针对传统无人机气动弹射介质压缩空气动力不足的问题，提出使用四氟乙烷代替空气作为气动介质弹射无人机的方法。四氟乙烷安全性高、容易受热发生相变进行膨胀做功，且相比空气具有更高的比热力学能，因此具有更高的膨胀做功能力。通过弹射试验验证了四氟乙烷用于弹射无人机的可行性，建立了以四氟乙烷为弹射介质的气动热力学数值模型，模型验证后进行了压缩空气与四氟乙烷弹射能力对比，进一步探讨了高压储气罐容积、阀门直径和低压室容积对四氟乙烷弹射无人机内弹道参数的影响，结论表明：四氟乙烷能够在毫秒级别的时间内将无人机弹射出筒，弹射能力优于压缩空气，能够完成500磅（1磅=0.453 6 kg）质量以上无人机弹射任务；注液密度一定时，随着高压储气罐容积增大，低压室压力、无人机加速度和无人机弹射出筒的速度逐渐增大，但速度增幅逐渐减小，所提算例的高压储气罐容积增大至500 L时，速度增幅接近为0，在满足指标的前提下，减小高压储气罐容积能降低低压室内压力峰值和温度峰值，可保证弹射安全；对于特定的弹射系统，阀门存在一个极限释放直径，超过该直径，无人机弹射速度将不再增加，只会增加加速度峰值；其他参数不变的情况下，适当增大低压室的容积可以有效降低无人机的加速度峰值，且无人机出筒时速度降低较少。

In response to insufficient aerodynamic power in traditional Unmanned Aerial Vehicle （UAV） pneumatic catapults， a method is proposed to use tetrafluoroethane （R134a） instead of air as the pneumatic medium for catapulting UAVs. Tetrafluoroethane is characterized by its high safety， ease of undergoing phase transition for expansion with heating， and higher thermodynamic potential compared to air. The feasibility of using tetrafluoroethane for UAV catapult is validated through catapult experiments， and an aerodynamic thermodynamic numerical model is established with tetrafluoroethane as the catapult medium. After model verification， the catapult ability of compressed air and tetrafluoroethane is compared， and the impacts of high-pressure gas storage chamber volume， valve diameter， and low-pressure chamber volume on the trajectory parameters of tetrafluoroethane catapult UAVs are further explored. The results indicate that tetrafluoroethane can catapult the UAV out of the tube within milliseconds， exhibiting superior catapult abilities compared to compressed air， and is capable of catapulting UAVs with a mass of over 500 pounds（1 pound = 0.453 6 kg）.When the liquid injection density is constant， the pressure of the low-pressure chamber， the acceleration of the UAV， and the catapult velocity of the UAV gradually increase with the grow in the high-pressure gas storage chamber volume， while the velocity increase gradually declines. When the numerical example increases to 500 L， the velocity increase is close to 0. While meeting the specified requirements， reducing the volume of the high-pressure gas storage chamber can decrease the pressure peak and temperature peak in the low-pressure chamber， so can ensure catapult safety. For a specific catapult system， there exists a critical release diameter for the valve； exceeding this diameter will only increase the peak acceleration instead of the UAV catapult velocity. Under unchanged conditions， appropriately increasing the volume of the low-pressure chamber effectively reduces the acceleration peak of the UAV， with a minimal decrease in catapult velocity when the UAV exits the tube.