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TECHNICAL REPORT (¢) 1994 Working-Group on Development Techniques (WOT) Published by the Working-Group on Development Techniques (WOT), University of ‘Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands. Copyright (a) 1990 by the Horking-Group on Development Techniques (WOT). Nevertheless, permission is hereby granted for reproduction of this material, in whole of in part, for educational, scientific or development-related purposes, except those Anvoiving commercial sale, provided that a) full citation gf the source ig given and b) sotification in wetting ts given Eo the Vorking-Group on Developnent Techniques (ROT). ‘This technical report is the result of four years of research. Ik is meant for people of the WOT to develop their knowledge about waterpunping windmills (= windpumps) and especially about the Dlever 450 windmill. It is also meant fer people in developing countries vbo have the 1dea to built the Diever 450, To understand the theory and conceptione which are used in the report the author assumes that the reader has ouffleient basic knowledge of wind energy. If this is not the casa the author advises to read first the WoT-publication ‘wind onergy for the third world’ (1it.1). The report reflects the development of the design and the results of the tests on the prototype. The author Le grateful to the people who helped te design the Diever 450, especially to A. da Roest, A. Schaap, C. Vos, 5. Vreeland, F. Van Costrum, J. Andringa, 6. Viogman, B. de Jong, G. Wijbenga and R. van Leeuwen. Frans Brughuis may 1996 List of symbols a Introduction 1.1. The 12PUS00 windai Ll 1,2. The evaluation of the 12PUS00 windmill 1.8. The requirement list . The rotor 2:1. The roter dimensions 2.2, The choice of the design tipspend ratio 2.3. The blades 2.4, The power and torque coefficient 2.5, Measurements of the windspeed-rotationapeed relation The safety system and the head construction 3.1. General 3.2. The hysteresis systen 3.4. The inelined hinged vane system 3.4, The strength calculations of the the transmission ‘ety system 4.1. The mechanism 4.2, The construction ang the strength The pump 5.1. General 5.2. The pumpred forces 5.3, The rotation speed 5.4. The pump dimensions 5.5. The strength calculations of the pumps 5.6. Tests of p-v.c. pumps 5.6.1. The aim of the tests 5.6.2, The test equipment, 5.6.9. The results 5.7, The choice of the p.v-c. pipe as pump cylinder . The toner 6.1. General 6.2, Forces on the tower top 6.2.1, At operating conditions (v= 12 m/s) page 3 6.2.2. At storm conditions (v= 40 m/s) a3 6.9. Forces on tha tower construction 50 6.8.4, At operating conditions (v= 12 m/s) 81 6.3.2. At storm conditions (v= 40 m/s) 53 6.4. Stresses in the towsrlegs 34 6.5. The Foundation 38 6.6. Forces on the tower during hoisting 36 7. Froperties and characteristics 58 7.4. The input-output relation 58 7.2, Prediction of the output 61 7.3. Costs and benefits 6 Cenciusions 65 Recommendations ve Literature 70 appendices: 1. Brawiags of the Diever 450 2. Tha choice of the tipspeed ratio + Graphs of the position, the speed and acceleration of the piston as function of the tine Results of the measurenents on the test rig Results of the measurements on the Diever 450 prototype crank with a variable length transaission with ball-bearings Installation af the 12PUS00 SYMBOLS description side area head Piston area area of the punprod area of the pumpred iron projected area reter area area of the rising main aide area rotor (= 7,5% of Ay) number of blades corde arag coefficient Ligt coefficient power coefficient torque coefficient starting torque cosfficient retor dianeter force admissible force peak force in the pumprod punprod force waterlifting head blade length buckting length power power output Mechanica! power of the rotor power input torque starting torque local cadius roter radius vrank Length resotion forces in K, L, Wand 8 stroke length unit windspard ws design windspeed m/s maximum Windspeed ms rated Windspeed m/s starting windspeed we tipspeed w/s angle of attack plade angle angle between actual position of main vane and its rest pesition angle of yaw (between rotor axis and wind direction) angle between hinge axis and vertical axis angle between rotor plane and relative flow epeed, tipspeed ratio design tipspesd ratio local speed ratio at radiue bydraulic efficiency of the pump installation efficiency of the pump installation mechanical efficiency of the pump tokal efficiency cf the winépump efficiency of the transmission volumetric efficiency of the pump roter angular