Akinori Matsuoka

Design and Development of a 14-Stage Axial Compressor for Industrial Gas Turbine

A 14-stage axial flow compressor was newly designed and tested for developing an advanced industrial gas turbine. In order to achieve a high thermal efficiency required for the new gas turbine, the compressor needed to have a significantly higher pressure ratio and higher efficiency than those of existing engines.The new design methodology used to this compressor design was based on an automated airfoil geometric optimization system combined with a 3D-CFD analysis, which resulted in arbitrary shaped airfoil design in most blade rows. A multi-stage CFD analysis was used effectively in order to adjust a loading distribution along stages and to obtain a proper stage matching.Before the full development of the gas turbine, an approximately two-thirds scaled compressor rig tests were conducted to verify the aerodynamic design and the structural reliability. The test results of the first build indicated a satisfactory level of efficiency and mass flow, but with a lack of sufficient stall margin. The second build with the re-staggered vanes was tested and its result showed improvements both in stall margin and in efficiency.The prototype test of developing an industrial gas turbine also had been conducted. The measured performance of the compressor which was scaled up from the second build rig compressor achieved the design target. Consequently, the aerodynamic design which considered the scale effects of the compressor was successful.© 2012 ASME

Development of an 8MW-Class High-Efficiency Gas Turbine, M7A-03

The M7A-03 gas turbine, an 8 MW class, single shaft gas turbine, is the latest model of the Kawasaki M7A series. Because of the high thermal efficiency and the high exhaust gas temperature, it is particularly suitable for distributed power generation, cogeneration and combined-cycle applications. About the development of M7A-03 gas turbine, Kawasaki has taken the experience of the existing M7A-01 and M7A-02 series into consideration, as a baseline. Furthermore, the latest technology of aerodynamics and cooling design, already applied to the 18 MW class Kawasaki L20A, released in 2000, has been applied to the M7A-03. Kawasaki has adopted the design concept for achieving reliability within the shortest possible development period by selecting the same fundamental engine specifications of the existing M7A-02 – mass air flow rate, pressure ratio, TIT, etc. However, the M7A-03 has been attaining a thermal efficiency of greater than 2.5 points higher and an output increment of over 660 kW than the M7A-02, by the improvement in aerodynamic performance of the compressor, turbine and exhaust diffuser, improved turbine cooling, and newer seal technology. In addition, the NOx emission of the combustor is low and the M7A-03 has a long service life. These functions make long-term continuous operation possible under various environmental restraints. Lower life cycle costs are achieved by the engine high performance, and the high-reliability resulting from simple structure. The prototype M7A-03 gas-turbine development test started in the spring of 2006 and it has been confirmed that performance, mechanical characteristics, and emissions have achieved the initial design goals.Copyright

Development of High Efficient 30MW Class Gas Turbine: The Kawasaki L30A

Kawasaki Heavy Industries (KHI) will launch the first unit of the L30A gas turbine, rated output of 30.9MW, and 41.2% of thermal efficiency. The L30A is a twin-shaft gas turbine designed for combined heat and power application (CHP) with lower emissions. The newly developed 14-stage compressor has a pressure ratio of 24.5 with an air flow of 86.5 kg/sec. KHI’s proven dry low emission (DLE) technologies are adapted to the combustion design, and NOx emission of 15 ppm (15% = O2) has been achieved. Also, the newly designed 2-stage gas generator turbine (GGT) employs the proven cooling design with conjugate heat transfer and flow (CHT) analysis, and 3-stage power turbine (PT) has the inter-locking type tip shroud which reduces vibration level for wide operating range of PT with lower pressure losses. The in-house verification tests have been conducted since 2010, to confirm design targets such as performance, emission, vibrations and temperatures were verified in exclusive test facility for the L30A. This paper describes the technical features of the L30A, the development activities and some verification test results.Copyright

Large-Scale DES Analysis of Unsteady Flow Field in a Multi-Stage Axial Flow Compressor at Off-Design Condition Using K Computer

The paper presents the results of large-scale numerical simulations which were conducted for better understanding of unsteady flow phenomena in a multi-stage axial flow compressor at off-design condition. The compressor is a test rig compressor which was used for development of the industrial gas turbine, Kawasaki L30A. The compressor consists of 14 stages, the front two stages and the front half stages of which were investigated in the present study. The final goal of this study is to elucidate the flow mechanism of the rotating stall inception in the multi-stage axial compressor for actual gas turbines, and according to the test data it is considered that the 2nd stage and the 5th or 6th stage are suspected of leading to the stall.In order to capture precise flow physics in the compressor, a computational mesh for the simulation was generated to have at least several million cells per passage, which amounted to 650 million cells for the front 2-stage simulation and two billion cells for the front 7-stage simulation (about three hundred million cells for each stage). Since these were still not enough for the large-eddy simulation (LES), the detached-eddy simulation (DES) was employed, which can calculate flow fields except near-wall region by LES. The required computational resources were quite large for such simulations, so the computations were conducted on the K computer (RIKEN AICS in Japan).The simulations were well validated, showing good agreement with the measurement results obtained in the test. In the validation, the effect of the boundary condition for the casing wall was also investigated by comparing the results between the adiabatic boundary condition and the isothermal boundary condition. As for the unsteady effect, the wake/blade interaction was investigated in detail. In addition, unsteady flow phenomena in the present compressor at off-design condition were analyzed by using data mining techniques such as vortex identification and limiting streamline drawing with the LIC (line integral convolution) method. The simulation showed that they could be caused by the corner separation on the hub side.Copyright

Heat transfer performance of capillary pumped thermal loops.

Capillary pumped thermal loops are very effective devices as the rejection system of waste heat from artificial satellites and space vehicles, since they can transfer the heat without external power and furthermore they are light weight, highly reliable and long life devices. They are, therefore, attractive devices for space engineering. The present paper describes theoretical evaluation method of the maximum heat transport capability of the capillary pumped thermal loops and simulation experiments to confirm the theoretical results and to observe stable operation of the loop by using of visible test loops. In addition, the means to increase the heat transport capacity of the loop has been discussed based on the estimation of the pressure loss in each process in the loop.