Arul K Prakash

Numerical simulation of fluid flow through various configurations like decelerated, free vortex, accelerated and spiral casing with different aspect ratios (AR) based on cross section has been studied using finite element method. An explicit Eulerian velocity correction scheme has been deployed to solve the Reynolds averaged Navier-stokes equations. The simulations have been performed to describe the fluid flow in high Reynolds number (106) regime. A streamline upwind Petrov Galerkin technique has been used for discretising governing equations. The pressure distribution inside the spiral casing has been studied. Total head loss for all configurations with various aspect ratios is modeled using response surface approximation. Subsequently, unconstrained non-linear minimization method is implemented to obtain optimum spiral casing by minimizing the total head loss.

Numerical simulations of fluid flow through various spiral casings like accelerated, free vortex and decelerated type with different aspect ratios (AR) are carried out to construct surrogates. These surrogates are utilised for analysing design sensitivity of spiral casing to obtain its optimal design. Responses like spiral velocity coefficient, total pressure loss and average radial velocities obtained from numerical computations are used for surrogates’ construction. Different surrogate models considered are Kriging, polynomial response surface, support vector regression and weighted average surrogate. Surrogates are validated using average error analysis for the selection of best surrogate. Weighted average surrogate performs well in most of the cases among all responses. Near optimal solutions obtained from the best surrogates are proposed.