School of Energy and Power Engineering, Beihang University, Beijing 100191, China.
Shaanxi Qianshan Avionics Co., Ltd., Xian, Shaanxi 710065, People's Republic of China.
Rev Sci Instrum. 2023 Feb 1;94(2):025009. doi: 10.1063/5.0127942.
The actuator is a fundamental component for a variable-area exhaust nozzle. Conventional actuators for variable-area exhaust nozzles are hydraulic actuators and electric motors. However, they are heavy, large, and structurally complex. Shape memory alloys (SMAs) are light, small, structurally simple, and have unique advantages not found in conventional actuators. However, SMA actuators occupy a large space in the radial direction and cannot be fixed to surfaces with different radii of curvature. Moreover, once designed, the actuating displacement of the actuator cannot be adjusted. To solve this problem, this study develops a novel non-embedded, adjustable, and flexible SMA actuator for variable-area exhaust nozzle actuation. An analytical model is presented to predict mechanical performance. Subsequently, experiments of this flexible SMA actuator are conducted to study the mechanical performance. A proof-of-concept, variable-area exhaust nozzle of the aeroengine is designed, fabricated, and tested to obtain the properties of the exhaust nozzle that are actuated by the flexible SMA actuator. In the experiments, the movement trajectory of the exhaust nozzle is captured using an image recognition technique, and the area changes of the exhaust nozzle are calculated. The results show that the actuator is flexible and can be bent at any angle from -90° to +90°. The actuating displacement of the flexible SMA actuator can be adjusted by increasing or decreasing the number of hinged units. In addition, the area change of the exhaust nozzle is 64.4%, exceeding the largest area change of 40% in previous studies on SMA-actuated exhaust nozzles.
作动器是变截面喷管的基本组成部分。变截面喷管的传统作动器有液压作动器和电动机。然而，它们重量大、体积大、结构复杂。形状记忆合金（SMA）具有重量轻、体积小、结构简单的特点，并且具有传统作动器所不具备的独特优势。然而，SMA 作动器在径向方向上占据很大空间，并且无法固定在曲率半径不同的表面上。此外，一旦设计完成，作动器的驱动位移就无法调整。为了解决这个问题，本研究开发了一种用于变截面喷管驱动的新型非嵌入式、可调节和灵活的 SMA 作动器。提出了一个分析模型来预测其力学性能。随后，对这种柔性 SMA 作动器进行了实验研究，以研究其力学性能。设计、制造和测试了一种航空发动机的概念验证变截面喷管，以获得由柔性 SMA 作动器驱动的喷管的性能。在实验中，使用图像识别技术捕捉喷管的运动轨迹，并计算喷管的面积变化。结果表明，作动器具有柔韧性，可以从-90°弯曲到+90°的任意角度。通过增加或减少铰接单元的数量，可以调整柔性 SMA 作动器的驱动位移。此外，喷管的面积变化为 64.4%，超过了以前 SMA 驱动喷管研究中最大 40%的面积变化。
