Hydraulic turbines, storage pumps and pump-turbines – Model acceptance tests
|Publication Date:||1 April 2019|
|ICS Code (Hydraulic energy engineering):||27.140|
This document applies to laboratory models of any type of impulse or reaction hydraulic turbine, storage pump or pump-turbine.
This document applies to models of prototype machines either with unit power greater than 5 MW or with reference diameter greater than 3 m. Full application of the procedures herein prescribed is not generally justified for machines with smaller power and size. Nevertheless, this document may be used for such machines by agreement between the purchaser and the supplier.
In this document, the term "turbine" includes a pump-turbine operating as a turbine and the term "pump" includes a pump-turbine operating as a pump.
This document excludes all matters of purely commercial interest, except those inextricably bound up with the conduct of the tests.
This document is concerned with neither the structural details of the machines nor the mechanical properties of their components, so long as these do not affect model performance or the relationship between model and prototype performances.
This document covers the arrangements for model acceptance tests to be performed on hydraulic turbines, storage pumps and pump-turbines to determine if the main hydraulic performance contract guarantees (see 4.2) have been satisfied.
It contains the rules governing test conduct and prescribes measures to be taken if any phase of the tests is disputed.
The main objectives of this document are:
- to define the terms and quantities used;
- to specify methods of testing and of measuring the quantities involved, in order to ascertain the hydraulic performance of the model;
- to specify the methods of computation of results and of comparison with guarantees;
- to determine if the contract guarantees that fall within the scope of this document have been fulfilled;
- to define the extent, content and structure of the final report.
The guarantees can be given in one of the following ways:
- guarantees for prototype hydraulic performance, computed from model test results considering scale effects;
- guarantees for model hydraulic performance.
Moreover, additional performance data (see 4.4) can be needed for the design or the operation of the prototype of the hydraulic machine. Contrary to the requirements of Clauses 4 to 6 related to main hydraulic performance, the information of these additional data given in Clause 7 is considered only as recommendation or guidance to the user (see 7.1).
It is particularly recommended that model acceptance tests be performed if the expected field conditions for acceptance tests (see IEC 60041:1991) would not allow the verification of guarantees given for the prototype machine.
A transposition method taking into account the model and prototype wall surface roughness for the performance conversion on pump-turbines, Francis turbines, and axial machines is described in IEC 62097. This method requires model and prototype surface roughness data and is takes into account the shift in nED, QED and PED factors for determining the transposition of efficiency between model and prototype. However, in the case of Francis machines with semi-spiral casing and axial machines, the transposition method has not been fully validated due to a lack of data. In addition, IEC 62097 does not apply to storage pumps, Pelton turbines, and Dériaz. Therefore, for these and otherwise specifically agreed upon cases where hydraulically smooth flow conditions are assumed on the model and the prototype, the transposition formula and procedure given in Annex D and Annex I can be applied. Applications and limitations of both this document and IEC 62097 transposition methods are discussed in Annex E.
The method for performance conversion from model to prototype needs to be clearly defined in the main hydraulic performance contract.
This document may also be applied to model tests for other purposes, i.e. comparative tests and research and development work.
If model acceptance tests have been performed, field tests can be limited to index tests (see IEC 60041:1991).
If a contradiction is found between this document and any other document, this document prevails.