Takeo Oda

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

Improvement on Ignition Performance for a Lean Staged Low NOx Combustor

KHI (Kawasaki heavy industries Ltd, Japan) and JAXA (Japan Aerospace Exploration Agency) have been working together since 2004 to improve lean staged concentric fuel injector technologies. One of the weak points of a lean staged fuel injector is said to be ignition / light around performance. Ignition characteristics were assessed on several fuel injector configurations in burner tests. Laser diagnosis, CFD analysis and high-speed video camera recording were used to understand the effect of fuel injector geometry on fuel spray distribution and ignition characteristics. They showed a clear relationship between the burner geometry and ignition characteristics. Light around characteristics was evaluated with the burner configuration optimized in burner tests. Light around performance deteriorated in multi sector unit compared to that in burner test. CFD analysis and some ignition tests with different configuration of combustor gave a clue to restore the light around characteristics deteriorated in multi sector unit.Copyright

Low NOx Combustor Research for a Mach 3 Turbojet Concept Validation Test Results

A unique idea of premixture jet swirl combustor (PJSC) was proposed for the ultra low NOx combustor of a Mach 3 turbojet. The combustor installed six simple premixing chambers which were arranged at certain angles to the center axis also to the circumference axis on the combustor dome. This arrangement formed large and strong recirculating flows necessary to stabilize flame at lean fuel air ratio conditions. The fuel mixing study revealed that the radial fuel injectors inserted in a premixing chamber exhibited a high degree of uniformity. Single can combustors of PJSC with three types of main fuel injectors were manufactured for the high temperature and high pressure combustion test program. All combustors performed stable combustion for a wide range of FAR and obtained combustion efficiency of 99.9 % at Mach 3 cruise conditions, namely inlet temperature of 1008 K, inlet pressure of 830 kPa and fuel air ratio of 0.0223. HTHPC-01 combustor, which installed the radial fuel injectors and had long mixing length, presented the best NOx emissions and achieved emission index of 2 g/kg fuel at that design condition. PJSC met the emission goal of HYPR project, and concept validation test was completed in success.Copyright

Development of the DLE Combustor for L30A Gas Turbine

This paper describes the development of the Dry Low Emission (DLE) combustor for L30A gas turbine.Kawasaki Heavy Industries, LTD (KHI) has been producing relatively small-size gas turbines (25kW to 30MW class). L30A gas turbine, which has a rated output of 30MW, achieved the thermal efficiency of more than 40%. Most continuous operation models use DLE combustion systems to reduce the harmful emissions and to meet the emission regulation or self-imposed restrictions. KHI’s DLE combustors consist of three burners, a diffusion pilot burner, a lean premix main burner, and supplemental burners. KHI’s proven DLE technologies are also adapted to the L30A combustor design.The development of L30 combustor is divided in four main steps. In the first step, Computational Fluid Dynamics (CFD) analyses were carried out to optimize the detail configuration of the combustor. In a second step, an experimental evaluation using single-can-combustor was conducted in-house intermediate-pressure test facility to evaluate the performances such as ignition, emissions, liner wall temperature, exhaust temperature distribution, and satisfactory results were obtained. In the third step, actual pressure and temperature rig tests were carried out at the Institute for Power Plant Technology, Steam and Gas Turbines (IKDG) of Aachen University, achieving NOx emission value of less than 15ppm (O2=15%). Finally, the L30A commercial validation engine was tested in an in-house test facility, NOx emission is achieved less than 15ppm (O2=15%) between 50% and 100% load operation point.L30A field validation engine have been operated from September 2012 at a chemical industries in Japan.Copyright

Research on a Methane-Fueled Low NOx Combustor for a Mach 3 Supersonic Transporter Turbojet Engine

Methane-fueled low NON combustor research had been conducted under the Japanese supersonic/hypersonic propulsion research program. A unique form of premixture jet swirl combustor (PJSC) was proposed for the ultra low NO x combustor of a Mach 3 turbojet engine, Fuel-air mixing tests and fundamental combustion tests were conducted to obtain the design data and combustion characteristics in the first phase of the research. A single can-type combustor was fabricated and high-temperature and high-pressure combustion tests were carried out for the evaluation on NO x emission reduction capability of the PJSC concept in the second phase. In the final phase of research, a multisector combustor was fabricated and the performance demonstration test was conducted for the final evaluation of the pollutant exhaust emission goals and the combustor performance goals set in the HYPR project. The sequential three-phased program was completed successfully, and the project goals of NO x emission, combustion efficiency, pressure loss and exit gas temperature pattern factor at the Mach 3 cruise condition, together with the ICAO regulatory levels for supersonic aircraft at LTO conditions, were all achieved in the performance demonstration test.