2000 Fiscal Year Final Research Report Summary
Fundamental Study on Comprehensive Multi-Purpose Utilization of Small Hydropower
| Project/Area Number |
10450074
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Fluid engineering
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| Research Institution | Yokohama National University |
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Principal Investigator |
KUROKAWA Junichi Faculty of Engineering, Yokohama National University, Professor, 工学部, 教授 (40017976)
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| Co-Investigator(Kenkyū-buntansha) |
IMAMURA Hiroshi Faculty of Engineering, Yokohama National University, Research Associate, 工学部, 助手 (30303077)
MATSUI Jun Faculty of Engineering, Yokohama National University, Assistant Professor, 工学部, 助教授 (40251756)
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| Project Period (FY) |
1998 – 2000
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| Keywords | Turbomachinery / Small Hydropower / Cross-flow Turbine / Variable Head / Variable Flow Rate / Variable Speed Control / Simplified Structure |
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| Research Abstract |
Purpose of this study is to propose an approach to comprehensive multi-purpose utilization of small hydropower and to provide the most appropriate hydropower recovery system and the optimal control for each purpose of utilizing small hydropower.
In the research and investigation period for 1998-1999, a cross-flow turbine that has simple construction and low fabrication cost has been selected as the most appropriate water turbine for medium and low head small hydropower and a thorough experimental investigation of the turbine was made. The performance characteristics of the turbine was investigated by varying head and flow, and for the purpose of simplifying the structure of the turbine, a guide vane in the nozzle inside was removed and the shape of the nozzle was modified optimally by using a numerical simulation. And for each purpose of utilizing small hydropower, such as generating electric power in an isolated site or connecting to power system etc., the most appropriate power genera
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ting system and the optimal operation method have been identified.
Because the guide vane of the turbine is removed, at sometime runaway speed phenomena may happen. Therefore in the year of 2000, the runaway speed characteristics of the turbine were firstly investigated, and a new air supply method that supplies air directly into the runner inside was proposed. Using this new air supply method, the turbine structure is more simplified by compacting the runner chamber of the turbine. As a result, the size of the turbine was remarkably reduced and in the meanwhile the maximum turbine efficiency was improved by 1.3%, and a 9% efficiency improvement was obtained in the high rotational speed range.
Furthermore, in order to utilize micro hydropower resource that has variable head more effectively, two variable speed micro hydropower systems that consist of low-cost commercial power electronic elements have been developed. One is composed of a synchronous generator and an electronic load governor for the purpose of applying to an isolated operation, and the other is composed of an induction generator for the purpose of connecting to power system. The experimental results showed that turbine performance and total system efficiency at off-design heads are improved much by using these systems. The performance characteristics of the simplified cross-flow turbine under variable head were also determined experimentally.
From the above results, the work of the study can contribute to effective utilization of small hydropower. Less
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