Study On Store Separation Experiment For Auxiliary Fuel Tank Model In A Wind Tunnel

Endurance is a significant index for the evaluation of the performance of an aircraft, and the most immediate and effective way to increase an aircraft’s endurance is to install auxiliary fuel tanks on it. It is necessary that the auxiliary fuel tanks have to be released when they run out of fuels or the mother plane encounters an emergency. However, tanks are easy to be distracted by the strong airflow during the release process, which may mutate the trajectory of the tank and leave the plane in danger. To avoid such dangerous situation, experiments for the trajectory analysis of auxiliary fuel tanks are required during the design stage of the plane to ensure the safety of the aircraft. Until now, taking free drop tests in wind tunnels where a similar airflow environment in which an aircraft flights is simulated is a principal method to measure the pose parameters of the auxiliary fuel tanks. So it is necessary to study the technology of the free drop tests for auxiliary fuel tank models. In this paper, an experimental system for the free drop test of auxiliary fuel tank models is designed and studied based on previous theoretical researches on wind tunnel experiments. The specific contents in this paper are as follows:(1) The overall design and verification experiments for the free drop system for auxiliary fuel tank models are completed, according to experimental requirements in wind tunnels. Results show that the developed free drop system is capable of controlling the position and attitude of the auxiliary fuel tank model precisely under conditions with large lateral loads caused by wind tunnel airflow.(2) A pose measurement system for free drop tests for auxiliary fuel tank models in the wind tunnel is developed according to the measurement demands of the model’s trajectory. The pose measurement method and image acquisition method were determined to meet the measurement requirement of auxiliary fuel tank models, as well as the layout and installation of marker points. Experimental results show that the proposed image acquisition can meet the experimental demands of free drop tests in wind tunnels, ensuring high qualities of the image acquisition.(3) Researches for the image processing of visual measurement were carried out, in order to solve the image matching difficulties caused by the rolling movement of grouped markers surrounding the model. The matching and recognition method based on color-coded self-luminous markers is formulated. Experimental results show that image matching relations can be established with the proposed method, which also helps to remove the hidden phenomenon of markers, ensuring the exact matching of binocular points.(4) A ground experimental platform based on the above researches for free drop tests for auxiliary fuel tank models is established according to the requirements of ground experiments. Moreover, simulation experiments in ground environments were conducted using the platform, with experimental results analyzed. Results show that the experimental system meets the requirements of free drop tests for auxiliary fuel tank models in wind tunnels.