speed rad/s aonsity of ale kayat density of concrete kant density of water kgyat stress Hmm admissible stress yen equivalent stress N/mm minimum stress N/a? maximon stress Nm surface stress N/mm? shear stress N/mm buckling factor CHAPTER 1 INTRODUCTTON In 1979 the WoT designed the 12PUSOO windmill. This windmili is built in India, indonesia, Bolivia, china, Tanzania and other countries After sevea ysars of experiences, in 1986, 1¢ was clear that the 1270500 design could be improved te get more output and a Longer life~ Therefore the WOT decided to redesign the windmill which resulted in a new windmill, the 19PU450, also called the Diever 480, Biever is the surnane of our oldest and most’ loyal member . e 4.1 The 12PUS00 windmitt The 12Py500 windmill is a Waterpumping windmil1, 1¢ has an horizontal-axis rotor with 12 blades and a dianeter Five meters. The tipspeet- ratio A (= tipepeed of the rotorblades divided by the windspeed, see 1it. 1) is two. The tower is a welded construction of angle-irons and at the top a pipe cf a", the tonerpipe. The tower has a height of eix meters, The tail uf the head construction carries a windvane ubieb turns the head around the towerpipe in order to keep the cuter perpendicular to the Hind. The safety system figure 1.1: the 12PUS00 ie half-autonatic. In case of “indnill a aavere storm it will unlock automatically tke hal groom the vail after which the head and rotor turne out of the wind. After the storm the rotor mst be 7 put perpendicular to the wind by hand. ‘The pump is a single-acting piston pump which consists of & Piston and two valves, one valve in the piston (pistcnvalve) and cne lower valve (footvalve), see it. 1. The pump has airchambers to smooth the flow and to reduce the shock forces in the pumprod. ‘The total weight of the windmill is 400 ky and the material coats in the tetherlands are about US$ 600 For wore information about the 12PUS90 ese Iit.2 and 3. 1,2 The evaluation of the 12P0500 windn!11 In 1886 the WOT evaluated the 12PUS09 with help of reports of T. Meyer, Rakish and Hajithia from India and J. Keuper from Indonesia and wich help of the experiences on the testfiald of the WOT. Especially the evaluaticn report of 155 installed 12PUSOO windmills Dy mr. Rakish is very detailed and accurate and therefore helpful. The conclusions of the evaluation (from mr. Rakish} ware: Feasibilicy studies are very important before starting to Antreduce windmills. - The quality of the fron profiles is often bad Sn developing countries. Pipes aren't circular, angle-irena aren't straight, the strength of the iren materials is small, ete. - The axis of the rotor ien't horizontal but a little bit sloping (70% of the windmills). - The blade supports (100% of the windmills) and the blade tips (308) are cracked, - There is too mich or to little play between the head and the towerpipe (70%). - Sometimes high windspeeds 1ift the head and rotor from the towerpipe - The safety system is wrong constructed or installed (80%), the teeth of the toothed handle wear out too auch. - The transmission: the crank is welded obliquely ‘the crankpin is bette obliquely te the crank the crank bearing and the crosshead bearing have too mich play ‘the wooden crosshead swalls because of rainwater and sticks Aozide the towerpipe ‘the crosshead wears out because the towerpipe 1s unround of has @ reugh inner wall ‘the crank is net renovable the crankholes are eccentric. - The pump: the airchambers leak often by leaking welds of washers ‘the washers dry up and scart to leak ‘the bronze bushes for gulding the pumprod wear out ‘the wooden piston swells in the water and sticks inside the punpoylinder the piston wears out too fast bud axial alignment of the pompeylinder and the 1 Other conclusions of the evaluation: ~ The tower is difficult to transport. ~ The tower is toe lew. - The pumprod pents and rubs against the rising main. + The safety system must be full-autonatic. That means that the rotor turns back in the wind after the storn. - Wylon for the bearings and sesame-wood for the eross-head is difficult to optatn. = The air escapes slowly out of the airchambers. when the airchamhers are full of water the shock forces in the pump rod increase much ~ The yaw bearing (nead-towerpipe) 1s tren on tron. 1t wears out when it has no Erequent lubrification. ~ The windmi1l ts too expensive for peor farners with less than 2,25 ha, land. There 1s nv intrest of the local people wnen there isn't sufficient guidance and participation 1.3 The raguirement list With help of the results of the evaluation a new List of requirements ip made: