Numerical Analysis Of Internal Flow On Axial－Volute In Turbine Machinery

Volute is one dispensable component of compressors and fans. The function of the volute is collecting the air from the rotor or the diffuser, and then sending them into the condenser or piping or even the outside. The complex internal flow has made volute to be one of the component costing most loss. The efficiency of matching between the volute and the rotor has took important part in the efficiency of the system. It has gradually been an important technical means to predict the internal flow structure of volute by using an existing, mature, commercial CFD package. In this thesis, a finite volume method solving three-dimensional Reynolds-averaged Navier-Stokes viscous partial differential equations is employed to study the internal flow field of whole system, which including meridian acceleration rotor, vaneless diffuser and volute, by using the commercial CFD code FLUENT. The hybrid structure/unstructured grid is adopted to mesh the complex computational domain. Standard two-equation k ?εturbulent model with standard wall functions is used to evaluate the turbulent diffusivity. The pressure-velocity coupling is solved using SIMPLE algorithm. Comparing with fluid pictures of special sections under different fluid passage, the internal flow of the volute especially the tongue, the second flow of different sections of the volute, this paper analyzed the internal flow of the volute, and the influence to the flow. Detailed flow field information of the volute is gained. Calculation results disclose that, the matching and the design of meridian acceleration rotor and the axial-volute is a kind of attempt. Under the low energy flow, the results of the internal flow is propitious to improve the internal flow, compared with the normal volute. Especially this matching is fit for the situation, in which the outside of the fan need a turning. The result of the matching between the diagonal compressor rotor and volute disclosed than, the internal flow of the non-axisymmetric volute is much better than the one of the axisymmetric volute Some instructive conclusions have been derived form this thesis, which will be helpful to experiment research of the volute, and the performance of the system.