Validation of Numerical Modeling of Gas Dynamics and Thermal State of the Boiler Unit

Abstract

The presented work was carried out by means of CFD modeling in order to validate the methods of numerical modeling of heat transfer from jets of red-hot gas to water moving in a thick-walled pipe. Such tasks are relevant, because to ensure smooth and efficient operation of boiler units, it is important to correctly determine the local heat flows from the flame torch to the screen pipes. The scientific novelty of the work consists in determining the correct methodology for building computer models of combustion and gas transport, which in the future will significantly expand the range of factors that can be involved in predicting the behavior of energy equipment.

The simulation of combustion of the methane-air mixture was performed in the environment of the ANSYS Student software complex using the Species Transport model. The finite-element mesh is hydridic. It was determined that the results of simulation of heat transfer from jets of incandescent gas to moving water through the wall of a thick-walled pipe separating them in SolidWorks Simulation and ANSYS-Fluent and ANSYS-CFX completely coincide. When the flow model is replaced by the combustion model, it is shown that the ignition of the mixture will occur in the calculated volume, and not immediately after the cut of the flame stabilizer. Differences in the temperature fields of the calculated volume, which were calculated by means of Fluent and CFX, were also determined. This is due to the fact that during the development of the model it was not possible for objective reasons to identically configure the Species Transport model used in Fluent and the RIF library of CFX combustion kinetics. In addition, it was determined that in the case of modeling the transport and combustion of gases, the temperature field of the pipe wall does not have sharply expressed overheated zones, as in the case of washing with a jet of red-hot gas. This indirectly indicates that thermal loads on the pipe wall will be less and the risk of the pipe burning out is reduced.