某高速自由射流风洞扩压器的振动控制研究

Vibration Control of Diffuser in a High Speed Free Jet Wind Tunnel

某高速自由射流风洞是一座为满足当前大尺度模型、宽迎角范围、大试验空间等特殊要求而建设的一座下吹-引射式暂冲型风洞。与连续式风洞相比,自由射流风洞受冲击更大,尤其是在风洞试验舱内扩压器开口射流处,由于气流脉动频率与结构固有频率耦合所产生的振动对整个风洞的运行影响极大。文中采用数值计算方法,分别计算出试验工况下气流的脉动频率和扩压器的固有频率。分析研究二者的耦合情况,从目前工程领域振动控制的角度出发,提出五种削弱扩压器振动的方法。通过不同的方式来减少由气流脉动频率与结构频率耦合共振所带来的影响,从而降低整个风洞运行的风险性。

This high speed free jet wind tunnel is an intermittent blowdown-ejector wind tunnel,which is built to meet the special requirements such as large scale model,wide angel range,large experimental space.Compared with the continuous wind tunnel,this free jet wind tunnel suffers a greater impact,especially in the opening jet of the diffuser in the test chamber,the vibration that is produced by the coupling of the airflow plusation frequency and structural inherent frequency has great influence on the whole tunnel operation.This paper calculates the airflow pulsation frequency and the diffuser inherent frequency by the method of numerical calculation.Through the analysis and the study of the coupling condition,this paper puts forward five ways to weaken the diffuser vibrarion from the angle of vibration control engineering fields.The impact of the coupling resonance of the airflow pulsation frequency and the structural frequency is reduced in different ways,thereby reducing the risk of the entire wind tunnel operation.