Application Cases

Experiment Name: Experimental Research on Piezoelectric Vibration De-icing of Airfoils

Experimental Principle:
Piezoelectric de-icing technology utilizes the inverse piezoelectric effect of piezoelectric materials. By exciting actuators installed on the surface of the structure, vibrations are induced in the structure to be de-iced. This generates shear stress at the interface between the structure and the ice layer. When the shear stress exceeds the adhesive strength between the ice layer and the structure's surface, the ice layer detaches from the surface.

Testing Equipment:
Signal generator, ATA-8202 RF power amplifier, transmitting piezoelectric element, receiving piezoelectric element, oscilloscope.

Experimental Procedure:
A signal generator was used to produce different types of waveform signals with fixed amplitude and frequency. The power amplifier selected was the ATA-8202 RF power amplifier produced by Aigtek, with an operational frequency range of 10 Hz to 20 MHz and a maximum output power of 100 W, meeting the requirements for high-frequency ultrasonic vibration experiments. The oscilloscope used was the Tektronix TDS1012 model. All experimental equipment was calibrated and tested to meet the experimental requirements. Additionally, for the energy transmission system, the resonance network matching affects the system's transmission power and efficiency. Effective resonance network design can improve transmission power and efficiency.

Experimental Results:
Two methods were used to obtain ice layers in the experiments:

1. "Rapid Freezing" Method: Ice was formed using a regular ice mold, and the regular ice blocks were then frozen onto the airfoil surface. This process simulates conditions where the ambient temperature is lower during aircraft icing.

2. "Gradual Freezing" Method: Liquid water was dripped onto the airfoil surface beforehand, and freezing was carried out under normal ice formation conditions. This method simulates conditions where the ambient temperature is slightly higher during aircraft icing.

   
   

Figure 5.8 shows a typical icing condition.

Multiple ground-based cold-environment de-icing experiments were conducted for three different layout configurations. Ice detachment was observed in each layout configuration. Under more effective de-icing conditions, it was found that ice near the piezoelectric elements detached the fastest, primarily due to the larger structural vibration amplitude in those areas. Ice in the central region of the wing leading edge detached slightly later, as the structural vibration in this area was smaller compared to that near the piezoelectric elements. Additionally, ice formed by the "rapid freezing" method detached more quickly, while ice formed by the "gradual freezing" method was more difficult to remove. This is because ice formed by the "rapid freezing" method had lower adhesive strength to the structure, while the slow freezing process in the "gradual freezing" method resulted in stronger adhesion at the interface between the ice and the structure, making it harder to remove. The experiments demonstrated the feasibility of the piezoelectric vibration de-icing method for airfoils.

Figure: Specifications of the ATA-8000 Series RF Power Amplifier