ASME PTC 6A
Appendix A To PTC 6, the Test Code for Steam Turbines
|Publication Date:||1 January 2000|
(a) This Appendix has been prepared to facilitate the calculation and correction of turbine test results by furnishing numerical examples of the procedures outlined in The Performance Test Code on Steam Turbines (PTC 6-1996). The feedwater heating cycles and gland leakoff systems have been simplified by avoiding unnecessarily long or repetitive calculations while still demonstrating the basic principles involved. Section 3 of this Appendix gives general guidance for making these calculations and comparisons to specified performance.
(b) Throughout this publication, the assumptions regarding turbine performance and the numerical values of corrections are hypothetical and should not be considered applicable to any particular unit.
(c) Except with written agreements to the contrary, the latest edition of the ASME Steam Tables, Thermodynamic and Transport Properties of Steam and its enthalpy-entropy diagram (Mollier chart), shall be used in the calculation of test results. When computers are used, they may link to compiled versions of the source code as supplied with the steam tables. As of January 1999 a new set of steam properties formulations, referred to as IAPWS IF-1997, became the international standard for calculations in the power industry. The IF-1997 formulations now supersede the IFC-1967 formulations that were used for the preceding three decades.
Steam turbine performance tests based on heat balances utilizing the IFC-1967 formulations, no matter when conducted, must still use the IFC-1967 formulations.
The numerical examples in this document are based on the use of the IFC-1967 formulations, as they merely demonstrate a computational procedure. In actual tests, the users must decide on the formulations appropriate for their circumstances.
(d) It is ASME policy that "all works, papers, and periodicals published by the Society shall require units to be in the International System (SI)." In response to that policy, all results are shown in both units, and a calculation example of a complete expansion condensing turbine is provided in U.S. Customary units (Section 6) and SI units (Section 6a).
(e) Performance Test Code 6 on Steam Turbines (PTC 6-1996) is the basic reference for this Appendix and will be termed "the Code" in further references herein. Reference should also be made to the ASME Performance Test Code Supplements on Instruments and Apparatus (PTC 19 Series) for guidance in the selection, installation, and use of instrumentation.
(f) The numerical calculations shown in Sections 6 through 13 in this Appendix have been computed in sufficient detail to illustrate the technique involved. In many instances, intermediate steps that lead to the final answer have been included using assumed guidelines for roundoff and number of significant figures. The reader is cautioned that the use of different guidelines or computational procedures may result in slightly different values but should have negligible effect on the results of a test.