scholarly journals Performance and Flow Field of a Gravitation Vortex Type Water Turbine

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Yasuyuki Nishi ◽  
Terumi Inagaki
Keyword(s):  
Free Surface ◽  
Flow Field ◽  
Simple Structure ◽  
Low Flow ◽  
Flow Area ◽  
Turbine Efficiency ◽  
Water Turbine ◽  
Low Head ◽  
Type Water ◽  
Turbine Output

A gravitation vortex type water turbine, which mainly comprises a runner and a tank, generates electricity by introducing a flow of water into the tank and using the gravitation vortex generated when the water drains from the bottom of the tank. This water turbine is capable of generating electricity using a low head and a low flow rate with relatively simple structure. However, because its flow field has a free surface, this water turbine is extremely complicated, and thus its relevance to performance for the generation of electricity has not been clarified. This study aims to clarify the performance and flow field of a gravitation vortex type water turbine. We conducted experiments and numerical analysis, taking the free surface into consideration. As a result, the experimental and computational values of the torque, turbine output, turbine efficiency, and effective head agreed with one another. The performance of this water turbine can be predicted by this analysis. It has been shown that when the rotational speed increases at the runner inlet, the forward flow area expands. However, when the air area decreases, the backward flow area also expands.

Study on the Flow Field of an Undershot Cross-Flow Water Turbine

2014 ◽  
Vol 620 ◽  
pp. 285-291 ◽  
Author(s):  
Yan Rong Li ◽  
Yasuyuki Nishi ◽  
Terumi Inagaki ◽  
Kentarou Hatano
Keyword(s):  
Free Surface ◽  
Flow Field ◽  
Water Depth ◽  
Open Channel ◽  
Rotation Speed ◽  
Cross Flow ◽  
Water Turbine ◽  
Low Head ◽  
New Type ◽  
Type Water

The purpose of this investigation is to research and develop a new type water turbine, which is appropriate for low-head open channel, in order to effectively utilize the unexploited hydropower energy of small river or agricultural waterway. The application of placing cross-flow runner into open channel as an undershot water turbine has been under consideration. As a result, a significant simplification was realized by removing the casings. However, flow field in the undershot cross-flow water turbine are complex movements with free surface. This means that the water depth around the runner changes with the variation in the rotation speed, and the flow field itself is complex and changing with time. Thus it is necessary to make clear the flow field around the water turbine with free surface, in order to improve the performance of this type turbine. In this research, the performance of the developed water turbine was determined and the flow field was visualized using particle image velocimetry (PIV) technique. The experimental results show that, the water depth between the outer and inner circumferences of the runner decreases as the rotation speed increases. In addition, the fixed-point velocities with different angles at the inlet and outlet regions of the first and second stages were extracted.

scholarly journals Economic Analysis on Design of a Simple Hydraulic Reaction Type Turbine for Low-Head Low-Flow Pico Hydro

2019 ◽  
Vol 9 (2) ◽  
pp. 3876-3980
Keyword(s):  
Water Resources ◽  
Economic Analysis ◽  
Manufacturing Process ◽  
Low Flow ◽  
Generation System ◽  
Reaction Type ◽  
Fabrication Cost ◽  
Water Turbine ◽  
Low Head ◽  
Type Water

The purpose of this paper is to establish a techno-economic analysis on the design of a new Z-Blade turbine focusing on problems of costing and manufacturing process which focus on a low-head and low-flow pico hydro. Pico hydro generation system with a capacity less than 5kw has been gaining increasing attention as preferred methods of clean power generation. Accordingly, the design and operating procedures as well as economic analysis for a Z-Blade reaction type turbine are described in detail. Furthermore, the constructive analysis of the literature on the simple reaction type water turbine are discuss through quantitative summarization, classification, costing and comparison. In this paper also, will re-evaluated the manufacturing process of the SRT and CPT based on techno-economic analysis and the disadvantages of both turbines are identified. Meanwhile, the additional features of Z-Blade will be investigated under low-head low-flow water resources with simple geometrical design and low fabrication cost. Ideally, this hydro generation system is inexpensive and has a simple fabrication method with costing estimation at only USD76, which comprises 7.6% of total cost of hydro-electric installation and capable of producing mechanical power up to 115W under low-head and low-flow water resources.

scholarly journals Study on an Undershot Cross-Flow Water Turbine with Straight Blades

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Yasuyuki Nishi ◽  
Terumi Inagaki ◽  
Yanrong Li ◽  
Kentaro Hatano
Keyword(s):  
Flow Field ◽  
Output Power ◽  
Cross Flow ◽  
Open Channels ◽  
Small Scale ◽  
Hydroelectric Power ◽  
Turbine Efficiency ◽  
Water Turbine ◽  
Low Head ◽  
Hydroelectric Power Generation

