EXPERIMENTAL STUDIES ON A NEW DEVELOPED MIXED-FLOW DRYER

摘要

Mixed-flow dryers are of great importance in worldwide agriculture for the drying of grain,corn and rice.Unfavorable dryer designs can result in uneven particle and air flow distributions and,thereby,cause inhomogeneous residence time and drying conditions.As a consequence,the grain drying can locally be very uneven with high fluctuations of the moisture distribution over the dryer cross-section.The main reasons are design and construction of the dryer apparatus and the discharge device.A new mixed-flow dryer design has been developed promising a more homogeneous drying,higher energy efficiency,and increased product quality.Firstly,the new dryer design was proved with respect to particle flow.For this purpose,a new test dryer was constructed.A series of particle flow experiments were performed using colored tracer particles.The flow of the tracer particles has been observed through a transparent acrylic front wall by image analysis.Based on a comparison with the traditional design,the advantages and disadvantages of the new design were evaluated.The experimental investigations were accompanied by numerical simulations of the particle flow using the Discrete Element Method.Based on it,the effects of design properties and different air duct arrangements were studied.