International Journal of Science, Engineering and Technology Research (IJSETR)

Volume 7, Issue 10, October 2018, ISSN: 2278 -7798

Design of Cross Flow Turbine (Runner and

Shaft)
San San Yi, Aung Myo Htoo, Myint Myint Sein

establishments, due to its simple structure and ease of

Abstract— In Myanmar, there are many water resources. manufacturing in the site of the power plant. A typical cross-
From these resources, hydropower can be produced to fulfill flow turbine consists of two main components namely the
the requirements of the electrical energy needs. Cross flow nozzle and the runner. A nozzle, which is rectangular shape
turbines are used widely in such small hydropower plants due
to their simple design, easier maintenance, low initial
that its width matches the width of runner. Its main function
investment and modest efficiency. This research is to design is to convert the total available head into kinetic energy and
cross flow turbine producing 90kW electric powers under a to convey water to the runner blades. The runner is the heart
head of 13 m and the flow rate of 1 m 3/s. The detail design of the turbine. The function of the form of drum-shaped
calculation of shaft that turbine is described in this research. which consisting of two or more parallel discs connected
The main aim of this study is to enhance and performance together near their rims by a series of curved blades [4].
characteristics of cross flow turbine which is designed by using
MATLAB program.

Index Terms— Cross Flow Turbine, Hydropower, Runner,

Shaft.

1) INTRODUCTION
The role of hydro plants becomes more and more
important in today’s global renewable energy. The small-
scale renewable generation may be the most cost effective
way to supply electricity to remote villages that are not near
transmission lines. Hydropower traditionally represents the
energy generated by damming a river and using turbine
systems to generate electrical power. The reaction turbines
require more sophisticated fabrication than impulse turbines
because they involve the use of larger and more intricately
profiled blades together with carefully profiled casings.
Cross flow turbine is easiest turbine to make in home
workshop [4].
The cross-flow turbine is a machine which provides shaft
power by extracting energy from a moving fluid. The nozzle
directs the water flow into the runner at a certain attack
angle. The water jet leaving the nozzle strikes the blades at
first stage. The water exits the first stage and was crossed to Figure 1. Path of water through turbine
the second stage inlet after existing the runner completely.
The portion of water that crosses the runner two times is The water starts enter from point A and strikes a blade
known as cross flow and the name of the turbine is derived AB. Then the water flow through the interior of the runner.
from this phenomenon. A cross flow turbine always has its The water strikes again to a blade CD and pass through the
runner shaft horizontal. exit [2].
Nowadays, the cross-flow hydraulic turbine is gaining
1.1) Design Consideration of Shaft
popularity in low head and small water flow rate
A shaft is the component of mechanical devices that is
used to transmit power from hydraulic power to mechanical
Manuscript received October, 2018.
San San Yi, Department of Mechanical Engineering, Pyay
power, shaft is rotating machine element, usually of circular
Technological University, Ministry of Education, Pyay, Myanmar, cross section having mounted upon it such elements as
Phone/+959795771030(e-mail: sansanyi2581981@gamil.com). gears, pulleys, flywheel, crank, sprockets, and other power
Aung Myo Htoo, Department of Mechanical Engineering, Pyay
Technological University, Ministry of Education, Pyay, Myanmar,
transmission elements. In the process of transmitting power
Phone/+959422454664 (e-mail: aungmyohtoo1979 @gmail.com). at a given rotational speed, the shaft is inherently subject to
Myint Myint Sein, Department of Mechanical Engineering, Pyay a torsional moment or torque [8].
Technological University, Ministry of Education, Pyay, Myanmar,
Phone/+959798404611 (e-mail: mmsein2019@gmail.com).

