Creation and research of numerical models of cyclones with inclined and horizontal inlets

Abstract

The article considers the challenges of using cyclone devices for cleaning gas emissions from solid fuel combustion in power engineering and industry. With the increasing energy consumption and generation, including the use of coal, the requirements for the efficiency of cleaning emissions from small solid particles of classes PM10 and PM2.5 are also rising. One of the key tasks is to maintain high cleaning efficiency while minimizing energy costs, which is also important for reducing the environmental impact of generation and industrial production. The article considers the design features of currently used cyclones, as well as existing approaches to their classification. The main focus is on modern areas of research related to numerical modeling based on CFD (Computational fluid dynamics) aimed at optimizing the design of separators. It is shown that most studies are carried out for cyclone operating conditions in production cycles, rather than in emission cleaning systems that operate at low suspended matter loads. Using the example of creating numerical models of cyclones with inclined and horizontal inlet pipes (CN-11, SK-CN-34), the article discusses certain features of geometry creation in the SpaceClaim Direct Modeler (SCDM) environment, which ensure the correctness of grid generation and calculations in the future. The results of numerical modeling carried out using the ANSYS Fluent software are presented. The turbulence model (RANS, Reynolds Averaged Navier – Stokes), methods for closing the Navier – Stokes equations (k-ε model with near-wall functions), and methods for calculating the dispersed part of the flow (Euler – Lagrange, DPM) are selected based on the conditions relevant to the systems for cleaning emissions from coal generation. The results indicate that, with the same pressure drop, the efficiency of settling suspended matter with a concentration of 100 mg/m3 or less in an apparatus with an inlet angle of 11° to the horizontal can be higher than that of a cyclone with a horizontal inlet.