Numerical Investigation of Cooling Characteristics of a Double-sided Composite Impeller with a New Micro Gas Turbine

Abstract

In order to achieve a micro gas turbine engine with higher thermal cycle parameters and higher aerodynamic performance, a double-sided composite impeller has been designed innovatively based on structures combined, thermal cycle process integration, and existing impingement cooling technology with the help of additive manufacturing technology, which is expected to increase the turbine inlet temperature and break the material limit. The double-sided composite impeller is numerically simulated by the method of gas-thermal coupling. The results showed that: First, compared with the turbine without cooling, the maximum turbine wall temperature and average turbine wall temperature of the turbine with impingement cooling technology decreased by more than 166.33K and 213.79K, respectively, and the minimum cooling efficiency and the average cooling efficiency of the turbine with impingement cooling technology increased by more than 34.32% and 46.8% respectively. Second, the physical property differences of nickel alloy materials in the same category have no obvious influence on the cooling characteristics of turbines. Finally, for GH4220 material, the turbine inlet temperature can be increased by more than 520K when the turbine material is kept in a stable working temperature range. This study opens the way for the higher turbine inlet temperature or the use of low-cost, lightweight materials such as titanium alloys.