Hideki Ogata

Development of a Lean Staged Combustor for Small Aero-Engines

As the amount of air traffic is rapidly increasing, the local air quality around airports and the global climate change are two major concerns. Under the circumstances, the regulation for NOx emission becomes more stringent year after year. Lean burn technology is one of the key technologies for the next generation civil aircraft engines. Kawasaki Heavy Industries (KHI) has been developing a Lean Pre-mixed Pre-vaporized (LPP) combustor for around 10,000 lb thrust class engine under the project of Environmentally Compatible Aircraft Engines for Small Aircraft (ECO)[1] led by New Energy and Industrial Technology Development Organization (NEDO) and Ministry of Economy, Trade and Industry (METI).In this paper the results of the LPP combustor development about reducing NOx emissions is presented. The LPP burner main premixed duct is designed to have better mixing fuel and air. KHI have achieved 30%CAEP4 NOx without deterioration of the other combustor performance. In general altitude relight would be one of the weak points for LPP combustion system. Successful lights were confirmed up to 30kft altitude condition in the multi sector rig, which is as good as that of the conventional combustors. Several LPP burners have been developed through CFD results. The burners have been spray-tested and combustion-tested in a single burner test rig in order to improve the burner potential. The burners selected in the single sector tests have been evaluated in a multi sector combustor rig with several combustor configurations. This paper describes the multi sector test results together with the brief introduction on burner development activities through burner tests.© 2012 ASME

Suppression of NOx Emission of a Lean Staged Combustor for an Aircraft Engine

Due to the increasing demands for environment protection, the regulation of NOx emissions from aircraft engines specified by ICAO have become more stringent year by year. A combustor with lean staged fuel injectors is one of the effective methods to reduce NOx emissions. Kawasaki heavy industries Ltd GTBC and Japan Aerospace Exploration Agency (JAXA) have been conducting joint research on a lean staged concentric fuel nozzle for a high pressure ratio aero engine. High pressure combustion tests were performed to clarify the effect of the contour of the air flow passage of the main premix duct, the arrangement of the swilers and the fuel injection position on the NOx emission especially at high power. Visualization of the fuel spray at elevated pressure inside of the premix duct using a model with transparent walls and a laser diagnostics technique showed clear relationship between the distribution of the fuel spray and the NOx emission.Copyright

Flow Behavior With an Oscillating Motion of the Impinging Jet in a Dump Diffuser Combustor

This paper presents flow behavior with an oscillating motion of an impinging jet upon a flame dome head and its reattachment to the casing wall, when a distorted flow is provided at the inlet of the dump diffuser combustor. A Laser-Doppler Velocimeter was used for the measurements of the time-averaged flow within a sudden expansion region. A surface pressure fluctuation survey on the flame dome head and flow visualization by a smoke wire technique with a high-speed video camera were conducted from the viewpoint of the unsteady flow features of the impinging jet. There exists a high-vorticity region at the jet boundary, resulting in the production of turbulence kinetic energy. In particular, higher vorticity is observed in the higher velocity side of the jet. The jet near the dome head has favorable characteristics about the flow rate distribution into the branched channel. Reynolds shear stress and turbulence energy are produced near the reattachment region. The jet has an oscillating motion near the dome head with asymmetric vortex formation at the jet boundary.