SIST EN 62364:2014
(Main)Hydraulic machines - Guide for dealing with hydro-abrasive erosion in Kaplan, Francis and Pelton turbines
Hydraulic machines - Guide for dealing with hydro-abrasive erosion in Kaplan, Francis and Pelton turbines
This Guide serves to:
a) present data on particle abrasion rates on several combinations of water quality, operating conditions, component materials, and component properties collected from a variety of hydro sites;
b) develop guidelines for the methods of minimizing particle abrasion by modifications to hydraulic design for clean water. These guidelines do not include details such as hydraulic profile shapes which should be determined by the hydraulic design experts for a given site;
c) develop guidelines based on “experience data” concerning the relative resistance of materials faced with particle abrasion problems;
d) develop guidelines concerning the maintainability of abrasion resistant materials and hard facing coatings;
e) develop guidelines on a recommended approach, which owners could and should take to ensure that specifications communicate the need for particular attention to this aspect of hydraulic design at their sites without establishing criteria which cannot be satisfied because the means are beyond the control of the manufacturers;
f) develop guidelines concerning operation mode of the hydro turbines in water with particle materials to increase the operation life; It is assumed in this Guide that the water is not chemically aggressive. Since chemical
aggressiveness is dependent upon so many possible chemical compositions, and the materials of the machine, it is beyond the scope of this Guide to address these issues. It is assumed in this Guide that cavitation is not present in the turbine. Cavitation and abrasion may reinforce each other so that the resulting erosion is larger than the sum of cavitation erosion plus abrasion erosion. The quantitative relationship of the resulting
abrasion is not known and it is beyond the scope of this guide to assess it, except to recommend that special efforts be made in the turbine design phase to minimize cavitation. Large solids (e.g. stones, wood, ice, metal objects, etc.) traveling with the water may impact turbine components and produce damage. This damage may in turn increase the flow turbulence thereby accelerating wear by both cavitation and abrasion. Abrasion resistant coatings can also be damaged locally by impact of large solids. It is beyond the scope of this Guide to address these issues. This guide focuses mainly on hydroelectric powerplant equipment. Certain portions may also be applicable to other hydraulic machines.
Wasserturbinen - Leitfaden für den Umgang mit hydroabrasiver Erosion in Kaplan-, Francis und Pelton-Turbinen
/
La CEI 62364:2013 est destinée à présenter les données disponibles concernant les taux d'abrasion par particules avec diverses combinaisons de qualité de l'eau, conditions d'exploitation, matériaux et propriétés des composantes; ces données ayant été obtenues sur différents sites hydroélectriques; développer des lignes directrices applicables aux méthodes de réduction au minimum de l'abrasion par particules par des modifications de la conception hydraulique utilisée en l'absence de particules. Ces lignes directrices n'abordent pas les détails tels que - les profils hydrauliques que les spécialistes en conception hydraulique déterminent pour un site donné; - développer des lignes directrices établies sur le 'retour d'expérience' concernant la résistance relative de matériaux confrontés aux problèmes d'abrasion par les particules; - développer des lignes directrices concernant la maintenabilité des matériaux résistant à l'abrasion et des revêtements de surface durs; - développer des lignes directrices relatives à la recommandation d'une méthode, que les propriétaires pourraient appliquer, et dont il convient qu'ils l'appliquent effectivement, afin de s'assurer que leurs spécifications montrent la nécessité d'accorder une attention toute particulière à la conception des formes hydrauliques propres à leur site sans imposer des critères