Numerical study of mixing in gas mixture generating system

Abstract

The subject of research is a gas-dynamic process of mixture formation with a given component mass fraction during overflow through the mixer nozzles in the mixture generation system. The aim of the study is the scientific and experimental evaluation of the mixer technical solutions to ensure the accuracy and homogeneity of the gas mixture. The current work conducts numerical study on the flow of a gas flow through the mixer nozzles of the mixture generation system, ensuring its stoichiometric component composition and homogeneity. The problem is solved by developing adequate mathematical models of gas-dynamic flow and analyzing the results of numerical simulations. The following results were obtained. A mixer with the nozzles in the mixture generation system has been created and a technical solution for its design has been scientifically substantiated. The areas of flow sections of mixer nozzles are experimentally established. A mathematical model of generating a mixture with a given component mass fraction was developed and a series of numerical experiments was conducted to study its overflow through the mixer. A 3D simulation was conducted using ANSYS CFX software. The stationary formulation of the problem is applied. In the nozzles of closed overflow of the mixer, the heat exchange of the gas flow with the walls is taken into account by solving a separate problem and determining the corresponding heat transfer coefficients. At the inputs to the mixer, the ratio of the initial pressure of the components of the mixture is determined, which ensures its stoichiometric composition. The fields of the gas flow velocities, the mass flow rate of the components of the gas mixture through the mixer, and pressure and temperature fields are obtained. Based on the simulation results, it was found that the design of the developed mixer ensures the creation of a gas mixture with a homogeneity of at least 3%. With a constant pressure ratio of the mixture components to the mixer inlet, the gas mixturedosing accuracy can be achieved at least 1%.

Keywords

• математична модель газодинамічного процесу
• закритичне перетікання
• числове моделювання
• гомогенність газової суміші
• коефіцієнт теплопередачі