Investigation of co2 diluted methane and propane swirling premixed flames using ch* chemiluminescence imaging

Utilization of hydrocarbon gaseous fuels, such as biogas, landfill gas and others, is a valuable contribution to sustainable energy production and climate changing control. The presence of CO2 in these gases decreases heat of combustion, flame temperature, flame speed and can induce flame blow-off and combustion instabilities. In order to better understand the problem, flame geometry and location was investigated using chemiluminescence (CH*) imaging technique. Combustion took place in a purposely built, lean, premixed, unconfined swirl burner, fueled by methane and propane diluted with CO2. The fuel type, air-to-fuel equivalence ratio and CO2 content were chosen as the independent variables. The CH* imaging by means of a commercial CCD camera, fitted with an optical filter, was used for flame investigation. The analysis of images showed that the CH* emission intensity, flame geometry and location were remarkably affected by the fuel type and the air-to-fuel equivalence ratio, while the CO2 dilution was of minor importance

Investigation of co2 diluted methane and propane swirling premixed flames using ch* chemiluminescence imaging

Utilization of hydrocarbon gaseous fuels, such as biogas, landfill gas and others, is a valuable contribution to sustainable energy production and climate changing control. The presence of CO2 in these gases decreases heat of combustion, flame temperature, flame speed and can induce flame blow-off and combustion instabilities. In order to better understand the problem, flame geometry and location was investigated using chemiluminescence (CH*) imaging technique. Combustion took place in a purposely built, lean, premixed, unconfined swirl burner, fueled by methane and propane diluted with CO2. The fuel type, air-to-fuel equivalence ratio and CO2 content were chosen as the independent variables. The CH* imaging by means of a commercial CCD camera, fitted with an optical filter, was used for flame investigation. The analysis of images showed that the CH* emission intensity, flame geometry and location were remarkably affected by the fuel type and the air-to-fuel equivalence ratio, while the CO2 dilution was of minor importance

Analysis of the performance of a low-power atmospheric burner for gas appliances for households and their impact on the emission and stability of the burner

The paper presents results of theoretical numerical research dealing with CO and NOx emission performed in the process of optimization of the performance of low-power atmospheric burners. The theoretical part of this paper, whose main goals were better understanding of the complex issues of methodology and establishment of performance prediction and optimization of low-power atmospheric gas burner included numerical variation of independent parameters, such as burner geometry, the coefficients of primary and secondary air and different gaseous fuels including biogas. The findings of theoretically obtained performance prediction and optimization of atmospheric burners were experimentally investigated in purpose built test rigs for a number of variable parameters. The obtained results fully justified the proposed models of performance prediction and burner optimization

Analysis of the performance of a low-power atmospheric burner for gas appliances for households and their impact on the emission and stability of the burner

The paper presents results of theoretical numerical research dealing with CO and NOx emission performed in the process of optimization of the performance of low-power atmospheric burners. The theoretical part of this paper, whose main goals were better understanding of the complex issues of methodology and establishment of performance prediction and optimization of low-power atmospheric gas burner included numerical variation of independent parameters, such as burner geometry, the coefficients of primary and secondary air and different gaseous fuels including biogas. The findings of theoretically obtained performance prediction and optimization of atmospheric burners were experimentally investigated in purpose built test rigs for a number of variable parameters. The obtained results fully justified the proposed models of performance prediction and burner optimization

Cooling of wood briquettes

This paper is concerned with the experimental research of surface temperature of wood briquettes during cooling phase along the cooling line. The cooling phase is an important part of the briquette production technology. It should be performed with care, otherwise the quality of briquettes could deteriorate and possible changes of combustion characteristics of briquettes could happen. The briquette surface temperature was measured with an IR camera and a surface temperature probe at 42 sections. It was found that the temperature of briquette surface dropped from 68 to 34°C after 7 minutes spent at the cooling line. The temperature at the center of briquette, during the 6 hour storage, decreased to 38°C

Potentials for usage of significantly reduced chemical mechanisms in numerical modeling of combustion processes

