Abstract
Theproblemofunstablecombustionoftenoccursintheafterburner,andtheconventional
afterburnerusesacircularholedirectinjectionnozzle.Althoughthestructureissimple,the
atomizationperformanceispoor.Basedonafluidself-excitedoscillator,anewtypeofself-
excitedoscillationsweepnozzlehasbeendeveloped.Thisstudymainlyfocusesontheproblem
ofunstablecombustionofflamesintherearofamodelcombustionchamberusinganewtype
ofsweepingnozzle.Theinfluenceofvariousparametersofthesweepingnozzleonunstable
combustionisstudied,andthecombustionefficiencyoftwotypesofnozzlesisobtained.
Inresponsetotheaboveissues,thisarticleconductedresearchexperimentsoncombustion
instabilityinamodelcombustionchamber.Designcombustionchambertestspecimensbased
ondesignprinciplesandreferencemanuals,andconductnumericalsimulationtoverifythe
design.Finally,flameinstabilitycombustionresearchwasconductedontheflamebehindthe
valueclassinthecombustionchamberofthemodel.Byprocessingpressurepulsationdataafter
experiments,theinfluenceofstructure,oilgasratio,sweepangle,nozzleaperture,andsweep
frequencyonunstablecombustionofsweptanddirectinjectionnozzlescanbeobtained.In
addition,combiningpressurepulsationdataandimageprocessingdatatoanalyzethe
generationlawofthermalacousticoscillationmodecharacteristics,andusingagasanalyzerto
calculatethecombustionefficiencyofdifferentnozzles.
Byprocessingandanalyzingpressurepulsationdataunderpresetoperatingconditions,it
wasfoundthatacharacteristicfrequencyisgeneratedaround145Hzduringcombustion,which
isconsistentwiththenumericalsimulationresultsandisafirst-orderlongitudinalfrequency.
Theresultsofflameselfluminescenceindicatethatthefla