Re: Public Database
M. O'Rosky,
as far as I know, there is no public database on flow properties. In some silo codes (e.g. DIN 1055 part 6) a few bulk materials with their properties are listed.
The problem is that flow properties like bulk density and friction may vary with moisture, particle shape, chemical composition, particle size distribution and other parameters. Also the stress acting on the bulk solid is an improtant parameter, especially for fine-grained, cohesive bulk solids. Thus, the best way is to measure the properties with the bulk solid under consideration, whereby the conditions, e.g. the stress, at which the material has to be handled, should be applied.
Best regards
Dietmar Schulze ■
Solid Physical Properties
Does the CEMA keep a database? (Conveyor Equipment Manufacturers Association) They have a classification system. If a data base does not exist is there a uniform classification system other than CEMA that can be applied to aid in design prior to testing a solid? I am familar with some early published work by Ralph Carr and Dr. A. W. Jenike. Seems that hrere should be some public data base with a classification somewhere? ■
Re: Public Database
Dietmar is totally correct in his response. The complete range of permutations of moisture, temperature, time consolidation, size shape, distribution, etc for a single bulk solid would form a database in its own right, and whilst the data would be present, how many engineers would be able to correctly interpret and apply the resulting data? Where would any liability for error be focussed? It is not sufficient to simply access data, but it is vital that the application and ramifications are also well understood by practising engineers. Simply getting a convergence right on a vessel is only the start of obtaining reliable operation - vessels need to be tailored to specific applications and modes of operation in many cases.
The cost of obtaining flow characteristics for materials is tiny compared to the cost of remedial work after a piece of equipment has been designed and installed.
Regards
Richard Farnish
e-mail: r.j.farnish@gre.ac.uk
http://www.bulksolids.com ■
Reply
Richard,
Thanks for your insight and expansion on the difficulties of bulk solids property classification.
I just thought that someone would have compiled a list(database) of properties of each solid under some standard condition of temperature pressure and moisture. I would have thought it would have included 1. Particle properties: surface area, porosity, surface characteristics, electrostatic charging, hardness, shape, hygroscopicity and specific gravity. 2. Bulk Properties: bulk density(dynamic,loose,packed) compressibility, porosity,particle size distribution, angle of repose, angle of fall, angle or slide, floodability, abrasiveness, and any other commented miscellaneous. ■
Public Database
Is there a public databse for flow properties of solids? I am most interested in densites and friction factors. ■