A note of caution on numerical scheme selection: Evidence from cyclone separator CFD simulations with appropriate near-wall grid sizes

Abstract

In this paper two things are done. (i) The appropriate numerical scheme set for computational fluid dynamics (CFD) simulations of cyclone separators with various vortex-finder-to-cone-tip diameter ratios (D⁎) has been achieved by comparing the mean flow patterns and performances simulated by two previously proposed numerical scheme sets. The predicted results revealed that the CFD simulations of different cyclone separator designs require the third-order accuracy scheme and proper near-wall grid sizes to preserve flow similarity, especially for cyclone separators with D⁎ < 1. Therefore, the present research alerts caution concerning the lower-order numerical scheme for cyclone separator CFD simulation. (ii) The present CFD work confirms that the near-wall grid size estimation method originally developed for gas cyclones is a possible method for estimating near-wall grid sizes for hydrocyclone with air core diameter (Da) ≤ 0.4Dv. In addition, the capabilities of pressure-strain sub-models for cyclone separator CFD simulations were preliminarily discussed.