Wave turbine analysis tool development

Abstract

Abstract : A quasi-one-dimensional (Q-1-D) computational fluid dynamic solver, previously developed and validated for pressure-exchanger wave rotors, is extended in the present work to include the blade forces of power producing wave rotors (i.e., wave turbines). The accuracy of the single-passage Q-1-D solver is assessed relative to two two-dimensional solvers: a single-passage code and a multi-block stator/rotor/stator code. Comparisons of computed results for inviscid, steady and unsteady flows in passage geometries typical of wave rotors reveal that the blade force model is accurate and that the correlation (effective stress and heat flux) terms of the Q-1-D passage-averaged formulation can be neglected. The ends of the rotor passages pose particular challenges to Q-1-D formulations because the flow there must at times deviate significantly from the mean camber line angle to match the port flow fields. This problem is most acute during the opening and closing of the rotor passages. An example sub-model is developed to account for the deviation between the flow departure angle and the mean camber line exit angle that occurs as an inviscid flow decelerates to meet a uniform pressure boundary. Comparisons of results from four-port wave turbine simulations reveal that the Q-1-D solver currently overpredicts wave turbine performance levels and highlight the need to devote future effort to the boundary conditions and sub-models of the Q-1-D solver.