In order to increase the efficiency of gas purification from the particles of up to 20 microns and to increase the service life of bag and electrostatic filters, the authors propose to use a centrifugal separation device with coaxially arranged pipes to be installed before the fine purification devices. The numerical studies of gas dynamics in a separation device were conducted in ANSYS Fluent software package. As a result of conducted numerical studies, it was found that the pressure loss in the centrifugal separation device is not more than 70 Pa at the inlet gas flow rate from 1 to 15 m/s and the width of rectangular hole within the range from 10 to 15 mm. The low pressure losses are caused by the design features; in particular, the resulting vortices in the inter-cylindrical space practically do not contact the wall surfaces of device. The equations of pressure loss depending on the width of rectangular holes and the hydraulic resistance coefficient of separation device depending on the inlet gas flow rate were obtained. The design coefficient of hydraulic resistance of separation device was equal to 0.45.

This article presents a rectangular separator, developed by the authors, for purification of a multiphase gas flow from the finely dispersed particles with a diameter of up to 10 µm. In order to increase the separation process efficiency, a research was conducted to determine the optimum thickness of I-beam elements within the separator at different values of the flow inlet rate and length of I-beam elements. It was found that change in the wall thickness of elements leads to a change in the flow structure, which causes a decrease in the dust particles collection efficiency.

This paper deals with the removal of moisture from the contaminated transformer oil. Design of a rectangular separator and the results of water-oil emulsion separation are shown in this paper. The influence of different values of the separator height and the distance between the rows of elements on the emulsion separation efficiency was studied. In order to calculate the process of removing the moisture from transformer insulating oil, the multiphase Eulerian-Eulerian model “Volume of Fluid” with the number of phases equal to 2 was applied in ANSYS Fluent software package. K–ε turbulence model was used for the calculations. The results were obtained while solving the nonstationary issue. In the course of numerical simulation, the object of study was the transformer oil T-1500U, containing some water amount. The results of numerical simulation of water-oil emulsion separation in a rectangular separator are shown. In the course of numerical studies, it was found that the use of a rectangular separator in order to remove the moisture from transformer oil allows it to be purified from water by 99.99%, providing that the geometrical dimensions of device are chosen correctly. The use of developed rectangular separator can be an alternative to the use of decanting tanks, various separators and other purification devices, which have extremely low rate of purification of contaminated spent oils. This separator allows purifying the transformer oil from water with a speed of 1-2 m/s while the efficiency is equal to 99.99%.

The paper deals with the problem of classification of bulk material, based on silica gel, larger than 30 µm, from dusty gas flow. In order to solve this problem, the design of a classifier with coaxially arranged pipes is proposed. According to the conducted studies, it is more efficient to use a classifier with an inner conical pipe to solve the problems of separating the particles from the gas flows of various sizes, since a greater value is achieved for the centrifugal, inertial, gravitational and other forces acting on the dusty flow, that contribute to knocking the particles out of its structure, than in a classifier with a cylindrical inner pipe. On average, the efficiency of a classifier with a conical inner pipe is by 35.3% higher than that of a classifier with a cylindrical inner pipe. Classification of particles of bulk material, based on silica gel, larger than 30 µm from the dusty gas flows is solved most effectively by using a classifier with a conical inner pipe and hd parameter of 50 mm and a classifier with a cylindrical inner pipe and hd parameter of –10 mm.

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