نوع مقاله : مقاله پژوهشی
نویسنده
دانشکده مهندسی مکانیک و هوافضا/ دانشگاه صنعتی شیراز
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسنده [English]
In this paper, a new approach based on energy balance is presented to predict the critical Weber number in a droplet breakup under the combined effects of turbulence and aerodynamic stresses. The energy balance approach, as it has good structural coordination with the conventional Taylor analog breakup model, can provide a suitable platform for modifying and upgrading the mentioned model. In this study, the range of length scale of the effective turbulent eddies on droplet breakup was calculated analytically. The results showed that the average length scale of the turbulent eddies participating in the droplet breakup is inversely proportional to the third root of its drag coefficient. It was also found that at Reynolds numbers above 1000, turbulent eddies with length scale of about 2.7 times the droplet diameter have the greatest effect on the breakup. At Reynolds numbers less than 1000, the size of the effective eddies is a function of the Reynolds number and decreases sharply as the Reynolds number decreases. Comparing the performance of the proposed model with the hybrid time scale model which previously presented for calculating the critical Weber number under combined turbulent and aerodynamic stresses showed that both models have approximately the same results at turbulence intensities greater than 30%. At medium and low turbulence intensities (5 to 30%) the proposed model predicted the value of critical Weber number up to 15% more than that of the hybrid time scale model. The results of both models are very consistent with the reported experimental data.
کلیدواژهها [English]
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