qui ne peuvent être satisfaits dans la mesure où les moyens à mettre en oeuvre ne sont pas maitrisables par les constructeurs; - développer des lignes directrices concernant le mode de fonctionnement des turbines hydroélectriques en présence de particules afin d'accroître la durée de vie. Ce guide fait l'hypothèse d'une eau chimiquement non agressive; étant donné que cette agressivité dépend des diverses compositions chimiques possibles, ainsi que des matériaux constitutifs de la machine, le domaine d'application de ce Guide ne traite pas de cette question. Ce guide fait également l'hypothèse de l'absence de cavitation au niveau de la turbine. En effet la cavitation et l'abrasion peuvent se renforcer mutuellement de sorte que l'érosion résultante est plus importante que la somme des deux. Comme aucune formulation quantitative de cette abrasion résultante n'est connue, ce guide n'a pas pour objet de l'évaluer, sauf pour recommander, lors de la phase de conception de la turbine, des efforts particuliers visant à minimiser la cavitation. Des solides de grand volume (comme des pierres, du bois, de la glace, des objets métalliques, etc.) véhiculés par l'eau peuvent percuter les composantes de la turbine et les endommager. Ces dommages peuvent pour leur part accroître la turbulence de l'écoulement et accélérer l'usure par cavitation et par abrasion. Les revêtements durs résistant à l'abrasion peuvent également être endommagés localement suite à l'impact de ces solides de grand volume. Ce guide ne traite pas de ces questions. Mots-clés: hydraulique, turbines, érosion hydro-abrasive
Hidravlični stroji - Navodilo za obravnavanje hidroabrazivne erozije pri Kaplanovih, Francisovih in Peltonovih turbinah
To navodilo je namenjeno:
a) predstavitvi podatkov o hitrosti abrazije delcev pri več kombinacijah kakovosti vode, pogojev obratovanja, materialov sestavnih delov in lastnosti sestavnih delov, zbranih na različnih vodnih lokacijah;
b) pripravi smernic za metode za zmanjšanje abrazije delcev s spremembami hidravlične zasnove za čisto vodo. Te smernice ne vključujejo podrobnosti, kot so oblike hidravličnega profila, ki naj bi jih določili strokovnjaki za hidravlično zasnovo za določeno lokacijo;
c) pripravi smernic na podlagi »podatkov iz izkušenj« v zvezi z relativnim uporom materialov, ki imajo težave z abrazijo delcev;
d) pripravi smernic v zvezi z sposobnostjo vzdrževanja materialov, odpornih na abrazijo, in trdih prevlek;
e) pripravi smernic za priporočen pristop, ki bi ga lahko lastniki uporabili in naj bi ga uporabili za zagotavljanje, da specifikacije izražajo potrebo po namenjanju posebne pozornosti temu vidiku hidravlične zasnove na njihovih lokacijah brez določitve meril, ki jih ni mogoče izpolniti, ker so načini za njihovo izpolnitev zunaj nadzora proizvajalcev;
f) pripravi smernic v zvezi z načinom delovanja hidroturbin v vodi z materiali delcev za podaljšanje dobe delovanja. V tem navodilu se predvideva, da voda ni kemično agresivna. Ker je kemična agresivnost odvisna od številnih možnih kemičnih sestav in materialov stroja, obravnavanje teh vprašanj ne spada na področje uporabe tega navodila. V tem navodilu se predvideva, da kavitacija v turbini ni prisotna. Kavitacija in abrazija se lahko medsebojno krepita, zaradi česar je posledična erozija večja od vsote kavitacijske erozije in abrazijske erozije. Količinska zveza posledične abrazije ni znana, pri čemer njena ocena presega področje uporabe tega navodila, razen za priporočilo, da se v fazi načrtovanja turbine posebna pozornost nameni čim večjemu zmanjšanju kavitacije. Večji trdni deli (npr. kamni, les, led, kovinski predmeti itd.), ki potujejo z vodo, lahko vplivajo na sestavne dele turbine in povzročijo škodo. Ta škoda lahko posledično poveča turbulenco toka ter tako pospeši obrabo zaradi kavitacije in abrazije. Prevleke, odporne na abrazijo, se lahko poškodujejo tudi lokalno zaradi udara večjih trdnih delov. Obravnavanje teh vprašanj presega področje uporabe tega navodila. To navodilo se osredotoča zlasti na opremo hidroelektrarn. Nekateri deli se lahko uporabljajo tudi za druge hidravlične stroje.
