The Investigation Of Flow Control Device Design Technique Of Wide Angle Diffuser In Continuous Transonic Wind Tunnel

The rapid development of the modern construction of China’s national defenseand aerospace aviation industry has put forward higher requirements for the windtunnel test equipment, ability and level to become a bottleneck restricting thedevelopment of the existing wind tunnel test equipment. Contemporary new windtunnels are continuous wind tunnels, in order to improve the flow field of quality andtesting efficiency and enhanced testing capacity. Among them, the continuoustransonic wind tunnel is very important test equipment, one of China’s independentdeveloped aviation and aerospace industries.Advanced continuous transonic wind tunnel strictly limited the performance ofthe wind tunnel sections. By the convergent section of the large contraction ratio toenhance the quality of the test section flow at the same time, the diffuser area ratio ismatch. The proliferation of large-scale wind tunnel segments often account for50%ofthe length of the wind tunnel circuit, designing high-performance wide-angle diffusercan effectively reduce the wind tunnel size, saving construction and operating costs.Depending on the different design structure, wide-angle diffuser appears varyingdegrees of flow separation; the separation of airflow will bring the diffuser and testsection airflow adverse effects. Therefore, the main task of the design for this sectionis to make the pressure losses as small as possible to inhibit the internal flowseparation, and improve the uniformity of the outlet flow. Flow situation is morecomplicated wide-angle diffuser to match the rectifier unit must be reasonable in thelimited space, while its internal flow mechanism is not yet fully, there are still manyrely on experience to complete the design work.The issues raised above0.6m continuous transonic wind tunnel as thebackground, two aspects of the summary of the design method and numericalsimulation of verification, continuous transonic wind tunnel wide-angle diffusionsegment of the internal screen rectifier design method, the following major elements:The first chapter is an introduction, based on the application of wide-anglediffuser in the continuous transonic wind tunnel, the application of wide-anglediffuser in domestic and foreign large-scale continuous wind tunnels, the wide-anglediffuser typical layout position and rectifying devices are introduced.In the continuous transonic wind tunnel, the screen is the most widely usedrectifying device and can effectively improve the flow uniformity. The second chapterdescribes the screen’s engineering design methods and characteristics of rectifier.Mainly to analyze and compare the theoretical basis and the scope of application of the common types of screen design method, and on this basis, sum up a preliminarydesign method which is more reasonable. Finally, according to the need for design,the screen parameters of the calculation methods and diffuser performance evaluationcriteria are given.The third chapter describes the numerical methods and meshing methods used inthe numerical simulation. Include the contents of the turbulence model, boundaryconditions, discretization scheme, the solution method, the screen of regional gridgeneration and wall mesh and other else.Chapter four targeted numerical simulation part of the work to be undertaken forthis article, validate the algorithm Using TWG wind tunnel and its scale model.Subsequently, using the conclusions reached by the authentication calculation，basedon8m×6m large low-speed wind tunnel and1.8m×1.4m research wind tunnelmodel,the effect of the cross-section shape of a large area ratio diffusion on the flowfield is studied, the quantitative conclusions of circular cross-section better than therectangular cross section is got.In Chapter five,0.6m continuous transonic wind tunnel wide-angle diffuser isused as calculation model, by the way of numerical simulation, the preliminary designmethod got in Chapter two are validated and optimized. Firstly, screen parameters canbe preliminary designed using this design method, next by adjusting the position ofthe two layers of screens and the distribution of screen loss coefficient, two sets ofideal design are got.Chapter six introduced the0.6m continuous transonic wind tunnel wide-anglediffuser loop integration calculation. Respectively on the empty wide-angle diffuserarrangement with the heat exchanger and wide-angle diffuser arrangement both withthe screens and heat exchanger are calculated. Finally, Integration of analogcompressor tail cover to the heat exchanger device after the wide-angle diffusersegment of the wind tunnel circuit. On the basis of Chapter five, finally get a set ofoptimal design of the screens, further optimization of the screen design method.On the basis of research and summarization, this article develops a designmethod of screen in the wide-angle diffuser of continuous transonic wind tunnel, andmaking0.6m continuous transonic wind tunnel to be the background of application.By means of numerical simulation, the design method has been validated andoptimized, and gets a relatively complete design proposal finally. This method can beused in the0.6m wind tunnel wide-angle diffuser design. The results fullydemonstrate that the design methods and simulation tools is reasonably practicable.