Research On Test System For Moving Belt Ground In The Low-Speed Wind Tunnel

Ground effect affects the aerodynamic characteristics of the aircraft during low-altitude flight process,providing the aircraft a higher lift-to-drag ratio while reducing the obstacle of the induced resistance.Therefore,we should pay special attention to ground effect and use it during flight.Studying the characteristics of ground effect is of great significance to the basic development,performance improvement and safety assurance of the aircraft.Wind tunnel experiment is the primary method of simulating ground effect,while the "moving belt ground" is the main method of wind tunnel experiment.The purpose of this paper is to design moving belt ground equipment for a Ф4.0m wind tunnel in the open test section,and complete the design of its mechanical system as well as control and monitoring system.First of all,this paper formulates the overall design plan of the moving floor test system and determines the transmission mode of moving belt.Detailed design requirements are put forward for the equipment size of the moving belt ground,the size of the moving belt,the speed of the movable belt,and the working time of the moving belt by this paper.It also proposes the layout plan of the moving belt ground in the wind tunnel test environment.Based on the design requirements,this paper proposes the composition of the mechanical system and the control system and the functions to be realized by each subsystem.Secondly,this paper investigates a number of industrial belt manufacturers and obtains their samples,compares the performance of each sample through a tensile test and selects the best one as the material of the moving belt.Based on the functions that each subsystem needs to realize,this paper analyzes the feasibility of multiple design schemes,and also completes the design of the motor drive subsystem,tensioning and correction subsystem,auxiliary belt changing subsystem,cooling subsystem,and failure protection subsystem.This paper also realizes the monitor of key parameters such as the speed of the motor,the runout of the moving belt,and the axial displacement of the moving belt.Finally,this paper completes the installation of the moving belt ground model in the simulated wind tunnel test environment.This paper observes whether the synchronous belt is jittery before the performance test,and decides if an improvement method of the installation of the motor is necessary.This paper carries out the model analysis of the moving belt ground and obtains the vibration shape of the movable belt ground at low frequency,and also obtains the frequency band that needs to be paid attention to in the experiment.In the performance test,this paper uses the vibrometer to test the vibration of each measuring point at several speeds and obtains the test data.