Design of the cross flow runner

The equations in this section are taken from:

• Arter, A., Meier, U., Harnessing Water Power on a Small Scale Hydraulics Engineering Manual(SKAT)
• Mockmore, C. A. Prof CEng, Merryfield, F. Prof CEng, The Banki Water Turbine, 1949
• Harvey, A, Micro Hydro Design Manual, (1993), ISBN 1-85339-103-4

Download PDF

Crossflow Water Turbine Design Manual

By ; Abhiroop Chattopadhyay

The crossflow water turbine is widely considered by many to be the most efficient and apt type of turbine for applications in micro‐hydro and picohydro projects. However, it should also be noted that designing this kind of a turbine is no child’s play.Nevertheless, in this article, I will show you exactly how the designing of the turbine is to take place. With a very basic knowledge of mathematics, it is possible to design and construct an efficient working water turbine. Before, designing, just get an idea about how must hydraulic power is theoretically available at a particular site.

Read More

The breastshot waterwheel: design and model tests

By: G. Muller and C. Wolter

The waterwheel is one of the oldest hydraulic machines known to humankind and has been in use since antiquity. Originally built of wood, the availability of new materials, namely wrought iron, and the increasing demand for mechanical power during the industrial revolution led, in combination with the development of hydraulic engineering, to the rational design of waterwheels, resulting in much increased performance and efficiency. Three distinct types of waterwheels evolved: the overshot, the breastshot and the undershot wheel.

Overshot wheels were investigated quite thoroughly and were found to have efficiencies of more than 85% for a broad range of flowrates from 0.2 to 1.0 Q/Qmax. Only one measurement of an undershot or Zuppinger wheel is known to the authors. Researchers from the Technical University of Stuttgart in 1977 measured the efficiencies of a 42 kW Zuppinger wheel which was built in 1886 and had been in continuous operation since. The measurements showed efficiencies of 71–77%. The breastshot wheel however, which was particularly popular in Britain,was never investigated. Read more

Building an Undershot Water Wheel

http://www.builditsolar.com

By Gary

An undershot wheel is a vertically-mounted water wheel that is rotated by water striking paddles or blades at the bottom of the wheel. The name undershot comes from this striking at the bottom of the wheel. This type of water wheel is the oldest type of wheel.

Downloads :

Building an Undershot Water Wheel (Pdf)

Waterwheel design xls

SMALL MICHELL (BANKI) TURBINE

SMALL MICHELL (BANKI) TURBINE:

A CONSTRUCTION MANUAL

BY

W.R. BRESLIN

The Michell or Banki turbine is a relatively easy to build and highly efficient means of harnessing a small stream to provide enough power to generate electricity or drive different types of mechanical devices.

Read more

Micro Pelton Turbines E.Book

If you want to make micro Pelton turbines , then you must read this e-book as a reference. This publication (e-book ) has its origin in a workshop on "Micro hydro power energy", organized by GATE, which was held in Eschbom, Germany. The aim of the workshop was to discuss relevant experience in planning and implementation of very small hydro power plants in developing countries, to determine problems and deficits in the technical and socioeconomic fields and to discuss masters on direct utilization of mechanical power. One of the deficits stated at this workshop concerned micro Pelton turbine installations.

Niederuzwil, September 1991
Markus Eisenring

Read E.Book

The Choice of Materials For Water Turbines

Photo by Ahmad Suhendra

Determination of material for water turbine is very important, because turbines work on conditions such as high pressure, abrasion caused by sand carried by the flow, and also of pH levels and salinity that can cause corrosion, so that the appropriate materials needed to treat the condition. There are several types of water turbines and materials used in their manufacture.
Penentuan bahan untuk membuat turbin air sangatlah penting, karena turbin bekerja pada tekanan tinggi, adanya pengikisan karena pasir yang terbawa air , juga derajat keasaman (pH air) dan kadar garam dalam air yang dapat menyebabkan korosi, maka untuk itu diperlukan bahan yang tepat untuk mengatasi hal tersebut.
Disini diperlihatkan beberapa jenis turbin air dan bahan yang digunakan untuk membuatnya.

Read More

Ref:
http://www.ivt.ntnu.no/ept/fag/tep4200/innhold/The%20choice%20of%20materials.pdf

An example design of the crossflow turbine, type BYS-T3

Picture : www.boutiquepower.com.au

You can use an example design of the crossflow turbine type BYS/T3 by Ueli Meier as a teaching or a comparison with the turbine you plan, if you look at and study the sample design,it will open your insights about how to design a crossflow turbine. For those just learning about the turbines may be found in many less obvious things but do not worry , a lot of reading on the internet resources that can help you to understand it. We hope you become part of people who care about the future of the planet by using renewable energy . Thanks

Read more
Ref : Ueli Meier , " Design of Crossflow Turbine BYS/T3 " , Swiss Center Appropriate Technology - Varnbuelstrasse 14 CH-9000 St.Gallen Switzerland

The microhydro plant

By Manfred Mornhinweg (manfred@ludens.cl)

My little paradise has a stream that provides enough water flow and head to run a small turbine, to provide electricity to my home. While writing this, the microhydro plant is being implemented, and here are some photos of the process.

