A Jet-Stirred Apparatus for Turbulent Combustion Experiments

TL;DR

This paper introduces a new jet-stirred combustion chamber design utilizing multiple impinging turbulent jets to generate highly isotropic turbulence for studying turbulent premixed flames, validated through FLUENT simulations.

Contribution

The paper presents a novel chamber design with multiple impinging jets and introduces three indices to compare turbulence configurations, demonstrating superior turbulence characteristics over conventional chambers.

Findings

Achieves near-zero mean flow with high turbulence intensity

Uses 8 inlets and outlets for optimal turbulence

Simulation results outperform traditional fan-stirred reactors

Abstract

A novel jet-stirred combustion chamber is designed to study turbulent premixed flames. In the new approach, multiple impinging turbulent jets are used to stir the mixture. It is well known that pair of counterflowing turbulent jets produces nearly a constant intensity along the jet axes. In this study, different numbers of impinging jets in various configurations are used to produce isotropic turbulence intensity. FLUENT simulations have been conducted to assess the viability of the proposed chamber. In order to be able to compare different configurations, three different non dimensional indices are introduces. Mean flow index, Homogeneity index, and Isotropicity index. Using these indices one can compare various chambers including conventional Fan-stirred Reactor. Results show that a concentric inlet/outlet chamber with 8 inlets and 8 outlets with inlet velocity of 20 m/s and initial intensity of 15% produces near zero mean flow and 2.5 m/s turbulence intensity which is much more higher than reported values for Fan-stirred chamber.