ASA 127th Meeting M.I.T. 1994 June 6-10

4pEA13. The resonance acoustic generators on the base of a cylindrical cavity and revolving drum.

Eugene D. Sviyazheninov

199178, Bolshoi stz., 61, St. Petersburg, Russia

The resonance generators of acoustic vibrations are developed from the viscous heat conductive compressible gas vibration research and from the specific applicable inventions. These inventions fall within the realms of acoustics and are intended for the generation of sonic and ultrasonic frequency ranges mechanical vibrations of stable fixed frequency at the cost of the store of the steady energy of compressed gas with the use of the resonance properties of acoustic cylindrical cavities. The cylindrical shape of the above-mentioned cavity resonators provides the monochromaticity of the generating signal, picking off the cavity's axis while exiting through the axial slots on its surface. The resonance phenomenon affords the optimal pumping of the fixed frequency oscillating power to the sonic screened system which lies at the heart of the device functioning. The utilization of resonance conditions are especially convenient as used in acoustics because the working media in this case---gas or compressible fluid---does not suffer from the great sharp and long-term periodical loads as opposed to the solids subjected to fatigue fractures. The offering resonance generators convert the steady mechanical energy of gas to another quality---the mechanical sound or ultrasound vibrations by means of the highly simple original way accompanied by the minimum losses. In comparison with currently available sound mechanical generators (purely mechanical, electromechanical, electromagnetic, electrodynamic, hydraulic, pneumatic, etc.), the proposed acoustic generators are considerably easier to produce, operate, and maintain, it is also more reliable, highly competing with them in efficiency. The most closely related design in conception is the radial siren, containing coaxially mounted cylindrical stator, rotor with openings and drive. With the important strengths of the prototype, among which are construction simplicity, high reliability, and large unit power, its weaknesses are bandwidth-duration product, operation instability, and moderate efficiency. These qualities can be improved by laying the resonance condition into the device foundation. The resonance properties of the static cylindrical cavity and the energy of radial gas streams regularly spaced on the surface of the uniformly rotating drum are used. The intensive acoustic vibrations are excited inside the cylindrical cavity at the fixed speed of drum revolution around the cavity. The required frequency of generated vibration and the speed of the revolving drum are determined by the cavity radius. The influence of centrifugal inertial forces affecting the gas streams flowing out from the rotating drum is taken into account. With allowance for it the high-frequency generators providing with the high-speed rotor must have it inside of the stator and the low-frequency ones may have the drum embracing the cavity resonator. The constructional features and the operation of the device are expounded, the exact quantitative relations for the described system are presented. The comprehensive theoretical and experimental investigations were instituted adding considerable support for the proficiency of the design. The development of the inventions to the practical usage will bring significant profit owing to simplicity, small costs of manufacturing, handling, and maintenance, and high reliability as well.