2) DESIGN PROCEDURE OF CROSS FLOW TURBINE The calculations for design procedure of the cros
1
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 International Journal of Science, Engineering and Technology Research (IJSETR)
Volume 7, Issue 10, October 2018, ISSN: 2278 -7798

s flow turbine runner involve in the following steps.

a  0.17 D1 (7)

10) Calculation of radius of blade curvature, (rc)

The curvature of blade accounts a lot for the efficient working of
TABLE I. PARAMETERS CONSIDERED FOR DESIGN
the turbine. It is varying directly with the size of turbine. The
Generator Output Power (P) 90kW following relation is used for the blade radius [7]:
Head (H) 13 m
rc  0.16D1
Flow Rate (Q) 1 m3/s
(8)

Overall Efficiency (o ) 75%

11) Calculation of radius of circle pitch of blade shape arc,
(R0)
Table I shows the parameters considered for designing 90 Pitch circle diameter is the circle from which the profile
kW cross flow turbine. of the blade radius is drawn the side plates of the runner. It
3) Calculation of output shaft power, P has the following relation: [7]
The output shaft power of the turbine in (Watt) can be R 0  0.37D1 (9)
calculated as
P  ogQH (1) 12) Calculation of spacing of blades, (t)
Proper blade spacing allows the water to strike on the
4) Calculation of turbine efficiency, (  ) blades for maximum thrust production, the blade spacing
The maximum efficiency can be calculated as depended upon the number of blades used in the turbine
[2] runner. Blade spacing can be calculated as: [2]
1 (2) KD
 K2 1 cos2   t
c 1 1
2 sin1
(10)
where, ψ = an empirical coefficient (about 0.98)
Kc = coefficient of water velocity, 13) Calculation of number of blades, (n)
The selection of optimum number of blades is very
(0.98 ~ 0.95)
important in the design of turbine runner, fewer numbers of
5) Calculation of specific speed, (Ns) blade may cause incomplete utilization of water available to
the turbine and excessive number of blades may cause the
172.556 pulsating power and reducing the turbine efficiency. The
Ns  (3)
H0.425 following relation exists for the number of blades in a
turbine runner: [2]
6) Calculation of turbine speed, (N) D
n  t1 (11)
N  H1.25
N s (4)
P
TABLE II. DESIGN RESULT DATA OF CROSS FLOW TURBINE RUNNER

7) Calculation of the runner outer diameter, (D1) Parameters Symbol Results Unit
Diameter of runner is selected depending upon the flow Angle of attack α1 16˚ -
conditions. If there is larger flow through the turbine select a Blade angle β1 30˚ -
larger diameter of turbine and for the low water flow Runner outer diameter D1 0.8 m
conditions, select a smaller diameter of turbine. The runner Runner length L 1 m
outer diameter (m) can be calculated as [7] Radius of outer circle r1 0.4 m
Radius of inner circle r2 0.27 m
D  Ku 60Kc 2gH (5) Radius of pitch circle R0 0.3 m
1
N Radius of blade curvature rc 0.128 m
Radial rim width a 0.136 m
8) Calculation of length of runner, (L) Number of blades n 18 -
Runner length (width) is calculated using Eq (6):
Q
L (6)
KD1Kc 2gH 14) Calculation of shaft diameter, (ds)
The diameter of shaft should have a value to bear the load
9) Calculation of radial rim width, (a) on the turbine. It should not be too larger that water strike the
The radial rim width (m) can be calculated as [2] shaft after passing through the first set of blades at the inlet:
P s
d  150 3 N
2
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 International Journal of Science, Engineering and Technology Research (IJSETR)
Volume 7, Issue 10, October 2018, ISSN: 2278 -7798

where, ds = diameter of shaft (m)

The designed cross flow turbine rotor 3D model was
Checking: (12) generated with Solid Works software.
D1
4
ds

