Optimization and debugging of a low-toxic combustion chamber with the use of numerical modeling of intrachamber processes

Abstract

In recent years, there has been a trend towards an increase in demand for microturbines. The microturbine application area is very wide. These are hybrid power plants for transport and specialized equipment, as well as power plants for providing electricity to homes, towns, businesses. When developing advanced gas turbine units, it is necessary to take into account sufficiently high requirements for economic and operational indicators. To improve the performance of microturbines, it is necessary to optimize and refine the basic elements. In particular, to reduce the emission of harmful substances, it is necessary to develop low-toxic combustion chambers. In this paper, we present the results of optimization and fine-tuning of a low-toxic combustion chamber with the use of numerical modeling of intra-chamber processes. The applied models of flow, combustion, radiation, NOx emission are described. The main parameters of the computational grid built for ¼ of the full-size combustion chamber are given. The boundary conditions necessary for the development of mathematical modeling of the flow and combustion processes are formulated. The results of comparison of the initial and optimized geometry of the combustion chamber in the form of patterns of temperature distribution, velocities, total pressure in the swirler, and the distribution of the mass fraction of nitrogen oxides NOx are presented. According to the results of optimization calculations, it can be concluded that relatively small changes in the size, shape and number of secondary air holes, the shape and dimensions of the flame tube, the diameter of the blade swirler and the shape and size of the nozzles of the gas injector have a significant effect on such indicators of the working process as: form, volume and location of the combustion zone; location and intensity of the mixing zone, which, as a consequence, greatly affects the integral parameters of the combustion chamber.