Matching Items (2)
Description
Rotary drums are commonly used for their high heat and mass transfer rates in the manufacture of pharmaceuticals, cement, food, and other particulate products. These processes are difficult to model because the particulate behavior is governed by the process conditions such as particle size, particle size distribution, shape, composition, and operating parameters, such as fill level and rotation rate. More research on heat transfer in rotary drums will increase operating efficiency, leading to tremendous energy savings on a global scale. This study investigates the effects of drum fill level and rotation rate on the steady-state average particle bed temperature. 3 mm silica beads and a stainless steel rotary drum were used at fill levels ranging from 10 \u2014 25 % and rotation rates from 2 \u2014 10 rpm. Four heat guns were used to heat the system via conduction and convection, and an infrared camera was used to record temperature data. A three-level, two-factor, full-factorial design of experiments was employed to determine the effects of each factor on the steady-state average bed temperature. Low fill level and high rotation rate resulted in higher steady-state average bed temperatures. A quantitative model showed that rotation rate had a larger impact on the steady-state bed temperature than fill level.
ContributorsBoepple, Brandon Richard (Author) / Emady, Heather (Thesis director) / Adepu, Manogna (Committee member) / W.P. Carey School of Business (Contributor) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
The way a granular material is transported and handled plays a huge part in the quality of final product and the overall efficiency of the manufacturing process. Currently, there is a gap in the understanding of the basic relationship between the fundamental variables of granular materials such as moisture content, particle shape and size. This can lead to flowability issues like arching and ratholing, which can lead to unexpected downtimes in the whole manufacturing process and considerable wastage of time, energy, and resources. This study specifically focuses on the development of a model based on the surface mean diameter and the moisture content to predict the flow metric flow function coefficient (FFC) to describe the nature of flow of the material. The investigation involved three parts. The first entailed the characterization of the test materials with respect to their physical properties - density, size, and shape distributions. In the second, flowability tests were conducted with the FT4 Powder Rheometer. Shear cell tests were utilized to calculate each test specimen's flow function parameters. Finally, the physical properties were correlated with the results from the flowability tests to develop a reliable model to predict the nature of flow of the test specimens. The model displayed an average error of -6.5%. Predicted values showed great correlation with values obtained from further shear cell tests on the FT4 Rheometer. Additionally, particle shape factors and other flowability descriptors like Carr Index and Hausner Ratio were also evaluated for the sample materials. All size ranges displayed a decreasing trend in the values of Carr Index, Hausner Ratio, and FFC with increasing moisture percentages except the 5-11 micron glass beads, which showed an increasing trend in FFC. The results from this investigation could be helpful in designing equipment for powder handling and avoiding potential flowability issues.
ContributorsDeb, Anindya (Author) / Emady, Heather (Thesis advisor) / Marvi, Hamidreza (Committee member) / Jiao, Yang (Committee member) / Arizona State University (Publisher)
Created2021