Figure 4. Cross flow turbine rotor

15) DESIGN CALCULATION FOR SHAFT

In this research, the suitable material is mild steel. Mild
steel is especially desirable for construction due to its weld
ability and machinability. Because of its high strength and
malleability, it is quite soft.
Figure 2. Cross flow turbine runner disc
7521.88 N ω = 4264.75 N/m
Fig. 2 2D Autocad drawing consists of the radial rim
width, outer diameter of cross flow turbine, inner diameter A C G
D B
E

of cross flow turbine and diameter of shaft. 0.3048 m 1m

0.3048 m
0.152 m

Fig. 3 shows the runner side disc with thickness 18 mm is 11786.63 N

cut and trim for 18 blades.The blades are fitted into slots of VLD
4742.93N-m
three discs of 800 mm diameter with thickness 18 mm and RA
RB
welded it. VBMD
13028.27N

HLD
R1 5242.58N-m
R2

HBMD


1

1

III

Figure 5. Loading and Bending Moment Diagram

Bending and torsional moments are the main factors

influencing shaft design.

Torque of the runner exerted by the fluids on the runner,

Figure 3. Cross flow turbine runner disc with 3D model from the basic formula of the hydraulic turbine, the torque
transmitted
The shaft of 101 mm diameter is also welded to the rotor r1v1 cos1  r2v2 cos2 
discs.The runner blades can be cut from a standard sheet T  Qr  (13)
metal or steel pipe and then be bent into the required blade  3 3 cos 3  r4v4 cos4  
v that the velocity triangles are identical with
It is assumed
profile.In some cases, to impove on the structural integrity
of the runner, more than three equally spaced discs are each other in 2 and 3, while mutual speeds are identical with
employed. each other in 1 and 4.

T  Qr1v1 cos 1  r4 v 4 cos

(14)
4 

The ASME code equation for solid shaft subjected to

3
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bb t t
 International Journal of Science, Engineering and Technology Research (IJSETR)
Volume 7, Issue 10, October 2018, ISSN: 2278 -7798

torsion and bending load (without 2axial load), [6]

3 16
d  k M 2  K M (15)

Ss
ASME code states for commercial steel shafting
Ss (allowable) = 55MN/m2 for shaft without keyway
Ss (allowable) = 40MN/m2 for shaft keyway
The critical speed (ω) of the shaft can be calculated by
using Rayleigh-Ritz Equation,

g
W
2
 (16)
W  2
Figure 8. Performance curve of Cross Flow Turbine(Guide Vane Vs
Efficiency)
δ = deflection due to weight (m)
Fig. 6 shows the variation of shaft power with flow
16) PERFORMANCE CHARACTERISTIC OF rate.According to the Fig. 7 effective shaft power and
TURBINE
Dimensional and non-dimensional design parameters are effective head are directly proportional, as the shaft power
head coefficient, flow coefficient and power coefficient. increase the possible effective head also increase. And then
These parameters are used to compare the performance performance curve of cross flow turbine (guide vane angle
characteristics of different turbine models. and efficiency) is inversely proportional as the guide vane
Both the operating characteristics and non-dimensional angle increase efficiency produced is going to decrease.
characteristics are plotted by using MATLAB program.
17) CONCLUSION
A complete design of cross-flow turbines is presented in
this research. The cross flow turbine is designed at a head of
13 m and flow rate of 1 m3/s to generate output power of 90
kW. It is applicable to wide range of flow rate adjusting the
runner length. In this research, runner diameter 0.8 m and
runner length 1 m are used. According to the length of
runner and three discs, benefits are to ensure sufficient
strength of blade and to prevent the bending blades. The
speed of turbine shaft is 150 rpm which is less than
calculated critical speed of
104.8 rad/s (1000rpm). Therefore, the shaft design is
satisfied. From the performance result, it is clear that the
Figure 6. Performance curve of cross flow turbine (shaft power Vs flow cross flow turbine need more flow rate to get higher power
rate)
output. The recommendations are suggested that the present
design could be implemented easily because it can be
installed with locally available materials and technology.