General Information
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Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Wasserturbinen - Leitfaden für den Umgang mit hydroabrasiver Erosion in Kaplan-, Francis und Pelton-Turbinen/Hydraulic machines - Guide for dealing with hydro-abrasive erosion in Kaplan, Francis and Pelton turbines23.100.01Fluid power systems in generalICS:Ta slovenski standard je istoveten z:EN 62364:2013SIST EN 62364:2014en01-januar-2014SIST EN 62364:2014SLOVENSKI
STANDARD
EUROPEAN STANDARD EN 62364 NORME EUROPÉENNE
EUROPÄISCHE NORM August 2013
CENELEC European Committee for Electrotechnical Standardization Comité Européen de Normalisation Electrotechnique Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Avenue Marnix 17, B - 1000 Brussels
© 2013 CENELEC -
All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 62364:2013 E
ICS 23.100.10; 27.140
English version
Hydraulic machines -
Guide for dealing with hydro-abrasive erosion in Kaplan,
Francis, and Pelton turbines (IEC 62364:2013)
Machines hydrauliques -
Guide relatif au traitement de l'érosion hydro-abrasive des turbines Kaplan, Francis et Pelton (CEI 62364:2013)
Wasserturbinen -
Leitfaden für den Umgang mit hydroabrasiver Erosion in Kaplan-, Francis- und Pelton-Turbinen (IEC 62364:2013)
This European Standard was approved by CENELEC on 2013-08-01. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
EN 62364:2013 - 2 -
Foreword The text of document 4/279/FDIS, future edition 1 of IEC 62364, prepared by IEC TC 4 "Hydraulic turbines" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as EN 62364:2013. The following dates are fixed: – latest date by which the document has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2014-05-01 – latest date by which the national standards conflicting with the document have to be withdrawn (dow) 2016-08-01
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such patent rights. Endorsement notice The text of the International Standard IEC 62364:2013 was approved by CENELEC as a European Standard without any modification. In the official version, for Bibliography, the following note has to be added for the standard indicated : IEC 60193:1999 NOTE Harmonised as EN 60193:1999 (not modified).
IEC 62364 Edition 1.0 2013-06 INTERNATIONAL STANDARD NORME INTERNATIONALE Hydraulic machines – Guide for dealing with hydro-abrasive erosion in Kaplan, Francis, and Pelton turbines
Machines hydrauliques – Guide relatif au traitement de l'érosion hydro-abrasive des turbines Kaplan, Francis et Pelton
INTERNATIONAL ELECTROTECHNICAL COMMISSION COMMISSION ELECTROTECHNIQUE INTERNATIONALE XC ICS 23.100.10; 27.140 PRICE CODE CODE PRIX ISBN 978-2-83220-829-8
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– 2 – 62364 © IEC:2013 CONTENTS FOREWORD . 5 INTRODUCTION . 7 1 Scope . 8 2 Terms, definitions and symbols . 8
Units . 8 2.1 Terms, definitions and symbols . 9 2.23 Abrasion rate . 11
Theoretical model . 11 3.1 Introduction to the PL variable . 13 3.2 Survey results . 15 3.3 Reference model . 16 3.44 Design . 17
General . 17 4.1 Water conveyance system . 17 4.2 Valve . 18 4.3 General . 18 4.3.1 Selection of abrasion resistant materials and coating . 18 4.3.2 Stainless steel overlays . 19 4.3.3 Protection (closing) of the gap between housing and trunnion . 19 4.3.4 Stops located outside the valve . 19 4.3.5 Proper capacity of inlet valve operator . 19 4.3.6 Increase bypass size to allow higher guide vane leakage . 19 4.3.7 Bypass system design . 20 4.3.8 Turbine . 20 4.4 General . 20 4.4.1 Hydraulic design . 20 4.4.2 Mechanical design . 22 4.4.3 Operation . 28 4.4.4 Spares and regular inspections . 29 4.4.5 Particle sampling and monitoring . 29 4.4.65 Abrasion resistant materials . 30
Guidelines concerning relative abrasion resistance of materials including 5.1abrasion resistant coatings . 30
General . 30 5.1.1 Discussion and conclusions . 31 5.1.2 Guidelines concerning maintainability of abrasion resistant coating materials . 32 5.2 Definition of terms used in this sublcause . 32 5.2.1 Time between overhaul for protective coatings . 32 5.2.2 Maintenance of protective coatings . 33 5.2.36 Guidelines on insertions into specifications . 34
General . 34 6.1 Properties of particles going through the turbine. 35 6.2 Size distribution of particles . 35 6.3 Mineral composition of particles for each of the above mentioned periods . 36 6.4Annex A (informative)
PL calculation example . 37 Annex B (informative)
Measuring and recording abrasion damages . 39
62364 © IEC:2013 – 3 – Annex C (informative)
Water sampling procedure . 52 Annex D (informative)
Procedures for analysis of particle concentration, size, hardness and shape . 53 Annex E (informative)
Tests of abrasion resistant materials . 56 Annex F (informative)
Typical criteria to determine overhaul time due to abrasion erosion . 67 Annex G (informative)
Example to calculate the amount of erosion in the full model . 68 Annex H (informative)
Examples to calculate the TBO in the reference model . 70 Bibliography . 73
