An evolutionary optimization of diffuser shapes based on CFD simulations

Abstract

SUMMARYAn efficient and robust algorithm is presented for the optimum design of plane symmetric diffusers handling incompressible turbulent flow. The indigenously developed algorithm uses the CFD software: Fluent for the hydrodynamic analysis and employs a genetic algorithm (GA) for optimization. For a prescribed inlet velocity and outlet pressure, pressure recovery coefficient C * p (the objective function) is estimated computationally for various design options. The CFD software and the GA have been combined in a monolithic platform for a fully automated operation using some special control commands. Based on the developed algorithm, an extensive exercise has been made to optimize the diffuser shape. Different methodologies have been adopted to create a large number of design options. Interestingly, not much difference has been noted in the optimum C * p values obtained through different approaches. However, in all the approaches, a better design has been obtained through a proper selection of the number of design variables. Finally, the effect of diffuser length on the optimum shape has also been studied.

Diffuser and Nozzle Design Optimization by Entropy Generation Minimization

“…Detailed information about 2-dimensional diffuser optimization can be found in [27] and [28], where c p is optimized using the standard k − turbulence model with wall functions and a similar parameterization as discussed here for the wall shape. In [27] the so-called Response Surface Approximation of c p based on a relatively small number of model evaluations is used as a surrogate for repetitive model evaluations during a conventional search strategy.…”

“…In [27] the so-called Response Surface Approximation of c p based on a relatively small number of model evaluations is used as a surrogate for repetitive model evaluations during a conventional search strategy. Different from [27], a genetic algorithm is used in [28] in order to test a large variety of polynomial wall parameterizations.…”

“…This has been done in earlier publications of different authors already, see [27,28] for diffusers. Here, we especially want to highlight the advantages of the SLA approach using every available information of entropy generation as a field variable and the opportunities to interpret the numerical results on a sound physical background.…”

Optimal Design by Adaptive Mesh Refinement on Shape Optimization of Flow Fields Considering Proper Orthogonal Decomposition

“…Subsequently, J. Haslinger and R. A. Makinen [4], B. Mohammadi and O. Pironneau [5], and M. Moubachir and J. P. Zolesio [6] constructed fundamental frameworks of flow-field shape-optimization problems. Recently, many researchers are examining the topic [7][8][9][10]. Efficient but accurate numerical methods must be used for such flow computations within an optimization process.…”

Optimum Design of a Two Step Planar Diffuser: A Hybrid Approach

“…The influence of vane shape on the hydrodynamic performance of a diffuser had been studied and thus, attempts were made to improve the performance of the pump stage by optimizing the shape of the diffuser vane. The optimum shape of a two dimensional symmetric diffuser had been optimized for handling incompressible turbulent flow by Ghosh et al (2009). From manufacturing point of view, it is difficult to construct a curved optimum diffuser.…”