In the mixed-flow dryers grain is transported step-by-step downwards the dryer shaft. At each discharge it is assumed that the grain bed moves in plug flow pattern. The bed material is assumed to be a connection of a series of single grain layers the drying behaviour of which is described by means of a single grain model. Although mixed-flow dryers are widely used it is still necessary to optimize many segment processes. For example there are big differences in vertical grain particle velocity causing differences in residence time. As a result, uneven drying occurs and, hence, under-drying or over-drying of single grain portions. To investigate the influences of the dryer walls and the air ducts on particle velocity distribution experiments were carried out. This paper presents experimental results for the fluctuation of wheat moisture content at the discharge device of a mixed-flow dryer. This phenomenon is caused by inhomogeneous mass flow during drying. The aim of the investigations was to measure the amplitude of the mass-flow fluctuation under different conditions. Hereby this work also submits the results of grain-flow computer simulated modelling experiments. In a future work for grain mass flow a mathematical model will be developed enabling improvements in the prediction of the drying process.
|Number of pages||7|
|Issue number||SPPL. ISS. 1|
|Publication status||Published - dec. 1 2011|
ASJC Scopus subject areas
- Agronomy and Crop Science