Aspects regarding particle size distribution and energy consumption when grinding husked rice seeds
2020
Voicu, G., University Politehnica of Bucharest (Romania) | Constantin, G.-A., University Politehnica of Bucharest (Romania) | Stefan, E.-M., University Politehnica of Bucharest (Romania) | Tudor, P., University Politehnica of Bucharest (Romania) | Munteanu, M.G., University Politehnica of Bucharest (Romania)
The paper presents part of the results obtained in the experimental investigations regarding the energy consumption in the grinding process of husked rice seeds in grinding machines with a closed chamber of small capacity (knife mill), with the evacuation of the milled material at the end of the milling. The milling indices are analysed and some specifications are made regarding the particle size distribution obtained in the milling process, correlated with the energy consumption when size reduction. Thus, the correlation of the size of the grinded particles, of the grinding index, of the surface increase, of the temperature increase and the energy consumed when shredding with the sample time, as well as other correlations between the specified indices are presented. Several mathematical functions are specified and their regression is made with the experimental data obtained when grinding husked rice seeds. It has been found that the specific energy of grinding increases directly proportional to the time of grinding, but only in the first phase of the process it is consumed to achieve a specific surface growth, in the second phase the surface growth is relatively low. It can be appreciated that the increase of the grinding time above a certain limit produces more intense heating of the material subjected to the grinding and reduced grinding due to the more intense friction between the milled particles and the increase of the heat transfer time. The paper also makes further details regarding the rice grinding indices and graphically presents their variation, some in relation to others.
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