Multicomponent Gas Swirl Premixed Combustion Characteristic Research

The Low swirl combustion?LSC?technology is a combustion mode which departure from the traditional mechanism to stabilize flame.With low rotational diffusion and no reflow turbulent flow to steady free diffusion of turbulent flame.The low swirl injector?LSI?has the characteristics of simpler structure,low cost,easy to fit the existing combustion and low NO_x emission.Therefore,the study of low swirl combustion has important application value and academic significance.In this paper the combustion chamber is self-designed and installed on the combustion experiment table,with propane,methane,and mixture as fuel.Through the variation of the center perforated plate,the swirl number is changed.The swirl number mainly used is S=0.521?0.545?0.575?0.623.This article respectively measures the flame spectrum of low swirl lean premixed combustion with spectrometer;takes the picture of low swirl lean premixed combustion flame shape with Canon EOS 7D camera;measures the axial and radial flame temperature of low swirl lean premixed combustion with Type B double platinum rhodium thermocouple;measures the flame emission of low swirl lean premixed combustion with Portable flue gas analyzer.The conclusions are shown as follows:?1?With the increase of swirl number S,OH and CH free radical relative intensity is decreased,when methane and methane-hydrogen mixture in the combustion process.?2?The blue flame structure converts the "W" type flame into the "broom" type flame and the distance between the front of the flame and the nozzle shortens with increasing swirl number.With the decrease of the fuel C-H ratio,flame colour is obviously diluted.After the mixing of hydrogen in methane,it will shorten the flame length.?3?There are high temperature region flanked by two peaks on the temperature profiles in the blue flame.The high temperature zone narrows and the temperature gradient becomes steeper on two sides of the temperature profile in blue flame with swirl number increasing.When the swirl number exceeds a certain value?critical swirl number S₀ between 0.575 to 0.598?,the upper flame temperature by bimodal type turns into a parabolic type.?4?With the increase of swirl number S,the radial temperature of low swirl flame center gradually decreases.?5?The NO_x and CO emissions level of LSI mainly depend on the gas composition and thermal load.With the increase of swirl number S,EI_NOx of low swirl flame increases.?6?Under the same working condition,low swirl flame combustion efficiency is higher than high swirl flame.