Authors & Affiliations
Vereshchagina T.N., Kudryaeva Y.V., Mikheev A.S.
A.I. Leypunsky Institute for Physics and Power Engineering, Obninsk, Russia
Vereshchagina T.N. – Chief Researcher, Dr. Sci. (Tech.). Contacts: 1, pl. Bondarenko, Obninsk, Kaluga region, Russia, 249033. Tel.: +7 (484) 399-83-60; e-mail:
Mikheev A.S. – Senior Researcher.
Kudryaeva Y.V. – Design Engineer 1st category.
Abstract
The acoustic characteristics of Helmholtz resonators connected by means of diaphragm orifice are considered in the article. These characteristics were calculated by the DeltaEC computer program. The purpose of the work is to master the program and verify the calculations by means of comparing with experimental data obtained in IPPE. The experimental model of Helmholtz coupled resonators consisted of two cylindrical chambers connected through an orifice in a thin diaphragm. Harmonic pressure oscillations were generated by a movable piston of the vibroelectrodynamic facility VEDS-200. The model was fastened on a fixed vibrator frame through small transition chamber. The amplitude and frequency of the piston oscillations were controlled by means of accelerometer KD-35. Pressure oscillations were measured using microphones installed flush the inner surface of each chamber at the middle of its height. The amplitude-frequency characteristics of pressure oscillations in chambers were defined by spectral analysis.
The DeltaEC model of coupled Helmholtz resonators was developed. The amplitude-frequency characteristics of pressure oscillations in the experimental model were calculated for five orifice sizes. The real part of acoustic impedance of the orifice was varied until the maximum calculated and experimental amplitudes were coincided. The air added mass (which is responsible for the imaginary part of the orifice impedance) was calculated according to the Fock formula. A good agreement of the calculated and experimental results allows us be sure the computational model is valid and the DeltaEC is applicable for such calculations.
Keywords
Helmholtz resonator, coupled resonators, acoustic impedance, added mass, hydraulic resistance, thermoacoustics, DeltaEC program, calculation model, amplitude-frequency characteristics
Article Text (PDF, in Russian)
UDC 534.2