Optimization of geometrical parameters of jet drive of cleaning centrifuges

    A.V. Snezhko, PhD in Engineering
    V.A. Snezhko, PhD in Engineering

    Azov-Black Sea Engineering Institute of Don State Agrarian University, Zernograd, Russia, avsnzk@rambler.ru

Abstract
Centrifuges with hydrojet drive were widely used in 1960-70 for oil cleaning in the engines. Nowadays some foreign companies apply them together with filters for oil cleaning in engines of vehicles and tractors. The most complex challenge in designing such centrifuges is the calculation of parameters of nozzle diaphragm. Its optimal solution depends on the specific technical requirements to separator under designing. Research objective is to substantiate the optimal geometrical parameters of hydrojet drive of cleaning centrifuges, and to develop its calculation method under different conditions of designing. Design parameters of hydrojet drive, such as nozzle diameter and its reactive arm, are calculated according to the condition of dynamic balance between the drive moment created by the liquid from nozzles, and the moment of resistance to rotation at the stable motion. Design, kinematic and power parameters of nozzle diaphragm that provide the driving kinetic moment of liquid are analyzed. The factors influencing on rotational resistance are determined. As a result, the equation of balance of specific energies is received: the energy spent for overcoming of rotational resistance, and the motive energy of fluid flow developed by hydrojet drive. The analysis of this equation allows to determine the optimal reactive arm and nozzle diameter. Formulas for calculation of minimal fluid consumption in hydrojet drive that provides the specific angular speed of rotor and the parameters of nozzle diaphragm corresponding to this consumption are received. With optimal design parameters of hydrojet drive, the coefficient of utilization of flow energy is maximal. The expression for calculation of the maximal efficiency coefficient of hydrojet drive is obtained. Results of theoretical researches are presented in graphic form. Design charts of optimal values of flow rate of liquid from nozzles, circumferential speed of nozzles, reactive arm, and also efficiency coefficient of hydrojet drive with its optimal parameters are given. A method and solution algorithm of two problems of hydrojet drive design are offered: the calculation of optimal design parameters of nozzle diaphragm for ensuring the maximal rotating speed of rotor, and also the calculation with the minimal power consumption of drive.

Keywords:
cleaning centrifuge; rotor; hydrojet drive; nozzle diaphragm; nozzle diameter; radius of nozzle offset; reactive arm.

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