Aerodynamic Design And Analysis Of Flight Load Delivery Simulation System

Wind tunnel system is the most basic test equipment in aerodynamics research.Wind tunnel test plays an important role in aircraft design and development.With the rapid development of aviation technology,new requirements have been put forward for the delivery of aircraft stores.In this paper,combined with the research status of wind tunnel test at home and abroad,aiming at the aerodynamic test problem of aircraft external store delivery,a flight load delivery simulation system is proposed and designed.It can provide test conditions for the external store delivery of the aircraft,simulate the aerodynamic environment of the aircraft in the high altitude flight state,including air density,corresponding altitude and flight speed,and realize the real aerodynamic load of the simulation aircraft in the process of hanging flight and delivery.In this paper,the flight load simulation system is studied:(1)Based on the requirement analysis of launch test,aiming at the special aerodynamic problems of short launch time and low pressure,the structure type of DC temporary impulse suction is proposed,and the main technical requirements and aerodynamic parameters of flight load launch simulation system are determined to provide theoretical basis for the follow-up research;(2)The structure and model of the flight load simulation system are designed and established.According to the aerodynamic fluid equation,the aerodynamic parameters of the system are preliminarily calculated,including the pressure loss of the front chamber,the mass flow rate,the Mach number of the flow field,the stability time of the flow field,etc;(3)Computational fluid dynamics(CFD)numerical simulation method is used to simulate the overall flow field of the system.The Mach number range of the test section is M=0.4 ? 0.8,and the corresponding stable time is 1.5s ? 0.9s.By comparing with the theoretical aerodynamic data,the flow field satisfying the test requirements is successfully established;(4)The techniques of improving the flow field quality and reducing turbulence and aerodynamic noise in the test section of the system are studied.The corner deflector of the system is acoustically optimized,which not only reduces the corner vortex and pressure loss,but also absorbs the aerodynamic noise up to 13 dB,improves the flow field quality and optimizes the test environment.After optimization,the starting time of the system can be reduced by 380 ms,the airflow fluctuation at the starting moment can be effectively restrained,and the quality of flow field can be improved.The following unique designs are adopted for the flight load launch simulation system:first,the low pressure suction scheme of negative pressure tank is adopted.The pressure in the front chamber is larger than that of the negative pressure tank,which increases the simulation Reynolds number of the test,reduces shock wave and reduces the turbulence degree of the flow field,thus achieving the purpose of improving the flow field quality;secondly,the design of combining the adjusting plate and safety gate can reasonably control the Mach of the flow field in the test section The number of the system makes the system have higher efficiency and improves the security of the system operation.