Estimation of frictional properties of energy plants chaff

Abstract

It has been established that chaff pourability has great influence on filling of vertical storages and unloading. Therefore, while designing vertical storages their silo diameter and height have to be selected taking account of chaff pourability and calculated slope angles of storage walls. If pourability decreases the silo height is increased and diameter reduced. This article analyses frictional properties of stem chaff of energy plants and optimal slope angles of the walls of storing and transportation implements. Experimental tests were accomplished by using common osier and Jerusalem artichoke stems, chopped by drum chopper of combine harvester Maral-125. The chaff fineness of these energy plants was assessed and compared; the dynamic frictional coefficient was established while the chaff slid along the surfaces of rolled steel, unpainted wood and plastic. During the experimental tests the dependence of the dynamic frictional coefficient and optimal slope angle of a wall on pressure force, which varied from 10 to 30 N, and chaff movement speed, which varied within 0.022–0.081 m/s range, were estimated. In summarizing these research results it was determined, that with an increase of chaff pressure force and movement speed, the frictional coefficient and optimal slope angle of the wall decreased. Significant differences between the frictional properties of chaff of common osier and Jerusalem artichoke stems were not observed.