Accuracy Improvement of a Photoacoustic Helmholtz Cell Model
M. Suchenek and L.J. Opalski
Institute of Electronic Systems, Warsaw University of Technology, Nowowiejska 15/19, 00-665 Warsaw, Poland
Received: November 6, 2013; Revised version: March 6, 2014; In final form: March 13, 2014
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This paper presents a method for improving accuracy of the frequency response of a photoacoustic Helmholtz cell model. The method generates simple non-linear corrections to well-established (reference) delay line model of the cell. The form of the correction functions is obtained from a study of a numerical fitting of the reference model to the measurement data. A novel integral accuracy measure is formulated to compare fit of cell models to actual measurements in the neighborhood of the resonance frequency, which is important for measurement applications of the cell. The two proposed correction functions modify effective values of duct parameters. Despite simplicity the proposed corrections make significant improvement of modeling accuracy, as shown with the integral measure but also with prediction accuracy of the resonance frequency and the cell quality factor. It is significant that substantial accuracy gain due to the corrections was confirmed with measurements of a second (testing) set of photoacoustic Helmholtz cells with geometrical parameter values which are different from these of the first set.

DOI: 10.12693/APhysPolA.125.1132
PACS numbers: 43.20.Ks, 43.20.Wd, 43.30.Zk, 43.38.Zp