Rezultati numeričkih modeliranja prezentovani u ovom radu, deo su istraživanja laboratorije za sagorevanje Mašinskog fakulteta u Beogradu, sprovedenog u okviru FP6 projekta 'FlexHEAT', koji su zajedno realizovale institucije iz šest evropskih zemalja a koji je finansiran od strane Evropske unije (www.flexheat.uni-erlangen.de). U radu su prezentovani uporedni rezultati numeričkih proračuna kojima se simulira sagorevanje goriva na bazi metana (prirodni gas, srpski gas, biogas i sl), a koji su dobijeni korišćenjem eksperimentalno proverenog, kompletnog hemijskog mehanizma GRI 3.0 koji čini 325 hemijskih reakcija i odgovarajućeg veoma redukovanog hemijskog mehanizama, koga čine 2 hemijske reakcije (od kojih je jedna povratna) razvijenog na bazi dvostepenog C.K. Westbrook & F.L. Dryer (WD) modela. Rezultati su dobijeni upotrebom programskog paketa 'ChemKin' i determinišu oblast i mogućnost primene ovako značajno redukovanih hemijskih mehanizama u CFD proračunima, u situacijama kada kompleksnost samog strujanja sa hemijskim reakcijama kroz složene geometrije gorionika i peći ne dozvoljava upotrebu složenijih hemijskih mehanizama.The paper presents comparison of the results obtained in numerical research conducted, with the aim to simulate combustion of methane-based fuels like natural gas, Serbian gas, biogas, etc. Presented results were obtained using experimentally verified, full chemical mechanism GRI 3.0, with 325 chemical reactions, and using selected, very reduced chemical mechanism, with only two chemical reactions, based on two-step C.K. Westbrook & F.L. Dryer (WD) model. 'ChemKin' software was used for all numerical simulations of chemical kinetics and 'Fluent' for CFD analysis. The goal was to determine possibilities and application fields of this very reduced chemical mechanism in CFD calculations, especially in cases when flows with chemical reactions through complex geometry of burners and furnaces, disable usage of full mechanisms

Potentials for usage of significantly reduced chemical mechanisms in numerical modeling of combustion processes

Rezultati numeričkih modeliranja prezentovani u ovom radu, deo su istraživanja laboratorije za sagorevanje Mašinskog fakulteta u Beogradu, sprovedenog u okviru FP6 projekta 'FlexHEAT', koji su zajedno realizovale institucije iz šest evropskih zemalja a koji je finansiran od strane Evropske unije (www.flexheat.uni-erlangen.de). U radu su prezentovani uporedni rezultati numeričkih proračuna kojima se simulira sagorevanje goriva na bazi metana (prirodni gas, srpski gas, biogas i sl), a koji su dobijeni korišćenjem eksperimentalno proverenog, kompletnog hemijskog mehanizma GRI 3.0 koji čini 325 hemijskih reakcija i odgovarajućeg veoma redukovanog hemijskog mehanizama, koga čine 2 hemijske reakcije (od kojih je jedna povratna) razvijenog na bazi dvostepenog C.K. Westbrook & F.L. Dryer (WD) modela. Rezultati su dobijeni upotrebom programskog paketa 'ChemKin' i determinišu oblast i mogućnost primene ovako značajno redukovanih hemijskih mehanizama u CFD proračunima, u situacijama kada kompleksnost samog strujanja sa hemijskim reakcijama kroz složene geometrije gorionika i peći ne dozvoljava upotrebu složenijih hemijskih mehanizama.The paper presents comparison of the results obtained in numerical research conducted, with the aim to simulate combustion of methane-based fuels like natural gas, Serbian gas, biogas, etc. Presented results were obtained using experimentally verified, full chemical mechanism GRI 3.0, with 325 chemical reactions, and using selected, very reduced chemical mechanism, with only two chemical reactions, based on two-step C.K. Westbrook & F.L. Dryer (WD) model. 'ChemKin' software was used for all numerical simulations of chemical kinetics and 'Fluent' for CFD analysis. The goal was to determine possibilities and application fields of this very reduced chemical mechanism in CFD calculations, especially in cases when flows with chemical reactions through complex geometry of burners and furnaces, disable usage of full mechanisms

Numerical analysis of lean premixed combustor fueled by propane-hydrogen mixture

A numerical investigation of combustion of propane-hydrogen mixture in a swirl premixed micro gas turbine combustor is presented. The effects of hydrogen addition into propane on temperature distribution in the combustor, reaction rates of propane and hydrogen and NO, emissions for different equivalence ratios and swirl numbers are given. The propane-hydrogen mixture of 90/10% by volume was assumed. The numerical results and measurements of NO emissions for pure propane are compared. Excellent agreements are found for all equivalence ratios and swirl numbers, except for the highest swirl number (1.13). It is found that the addition of hydrogen into propane increases NO, emission. On the other hand, the increase of swirl number and the decrease of equivalence ratio decrease the NO, emissions

