Vertical Wall Loads in a Model Grain Bin with Non-Axial Internal Inserts

Abstract

A study was conducted to estimate the degree of load asymmetry in a bin with non-axialinternal inserts. Internal inserts in the form of an annulus segment of various dimensions wereattached to the wall and their influence on vertical wall loads during centric filling and discharge in amodel bin were measured. Wall and floor loads were measured in a corrugated walled, model grainbin with a diameter of 2.44 m and a height of 7.3 m filled with soft red winter wheat to a depth of 6.7m (height-to-diameter ratio of 2.75). Tests were conducted with inserts that extendedcircumferentially 30 , 60 or 90 around the bin, having a width of 7.6, 15 or 23 cm and attached tothe bin wall at H/D ratios of 0.31, 0.62 or 0.95. These inserts represented between 1 and 8.6% of thebin floor area.<br><br>The results showed that with centric filling considerable asymmetry of static wall loads occurred. Thereason for this was the horizontal component of velocity of the grain stream filling the bin. Thisproduced a wall moment of approximately 3 kNm. The wall moment generated by imperfect centricfilling was decreased or increased when the insert was installed depending on its angular position.For a 23 cm wide, 90 insert, which was the worst observed situation, the wall moment wasapproximately equal (5 kNm) to that produced by eccentric discharge through an orifice located at adistance of 0.3 radius from the bin center. The onset of symmetric discharge resulted in an increasein vertical wall load and a decrease in the wall moment. A change of flow pattern from mass flow tofunnel flow, as well as the influence of the insert were clearly shown by the change in wall momentwith discharge time.