Numerical and experimental analysis of vertical spray control patternators

The experimental vertical spray control walls have the purpose of picking up the liquid delivered by trained sprayer for providing the liquid distribution profile in height. Theoretically this should correspond to the ideal profile, which consists in a uniform distribution on the vegetation. If the profile is different from the ideal, a parameter setup is required on the sprayer. Nonetheless, some problems are hidden in the aforementioned statements: i) no wall measures exactly the distribution profile (i.e. the flow through the sections in the vertical plane, parallel to the direction of advancement of the sprayer). Compared to real profile, sensitive errors are introduced: the evaporation of the drops, the deviation of the air flows caused by the sensors panel themselves; by the possibility that the drops bounce on the wall panels, also due to the current of air that can push the liquid veil laterally or upwards, Moreover, everything varies depending on the geometry of the sensors, air velocity, air humidity; ii) no one knows what exactly is the optimal distribution profile. It is often considered as optimal a profile that reflects the amount of leaf area subtended by each section absorber: however, it is evident that the path of the droplets changes according to the sprayer typology (eg. radial-flow or horizontal flows). In this work a combined numerical-experimental approach is adopted, in order to assess some of the aforementioned issues: numerical data obtained by using computational fluid dynamics models are compared and validated with experimental data, in order to assess the reliability of numerical simulations in configurations which are difficult to analyze using an experimental setup

Characterization of biomass emissions and potential reduction insmall-scale pellet boiler

6noIn recent years it has been proved that residential biomass combustion has a direct influence on ambient air quality, especially in the case of cereals. The aim of this study is the characterization of the emissions in small-scale fixed-bed pellet boiler (heat output of 25 kW) of beech and corn, and of its potential reduction to an addition of calcium dihydroxide. In the biomass combustion test 7 fuel mixtures were investigated with regard to the particulate content (PM10), gaseous emissions and combustion chamber deposit. The corn kernels tanned with calcium dihydroxide determined a decrease in particulate emissions (54±13 mg MJ− 1) in comparison to corn, whereas in the combustion of corn pellet with 1% calcium dihydroxide high emissions were observed (193±21 mg MJ− 1). With regard to SO2 emissions, the combustion of corn with the additives make a reduction in comparison to additive-free corn.openopenDELL'ANTONIA D.;Pergher G;Cividino SRS;Gubiani R;Cecchini M;Marucci ADell'Antonia, D.; Pergher, G; Cividino, Srs; Gubiani, R; Cecchini, M; Marucci,