Small-scale hydroelectric power generation has recently attracted considerable attention. The authors previously proposed an undershot cross-flow water turbine with a very low head suitable for application to open channels. The water turbine was of a cross-flow type and could be used in open channels with the undershot method, remarkably simplifying its design by eliminating guide vanes and the casing. The water turbine was fitted with curved blades (such as the runners of a typical cross-flow water turbine) installed in tube channels. However, there was ambiguity as to how the blades’ shape influenced the turbine’s performance and flow field. To resolve this issue, the present study applies straight blades to an undershot cross-flow water turbine and examines the performance and flow field via experiments and numerical analyses. Results reveal that the output power and the turbine efficiency of the Straight Blades runner were greater than those of the Curved Blades runner regardless of the rotational speed. Compared with the Curved Blades runner, the output power and the turbine efficiency of the Straight Blades runner were improved by about 31.7% and about 67.1%, respectively.

Performance and Flow Field of Gravitation Vortex Type Water Turbine using Volute Tank

2021 ◽  
Vol 14 (3) ◽  
pp. 229-246
Author(s):  
Yasuyuki Nishi ◽  
Daichi Sukemori ◽  
Terumi Inagaki
Keyword(s):  
Flow Field ◽  
Water Turbine ◽  
Type Water

Control of Self-Excited Flow Oscillations in Vaneless Diffuser of Centrifugal Compression Systems

1982 ◽  
Author(s):  
A. N. Abdelhamid
Keyword(s):  
Flow Field ◽  
Performance Improvement ◽  
High Flow ◽  
Low Flow ◽  
Flow Oscillation ◽  
Vaneless Diffuser ◽  
Flow Area ◽  
Flow Measurements ◽  
Flow Rates ◽  
Flow Oscillations

Experiments were conducted to evaluate the effectiveness of axisymmetric diffuser exit throttle in delaying the occurrence of self-excited flow oscillation in vaneless diffusers. Sharp edge rings were installed at diffuser exit in order to change the exit flow area. Tests were carried out with the rings attached to one or both of the diffuser walls. Steady and unsteady flow measurements were used to determine the flow field in the diffuser at the onset of the flow oscillations. Results showed that the occurrence of flow oscillation was continuously delayed as the diffuser exit flow area was reduced for all these configurations and impeller speeds. Comparison between the performance of the compression system with and without diffuser exit blockage indicated that although large losses occur at high flow rates, the use of diffuser exit rings resulted in overall diffuser performance improvement at low flow rates. Retractable diffuser exit rings would therefore be ideal for centrifugal compression systems with vaneless diffuser.

Influence of Tank Shape on Performance and Flow Field of a Gravitation Vortex Type Water Turbine

2019 ◽  
Vol 2019.25 (0) ◽  
pp. 19H09
Author(s):  
Daichi SUKEMORI ◽  
Yasuyuki NISHI ◽  
Terumi INAGAKI
Keyword(s):  
Flow Field ◽  
Water Turbine ◽  
Type Water

scholarly journals Performance Analysis of Z-Blade Reaction Type Turbine for Low-Head Low Flowrate Pico Hydro

2021 ◽  
Vol 85 (2) ◽  
pp. 51-65
Author(s):  
Mohd Farriz Basar ◽  
Fatin Syakira Mohd Hassan ◽  
Nurul Ashikin Rais ◽  
Izzatie Akmal Zulkarnain ◽  
Wan Azani Wan Mustafa
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Rotational Speed ◽  
Low Flow ◽  
Practical Case ◽  
Reaction Type ◽  
K Factor ◽  
Water Turbine ◽  
Low Head

The study explores the performance characteristics of a Z-Blade reaction type water turbine and investigates a test unit for an ideal and practical case using the governing equations derived from the principles of conservation of mass, momentum, and energy. Various analyses are conducted with consideration of the ideal and possible operating condition for low-head (3 m to 5 m) and low-flow (2.5 L/sec and below) water resources. The relationship of the fluid flow friction known as k-factor with mass flow rate and angular velocity for a Z-Blade turbine model is discussed. The measured performance of two PVC pipe sizes (0.5 inch and 1 inch) of a Z-Blade turbine is presented and evaluated against theoretical results. This work also describes the simple concept of a Z-Blade turbine for a pico-hydro application. A large variation in k-factor with a 1% difference in rotational speed and mass flow rate is presented. The coefficient k-factor is also demonstrated as a strong parameter influencing the mass flow rate and rotational speed performance. This coefficient also has a significant impact on the conversion of potential energy into power output.

314 Study on Flow Field of a Gravitation Vortex Type Water Turbine

2015 ◽  
Vol 2015.23 (0) ◽  
pp. 189-190
Author(s):  
Tomoaki TANEMURA ◽  
Yasuyuki NISHI ◽  
Terumi INAGAKI ◽  
Yanrong LI ◽  
Hiroshi OBATA
Keyword(s):  
Flow Field ◽  
Water Turbine ◽  
Type Water
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