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 them
b) In Clauses 3 and 4, corrections of the typographical errors
c) 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 5
e) 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 surface
f) 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 method
g) In Clauses 6 and 7, correction of typographical errors
h) In Clause 8 (former Clause 7), introduction of new figures for clarifying the “2 step” method and the alternative method
i)  In Annex A, modification of the flux diagram to be in compliance with IEC 60193
j)  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 machines
k) In Annex C, deletion of the clause which describes the direct step-up procedures for axial flow machines
l)  In Annex D:
–  notes become main text
–  change of variable names in Subclause D.1 for clarifications
m) Addition of Annex E, about comparison of IEC standards dealing with models: 60193 and 62097
n)  In Annex F, clarifications of equations by adding more subscripts
o)  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 obtained at optimum test conditions
p)  Simplification of structure, calculation of optimum and individual point, step up calculation with h_hAmax
Keywords: Hydraulic Machines, Radial And Axial Performance Transposition.