The present study investigates the heat transfer performance of W-shaped ribs in a rectangular channel with typical geometries and flow conditions for a combustor liner cooling passage. In order to assess the Reynolds number dependence on heat transfer enhancement by the ribs for the combustor cooling passage, experiments were conducted with channel Reynolds number ranging from 40,000 to 550,000. The ribs were located on one side of the channel and the rib height-to-hydraulic diameter ratio (e/Dh) was 0.006 to 0.014, which simulate the combustor liner cooling configurations. Rib pitch-to-height ratio (P/e) was 10. Rib-roughened copper plates with constant temperature were used to measure the averaged heat transfer coefficients. Measured results show that the heat transfer enhancements of about 3 were obtained over that of a flat plate at high Reynolds numbers for all cases. The slope of heat transfer coefficient becomes constant with increasing Reynolds number because of the laminar-turbulent transition around the ribs, which is considered to occur at Reynolds number based on rib height of about 1,000. Pressure loss measurements showed that the friction coefficients are constantly 3–4.5 times higher than those of a flat plate for a fully turbulent flow such as a combustor cooling passage. Pressure loss by ribs seems not to have a significant impact to the overall combustor performance. Numerical calculations were conducted additionally for all test cases. Predicted amount of heat released from the ribs contributes about 40% of overall heat release even for low ribs. Heat transfer on the rib surface is essential in the evaluation of the rib-roughened cooling passage.

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.

The present study investigates the heat transfer performance of W-shaped ribs in a rectangular channel with typical geometries and flow conditions for a combustor liner cooling passage. In order to assess the Reynolds number dependence on heat transfer enhancement by the ribs for the combustor cooling passage, experiments were conducted with channel Reynolds number ranging from 40,000 to 550,000. The ribs were located on one side of the channel and the rib height-to-hydraulic diameter ratio (e/ D),) was 0.006-0.014, which simulate the combustor liner cooling conflgurations. Rib pitch-to-height ratio (Pie) was 10. Rib-roughened copper plates with constant temperature were used to measure the averaged heat transfer coefficients. Measured results show that the heat transfer enhancements of about 3 were obtained over that of a flat plate at high Reynolds numbers for all cases. The slope of heat transfer coefficient becomes constant with increasing Reynolds number because of the laminar-turbulent transition around the ribs, which is considered to occur at Reynolds number based on rib height of about 1000. Pressure loss measurements showed that the friction coefficients are constantly 3-4.5 times higher than those of a flat plate for a fully turbulent flow such as a combustor cooling passage. Pressure loss by ribs seems not to have a significant impact to the overall combustor performance. Numerical calculations were conducted additionally for all test cases. Predicted amount of heat released from the ribs contributes about 40% of the overall heat release even for low ribs. Heat tran.sfer on the rib surface is essential in the evaluation of the rib-roughened cooling passage.

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.

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.