The Influencing Factors in Acoustic Nonlinearity Parameter B/A Measurement

In this paper, the nonlinearity parameter B/A of ethanol has been measured under different emitted voltages, temperatures, multiple frequencies and stop-band attenuations. The experimental apparatus and technique used to measure B/A in ethanol was the finite amplitude insert-substitution method. This method was applied within the emitted voltages from 30.0 to 150.0V and at temperatures of between 22 and 45°C, and different frequencies at 1.0MHz, 2.25MHz, 3.5MHz, 5.0MHz and in attenuations from 30.0 to 120dB. Experimental results (Fig.4, Fig.5, Fig.6, Fig.7) show that: (1) The value of B/A has almost a linear increase with temperature and a linear decrease with frequency. (2) Parameter B/A is independent of the stop-band attenuations and has a little decrease with different emitted voltage.