EN IEC 62097:2019

IEC 62097:2019 establishes the prototype hydraulic machine efficiency from model test results, with consideration of scale effect including the effect of surface roughness.This document is intended to be used for the assessment of the results of contractual model tests of hydraulic machines.This second edition cancels and replaces the first edition published in 2009. This edition constitutes an editorial and technical revision.This edition includes the following significant technical changes with respect to the previous edition:a) In introduction, clarifications have been brought such as addition of a sentence which declares the precedence of IEC 62097 over IEC 60193 if any mismatch is found between themb) In Clauses 3 and 4, corrections of the typographical errorsc) In Clause 3: changes to be in accordance with presentation of the terms and structure of IEC 60193 (except for the water temperature)d) In Clause 4:– Deletion of the clause providing the direct step-up procedures for a whole turbine– Introduction of a global view by using turbine A and turbine B instead of model turbine, reference model turbine and prototype turbine– Move of section dealing with “surface roughness of model and prototype” in a new Clause 5e) In Clause 5:– Introduction of additional chapters to answer comments raised at the CDV stage and to clarify the subject of surface roughness of model and prototype– Introduction of new tables for minimum recommended prototype roughness for new radial or diagonal machines and for new axial turbines– Addition of the explanation about roughness measurement of heavily rusted surfacef) In Clause 7 (former Clause 6):– Introduction of a new subclause for clarifications about the assumed maximum hydraulic efficiency, h_hAmax– Deletion of the requirement of mutual agreement for the application of the step-up formula for very high efficiency machines exceeding h_hAmax– Clarifications of the equations from 22 to 33 by doubling the equations for suiting the “two step methodg) In Clauses 6 and 7, correction of typographical errorsh) In Clause 8 (former Clause 7), introduction of new figures for clarifying the “2 step” method and the alternative methodi) In Annex A, modification of the flux diagram to be in compliance with IEC 60193j) In Annex B:– Correction of the equation to obtain Δ_ECO– Deletion of the clause which describes the direct step-up procedures for radial flow machinesk) In Annex C, deletion of the clause which describes the direct step-up procedures for axial flow machinesl) In Annex D:– notes become main text– change of variable names in Subclause D.1 for clarificationsm) Addition of Annex E, about comparison of IEC standards dealing with models: 60193 and 62097n) In Annex F, clarifications of equations by adding more subscriptso) The Excel sheets attached to the standard are revised as itemized below– Deletion of the routine regarding the direct step-up procedures for a whole turbine– Deletion of the notice which requires mutual agreement when the step-up is applied to high efficiency machines exceeding h_hAmax– Addition of the routine to process the normalization of test data ob