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chapter 5 turbulent diffusion flames - FedOA

chapter 5 turbulent diffusion flames - FedOA

more than one order of

more than one order of magnitude larger than that of particles with sizes larger than 20 nm confirming the very low concentration of soot in the analyzed flame. DMA Air 100 Probe Flame Methane Fig. 3.42 Experimental set-up for DMA measurements. dN/dLOG(D P), cm -3 1.E+06 1.E+05 1.E+04 1.E+03 1 10 100 D P, nm Fig. 3.43 Size distribution function of the particles detected at 10 cm along the flame axis of the turbulent methane flame.

CHAPTER 6 BURNERS FOR HOME APPLIACES As consequence of the numerous experimental data obtained in laboratory burners configurations burning methane, an experimental study of the combustion characteristics of new natural gas burners used for home and water heating appliances has been performed during the thesis with the aim of evaluating the effect of burner configurations and operating conditions on the emissions of gaseous pollutants and organic carbon nanoparticles. The previously described in- situ optical diagnostics, based on laser induced emission spectroscopy (LIE), and ex-situ measurements, based on scanning mobility particle sizer (SMPS), and particles collection by water-based sampling technique, are used in order to evaluate the total particulate concentration and size distribution functions. Three different burners configurations: two premixed and one diffusive are studied under various operative conditions. Measurements have shown that particulate matter with size in the 1 nm to 10 nm size range is formed in all the examined conditions. The emitted mass concentration of these compounds is very low, of the order of 0.001 ppm. They are formed in large number concentrations in the flame region but are also strongly oxidized in the post-oxidation region of the devices. Soot particles with size larger than 10 nm are not formed in all the examined conditions. 6.1 BURNERS CONFIGURATION The home heating burners consist in two premixed differentiated by the knitted metal fibre and the drilled cylindrical heads and one diffusive constituted by a five-tube injector of gaseous hydrocarbons (Toniato et al. [81]). The burners have been operated in free atmosphere and in commercial devices. 101

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