Published on 26 October 2019
Introduction. It is known that advanced modern statistical filters cannot hold all small solid inclusions in oil due to their negligible size. At the current level of mechanical engineering, the centrifugal method of separating oil from solid inclusions is the most effective and promising way of high-quality oil refining. With this separation method, the centrifugal force acting on each solid particle of the mixture stops it on its way to the oil intake hole, and then transfers this particle to the sludgecollecting place. An analysis of the literature on the problem of separation of oil with solid inclusions shows that the theoretical provisions of the centrifugal separation process have not yet been developed, and there are no design formulas that allow the selection of the overall dimensions of rotating elements and the frequency of rotation of these elements providing highquality oil separation. The scientific developments of this article fill this gap in the field of application of the centrifugal separation method. The purpose of the research is to develop a mechanicalmathematical model of the centrifugal process for cleaning small solid impurities from the connecting rod journals of the crankshaft of an internal combustion engine of mining machines. Research Methodology. To develop a mechanical and mathematical model, the process of centrifugal separation of solid inclusions in oil of an internal combustion engine of mining machines was simulated based on boundary value problems for the differential equations of incompressible fluid flow in a cylindrical tube and the differential equations of motion of small solids in a fluid. In the compiled differential equations, in addition to the inertial forces, both centrifugal forces and the forces of resistance to the movement of the liquid in the tube and the forces of resistance to the movement of the solid in the liquid are taken into account. As input parameters, the obtained mechanical-mathematical model contains all the overall dimensions of the device elements and its rotation frequency. Research results. The resulting set of calculation formulas makes it possible to calculate the kinematic and dynamic characteristics of the entrained solid particle and thereby select the neck rotation frequency so that solid inclusions do not advance to the oil drain hole, and particles created by the centrifugal force move to the sludge-collecting place. This will ensure high-quality centrifugal cleaning of oil from solid inclusions. The results of the obtained calculation formulas were implemented on a computer. The following important conclusions were obtained: at the above values of the input parameters of the device to ensure oil separation, the neck rotation speed should be At a rotation speed in the device, a reverse hydraulic process occurs, i.e. the oil flows from the area to the area through the tubes. According to the obtained calculation formulas, computer calculations were performed with the above numerical values of the input parameters. The frequency of rotation of the neck varied within. As the frequency increases, the ejection rate decreases sharply. This decrease is due to the fact that the centrifugal force slows down the flow rate of oil in the tube and at the same time, the ejection of particles from the tube is inhibited. The results of the presented computational experiments show that in a wide range of variation of the rotation frequency, the particle acceleration sharply increases within and is pressed against a cylindrical surface. Conclusion: 1. A mechanical-mathematical model of the process of centrifugal separation of solid inclusions in the oil of an internal combustion engine of mining machines has been developed. In the compiled differential equations, in addition to the inertial forces, both centrifugal forces and the forces of resistance to the movement of the liquid in the tube and the forces of resistance to the movement of the solid in the liquid are taken into account. 2. As a result of solving the boundary value problems that simulate the process of oil separation in the engine, calculation formulas are obtained for calculating the flow velocity and the rotational speed of the sleeve. 3. The listed calculation formulas as input parameters contain all the overall dimensions of the elements of the device and its rotation frequency. In this regard, the results obtained allow the selection of the dimensions of the device and the rotational speed of the sleeve, providing high-quality cleaning of oil from solid inclusions.
Tags: горные машины, двигатель внутреннего сгорания, сепарация масла, математическая модель движения, расчетные формулы.
ISSN 1998-4502 (Print) ISSN 2499-975Х (Online)