Авіаційно-космічна техніка та технологія (Jun 2018)
COMPARATIVE ANALYSIS OF METHODS OF COMPUTATION OF AMPLITUDE OF PRESSURE OSCILLATIONS CREATED BY THE CAVITATIONAL GENERATOR
Abstract
One of the devices implementing energy-saving technologies is a Venturi tube of special geometry, called the cavitations generator of fluid pressure oscillation (hereinafter referred to as the generator). It converts the steady-state flow of process fluid into a discrete-impulse flow of increased power and has the simplicity of manufacturing that lacks moving parts, does not require additional energy sources and seamlessly fits into existing equipment. The practical use of the generator in engineering, metallurgy, the chemical industry and in mining, can reduce the specific energy consumption by up to 50%. The purpose of this paper is a comparative analysis of the existing methods for calculating the amplitudes of pressure oscillations generated by the generator and the choice of a method that makes it possible to determine the amplitudes with an acceptable accuracy. The technique is based on the determination by various computation methods of peak-to-peak values of the fluid pressure from the cavitations flow regime. The results are presented in the form of calculated dependences of the of peak-to-peak oscillation values of the fluid pressure on the value of the cavitations parameter and their comparison with the experimental data. Scientific novelty. It is established that the method using the finite-element discretization of the generator and outlet pipeline construction with fluid moving in it satisfactorily describes the parameters of the oscillatory process in various elements of the hydraulic system. However, the model requires some correction in the part of the description of the basic dependencies describing the dynamics of the cavitations flow in the generator, if it is necessary to more agreement with the experimental data. This model is convenient for carrying out multi-purpose research works, including experimental data correction, but its application for engineering calculations causes certain difficulties in the part of programming and the length of preparation for the calculations. The refined linear mathematical model of the generator makes it possible to obtain a quantitative agreement between the experimental and theoretical dependences of the amplitude of fluid pressure oscillations on the cavitations parameter by engineering methods. The practical significance of the results obtained is that the refined linear mathematical model of the generator makes it possible to establish at the design stage a rational regime of the hydroimpulse action of the generator (the peak-to-peakvalues of fluid pressure oscillations) at a certain pressure in the process pipeline of an industrial plant and does not require additional experimental studies
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