A Study of High-Mach-Number, High Temperature Application of a Small, Single-Stage, Axial-Flow Gas Turbine

摘要

The report presents the results of a study to determine the merit and feasibility of using a single-stage axial turbine as a compressor drive (gasifier) turbine in a small, high-temperature, high-pressure-ratio, turboshaft/free-shaft engine. Turbine inlet temperatures up to 2300F, with cooling, compression ratios from 16:1 to 20:1 and shaft speeds from 50,000 to 70,000 rpm were investigated. Results of a generalized analysis showed that with cooling there is a broad design range with acceptable and competitive engine performance, within allowable stress limitations, over the full intervals of inlet temperature and pressure ratios investigated. Rotor inlet Mach numbers were found to be subsonic over the entire range, which eliminates the need for thin, sharp-leading-edge, supersonic blade designs, thus simplifying rotor blade cooling problems at high temperatures. The major conclusions of the study are that single-stage, axial-flow gasifier turbines for the intended application are competitive in performance, have no Mach number penalties, are practical to build, and are within the reach of current advanced technology. (Author)