Investigation of Particle and Air Flows in a Mixed-Flow Dryer

Weigler, Fabian; Scaar, Holger; Mellmann, Jochen

doi:10.1080/07373937.2012.703742

Cited by 23 publications

(16 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…No tracer gas could be detected at these remote outlet air ducts. The tracer gas measurements confirmed the non-uniform airflow behaviour in the diagonal air duct arrangement as has been previously investigated by model simulations [31].…”

Section: Residence Time Distribution (Rtd)supporting

confidence: 79%

“…The angle of repose of wheat and rapeseed was measured (Table 1) and used to discretise the numerical model. For more details about the measuring method, see [31,32]. The first method that has been selected to investigate the airflow distribution was the experimental determination of the isobar distribution between inlet and outlet air ducts.…”

Section: Bed Materialsmentioning

confidence: 99%

“…A comprehensive review on CFD application in simulating and designing drying processes was given by Jamaleddine and Ray [29]. Recent research results on particle and air flow in MFD have been published by Keppler et al [30] and Weigler et al [31,32], among others.…”

Section: Introductionmentioning

confidence: 97%

See 2 more Smart Citations

Experimental and numerical study of the airflow distribution in mixed-flow grain dryers

et al. 2015

Self Cite

View full text Add to dashboard Cite

The aim of this study was to investigate the airflow distribution in the mixed-flow dryer (MFD) and to study the effect of different bed materials and air duct arrangements. The results were used to validate the numerical model developed in a previous work based on the Computational Fluid Dynamics (CFD). A series of experiments have been conducted at a semi-technical MFD test dryer with horizontal and diagonal air duct arrangement.Wheat and rapeseed were used as bed materials. The experiments were performed under isothermal conditions. Two experimental methods were selected and adapted to the measuring problem -the measurement of the isobar distribution within the grain bed and the residence time analysis using the tracer gas pulse method.As could be shown, the isobar distributions measured for wheat and rapeseed agreed well with the model predictions. The numerical model could well calculate the influence of the bed material with its different particle characteristics (e.g. particle shape, particle size, bed porosity). The results obtained from the residence time analysis confirmed the known quartering of the air stream flowing from one inlet air duct to the four surrounding outlet Downloaded by [New York University] at 20:13 22 July 20152 air ducts for the horizontal air duct arrangement. Whereas, in the diagonal air duct arrangement, the air steam from one inlet air duct was nearly halved flowing to the two adjacent diagonal outlet air ducts. These results were confirmed by investigations of the air velocity distribution within the grain bulk. Further experiments are necessary to refine the model. For it, the residence time and isobar measurements will be extended to study the influence of different air properties under real drying conditions, the effect of structural elements and dryer designs.

show abstract

Section: Residence Time Distribution (Rtd)supporting

confidence: 79%

Section: Bed Materialsmentioning

confidence: 99%

See 1 more Smart Citation

Experimental and numerical study of the airflow distribution in mixed-flow grain dryers

et al. 2015

Self Cite

View full text Add to dashboard Cite

show abstract

“…More recently, the authors developed an advanced DEM model. [16] This model was applied in this work to detect inhomogeneities of the particle flow due to design deficits. To validate the discrete model and to study the effect of design elements, particle flow experiments were performed for both the traditional and the new MFD design.…”

Section: Introductionmentioning

confidence: 99%

Experimental Studies on a Newly Developed Mixed-Flow Dryer

et al. 2013

Self Cite

View full text Add to dashboard Cite

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 gas-solids contact 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 that promises 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 was performed using colored tracer particles. The flow of the tracer particles was 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 pattern using the discrete element method. The effects of design properties and different air duct arrangements were studied. The present results show that we are at the beginning of a new development concerning the optimization of mixed-flow drying apparatuses.

show abstract

“…As could be demonstrated the particle flow through the center of the dryer is faster than at the side walls. In order to investigate the bulk motion and thus the distributions of the particle velocity and the residence time in a MFD precisely, Iroba et al [8] and Weigler et al [9] developed two-dimensional models based on the Discrete Element Method (DEM). Using the discrete calculations particle trajectories in a mixed flow dryer were determined.…”

Section: Introductionmentioning

confidence: 99%

Development of a novel mixed flow dryer design

Weigler¹,

Scaar²,

Franke³

et al. 2015

HAE

Self Cite

View full text Add to dashboard Cite

Mixed flow dryers (MFD) are widely used in agriculture for the drying of various crops including maize and rice. As compared to other drying methods in the industrial drying, mixed flow dryers still have considerable potential for improving energy efficiency. The comparatively high primary energy consumption is mainly caused by uneven drying, which, in turn, is caused less by poor dryer control rather than by unfavorable dryer design. In order to optimize the processes in agricultural engineering, such as the mixed flow dryer, numerical methods are being increasingly used. Optimizing of the dryer geometry provides a high potential to further increase the efficiency of MFD.

show abstract

Investigation of Particle and Air Flows in a Mixed-Flow Dryer

Cited by 23 publications

References 32 publications

Experimental and numerical study of the airflow distribution in mixed-flow grain dryers

Experimental and numerical study of the airflow distribution in mixed-flow grain dryers

Experimental Studies on a Newly Developed Mixed-Flow Dryer

Development of a novel mixed flow dryer design

Contact Info

Product

Resources

About