The Design And Improved Research Of The Highly Loaded Helium Compressor

In recent years, a "fourth-generation advanced nuclear energy systems" concept has been proposed by the international community, which has the advantages of good inherent nuclear safety; being competeitive with other power generation methods in economy, and short construction period. So HTR is a promising fourth generation of advanced nuclear energy system technologies. High Temperature Reactor HTR helium turbine is the key equipment, and the aerodynamic design of helium compressor is one of the difficulties.A design study of the multistage axial helium compressor of a 300MWe nuclear gas turbine is presented in this paper. Using CFD software to develop a helium compressor cascade, study the aerodynamic design features of helium compressor and the basic characteristics of dynamics. Research the important design parameters to the selection of the compressor, and get the cascade through the thickness distribution superimposed on the camber curvture, turning angle controlled by quadratic, control the thickness distribution of four polynomials, and the maximum thickness position of four polynomial controls. The three-dimensional numerical simulation shows that the helium cascade can achieve the desired aerodynamic design goals.In order to solver the problems charactered by small single stage pressure ratio and numerous stages, it is necessary to research the highly loaded design methods. Numerical simulation is applied to analysis the aerodynamic performance and flow field feature of the highly loaded cascade adopted high flow coefficient high load coefficient and high reaction.Some three-dimensional airfoil improved methods and three-dimensional airfoil design methods are applied to control the serious separated flow, such as adjusting the position of blade maximum camber deflection position; redistributing radial compression work; redistribution spanwise relative airfoil thickness, custom tailoring airfoils and bowed stator vane. And the results show that the corner separation has elimited, the dimension and intensity of passage vortes have weakened and tip vortes have decreased, so that the performance of the first stage of the helium compressor cascades has increased. The single pressure ratio of this highly loaded design has increased from 1.03 to 1.05; stage number decreased from 16 to 10, and at the same time the high efficiency and broad stable operating range at design rotational speed ensured. A new velocity triangle and the characteristics of its applications aim at the specific property of helium will be investigated. To increasing the pressure ratio more, the new velocity triangle will be used in three-dimensional helium copressor cascade by numerical simulation. The selection of degree of reaction will be invecstigeted for the helium compressor cascade aerodynamic performance. The results show that the load the greater the advantage of high degree of reaction is more obvious. In order to further close to the design goal, change the radial distribution of blade loading to reduce the low energy of the fluid accumulated in the hub; the effection of increase or decrease the blade thickness on the aerodynamic performance will be investigated. The results show that the diffuser will be better and the flow properties of the cascade will be higher by the thinning of the blade.The aim of the highly loaded helium will be successful by the new velocity in three dimensional. The single stage pressure of the helium compressor will be increased to 1.08, and stage number will be reduced to 6. Comparing to the performance curves of pressure ratio and the efficiency at design rotational speed between the final new highly loaded design and base one, the high efficiency and broad stable operating range can be assured.