Aerodynamic Analysis And Numerical Opti- Mization Of A Small Turbine

Owing to the structural limit, the flow efficiency of a small turbine is generally very low. In this paper, numerical simulation has been carried out to analysis the aerodynamic characteristics of a small turbine. The main contents are as follows:1. Based on a numerical simulation, this paper analyzed the flow characteristics of a small turbine under the conditions of with or without the shroud ceal. Then this paper changed the unreasonable designs of the meridian passage. Using the new meridian passage, the efficiency was improved from 78.3% to 79.0% while the mass flow rate was also improved.2. The shroud ceal in the blade part of the turbine was optimized. By comparing the different structure of the shroud ceal, this paper obtained a better ceal. As a result, the shroud ceal with trapezoid structure obtained a better effect and a suitable gap between blade and shroud ceal was also an important factor.3. Base on the optimization of the shroud ceal, this paper redesigned the blade profile which caused high losses in the flow field. Using the new blade profile, the flow field of the turbine was improved. The efficiency of the turbine was improved by 1.40% while the mass flow rate was improved by 1.95%.4. By using the bowed-blade in the stator, the rotor part and the stator part were fit to each other. The results showed that the flow angle of the rotor at the inlet was improved after using the bowed-blade in the stator and the efficiency of the turbine was improved while the mass flow rate was at the design point. The optimized turbine was improved at the whole operating range while the mass flow rate was the same as the prototype and the efficiency of the turbine was improved from 78.99% to 82.83%.By using the optimizing method as above, the performance of the turbine was significantly improved. The efficiency at the design point was improved from 78.3% to 82.8%.