某型无人机起落架放下阶段缓冲器气液流动特性研究

在设计飞机油气混和型式的可收放起落架时，应充分考虑其内腔之间的介质流动特性。以某型无人机起落架缓冲器阻尼孔径、充油量为研究对象，采用单因素实验法对各因素引起的缓冲器内部气液流动变化进行分析，通过Fluent 软件对放下阶段不同阻尼孔径、充油量下的缓冲器气液特性进行仿真计算。结果表明：起落架放下过程缓冲器阻尼孔油液流量只与孔径大小有关，不受缓冲器充油量影响；在该型号无人机要求的637 mL 充油量下，缓冲器阻尼孔孔径应大于6 mm；对于其他型号起落架缓冲器，当确定了充油量后，应将满足放下阶段缓冲器气液充填作为缓冲器阻尼孔设计标准之一。

Gas-liquid flow characteristics of buffers in the landing gear of a certain type of UAV landing gear drop stage

When designing the retractable landing gear of aircraft oil-gas mixed type, the medium flow characteristics between the inner cavities should be fully considered, and the damping aperture and fuel filling amount of a certain UAV landing gear buffer should be taken as the research object, and the single factor experimental method was used to analyze the changes of gas-liquid flow inside the buffer caused by each factor, and the gas-liquid characteristics of the buffer under different damping apertures and oil filling amounts in the lowering stage were simulated and calculated by Fluent software, and the results showed that the damping hole oil flow during the landing gear lowering process is only related to the size of the pore size, not affected by the oil filling amount of the buffer, the damping hole flow rate in the buffer is not related to the liquid level height of the upper cavity of the buffer during the buffer is lowered, the smaller the damping pore diameter, the smaller the flow rate, but the oil filling time is affected by the oil filling amount and pore size, the more oil filling, the less oil required for the lower cavity of the buffer, the shorter the gas-liquid filling time. Under the 637ml oil filling required by this type of UAV, the buffer oil filling time under the 6mm aperture has reached 131s, which exceeded the 2 minutes required for the completion of gas-liquid filling of the buffer cavity of the landing gear of this model, which affects the landing gear buffer performance of the aircraft landing stage, so for the landing gear of this model, the buffer damping aperture should be greater than 6mm. For other types of landing gear buffers, when the oil filling amount is determined, the gas-liquid filling of the buffer that meets the drop stage should be used as one of the buffer damping hole design criteria.