| The micro turbine engine, with its merits in small size, high thrust-weight ratio and high speed. It is widely used in the field of drones. The turbine power system research in hydroelectricity development becomes the hot spots in the field of new energy, So the manufacture of micro turbine rotor is very important.Due to the complex type micro turbine blade surface structure and Small gap between leaf, so traditional mechanical manufacture is difficult, Investment casting method to achieving the overall shape of the micro turbine. And investment casting on the parts precision and surface roughness is better than that of other casting method, but the investment casting process is complex,process parameters, so in terms of production of complicated thin wall parts and complex parts, product defect is higher.In this paper a micro turbine engine turbine as the research object, To deal with the complicated thin-walled structure of leaf shape of micro-turbine, taking investment precision casting ways. Purpose is to improve the quality of turbine castings surface, reduce turbine castings internal shrinkage, shrinkage cavity, and the defects of short run. Mainly in the following content: Completed the turbine castings three-dimensional structure diagram, the determination of turbine castings machining allowance and the turbine castings, the turbine casting mold design and optimization, living around to open mold and designing block for turbine blade shape. According to the structure characteristics of the micro turbine, design of turbine gating system and technological parameters. Using Pro CAST casting filling and solidification numerical simulation analysis, use the temperature field, velocity field and solid fraction analysis results,Judge may produce castings defects such as shrinkage, shrinkage cavity and short run. To add on the gating system was optimized, the four groups for the draft Angle 8°inside the symmetry of turbine castings feeding runner. On the shell mould preheating temperature, casting speed and pouring temperature and pouring process parameters optimization, the pouring temperature is 1480 ℃~1500 ℃,the casting speed is 40mm/s~50 mm/s and the shell mould preheatingtemperature is 950 ℃~1050 ℃.For micro turbine investment casting process design, mainly for the wax models and production type shell process, the design and optimization. Taking the medium temperature wax wax mold, shell using silica sol binder, the surface material selection zircon powder, back layer material selection kaolinite clinker, the parameters of shell making was optimized, determining the dewaxing and roasting method of shell mold,investment casting process was optimized.Finally pouring process parameters are optimized by the numerical simulation and optimization of the investment casting process, the quality of the turbine was improved, received a complete set of investment casting turbine casting process design of a micro turbine engine. |
