不对称激励函数对水环境下合成射流激励器推力影响及其机理研究  

Thrust Characteristics of Synthetic Jet Actuator Underwater with Asymmetric Forcing Profile and Its Working Mechanism

作　　者：耿令波[1,2] 胡志强[1] 林扬[1] 衣瑞文[1,2] 

机构地区：[1]中国科学院沈阳自动化研究所机器人学国家重点实验室,沈阳110016 [2]中国科学院大学,北京100049

出　　处：《机械工程学报》2017年第7期13-22,共10页Journal of Mechanical Engineering

基　　金：国家重点研发计划课题(2016YFC0301601);中国科学院青年创新促进会资助项目

摘　　要：合成射流是一种新型水下推进方式,合成射流激励器具有体积小、质量轻、结构简单等优点,非常适合水下机器人的推进及姿态调节。合成射流的推力及推进效率受激励函数影响较大,目前,合成射流大都采用对称型激励函数,激励函数对称度对推力及推进效率的影响尚处于研究空白。为了研究这一影响及其作用机理,对一种合成射流激励器在具有不同对称度的激励函数作用下的推力进行了数值计算,激励函数为正弦型。数值计算采用基于动网格的有限体积法,进行了网格无关性分析,并将数值计算结果与已有的试验数据进行了对比,证实了数值方法的有效性。通过对比不同激励函数作用时的推力及推进效率,发现激励函数对称度较高时,推力较大,吸入与排出流体任一过程频率的降低均会导致推力的减小。另外,还发现,即使激励器的动量变化方向反向,激励器平均作用力的方向仍保持不变。建立了合成射流激励器作用力的数学模型,该模型可以解释合成射流作用力随激励函数对称度的变化规律。Synthetic jet is a new type of underwater propulsion method with the merit of small size, light weight and high efficiency. All of which makes it a good choice for the actuation and steering of underwater robots. The forcing profile of the synthetic jet actuator has a great effect on its average thrust. In order to study the working mechanism of the effect of the forcing profile on the thrust characteristics of the synthetic jet actuator, the finite volume numerical method is applied to analyze the 3D, unsteady, viscosity and incompressible flow-field of a synthetic jet actuator. The forcing profile is set to be of sinusoidal type with different frequency during injection and ejection period. It can be seen from the numerical result that the decrease of the frequency of either of the injection or the ejection period will bring down the average thrust of the synthetic actuator. It can also be seen that the direction of the average thrust can＇t be reversed by the frequency change of the injection and ejection period. The mathematical model of the thrust is established which can be used to explain these characteristics.

关 键 词：合成射流 不对称激励函数 推力模型 作用机理 

分 类 号：TG156[金属学及工艺—热处理]