APPENDIX

TABLE III. RUNNER DIAMETER AND BLADE THICKNESS

Runner
200 300 450 700 800 1000
Diameter, mm
Blade
Thickness, 3.2 4.5 6 9 10 12
mm

TABLE IV. VALUE OF BENDING MOMENT FACTOR KB

TORSIONAL MOENT KT

Figure 7. Performance curve of cross flow turbine (shaft power Vs

effective head)
For stationary shafts: Kb Kt

Load gradually applied 1.0 1.0

Load suddenly applied 1.5 to 2.0 1.5 to 2.0

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 For rotating shafts: Kb Kt

Load gradually applied 1.5 1.0

Load suddenly applied
(minor shock) 1.5 to 2.0 1.0 to 1.5
Load suddenly applied
(heavy shock) 2.0 to 3.0 1.5 to 3.0

ACKNOWLEDGMENT
The author thanks in respect to Dr. Zin Ei Ei Win, Head
and Professor of Mechanical Engineering Department, for
her helpful and valuable suggestion, supervision, kindness,
painful and guidance throughout this research. Special
appreciation is intended to her supervisor Dr. Aung Myo
Htoo, Professor, Pyay Technological University, for his
supervision, support, guidance and encouragement
throughout this study. Moreover, the author also would like
to thank Daw Myint Myint Sein, Lecturer, Pyay
Technological University, for her supports and advice.
Finally, special thanks are given to her parents, brothers and
sisters for their constant understanding, encouragement and
support to make this research without any difficulty.

REFERENCES
18) R. L. Daugherty, ‘‘Hydraulic Edition’’, A Text on Practical Fluid
Mechanics, 1937.
19) C, A. Mockmore and F. Merrifield: ‘‘The Banki water turbine’’
Engineering Experiment Bulletin Series, No.25, (February 1949).
20) Simon & Schuster, ‘‘Design of Machine Elements’’, First published
by Prentic Hall, (1991).
21) Cleo Penche, ‘‘Layman’s Guide Book on How to Develop A Small
Hydro Site’’, Published by ESHA, Second Edition, Belgium, (June
1998).
22) G John Frunze, ‘‘Compendium in Small Hydro’’, Holme Bygade 12,
8400 Ebelt Denmark, (2000,2002).
23) Daw Than Than Htike, ‘‘MACHINE DESIGN’’, Yangon
Technological University, Department of Mechanical Engineering,
(October 2002).
24) Nippon Koei/JEEJ, Japan International Cooperation Agency, The
Study on Introduction of Renewable Energies in Rural Area in
Myanmar, Volume 6, Part 6-3 Appendix 3, (July 2003).
25) Ma Khet Khet Mann, ‘‘Shaft and Casing Design of 100kW Cross
Flow Turbine for Micro Hydro Power Plant’’, (June 2009).

San San Yi holds her BE (Mechanical) Degree from Meiktila

Technological University, Meiktila, Myanmar in 2005.After that, she had
been working at Department of Mechanical Engineering, in TU(Hmawbi)
from 2007 to 2014. Now she has currently been working as a Lecturer at
the Department of Mechanical Engineering in Pyay Technological
University from 2014 to until now. Her research field is in fluid dynamics.
Aung Myo Htoo receives his BE (Mechanical) Degree from Mandalay
Technological University, Mandalay, Myanmar in 2002.He also has got
ME(Mechanical) from Yangon Technological University, Yangon,
Myanmar in 2003 and his Ph.D degree from MTU, Mandalay
Technological University, Mandalay, Myanmar in 2007.Now he is
currently working as an Professor at the Department of Mechanical
Engineering, in PTU. His research field is in fluid dynamics.
Myint Myint Sein has been working as a Lecturer at Department of
Mechanical Engineering, PTU since 2016.She previously served as a tutor
in the Department of Mechanical Engineering, Hinthada (GTI). She holds a
BE(Mechanical) and ME(Mechanical) in 1993 from YTU. She had been
working as a Lecturer in Maubin, Insein, Mandalay and Thanlyin from
2000 to 2016. Her research field is in Renewable Energy.