Development of high-efficiency and low-cost unshrouded turbine runner for small scale hydropower plant

Research output: Contribution to journalConference article

Abstract

Facing a growing demand for low initial cost and high-efficiency small scale hydropower plants, a new type of Francis turbine was developed for Kazunogawa small hydropower plant with cooperation from industrial, governmental, and academic sectors. To reduce the cost of the turbine while increasing its efficiency, a prototype turbine with an unshrouded runner and a cylindrical casing was developed. The unshrouded runner was designed by Waseda University. Typically, the turbine runner for small scale hydropower is manufactured via a casting method; however, the unshrouded runner can be milled with a 5 axis CNC machine, thereby reducing cost and manufacturing lead time. A cylindrical casing has advantages of low fabrication cost and compact footprint. However, it had lower efficiency compared to a spiral casing with conventional design. Therefore, in this study, topology optimization based on CFD analysis was conducted on the casing and double circular cascade to improve efficiency. In addition, the axial thrust was estimated from CFD analysis to design the bearings and to determine the runner gap. Finally, a performance test was conducted on-site and peak efficiency of 91% was confirmed. This paper also reports the follow-up observation of the prototype turbine after commercial operation started.

Original languageEnglish
Article number022055
JournalIOP Conference Series: Earth and Environmental Science
Volume240
Issue number2
DOIs
Publication statusPublished - 2019 Mar 28
Event29th IAHR Symposium on Hydraulic Machinery and Systems, IAHR 2018 - Kyoto, Japan
Duration: 2018 Sep 162018 Sep 21

Fingerprint

small scale hydropower
turbine
cost
footprint
topology
manufacturing
thrust

ASJC Scopus subject areas

  • Environmental Science(all)
  • Earth and Planetary Sciences(all)

Cite this

@article{2ff98639259c457799aeb1811e968d48,
title = "Development of high-efficiency and low-cost unshrouded turbine runner for small scale hydropower plant",
abstract = "Facing a growing demand for low initial cost and high-efficiency small scale hydropower plants, a new type of Francis turbine was developed for Kazunogawa small hydropower plant with cooperation from industrial, governmental, and academic sectors. To reduce the cost of the turbine while increasing its efficiency, a prototype turbine with an unshrouded runner and a cylindrical casing was developed. The unshrouded runner was designed by Waseda University. Typically, the turbine runner for small scale hydropower is manufactured via a casting method; however, the unshrouded runner can be milled with a 5 axis CNC machine, thereby reducing cost and manufacturing lead time. A cylindrical casing has advantages of low fabrication cost and compact footprint. However, it had lower efficiency compared to a spiral casing with conventional design. Therefore, in this study, topology optimization based on CFD analysis was conducted on the casing and double circular cascade to improve efficiency. In addition, the axial thrust was estimated from CFD analysis to design the bearings and to determine the runner gap. Finally, a performance test was conducted on-site and peak efficiency of 91{\%} was confirmed. This paper also reports the follow-up observation of the prototype turbine after commercial operation started.",
author = "T. Aida and Yohei Nakamura and Kazuyoshi Miyagawa",
year = "2019",
month = "3",
day = "28",
doi = "10.1088/1755-1315/240/2/022055",
language = "English",
volume = "240",
journal = "IOP Conference Series: Earth and Environmental Science",
issn = "1755-1307",
publisher = "IOP Publishing Ltd.",
number = "2",

}

TY - JOUR

T1 - Development of high-efficiency and low-cost unshrouded turbine runner for small scale hydropower plant

AU - Aida, T.

AU - Nakamura, Yohei

AU - Miyagawa, Kazuyoshi

PY - 2019/3/28

Y1 - 2019/3/28

N2 - Facing a growing demand for low initial cost and high-efficiency small scale hydropower plants, a new type of Francis turbine was developed for Kazunogawa small hydropower plant with cooperation from industrial, governmental, and academic sectors. To reduce the cost of the turbine while increasing its efficiency, a prototype turbine with an unshrouded runner and a cylindrical casing was developed. The unshrouded runner was designed by Waseda University. Typically, the turbine runner for small scale hydropower is manufactured via a casting method; however, the unshrouded runner can be milled with a 5 axis CNC machine, thereby reducing cost and manufacturing lead time. A cylindrical casing has advantages of low fabrication cost and compact footprint. However, it had lower efficiency compared to a spiral casing with conventional design. Therefore, in this study, topology optimization based on CFD analysis was conducted on the casing and double circular cascade to improve efficiency. In addition, the axial thrust was estimated from CFD analysis to design the bearings and to determine the runner gap. Finally, a performance test was conducted on-site and peak efficiency of 91% was confirmed. This paper also reports the follow-up observation of the prototype turbine after commercial operation started.

AB - Facing a growing demand for low initial cost and high-efficiency small scale hydropower plants, a new type of Francis turbine was developed for Kazunogawa small hydropower plant with cooperation from industrial, governmental, and academic sectors. To reduce the cost of the turbine while increasing its efficiency, a prototype turbine with an unshrouded runner and a cylindrical casing was developed. The unshrouded runner was designed by Waseda University. Typically, the turbine runner for small scale hydropower is manufactured via a casting method; however, the unshrouded runner can be milled with a 5 axis CNC machine, thereby reducing cost and manufacturing lead time. A cylindrical casing has advantages of low fabrication cost and compact footprint. However, it had lower efficiency compared to a spiral casing with conventional design. Therefore, in this study, topology optimization based on CFD analysis was conducted on the casing and double circular cascade to improve efficiency. In addition, the axial thrust was estimated from CFD analysis to design the bearings and to determine the runner gap. Finally, a performance test was conducted on-site and peak efficiency of 91% was confirmed. This paper also reports the follow-up observation of the prototype turbine after commercial operation started.

UR - http://www.scopus.com/inward/record.url?scp=85063873429&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85063873429&partnerID=8YFLogxK

U2 - 10.1088/1755-1315/240/2/022055

DO - 10.1088/1755-1315/240/2/022055

M3 - Conference article

VL - 240

JO - IOP Conference Series: Earth and Environmental Science

JF - IOP Conference Series: Earth and Environmental Science

SN - 1755-1307

IS - 2

M1 - 022055

ER -