Analysis of the process of immersion of kernels in liquids with different specific mass

Abstract

In a grain pile there is material other than grain including poisonous ergot sclerotia. Grain and sclerotia of ergot by linear dimensions and speed of soaring have similar characteristics. Complete separation of grain from ergot by these properties in a single process is impossible. Cleaning seeds from ergot sclerotia with the specific mass less than the specific mass of grain is possible in a salt solution. To mechanize the separation of ergot sclerotia from rye seeds by the wet method, there is an urgent need in the development of an appropriate device. Under study was an immersion in water (ρzh = 1.0∙103 kg/m3 ) and aqueous solutions of sodium chloride (NaCl) with a specific mass ρzh = 1.09∙103 and 1.15∙103 kg/m3 of individual rye grains with their specific mass ρz = 1.2...1.5∙103 kg/m3 , length lz = 5.0...10.0 10-3 m, width в = 1.4...3.6∙10-3 m and thickness δ = 1.2...3.5∙10-3 m. Theoretical studies were carried out on the basis of mathematical modeling methods using the laws of hydrodynamics, which were confirmed by experimental studies with winter rye grains of the Falenskaya 4 variety with a specific mass ρz = 1.1...1.3 103 kg/m3 , length lz = 5.0...8.0∙10-3 m, width в = 1.4...3.6∙10-3 m and thickness δ = 1.2...3.5∙10-3 m. It has been established that the calculated values of the immersion velocity of cylindrical kernels and spheroidal kernels in comparison with the experimental values in water (ρzh = 1.0∙103 kg/m3 ) is not more than 2%, and in aqueous solutions of sodium chloride (NaCl) the specific mass ρzh = 1.09∙103 and 1.15∙103 kg/m3 – 7 and 10%, respectively. This approach to determining the speed of immersion of grain in liquid can be used in the development of the machine for cleaning grain according to specific mass using wet method to substantiate its structural and technological parameters.

Influence of the angle of the bath bottom inclination in ergot isolation device on grain immersion in a liquid

“…The speed of movement of grain in a liquid is an important parameter when developing a machine for cleaning grain material by density in a wet way to justify its structural and technological parameters [23].…”

“…(1) where mz -the weight of the grain, kg; g -gravity acceleration, g = 9.81 m/s 2 . After analyzing the expression (1), the speed of immersion in a liquid was obtained for a cylindrical grain [23]:…”

“…where rz -the radius of the cylindrical grain, m; ρz -the density of the grain, kg/m 3 ; ρzh -fluid density, kg/m 3 ; c -the hydrodynamic drag coefficient, depending on the Reynolds number. According to the scientific work [23] for a spheroidal grain, the rate of immersion in a liquid is expressed by the following equation:…”

“…(3) Taking into account the parameters (width and thickness) of the rye grains under consideration and the assumption of the speed υz of the movement of the grain in the liquid 0.05...0.10 m/s, the kinematic viscosity of the liquid ν = 1.01•10 -6 m 2 /s (at a water temperature of 20 0 C) the coefficient c of hydrodynamic resistance for a cylindrical grain c = 1.2, and for a spheroidal grain c = 0.9 [23,24].…”

“…where Vz -the volume of the grain, m 3 ; lz -the length of the grain, m. The force FА of Archimedes when immersed in a liquid cylindrical grain is equal to the weight of the liquid displaced by it [23]:…”