Acoustic admittance analysis

The most important parameter in the analysis of pressure-coupled combustion instability is the acoustic admittance Y, which is the ratio of the amplitude of the acoustic velocity V to the amplitude of the acoustic pressure amplitude of the acoustic velocity V to the amplitude of the acoustic pressure P ... [Pg.53]

Friedly (F4) expanded the theoretical analysis of Hart and McClure and included second-order perturbation terms. His analysis shows that the linear response of the combustion zone (i.e., the acoustic admittance) is not sign-ficantly altered by the incorporation of second-order perturbation terms. However, the second-order perturbation terms predict changes in the propellant burning rate (i.e., transition from the linear to nonlinear behavior) consistent with experimental observation. The analysis including second-order terms also shows that second-harmonic frequency oscillations of the combustion chamber can become important. [Pg.54]

Hillman et al. measured the quartz crystal impedance to determine changes in rigidity, swelling and ionic exchange in conducting polymer films [57, 58] and have also used dynamic quartz crystal impedance of modified electrodes during film growth and redox conversion [57] by qualitative analysis of the acoustic admittance-frequency peak width. [Pg.477]

Many experimental methods sueh as fluoreseenee, reflection Fourier transform infrared, NMR, quartz resonators, and acoustic wave admittance analysis, are used to study diffusion of solvents. " Special models have been developed to study process kinetics based on experimental data. [Pg.342]

Bulk acoustic wave admittance analysis was used to study solvent evaporation during curing. Three characteristic stages were identified in the first stage viscosity increases accompanied by a rapid decrease in diffusion rate in the second stage the film is formed, the... [Pg.343]