a compressor topology less susceptible to the phenomenon of vortex shedding, and thus, surge. Finite volume simulations will be carried out in OpenFOAM and the sensitivity of the problem will be computed through the finite element method, implemented in FEniCS. As a result, minimisation of vortex shedding to mitigate surge is expected. This research is within the thematic project conducted by the Research Centre for Greenhouse Gas Innovation (RCG2I), CPE FAPESP-Shell Brazil.