Read more

Walsh River Micro-Hydro Turbine Contruction Guide

Prepared by Max Enfield, December 2007, revised March 2010

These notes are intended as a guide to those wishing the construct a Banki-crossflow turbine like that were previously available and used in the Walsh River Micro-Hydro Systems. The focus of the notes is on construction details, rather than design.

The Walsh River Micro-Hydro System derived its name from the Walsh River in Far North Queensland, where the prototype system was installed. The system concept was developed and prototyped in 1991 by Jerry Jeffress and features the integration of custom made Banki-crossflow turbines, with Baldor DC generators and AERL Hydromax DC:DC step down controllers. It can also be used to pump water, indeed it has been used to pump water and generate electricity simultaneously.

Read more

The Number of Blades for Crossflow Turbine

By Ahmad Suhendra

Example :

A crossflow turbine is designed with blade angle β1=30 0 (angle between the relative velocity and tangential velocity) and α1=16 0 (angle between the absolute velocity and tangential velocity). The turbine have a rotation speed of 750 rpm on the net head 10 m, flow 100 lt / s, what is the specific speed, absolute and tangential velocity , outside diameter of the disc, blades spacing and number of baldes?

Crossflow turbine requirements are :

• ns = 42 – 170 (classical based on metric HP)
• Ns = 0.86* ns (True metric specific speed)
  
• Nt = 100 -1000 rpm (nominal speed)

1.Specific Speed

ns (rpm) = 3.65 x Nt (rpm) x Q(m^3/s)^ 0.5 / H_netto(m)^ 0.75

= 3.65 * 750 * 0.01^ 0.5 / 10^ 0.75

= 48.7 rpm ----> Ok, Crossflow

2.Absolute Velocity of water

kc = 0.967 Coefficient dependent upon the nozzle

C = kc * (2 * g * Head)^ 0.5

= 0.967 (2 * 9.8 * 10 )^0.5

= 13.54 m/s

3.Tangential velocity

U1 = ( C * Cos α1) / 2

= ( 13.54 * Cos 16 )/ 2

= 6.51 m/s

4. Outside diameter of disc

D1 = 60 * U1 / (phi * Nt)

= 60 * 6.51 / 3.14 * 750

= 0.166 m

Then :

S1 = k * D1----> k = 0.075 – 0.1 (respectively)

Taken k = 0.087

S1 = 0.087 * D1

= 0.087 * 0.166

= 0.0144 m

5. Spacing of blades in disc

t = S1 / Sin β1

= 0.0144 / Sin 30

= 0.0288 m

6.Number of Blades

Z = phi * D1 / t

= 3.14 * 0.166 / 0.0288

= 18 blades (20 were used for design)

Ref : Mockmore C.A and Merryfield Fred " The Banki Water Turbine " , Bulletin Series No:25 Oregon State College Corvallis

What is the blade length (bo) limits on crossflow turbine ?

By Ahmad Suhendra

Crossflow turbine blade has a length limit that must be met in the design, for the turbine at an angle α1=16 o, nozzles coef. kc = 0.98 and k = 0.075 to 0.10 are as follows:

1). C (m/sec) = kc.(2.g.H)^0.5
2). Phi.D1.Nt / 60 = (C. cos α1)/2

Then:
The diameter of blade is :
3). D1 (m) = 39.85 H ^ 0.5 / Nt

Blade length (bo) is obtained from the following equation(4)
4). Q(m^3/sec ) =(So.bo)[ kc ( 2.g.H )^0.5 ]
5). So(m) = k D1

By entering the equation (5) and (3) into equation (4) is obtained :
The blade length (bo) limits is :

6). bo = ( 0.058 Q.Nt / H ) to ( 0.077 Q.Nt / H )

Where:

• g is the constant of gravity 9.8 m/s^2
• C is the absolute velocity of water (m/sec)
• Phi is 3.14
• Nt is the nominal turbine speed (rpm)
• D1 is the diameter of Disc (m)
• So is the thickness of the water jet (m)
• H is the net head (m)

Ref : Edy Sunarto , dkk,” Pedoman Rekayasa Tenaga Air (Hydropower Engineering Guidelines) ”, UPT Hidro Elektris BPPT, Jakarta 1991

What is the maximum performance of crossflow turbine?

By Amad Suhendra

Sonnek (1923) modified the banki theory assuming a constant angle of the blade equal to 30 , so that the expression resulted in maximum performance:

ηmax = 0.863-0.264 *(D / H)

D is the diameter of turbine (disc) and H is the net head

Ref : Ariel R.Marchegiani , "Turbina de Flujo Transversal O Michell-Banki", Universidad Nacional Del Comahue

How to calculate the diameter and number of nozzles for Pelton turbine

By Ahmad Suhendra

Example :

A Pelton turbine is planned to be working on the head netto 80 m and a flow 20 liters / s , what is the number of nozzles installed on these turbines?