Figure 1 – Estimation of the characteristic velocities in guide vanes, Wgv, and runner, Wrun, as a function of turbine specific speed . 13 Figure 2 – Example of flow pattern in a Pelton injector at different load . 14 Figure 3 – Example of protection of transition area . 19 Figure 4 – Runner blade overhang in refurbishment project . 21 Figure 5 – Example of “mouse-ear” cavitation on runner band . 22 Figure 6 – Detailed design of guide vane trunnion seals . 23 Figure 7 – Example of fixing of facing plates from the dry side . 25 Figure 8 – Head cover balancing pipes with bends . 26 Figure 9 – Step labyrinth with optimized shape for hard coating . 28 Figure 10 – Development of spiral pressure over time . 33 Figure D.1 – Typical examples of particle geometry . 55 Figure E.1 – Schematic of test rig used for test 1 . 56 Figure E.2 – ASTM test apparatus . 58 Figure E.3 – Test coupon . 59 Figure E.4 – Slurry pot test facility . 60 Figure E.5 – High velocity test rig . 61 Figure E.6 – Samples are located on the rotating disk . 62 Figure E.7 – Comparison of two samples after testing . 62 Figure E.8 – Whole test system of rotating disk . 62 Figure E.9 – Schematic of test rig used for test 8 . 64 Figure E.10 – Testing of samples on hydro abrasive stand . 65 Figure E.11 – Cover of disc . 65 Figure E.12 – Curve of unit abrasion rate with circumference velocity for 3 kinds of materials . 66
Table 1 – Data analysis of the supplied questionnaire . 16 Table 2 – Overview over the feasibility for repair C . 33 Table 3 – Form for properties of particles going through the turbine . 35 Table 4 – Form for size distribution of particles . 36 Table 5 – Form for mineral composition of particles for each of the above mentioned periods . 36 Table A.1 – Example of documenting sample tests . 37 Table A.2 – Example of documenting sample results . 38 Table B.1 – Inspection record, runner blade inlet form . 44
– 4 – 62364 © IEC:2013 Table B.2 – Inspection record, runner blade outlet form . 45 Table B.3 – Inspection record, runner band form. 46 Table B.4 – Inspection record, guide vanes form. 47 Table B.5 – Inspection record, facing plates and covers form . 48 Table B.6 – Inspection record, upper stationary seal form . 49 Table B.7 – Inspection record, upper rotating seal form . 49 Table B.8 – Inspection record, lower stationary seal form . 50 Table B.9 – Inspection record, lower rotating seal form . 51 Table E.1 – Relative wear resistance in laboratory test 1 . 57 Table E.2 – Relative wear resistance in laboratory test 2 . 57 Table E.3 – Relative wear resistance in laboratory test 3 . 58 Table E.4 – Relative wear resistance in test 4 . 59 Table E.5 – Results of test . 60 Table E.6 – Results of test . 61 Table E.7 – Results from test . 63 Table E.8 – Relative wear resistance in laboratory test 8 . 64 Table E.9 – Results of relative wear resistance for some materials (U = 40m/s) . 66 Table G.1 – Calculations . 69 Table H.1 – Pelton turbine calculation example . 70 Table H.2 – Francis turbine calculation example . 71
62364 © IEC:2013 – 5 – INTERNATIONAL ELECTROTECHNICAL COMMISSION ____________
HYDRAULIC MACHINES –
GUIDE FOR DEALING WITH HYDRO-ABRASIVE EROSION
IN KAPLAN, FRANCIS, AND PELTON TURBINES
FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with may participate in this preparatory work. International, governmental and non-governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for Standardization (ISO) in accordance with conditions determined by agreement between the two organizations. 2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international consensus of opinion on the relevant subjects since each technical committee has representation from all interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any misinterpretation by any end user. 4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications transparently to the maximum extent possible in their national and regional publications. Any divergence between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter. 5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any services carried out by independent certification bodies. 6) All users should ensure that they have the latest edition of this publication. 7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and members of its technical committees and IEC National Committees for any personal injury, property damage or other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is indispensable for the correct application of this publication. 9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent rights. IEC shall not be held responsible for identifying any or all such patent rights. International Standard IEC 62364 has been prepared by IEC technical committee 4: Hydraulic turbines. The text of this standard is based on the following documents: FDIS Report on voting 4/279/FDIS 4/283/RVD
Full information on the voting for the approval of this standard can be found in the report on voting indicated in the above table. This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
– 6 – 62364 © IEC:2013 The committee has decided that the contents of this publication will remain unchanged until the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data related to the specific publication. At this date, the publication will be
• reconfirmed, • withdrawn, • replaced by a revised edition, or • amended.
