Physical Mechanisms and Conditions of Excitation of Vibratory Combustion of Solid Fuels
- PDF / 1,163,067 Bytes
- 11 Pages / 594 x 792 pts Page_size
- 97 Downloads / 179 Views
Journal of Engineering Physics and Thermophysics, Vol. 93, No. 6, November, 2020
PHYSICAL MECHANISMS AND CONDITIONS OF EXCITATION OF VIBRATORY COMBUSTION OF SOLID FUELS O. G. Stonik, V. D. Geshele, and S. A. Kovalev
UDC 536.46
The authors have obtained experimental characteristics of the self-oscillating process of vibratory combustion of a solid fuel. As a result of the analysis of the obtained diagrams of amplitude and frequency characteristics of the self-oscillating process of vibratory combustion of a solid fuel depending on the position of the combustion zone in a Riecke tube, the fuel structure, and methods of charging, the authors have made the following assumption. Two types of processes coexist during the vibratory combustion of a solid fuel: for the fundamental harmonics of the oscillating process of low frequency, the energy approach known in the literature, and for harmonics of higher frequency, the vortex mechanism. Methods of experimental verification of this assumption have been developed and used. Experimental results confirm the proposed model of vibratory combustion of a solid fuel. A theoretical computational procedure for the development of vibratory combustion has been worked out. A theoretical study of the motion of a combustion wave at stochastic parameters of the process of heat release has been made. Keywords: vibratory combustion, self-oscillation, acoustic radiation, ignition, combustion intensity, amplitude, frequency, solid fuel. Introduction. The process of self-excitation of thermoacoustic vibrations of a gas was considered for the first time in the works of Higgins and Rayleigh [1]. High-power pressure and temperature oscillations occurring during the vibratory combustion in power installations frequently result in the failure of structural elements. We observe, e.g., the burnout of the walls of the combustion chamber liner or its buckling. In the case of aircraft engines such phenomena may cause severe accidents. Such occasions are known in aviation [2]. On the other hand, in vibratory combustion, volumetric heat release increases, heat transfer to furnace walls is improved, and the completeness of combustion increases. Undoubtedly, such properties of vibratory combustion are attractive when various energy-intensive furnaces are developed. The overwhelming majority of investigations of vibratory combustion is devoted, both theoretically and experimentally, to the combustion of gaseous and liquid fuels. The obtained calculated regularities, the experience gained, and experimental results of these investigations cannot be applied without correcting when furnaces for a solid fuel are designed. This requires special investigations taking account of the special features of burning of a solid fuel by means of vibratory combustion. As far as studying this issue is concerned, we should note the works of scientists of the Kazan school [3, 4]. An analysis of conditions for the excitation of thermoacoustic vibrations of a gas, which is the most popular at present, is the "energy" approach
Data Loading...