Pelton turbine requirements are :

• ns (specific speed , rpm) = 8 – 72 rpm
• Nominal speed = 500 – 1500 rpm

1.Specific speed of turbine

• Taken 1500 rpm as nominal turbine speed (N_turbine)
• Flow (Q) = 0.020 m3/s
• H_netto = 80 m

ns = 3.65 *N_turbine (rpm) * Q(m^3/s) 0.5 / H_netto(m)^ 0.75

= 3.65 * 1500 rpm * (0.020 m3/s)^0.5 / (80 m)^0.75

= 774.28 / 26.75 = 28.95 rpm

Based on the practical calculation,

• If ns >= (8) and < (29.5) then 1 nozzles
• If ns >= (29.5) and < (42) then 2 nozzles
• If ns >= (42) and < (54) then 3 nozzles
• If ns >= (54) and < (58) then 4 nozzles
• If ns >= (58) and <=(72) then 6 nozzles

ns = 28.95 rpm -------> Ok, Pelton turbine with one nozzles

2. Absolute velocity of water

kc ( nozzles coef.) = 0.96 to 0.98, Taken kc = 0.98

C = kc (2 * 9.8 m/s^2 * H_netto(m) )^ 0.5

= 0.98 (2 x 9.8 x 80 ) 0.5 = 38.81 m/s

3. Diameter of nozzles

Dn = [ (4 x Q/(number of nozzles)) / (phi x C) ] ^0.5

= [ 4 x (0.020/1) / (3.14 x 38.81)] ^0.5

= [ 0.08 / 121.86 ] 0.5 = 0.0256 m or 26 mm

Ref : Edy Sunarto dan Markus Einsering”,Turbin Pelton Mikro”, MHPG Andi Offset Yogyakarta 1992

The Errors that often occur in the design M.H.P

The error often made in the design M.H.P (Micro Hydro Power Electric) is:

1. Take a careless flow design through without consideration / calculation of hydrological cycle (region wide catchment rainfall, rainfall, watershed conditions etc.) in the area to be built Micro Hydro Power of Labor (M.H.P), so that the generator does not work optimally or decrease the age (under age design).

2. Penstock pipes placed in the area of unstable slopes, especially with the level slope more than 35% (landslide), so that placement in the penstock / analysis to be performed on the anchor structure of the soil strength

3. Making buildings intake (dam) that does not take into account / downstream flow of attention to scrape the dam foundation, that can be suddenly forebay (vessel) of water shortages.

The state of art of Hydrokinetic power in Brazil

By Geraldo L. Tiago Fo, PhD

Abstract

This paper presents the state of the art of free-flow hydro power turbine, also known as a hydro kinetic turbine in Brazil. This kind of turbine is designed to generate electricity using only the kinetic energy of water flow in rivers and is used to generate electricity on isolated communities in the inland of Brazil.

Moreover it is relevant to say that the developed technology proved is necessary to be robust and suitable for the extremely severe conditions of the remote and isolated villages, since it is has been functioning uninterruptedly from several years with a minimum maintenance. This type of small hydro kinetic power plant typically can provide up to 2 kW of electric power, being a reliable alternative for the electrification of remote and isolated households, communities or social end-users.

Click Here

Water Turbine Speed

Type of turbine	Nominal speed(n rpm)	Runaway speed
Semi Kaplan, single regulated	75-100	2-2.4
Kaplan, double regulated	75-150	2.8-3.2
Small-medium Kaplan	250-700	2.8-3.2
Francis (medium & high head)	500-1500	1.8-2.2
Francis (low head)	250-500	1.8-2.2
Pelton	500-1500	1.8-2
Crossflow	100-1000	1.8-2
Turgo	600-1000	2

Selection type of turbine

Selection type of turbine

To determine the type of water turbine that will be used in the design of a power micro hydro, need specific speed is calculated. Specific Speed (ns) is defined as the speed in rounds per minute of a turbine in the delusion that all the geometrical indeed similar to the turbine is able to lift 75 kg of water per second up to a height of 1 meter.

ns = 3.65 . n . Q ^0.5 . H ^{(- 0.75)}

ns = 270 – 1000 Kaplan/Propeller
ns = 60 – 350 Francis
ns = 42 – 170 Cross flow
ns = 8 – 72 Pelton
Where :
n = Round turbine speed /Nominal speed (rpm)
Q = Design flow (m3/det)
H = Net Head (m)

RANCANG BANGUN TURBIN PELTON MIKRO

By Ahmad Suhendra
Technical guidance of micro pelton turbine design for areas that have high head but small discharge.
Petunjuk teknis rancang bangun turbin pelton mikro untuk daerah yang memiliki head tinggi tetapi debit (flow) kecil.
klik disini