Market leading technologies coupled with the highest quality services

Ebara Engineering Review No.203

Suppression of Cavitation in a Francis Turbine using the Inverse Design Method

by Hidenobu OKAMOTO, & Akira GOTO

A suppression of cavitation in a Francis turbine was attempted using the inverse design method. Blade loading parameters and influences by rake angles were studied. Numerical prediction of the blade-surface static pressure of a conventional runner and that of a runner designed using the inverse design method was done by CFD analysis and the results were compared. The inter-runner static pressure distribution was suppressed based on blade loading parameters. Consequently, the suppression of cavitation was achieved by increasing the minimal inter-blade static pressure. It was found that the inter-runner minimal static pressure was sensitive to the rake angle. Accordingly, blade loading parameters and rake angle control were used to design (using the inverse deign method) a runner which carried high cavitation resistance properties. Such results suggested the possibility that the inverse design method could be an effective tool for designing turbine runners.

Inverse design method, Cavitation, Francis turbine, Runner, Blade loading parameters, Rake angle, Static pressure, Suppression, CFD (Computational Fluid Dynamics)

Activated Sludge Treatment System using Dynamic Filtration

by Yosei KATSU, Toshihiro TANAKA, Asei MIZUOKA, & Masaaki NISHIMOTO

Activated sludge treatment using dynamic filtration was studied by conducting continuous treatment of actual sewage. Dynamic filter modules were equipped in a denitrification process for apartment complex wastewater, as well as in a food wastewater activated sludge process. Favorable filtration and stable nitrogen removal was indicated for the former. As for the latter, a mean flux exceeding 2 m/day and a mean filtrate SS concentration of 10 mg/l were attained by a pilot plant (capacity: 100 m3/day max.). These results suggested the high filtration performance of the dynamic filters, as compared to that of conventional sedimentation ponds.

Activated sludge, Solid-liquids separation, Dynamic filtration, Flux, Turbidity, Denitrification

Development of Three-dimensional Image Modeling Systems

by Toshio HARA, & Masahiro SHIGYOU

Three-dimensional digital data is becoming a standard in the machinery manufacturing industry. EBARA's new 3-D digital image system enables a swift and easy creation of 3-D image models from 2-D drawings and catalog manual data. A mother model is made by converting a mechanical 3-D/CAD model to an engineering 3-D/CAD model. The system's parametric auto generation function then creates a 3-D image model from this mother model. The resulting 3-D image model has various usage, and can be used for reviewing plant layouts, reviewing design factors of pipelines, or for maintenance support of training systems.

Three dimensinolcal engineering, Three dimensional model, Three dimensional image model, Parametric data, Design review, Digital engineering, Clay model, Super clay model, Hybrid model, Mother model

Emission Reduction System and Other Equipment for Arakawa Drainage Pump Station


The pump facility for the Arakawa Drainage Pump Station (planned pumping rate: 19.045 m3/sec. and current pumping rate 8 m3/sec.), under construction since May 2001, has been completed in September 2003. The new pumping facility, constructed underground, was employed as part of an improved floodwater control, i.e. to change the sewage flow from a combined to a separate type. A dual fuel system and vertical gas-turbine engines are used. Fuel gas is treated using fuel gas under routine conditions and kerosene is stored for use as auxiliary fuel, thus improving reliability. A Nitrogen removal system featuring the use of liquefied ammonium is used for reducing NOx in the flue gas.

Gas turbine-engine, Fuel gas, Gas compressor, Flue gas De-NOx equipment, Ammonia, Catalyst

Ventilation System for the Higashiyama Tunnel

by Wataru SUGIYAMA, Nobuyuki KATO, & Shinobu NAGAYOSHI

EBARA's transverse ventilation system, featuring concentrated exhaust, has been installed in the Higashiyama Tunnel in Nagoya City. This system is an outcome of intensive research on a ventilation system capable of removing both vehicle exhaust gas and smoke which may result in vehicle fire in the tunnel, including supplying fresh air into the tunnel. Air pollution factors had also been sufficiently worked out. EBARA ventilation system includes that installed at the Midoribashi Ventilation Station (for one direction) and the ventilation control equipment for the entire length (for both directions) of the tunnel. The following outlines the system which has been operating smoothly since March 29, 2003.

Higashiyama Tunnel, Midoribashi Ventilating Station, Tunnel ventilation, Transverse ventilation system with concentrated exhaust, Variable pitch exhauster, Control system of air flow velocity, Quantity control plate, Electrostatic precipitator, Fire test

100 MW Class Power Plant for E-Square Co., Ltd.

by Toshiaki MIYASHITA, Sadayoshi TAKAHASHI, & Junichi ENZAWA

The Kazusa Power Plant, a 100 MW class combined-cycle power generation plant (gas turbine× & steam turbine×1), developed by Ennet Corporatioin (Power producer and supplier) and EBARA for E-Square Co., Ltd. has been operating since April 2003. The steam turbine (Model 2SQNV-9) is a 10-stage, multi-valve, condensing horizontal type while the gas turbines (Model FT8) are an aero-derivative type. This plant follows a DSS (Daily Start Stop) schedule and a stable power supply is being provided for supplementing Ennet Corporation power control.

Power producer and supplier, Combined cycle, Gas turbine, Steam turbine, Heat recovery steam generator, Distributed control system, Startup and shut down sequence, 10' stage multi-valve condensing turbine, Aero-derivative

Wind Turbine Systems for Mutsu-Ogawara Wind Farm and Iwaya Wind Park

by Hiroshi ISHII, Kenji YAMASAKI, & Akira YOKOTA

The Mutsu-Ogawara Wind Farm and Iwaya Wind Park located in Shimokita Peninsula, Aomori Prefecture, constitute Japan's largest-scale wind turbine power generation facilities. EBARA has used it's accumulated knowledge and expertise, as well as leading edge techniques to design and manufacture a total of 60 large-scale wind turbine systems (1500 kW) installed at these two locations. These facilities are expected to become models of future large-scale wind farms in Japan.

Wind turbine generator, Mutsu-Ogawara, Iwaya, Wind Farm, Wind Park, Large scale

Current Status of International Standardization Related to Drinking Water Supplies and Trends in ISO/TC224 Implemented to Services Related to Drinking Water Supply and Sewerage

by Kazunari YOSHIMURA

ISO standards and protocols being implemented worldwide are causing an impact on Japanese waterworks. The Japanese Committee on ISO/TC224 is engaged in advocating matters related to drinking water supply and sewerage services in Japan. Some issues faced in Japan, due to the inactivation in the water demand, reduction in the population, high costs needed to modify existing waterworks facilities, including the privatization of such facilities. The following discusses general matters on international standardization in Japan, including the current status of and trends in TC224 implementation.

International standard, International Standard Organization, International Electrotechnnical Commission, World Trade Organization, Technical Barrier to Trade, Technical Committee 224, Performance indicators, International Water Association, Public health, Environmental protection