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62364 © IEC:2013 – 7 – INTRODUCTION Many owners of hydroelectric plants contend with the sometimes very aggressive deterioration of their machines due to particle abrasion. Such owners must find the means to communicate to potential suppliers of machines for their sites, their desire to have the particular attention of the designers at the turbine design phase, directed to the minimization of the severity and effects of particle abrasion.
Limited consensus and very little quantitative data exists on the steps which the designer could and should take to extend the useful life before major overhaul of the turbine components when they are operated under severe particle abrasion service. This has led some owners to write into their specifications, conditions which cannot be met with known methods and materials.
– 8 – 62364 © IEC:2013 HYDRAULIC MACHINES –
GUIDE FOR DEALING WITH HYDRO-ABRASIVE EROSION
IN KAPLAN, FRANCIS, AND PELTON TURBINES
1 Scope This Guide serves to: a) present data on particle abrasion rates on several combinations of water quality, operating conditions, component materials, and component properties collected from a variety of hydro sites; b) develop guidelines for the methods of minimizing particle abrasion by modifications to hydraulic design for clean water. These guidelines do not include details such as hydraulic profile shapes which should be determined by the hydraulic design experts for a given site; c) develop guidelines based on “experience data” concerning the relative resistance of materials faced with particle abrasion problems; d) develop guidelines concerning the maintainability of abrasion resistant materials and hard facing coatings; e) develop guidelines on a recommended approach, which owners could and should take to ensure that specifications communicate the need for particular attention to this aspect of hydraulic design at their sites without establishing criteria which cannot be satisfied because the means are beyond the control of the manufacturers; f) develop guidelines concerning operation mode of the hydro turbines in water with particle materials to increase the operation life; It is assumed in this Guide that the water is not chemically aggressive. Since chemical aggressiveness is dependent upon so many possible chemical compositions, and the materials of the machine, it is beyond the scope of this Guide to address these issues.
It is assumed in this Guide that cavitation is not present in the turbine. Cavitation and abrasion may reinforce each other so that the resulting erosion is larger than the sum of cavitation erosion plus abrasion erosion. The quantitative relationship of the resulting abrasion is not known and it is beyond the scope of this guide to assess it, except to recommend that special efforts be made in the turbine design phase to minimize cavitation. Large solids (e.g. stones, wood, ice, metal objects, etc.) traveling with the water may impact turbine components and produce damage. This damage may in turn increase the flow turbulence thereby accelerating wear by both cavitation and abrasion. Abrasion resistant coatings can also be damaged locally by impact of large solids. It is beyond the scope of this Guide to address these issues. This guide focuses mainly on hydroelectric powerplant equipment. Certain portions may also be applicable to other hydraulic machines. 2 Terms, definitions and symbols
Units
2.1The International System of Units (S.I.) is adopted throughout this guide but other systems are allowed.
