Study of tangential stickiness force of mixtures based on organic sapropel

Traditional methods of using organic sapropel in agriculture are energy-intensive and require adaptation to modern climatic and economic conditions. The specific characteristics of organic sapropel deposits ensure a moisture content in the range of 92…98%. Therefore, attention should be focused on identifying methods for application of organic sapropel at its natural deposit moisture content without dehydration. To enable mechanized application of sapropel with this moisture content to soil, it is advisable to mix it with organic sorbents. Such organic sorbents include chopped straw from cereal crops, wood sawdust, and similar materials. For the local strip application of a mixture based on sapropel with its natural moisture content during the planting of agricultural crops, we developed a design and manufactured a prototype machine. When justifying the design parameters and operating modes of such machine, the values of the tangential stickiness force of the described mixtures are required. To determine the values of the specific tangential stickiness force and the tangential stickiness coefficient of sapropel-based mixtures, a device for studying shear force, equipped with an electronic displacement indicator, was used. The stickiness force was studied for mixtures of organic sapropel with wood sawdust, chopped flax straw, and winter wheat straw. The sapropel content in the mixtures was varied from 85 to 91%. Stainless steel, reinforced rubber, and polypropylene were used as sliding surfaces. The results of the study showed that the highest tangential stickiness coefficient was observed for the reinforced rubber sliding surface for all mixture variants. The maximum average value of this coefficient, 0.083, was obtained for a mixture with chopped wheat straw at a sapropel content of 91%. The maximum average value of the specific tangential stickiness force, 545 Pa, was obtained for the mixture with wood sawdust on the polypropylene friction surface.