Application Cases

【Overview】
In this study, the Aigtek ATA-308 power amplifier was used to build an ultrasonic experimental system. This research considered the nonlinear behavior of bubble cavitation, and a simulation method based on the nonlinear Keller-Miksis equation was developed to predict cavitation effects. To comprehensively validate the accuracy of this simulation method in predicting sound fields, both qualitative and quantitative experiments on acoustic cavitation effects were conducted. The method was subsequently used to simulate the three-dimensional distribution of acoustic cavitation and analyze the influence of key process parameters on cavitation performance, providing valuable guidance for optimizing the structural design of ultrasonic reactors and their industrial-scale applications. The simulation results indicate that excessively high power does not necessarily enhance cavitation activity, as cavitation shielding effects may be the dominant factor suppressing sound field intensity. The width of the reactor provides spatial room for the development of acoustic cavitation activity. A reactor width corresponding to 10 wavelengths facilitates effective wave superposition, maximizing the optimization of cavitation volume and distribution uniformity. Stable standing wave formation depends on the liquid level. In a 300 mm wide reactor, the optimal cavitation state is achieved when the liquid level corresponds to 4 wavelengths. Based on orthogonal analysis, the optimal parameter combination for cavitation performance was determined to be 45 W power, a reactor width of 10 wavelengths, and a liquid level of 6 wavelengths.

Experiment Name: Application of Power Amplifier in Testing Applications for Exciting Piezoelectric Ceramic Vibration to Generate Ultrasonic Fields

Research Direction: Ultrasonic Cavitation

Experimental Content:
By adjusting the input parameters of the power amplifier to control the driving power of the piezoelectric ceramic, the sound pressure information of the induced ultrasonic field under different experimental conditions was measured.

Testing Equipment:
Signal generator, ATA-308 power amplifier, transducer, digital oscilloscope, hydrophone, piezoelectric ceramic, computer, etc.

Experimental Procedure:

Figure: Schematic Diagram of the Experimental Test System

Figure: Physical Setup of the Experimental Test System

The ultrasonic experimental system consisted of a signal generator that produced a sinusoidal wave of a specific frequency. The signal was then amplified by a power amplifier (ATA-308, Aigtek) to achieve the required peak-to-peak voltage. The piezoelectric ceramic of the transducer was excited by the alternating voltage signal, generating displacement that was transmitted to the liquid, forming a standing wave pressure field. The specific experimental procedure was as follows:

(1) Tap water was poured into the ultrasonic reactor, and the liquid level was adjusted to 125 mm. After the liquid surface stabilized and no bubbles were visually observed, the equipment was turned on.

(2) The signal generator was set to output a sinusoidal wave with a frequency of 40 kHz. The peak-to-peak voltage was adjusted within the range of 0–5 Vpp and amplified by a specified factor using the power amplifier (gain range 0–180×). The output leads (red for positive, black for negative) were connected to the positive and negative terminals of the transducer. Under electrical signal excitation, the piezoelectric ceramic underwent mechanical deformation, and the transducer vibration was transmitted through the reactor wall to the water, generating acoustic radiation.

(3) The operating time of the ultrasonic transducer was kept within 5 minutes. After the measurement conditions stabilized, the current and voltage across the transducer were measured using the power amplifier and impedance matching, and the driving power was calculated. Simultaneously, the sound pressure signals at different positions in the water were monitored using a hydrophone.

Experimental Results:

Figure: Experimental Results

Under the specified amplification factor settings, the Welch power spectrum at the corresponding measurement points was obtained. This power spectrum was a superposition of discrete line spectra and a continuous spectrum. At the corresponding positions, ultrasonic energy corresponding to the fundamental frequency (line spectrum) and cavitation energy corresponding to subharmonics (continuous spectrum) were present. From the sound pressure distribution curve along the central axis, the amplitude was highest at the vibrating end face of the transducer. Thereafter, due to bubble cavitation effects, the sound pressure energy continuously decreased with increasing distance. Using the electrical power measurement method, the peak-to-peak voltage across the transducer was measured as 520 Vpp, with a corresponding peak-to-peak current of 0.476 Ipp. The calculated acoustic driving power was approximately 30.94 W.

Advantages of Aigtek Amplifiers in This Application:

1. High voltage output capability – Generates the driving voltage required to effectively excite ultrasonic cavitation effects.

2. Wide bandwidth and low distortion – Accurately reproduces sinusoidal waveforms, ensuring the accuracy of fundamental frequency sound field and harmonic measurements.

3. Continuously adjustable gain – Enables fine control of driving power, adapting to different cavitation intensity testing requirements.

Recommended Product: ATA-308C Power Amplifier

Figure: ATA-308C Power Amplifier Specifications and Parameters