62364 © IEC:2013 – 9 –
Terms, definitions and symbols
2.2For the purposes of this document, the following terms, definitions and symbols apply. NOTE They are also based, where relevant, on IEC/TR 61364. Sub-clause Term Definition Symbol Unit 2.2.1 specific hydraulic energy of a machine specific energy of water available between the high and low pressure reference sections 1 and 2 of the machine Note 1 to entry: For full information, see IEC 60193. E J/kg 2.2.2 acceleration due to gravity
local value of gravitational acceleration at the place of testing Note 1 to entry: For full information, see IEC 60193.
g m/s2 2.2.3 turbine head
pump head available head at hydraulic machine terminal
H = E/g H m 2.2.4 reference diameter reference diameter of the hydraulic machine Note 1 to entry: For Pelton turbines this is the pitch diameter, for Kaplan turbines this is the runner chamber diameter and for Francis and Francis type pump turbines this is the blade low pressure section diameter at the band Note 2 to entry: See IEC 60193 for further information. D m 2.2.5 abrasion depth depth of metal layer that has been removed from a component due to particle abrasion S mm 2.2.6 characteristic velocity characteristic velocity defined for each machine component and used to quantify particle abrasion damage Note 1 to entry: See also 2.2.20 to 2.2.24. W m/s 2.2.7 particle concentration the mass of all solid particles per m3 of water solution Note 1 to entry: In case the particle concentration is expressed in ppm it is recommended to use the mass of particles per mass of water, so that 1 000 ppm approximately corresponds to 1 kg/m3. C kg/m3 2.2.8 particle load the particle concentration integrated over the time, T, that is under consideration
∫×××=TdttKtKtKtCPL0hardnessshapesize)()()()( ××××≈∑=NnnsnnnnTKKKC1hardnessshapesize,,,, C(t) = 0 if no water is flowing through the turbine. If the unit is at standstill with pressurized spiral case then C(t)=0 when calculating PL for runner and labyrinth seals, but C(t)≠0 when calculating PL for guide vanes and facing plates. PL kg × h/m3 2.2.9 size factor factor that characterizes how the abrasion relates to the size of the abrasive particles Ksize
2.2.10 shape factor factor that characterizes how the abrasion relates to the shape of the abrasive particles Kshape
2.2.11 hardness factor factor that characterizes how the abrasion relates to the hardness of the abrasive particles Khardness
– 10 – 62364 © IEC:2013 Sub-clause Term Definition Symbol Unit 2.2.12 material factor factor that characterizes how the abrasion relates to the material properties of the base material Km
2.2.13 flow coefficient coefficient that characterizes how the abrasion relates to the water flow around each component Kf mm × s3,4 kg × h × m. 2.2.14 sampling interval the time interval between two water samples taken to determine the concentration of abrasive particles in the water Ts h 2.2.15 yearly particle load the total PL for 1 year of operation, i.e. PL for T = 8 760 h calculated in accordance with 2.2.8 PLyear kg × h/m3 2.2.16 maximum concentration the maximum concentration of abrasive particles over a specified time interval Cmax kg/m3 2.2.17 particle median diameter the median diameter of abrasive particles in a sample, i.e. such diameter that the particles with size smaller than the value under consideration represent 50 % of the total mass of particles in the sample dP50 mm 2.2.18 wear resistance index abrasion depth or volume of a reference material (generally some version stainless steel) divided by the abrasion depth or volume of the material in question, tested under the same conditions WRI - 2.2.19 impingement angle the angle between the particle trajectory and the surface of the substrate
o 2.2.20 characteristic velocity in Francis guide vanes
characteristic velocity in Kaplan guide vanes flow through unit divided by the minimum flow area at the guide vane apparatus estimated at best efficiency point
00gvBZaQW××=
Wgv
m/s 2.2.21 characteristic velocity in guide vanes of Kaplan, Francis or tubular turbines speed of the water flow at guide vane location
EW××=250gv,
Wgv
m/s 2.2.22 characteristic velocity in Pelton injector speed of the water flow at injector location
EW×=2inj
Winj
m/s 2.2.23 characteristic velocity in Kaplan or Francis tubular turbine runner the relative velocity between the water and the runner blade estimated with below formulas at best efficiency point
2222222run4DQcDnucuW××=××=+=ππ Note 1 to entry: In calculation of c2 for Kaplan turbines, the hub diameter has been neglected in the interest of simplicity. Wrun m/s 2.2.24 characteristic velocity in Pelton runner speed of the water flow at a Pelton runner
EW××=250run,
Wrun
m/s 2.2.25 discharge (volume flow rate) volume of water per unit time passing through any section in the system Q m3/s 2.2.26 guide vane opening average shortest distance between adjacent guide vanes
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