General Design And Research For Large Scale Trisonic Wind Tunnel

The wind tunnel is the basic test facility for aerodynamic study and aircraftdevelopment, and the large scale high speed wind tunnel plays important role in thestudy of aerodynamic problems of trisonic range. With the development of differentkinds of advanced aircrafts, higher testing ability and higher precise simulation arerequired for trisonic wind tunnels. At present, the existing aerodynamic facilities of ourcountry can’t satisfy the requirements because of their small size, no calibration windtunnel and low testing ability.To satisfy the requirements of the advanced aircrafts such as large scale airplanes,new generation fighter plane, cruise missiles, large launch rockets, and so on, thetrisonic wind tunnel should have the features of large size test section, high simulationability for Re, high accuracy in wind tunnel control and data measurement and enoughequipment of testing technologies.In the paper, the specific requirements for the simulation ability of trisonic windtunnels are analyzed in the course of developing new aircrafts, and the totaltechnological indices for a large scale, transient, blow-down, trisonic wind tunnel areobtained, including testing ability and precise, Mach number range, Reynolds numberrange, test section size, and so on. Before the proper design of each component of awind tunnel to satisfy the total technological indices, the aerodynamic data must beprovided, which mainly includes the aerodynamic loading on each component and thecontour data of some important components. This paper presents the theoretical basisand formulae to calculate the crucial flow parameters in the aerodynamic design of atrisonic wind tunnel, and the discussion on the design method and technical measuresused in the component design. The technologies available in increasing the quality offlow field, reducing turbulence of flow and controlling the noise in the test section arealso studied.The wind tunnel presented in this paper is the first set of trisonic wind tunnel athome with realizable Mach number range of0.4-4.0and the size of test section is2.4m×2.4m. The total layout of the wind tunnel is characterized as follows: the flexibleplates of nozzle driven by electric-screw, and the outlet of flexible nozzle is jointed withsupersonic test section; so the quality of flow field is increased and the change of Machnumber is more conveniently; the supersonic diffuser is a combination of regulatingplates and grids; the flow field in the test section can be regulated using plenum suction,injection seal regulation and the second throat change by grids, so the operationefficiency of the wind tunnel is highly increased, and the Mach numbers in the subsonicrange can be controlled more quickly and precisely, at the same time, the wind tunnelpossesses the ability of changing the angle of attack while keeping the Mach number stable; the multi-nozzle central injector is adopted as auxiliary suction facility, whichgreatly decreases the needed stagnation pressures, thus reduces the loads on models andbalances, extends the available range of the air source with limited volume and prolongsthe work time of the wind tunnel.