APPLICATION OF ANSYS CFX SOFTWARE FOR MODELING OF GAS FLOW MOVEMENT IN A REACTION CHAMBER WHEN SORBENT IS OBTAINED ON THE BASIS OF THERMALLY EXPANDED GRAPHITE

Abstract

The work is devoted to the description of technology of evaluation of the characteristics of the reaction chamber for obtaining thermally expanded graphite, as a sorbent for oil products, using methods of numerical gas dynamics based on the use of the ANSYS - 12 software complex. The purpose of this study is to optimize the geometric and thermal parameters of the reaction chamber, which provides the maximum degree of thermal expansion of oxidized graphite.

The following assumptions and limitations were used in the calculations: simulation was performed using a compressed ideal gas model, a standard SST turbulent viscosity model was used, there is no heat exchange through the walls of the chamber with the environment, the simulation was carried out without the supply of expanded graphite powder, instead of supplying air (with an initial temperature of 300 ° K) in the amount equivalent to graphite to calculate the equal value of heat absorption, the chemical reaction of combustion of the fuel-air environment was not taken into account (1500 ° K gas was fed into the chamber), limit conditions of type "opening" (T = 300 ° K, P = 0 Pa - excess pressure), the boundary condition of type "inlet" was set in the form of air flow taking into account its temperature. The boundary conditions were determined on all surfaces of the computational domain and included the conditions on the solid walls, at the inlet and outlet, the boundary conditions on the solid walls were determined from the condition of the flow adherence to the smooth adiabatic wall. The simulation results made it possible to achieve stable operation of the ejector by which the graphite is fed into the reaction chamber. The need to re-profile the chamber to provide a more stable vortex flow within the reaction chamber was detected to allow for the separation of expanded and unexpanded graphite, increasing the reaction time of the expansion, increasing the magnitude of thermal expansion of oxidized graphite, creation of a uniform thermal field in the reactor, which increased the sorption capacity of thermally expanded graphite.