Research Of Relationship Between Grain Bulk Density And Depth And The Sensor's Developed

Bulk grain in the granary belongs to ideal granular with no adhesive strength, the physical properties between solid and liquid?Due to the influence of gravity, The surface height of bulk grain decreases with time, leading to a bulk grain volume, density changes.Granary grain in stratified analysis, with the accumulation of grain layer, the grain surface increases, one layer of grain after into the warehouse subjected by grain pressures of the upper layers, the layer of grain will produce a certain amount of compression, thus cause the grain density change, and because the different number of the upper layers of grain, lead to the amount of compression in each layer is also different, so the density of each layer is also different.Because of the lack of scientific and reasonable calculation model for bulk grain density, directly affects the accurate accounting of grain storage quantity.along with the influence of other factors such as storage time, grain density must be change, therefore use one grain layer density in a depth instead of overall goal of grain heap density is not reasonable.In this paper, through a variety of attempts to challenge sensor production difficulties, Develop one type of pressure sensor, and emplaced in the simulation warehouse, at the same time emplaced variety end product sensors as reference, through simulation warehouse automatic storehouse changing, mutual monitoring the change of bottom pressure a complete process of grain in and out. Experiment in simulation warehouse verified the self-made pressure sensors has a certain practical value, lay the foundation for the development of the pressure sensor that dedicated for grains.The subsidence process of Grain surface is also the self-compacting process of grain heap, Another purpose of experiment in simulation warehouse is expect to find the change of bottom process in the self-compacting process of grain heap, in order to through the grain heap pressure extrapolate the grain bulk density.Analysis the data of simulation warehouse experimental, verified the bottom pressure of grain heap have the characteristic of nonuniformity and randomness. And the self-compacting grain heap caused the change of bottom pressure is very small,and the existing sensor precision is not enough to accurately detect them.The compression capacity of a layer of grain lead by the super grain extrusion, can use porosity and density to reveal it.In this word use the particle flow code (PFC) software PFC3D built up bynumerical model of the test of simulation warehouse, analyzes the ideal condition after grain into the warehouse the changes of porosity with depth,and the settlement of food particles at different depth in the process of the grain stress equilibrium, and calculated grain density correction formula of the ideal condition.Provide theoretical support for grain storage density of basic research, provides reference for the research of bulk material.