Efficiency is a crucial design parameter in any turbine development. This research presents a detailed investigation on the efficiency of a modern transonic high-pressure turbine. The work ...

Performance analysis of a transonic high-pressure turbine

A new reduced order through-flow analysis system for the preliminary design of axial turbomachines is presented. It has flexible models for losses, deviation, blockage, etc., uses real gas/liquid thermodynamics and handles flow and geometry at three spanwise locations. It is applicable to both compressors and turbines of either subsonic or supersonic flow type. The essential features of the system, including a comparison of its predictions with test data, are presented in the paper. NOMENCLATURE

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The Reduced Order Through-Flow Modeling of Axial Turbomachinery

This paper describes the design and performance of a high work single-stage research turbine with a pressure ratio of 5.0, a stage loading of 2.2, and cooled stator and rotor. Tests were carried out in a cold flow rig and as part of a gas generator facility. The performance of the turbine was assessed, through measurements of reaction, rotor exit conditions and efficiency, with and without airfoil cooling. The measured cooled efficiency in the cold rig was 79.9 percent, which, after correcting for temperature and measuring plane location, matched reasonably well the efficiency of 81.5 percent in the gas generator test. The effect of cooling, as measured in the cold rig, was to reduce the turbine efficiency by 2.1 percent. A part-load turbine map was obtained at 100, 110, and 118 percent design speed and at 3.9, 5.0, and 6.0 pressure ratio. The influence of speed and the limit load pattern for transonic turbines are discussed. The effect of the downstream measuring distance on the calculated efficiency was determined using three different locations. An efficiency drop of 3.2 percent was measured between the rotor trailing edge plane and a distance four chords downstream.

The Design and Performance of a High Work Research Turbine

This paper presents results of rig testing of a transonic, single-stage turbine at off-design conditions. Mapping of the 3,4 pressure ratio, 1.9 stage loading turbine ranged from 70 through 120 percent of design speed and 75 to 125 percent of design pressure ratio. Results show expansion efficiency dropping over 4 percent from 100 to 80 percent of design speed at design pressure ratio, while remaining within half a percent from 90 to 110 percent of design pressure ratio at design speed. Efficiency lapse rate from equivalent sea-level to cruise altitude Reynolds numbers at the design point was measured and found to be worth over 1.5 percent. Analyses of test results using a viscous three-dimensional solver showed very good agreement for the efficiency change with speed.

Off-Design Performance of a Single-Stage Transonic Turbine

The NASA-sponsored Energy Efficient Engine (E3) Program, intended to develop and demonstrate the technology for reducing fuel consumption in future environmentally acceptable turbofan engines, is presented. The development of the flight propulsion system design is outlined and the resulting preliminary design is presented. Component design and subcomponent supporting technology verification work in progress is discussed, with attention given to fabrication development, the transition duct, mixer design, the fan, the high-pressure compressor, the combustor, and the high-pressure turbine. It is noted that the detailed design of the core components is essentially complete and fabrication of the hardware has begun, with the program on schedule toward testing in 1982.

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The Energy Efficient Engine (E3): Advancing the State of the Art

The experimental results of the evaluation of two high work, transonic, single-stage turbines investigated under the Energy Efficient Engine (E3) Program are presented. The objective of the E3 program is to provide an advanced technology base for a new generation of fuel-conservative turbofan engines. A single-stage turbine required fewer cooled airfoils, a reduced number of leakage paths and no interstage seals. These advanced energy efficient engines require high engine pressure ratios resulting in high expansion ratio, transonic, turbine designs which must have high aerodynamic efficiency. The goal of the turbine program is to develop a high pressure turbine that is compatible with the overall engine design and has an uncooled efficiency of 90.8 percent.

I. D. Singer

Papers

Results From Tests on a High Work Transonic Turbine for an Energy Efficient Engine