Characterization of kinetic swirling flame of biogas using CH* visualization

Zemlje Evropske unije su prihvatile, a time praktično i Srbija, da do 2030. koriste najmanje 32% energije iz obnovljivih izvora. Među obnovljivim energetskim izvorima biogas zauzima značajno mesto. Prisustvo CO2 (30 – 60%) u biogasu, snižava toplotnu moć goriva, temperaturu i brzinu prostiranja plamena, pogoršava stabilnost plamena, utiče na emisiju zagađujućih komponenti i u krajnjem slučaju, dovodi do gašenja plamena. Promenljiv sadržaja CO2 u gorivu otežava upravljanje procesom sagorevanja i utiče na performanse uređaja za sagorevanje. Predmet ove disertacije je istraživanje uticaja vrste goriva - biogasa, metana i propana, sadržaja CO2 u gorivu, koeficijenta viška vazduha i ugla lopatica usmernog kola vrtložnog gorionika, na položaj i geometriju turbulentnog, kinetičkog plamena, metodom vizuelizacije CH* hemiluminescencije pomoću komercijalne digitalne kamere opremljene CCD senzorom i optičkim filtrom, i korišćenjem softvera za obradu slike. Za eksperimentalno istraživanje upotrebljen je namenski konstruisan vrtložni gorionik sa prethodno pripremljenom, predmešanom smešom goriva i vazduha i sagorevanjem u slobodnom prostoru. Dobijeni rezultati pokazuju da je intenzitet hemiluminescencije CH* propana oko dva puta veći u odnosu na biogas i metan. Sva ispitivana goriva su slično reagovala na sadržaj CO2. Uticaj koeficijenta viška vazduha na intenzitet emisije CH*, položaj i oblik plamena je vrlo izražen, dok je uticaj prisustva CO2 znatno manji. Postavljene su korelacije između intenziteta emisije CH*, položaja i geometrije plamena, koeficijenta viška vazduha i sadržaja CO2 u gorivu. Pokazano je da je korišćenjem predložene optičke metode za vizuelizaciju plamena i merenjem relativnog intenziteta emisije CH* moguće identifikovati promenu kvaliteta goriva, promenu udela CO2 u gorivu i promenu koeficijenta viška vazduha. Praktična primena rezultata ove disertacije se odnosi na mogućnost primene sistema za vizuelizaciju, kao i predložene korelacije za upravljanje radom gorionika i praćenje njegovog rada.The EU countries have accepted, and thus practically Serbia, to target for the share of renewable energy consumed, should be at least 32% by 2030. Among the renewable energy sources, biogas holds the important place. The presence of CO2 in biogas, decreases the fuel calorific value, flame temperature, and velocity, worsens flame stability, affects emission of pollutants and finally the flame is extinguished. The variable content of CO2 in fuel makes control of combustion more difficult and affects the performance of combustion devices. The subject of this dissertation is an investigation of the effects of fuel type: biogas, methane and propane, the content of CO2 in fuel, air equivalence ratio and the blade angle of swirl burner on position and geometry of turbulent, kinetic flame, making use of a commercial digital camera’s CCD sensor fitted with an optical filter for CH* chemiluminescence visualization and the software for image processing. For the experimental investigation a purposely built swirl burner is used with a prepared fuel and air mixture, burning in the open space. The results show that the CH* chemiluminescence the intensity of propane is about twice as the intensity of biogas and methane. All the tested fuels reacted in a similar way on the CO2 content in fuel. The effect of air equivalence ratio on the CH* chemiluminescence intensity, flame position, and the flame shape is very pronounced, while the impact of CO2 content is much smaller. The correlations were established between the CH* chemiluminescence intensity, the position and flame shape and the air equivalence ratio and the CO2 content in fuel. It is shown that using the proposed optical method for flame visualization and measurements of the relative CH* chemiluminescence intensity, it is possible to identify changes in fuel quality, the CO2 content in fuel and changes of the air equivalence ratio. The flame visualization and the proposed correlations can be used to monitor and control of a burner

Numerical modeling of Nomex honeycomb core composite plates at meso scale level

Kompozitne ploče sa saćastom ispunom se sve više koriste pri izradi primarnih vazduhoplovnih struktura. Ovi materijali koriste se pri konstrukciji oplata trupova letelica, centralnih i spoljnih torzionih kutija krila, oplata pogonskih grupa, vrata stajnih trapova, komandnih površina kao što su spojleri i eleroni. Da bi se odredila polja napona i deformacija opterećene strukture neophodno je poznavanje svih elastičnih koeficijenata. U ovom radu, metod za određivanje svih potrebnih elastičnih koeficijenata ispune i ploča je predstavljen. Koristeći se eksperimentalno dobijenim rezultatima za papir NOMEH (tip 410 ) kao i fenolnu matricu materijalni model je predstavljen, izrađen je model konačnih elemenata kompozitne ploče sa saćastom ispunom i numerički je simuliran test savijanja u tri tačke. Dobijeni rezultati upoređeni su sa rezultatima dobijenim eksperimentom. Primećeno je dobro slaganje između predloženog modela materijala i eksperimentalno dobijenih vrednosti.Honeycomb core composite plates are becoming more important in the construction of primary aerospace structures. Nowadays, these types of materials are used for construction of fuselage skins, central and outer wing boxes, engine tail cones, landing gear doors, command surfaces like spoilers and ailerons etc. To determine the stress strain field in loaded honeycomb plates elastic coefficients are required. In the present work, a method for determining all required elastic coefficients for the core and plates is presented. Using experimentally obtained values for Nomex paper (type 410) and phenolic resin material model is presented and FEA model of composite plate with honeycomb core is created and three point bend test is simulated. Numerically obtained stress and strain values are compared to the experiment. Good agreement between proposed material model and experimentally obtained values is observed