کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
6478293 1427916 2017 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Transient model for soot formation during the combustion of single coal particles
ترجمه فارسی عنوان
مدل گذار برای تشکیل دوده در طی احتراق ذرات تک ذغال سنگ
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی مهندسی شیمی (عمومی)
چکیده انگلیسی

A transient mathematical model was developed to describe soot formation during the combustion of single coal particles based on the static semi-empirical model presented by Fletcher and coworkers. Sensitivity analyses of the model parameters show that soot emissivity and mass diffusivity of tar play an important role in predicting soot volume fraction (fv) and flame temperature (Tf). The model was applied to simulate the combustion of single bituminous coal particles with initial diameter (2r0) of 83 µm in a drop tube furnace and air atmosphere. It was found that soot is only formed within the first ∼ 5 ms after the appearance of the volatile flame. Although most of the soot is oxidized during the volatile flame phase, a small portion of soot still remains during the char combustion. Due to the soot presence, the volatile flame duration is extended by 2.6 ms. Compared with the soot-free flame, the sooting flame has remarkable lower Tf and its peak Tf value is ∼ 410 K lower. As a consequence, char combustion starts at a temperature that is ∼ 125 K lower than that of the soot-free case. Spatially, the peak fv at 16.6 ms appears at 4.5 r0 and soot oxidation zone spans to ∼ 10 r0. The model was validated by comparing the predicted Tf and fv under different O2 mole fractions (xO2) with recent experimental results reported by Khatami and coworkers. The predicted trends are consistent with those of the experimental results. With increasing xO2, Tf increases, but the increase rate becomes more gradual at a large xO2. While for fv, a non-monotonic variation is observed, where soot first increases and then decreases with a peak value occurring at xO2 ≈ 40%.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Proceedings of the Combustion Institute - Volume 36, Issue 2, 2017, Pages 2131-2138
نویسندگان
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