کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
144307 438927 2012 14 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Predicting bulk powder flow dynamics in a continuous mixer operating in transitory regimes
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی مهندسی شیمی (عمومی)
پیش نمایش صفحه اول مقاله
Predicting bulk powder flow dynamics in a continuous mixer operating in transitory regimes
چکیده انگلیسی

Over recent years there has been increasing interest in continuous powder mixing processes, due mainly to the development of on-line measurement techniques. However, our understanding of these processes remains limited, particularly with regard to their flow and mixing dynamics. In the present work, we study the behaviour of a pilot-scale continuous mixer during transitory regimes, in terms of hold-up weight and outflow changes. We present and discuss experimental results concerning the start-up dynamics of a Gericke GCM 500 mixer, for which a specific experimental protocol has been developed to determine the evolution of the hold-up in the mixer and the real outflow. Empirical relationships are derived so as to link hold-up weight variations with operating conditions. A simple stochastic approach, based on a non-homogeneous Markov chain, is developed to simulate the bulk particle flow and transport in the continuous mixer at a macroscopic level. Although this simple model is only based on the start-up behaviour, it provides a full description of the mixer dynamics in response to strong perturbations on the flow rate or on the rotational speed of the stirring device, such as negative or positive steps. This model is validated experimentally for a wide range of operating conditions, and constitutes a first approach to process control.

Figure optionsDownload as PowerPoint slideHighlights
► A simple Markov chain model was developed to describe bulk flow dynamics in a continuous mixer.
► It describes real outflow rate and hold-up weight in steady and unsteady states.
► When the hold-up weight reaches a threshold, a steady state regime is established.
► Before the threshold, the system obeys the rules of a non-homogeneous Markov chain.
► Empirical relations are derived from experimental data to implement the model.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Advanced Powder Technology - Volume 23, Issue 6, November 2012, Pages 787–800
نویسندگان
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