Design for Additive Manufacturing: Internal Channel Optimization

Abstract

The new possibilities offered by Additive Manufacturing (AM) can be exploited in gas turbines to produce a new generation of complex and efficient internal coolant systems. The flexibility offered by this new manufacturing method needs a paradigm shift in the design approach and a possible solution is offered by Topology Optimization. The overall goal of this work is to propose an innovative method to design internal channels in gas turbines that that fully exploit AM capabilities. The present work contains a new application of a Fluid Topology sedimentation method to optimize the internal coolant geometries with minimal pressure losses while maximizing the heat exchange. The domain is considered as a porous medium with variable porosity: the solution is represented by the final solid distribution that constitutes the optimised structure. In this work the governing equations for an incompressible flow in a porous medium are considered together with a conjugate heat transfer equation that includes porosity dependent thermal diffusivity. An adjoint optimisation approach with steepest descent method is used to build the optimisation algorithm. The simulations are carried out on two different geometries: a U-Bend and a straight duct. For the U-Bend a series of splitter is automatically generated by the code, minimizing the stagnation pressure losses. In the straight duct the impact of different porosity dependant thermal diffusivity is analysed to achieve high thermal exchange. The results show “rib like” structures that enhance the heat transfer.

Experimental Investigation of Numerically Optimized Wavy Microchannels Created Through Additive Manufacturing

“…Dede et al [32] used topology optimization to additively manufacture a heat sink for electronics cooling; the authors' optimized heat sink showed higher heat transfer performance than their baseline. Other topology optimization studies [33,34] have been numerical in nature, but show great promise for future production.…”

A New Strategy for Railway Bogie Frame Designing Combining Structural–Topological Optimization and Sensitivity Analysis

“…A high-performance chassis design of an automotive vehicle body has been innovated using topological optimization [3]. Similar approaches have been used to improve the design procedure for turbomachinery components, especially if combined with additive manufacturing techniques [4][5][6][7][8]. Referring to railway applications, the anchor bracket has been redesigned by taking advantage of a topology optimization process and introducing composite materials [9].…”

Topology optimisation of turbulent flow using data-driven modelling

“…Favourable cells are then rewarded by increased permeability and counterproductive cells penalised by reducing their permeability. Over several iterations, the optimised fluid path is revealed as the regions in which sensitivities remained favourable and the permeability stayed high enough for the region to be considered fluid (Pietropaoli et al 2016). The corresponding optimised solid geometry is taken as the opposing regions in Responsible Editor: Emilio Carlos Nelli Silva which the permeability has been reduced to zero.…”