Investigation of the process of gravitational unloading of energy willow cuttings in conditions of static and dynamic arch formations

Abstract

One of the promising sources of renewable energy is biomass energy, which has great potential for increasing the volume of cultivation of crops such as energy willow. Willow planting is carried out by machines in which the planting material is fed manually, which significantly limits the possibilities of increasing the efficiency of the units. When creating an automaton for planting such material, the problem arose of high-speed and accurate feeding of cuttings, which led us to search for ways to substantiate the movement of cuttings when unloading from a storage tank. The paper proposes to consider a method of planting automation by gravitational unloading of planting material from slotted bins. It is known from the practice of the functioning of bunkers that the main obstacle to unloading lumpy materials is the phenomenon of bridging, which, interrupting the natural flow of materials, negatively affects their consumption characteristics. The study of the process of unloading and the shape of the formed vaults suggests that in the case of such material as cuttings of energy willow, in addition to the general reasons for the formation of vaults and the regularities in the formation of their shape, others also arise. A feature of plant cuttings is their rod-like shape, which complicates bridging, and causes such additional conditions and factors as distortions of cuttings in the layer, irregular shape of cuttings, uneven pinching along the length, etc. Based on the obtained characteristics of the movement, it is proposed to consider the array of cuttings during their unloading as an incompressible two-phase pseudo-fluid, in which the cuttings are a discrete component, and the air filling the space between them acts as a gaseous compound. With such assumptions, the unloading process can be considered from the point of view of multiphase systems and the Navier-Stokes equation can be applied to the movement of the cuttings. The use of the obtained data in further studies will make it possible to more fully take into account all the factors arising in the process of unloading and bridging, which is important in the study and improvement of this process.