1. Impulse Turbine with Self-pitch Controlled Guide Vanes for Wave Power Conversion: Performance of Mono-vane

Type, International Journal of Offshore Polar Engineering.

2. A Review of Impulse Turbines for Wave Energy Conversion, Renewable Energy Journal.

3. Experimental Investigation on the Dynamic Response of a Moored Wave Energy Device under Regular Sea

Waves, Ocean Engineering Journal.

4. Hydrokinetic Energy Conversion Systems and Assessment of Horizontal and Vertical Axis Turbines for River and

Tidal Applications, Applied Energy Journal.

The turbine can be used for very small head differences and large flow volume

(suitable for river, artificial channel and ocean conditions). The wheel is designed

with eleven blades installed in different arrangements of blades. One important of

this tidal energy converter is environmentally friendly and simple in operating and

maintenance.

Hydrokinetic conversion systems, albeit mostly at its early stage of development,

may appear suitable in harnessing energy from such renewable resources (tides,

wind, etc.). A concept of tidal energy converter (TEC) which is based on shape of

the conventional water wheels, is introduced in this study. Basically, this turbine

has several special features that are potentially more advantageous than the

conventional tidal turbines, such as propeller type tidal turbines. The research

aims to study the potential possibility of eleven-blade turbine using Computational

Fluid Dynamics (CFD) in extracting the hydrokinetic energy of tidal current and

converting it into electricity, and evaluate the performance of the turbine at

different given arrangements of blades which are inclined to the wheel centreline

with angles of 0, 10, 20 and 30 degrees. In all cases of tip-speed ratio (TSR), the

straight blades type (or inclined to the wheel’s centreline with an angle of 0

degree) showed the most effective performance than the others. In the other

words, this type extracts tidal stream energy better than all cases in the study. In

addition, the torque extraction at the rotor shaft of the 0 degree inclined blade type

is the most uniform comparing to the others due to the less interrupted and

fluctuated generation of force for a period of time.

Comparison of performance between different types (especially 0 and 30-degree cases) was done using visualizations of pressure and

force contours on blade surface no. #1 as shown in the picture below. It indicated that the 0-degree type has the highest values of force

distributed on the blade surface at different tip speed ratio (TSR) values.

Abstract

A Numerical Study on Performance of

Water Wheel Type Tidal Turbine M. H. Nguyen, H. C. Jeong, B. G. Kim, J. H. Kim, C. J. Yang

Mokpo National Maritime University, Mokpo City, Republic of Korea

Results

Turbine Design

Conclusions

Meshing Method and Boundary Conditions

References

International Conference on Ocean Energy (ICOE) 2016 – Edinburgh – 23-25 February 2016

High quality mesh strategy is done using ANSYS-Meshing for two calculation

domains: rotor and stationary parts. The dimensionless wall (Y-plus) is ranged

from 1-7 at rotor blades region.

Comparison of force and torque variations extracted in one revolution from the blade No.#1 between 0 and 30-degree types.

Comparison of power efficiency among four kinds of blade arrangement at different TSRs.

1. The 0deg. inclined blade WWT shows the best performance in comparison to

the others, highest discrepancy at TSR 1.2, up to over 10% power coefficient

deviation.

2. WWT works efficiently at TSR range from 0.9 to 1.1, up to 38% power

coefficient at TSR = 1 for 0deg. inclined blade type.

3. When increasing the working angles of the blade inclined to the center of the

rotor, the force of the water flow acting on the blade will be reduced. As a

result, the torque and power extracted will be reduced as well, especially at

TSRs higher than TSR = 1.

4. This kind of turbine has some more advantages than the conventional

turbine, like propeller types, etc. about manufacture, repair and maintain.

00

Hub

300

Blade

Hub

Water

flow

Water

flow

Rotor diameter (m) 1.2

Rotor width (m) 0.5

Blade dimensions (m)

(L x W x T) 0.3 x 0.5 x 0.01

constant for all cases

Number of blades 11

Rated flow speed (m/s) 1 (fixed)

Working angles of blade 00, 100, 200 and 300

Hub

Blades

ω

Water flow

V1

d d

V2

F

ω

Hub

Hub

Side

wall

Inflation

Y-plus

TSR 0.7 0.8 0.9 1 1.05 1.1 1.2

RPM 11.141 12.733 14.324 15.916 16.712 17.508 19.099

Operating Principle

Water flow

Blade No. #1

Water flow

Blade No. #1

Front face Back face Front face Back face

Front face Front face

-200

-150

-100

-50

0

50

100

150

200

250

0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360

Force-TSR 1 - 30deg Torque-TSR 1 - 30deg

Torque-TSR 1 - 0deg Force-TSR 1 - 0deg

Positive value

Negative value

-200

-150

-100

-50

0

50

100

150

200

250

0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360

Force-TSR 1.1 - 30deg Torque-TSR 1.1 - 30deg

Torque-TSR 1.1 - 0deg Force-TSR 1.1 - 0deg

Positive value

Negative value

TSR = 1

Comparison of water flow-turbine interaction at different TSRs for 30-degree type.

TSR = 0.9 TSR = 0.7

TSR = 1.2 TSR = 1.1

0

0,1

0,2

0,3

0,4

0,6 0,7 0,8 0,9 1 1,1 1,2 1,3

TSR

Power Coefficient

30deg inclined type 0deg inclined type

10deg inclined type 20deg inclined type

0

0,1

0,2

0,3

0,4

0,6 0,7 0,8 0,9 1 1,1 1,2 1,3

TSR

Torque Coefficient

30deg inclined type 0deg inclined type

10deg inclined type 20deg inclined type

Rotor blades Conversional

equipment

Channel

Inlet

The study was tested at different TSRs, ranged from 0.7 to 1.2 by fixing inflow

velocity at 1m/s, but changing rotational speed.