20 1930 Sand in the ball trajectory

1930s, its research is to experiment with a glass cover Peng Bao sand making machine in the next instant photo camera photo in the sand trajectory ball. Determining steel plant When dropping the ball for sports, track composed by the circle and parabola. Then analyzed using mathematical methods Establish round ball movement and his movement basic equations, and with this set of forces · programs to solve The ball trajectory die each special point geometry, and then from quantitative mathematical L Description track ball movement. According to their research, just know Sand specifications, Speed ​​and ball rate, we can solve all kinds of problems about ball movement. Including the critical speed Rate from diarrhea fell into the limits of Paola sports movement, the kinetic energy of the ball movement, the largest Drop height, the appropriate rate ball, ball energy state regulation until the required computing Sand Power and so on. It should be said, E. w. Ball movement theory Davies, who is tight And complete, but so far has not yet better theory can replace them. when However, it should be noted that the traditional theories have their flaws, because they are in Assumptions only installed inside the ball slide and sand and no balls no effect each other pushdown Lead out of its assumptions and the actual discrepancy. However, experiments and production practice table Ming Dynasty, when the memory of water and ore crusher and ball bearing filling rate of 40% to 50%, Ball almost no slip, consistent with the theoretical hypothesis prerequisite, and industrial hygiene Ball bearing production rate of more than filling in 4D% to 50%, was in line with the requirements of the above theory. Therefore, the traditional theory still has use value. If the ball is in the filling sand charge Less than 40% ball severe slippage, beyond the theoretical derivation time Assumption conditions, could not be to solve the problem with this theory. As the subsequent emergence of high Speed ​​and supercritical grinding, due to the high rate of speed and ball bearing filling under supercritical reduced 40% to 20%, there is a serious slippage ball, between the ball and the ball bearing and liner There is a relatively sharp slide, which is the theory should be used with attention. Because of the number of Weiss et al traditional theory has some flaws, so many years have promise More researchers attempted to fix it, to make it even better. Consider the ball slip line: If The ball height L liter repair 6r "; some think the ball charge motion within the Sand Not just thrown down and spilled down two minutes, and there should be mixed in between, and We believe that all three state with grinding conditions change mine converted into each other to each other, even into Davis et al step with the theory put forward different views, that the sand in the media and materials Qian in - a "slightly mobile core," not falling parabolic trajectory, it is a complex curves, and finally the trajectory of media and export ore only program, "etc.