ANSI ASME PTC 6A-2000 Appendix A To PTC 6 the Test Code for Steam Turbines.pdf

1、 Intentionally left blank Date of Issuance: July 2, 2001 This document will be revised when the Society approves the issuance of the next edition. There will be no Addenda issued to ASME PTC 6A-2000. Please note: ASME issues written replies to inquiries concerning interpretation of technical aspects

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8、 electronic retrieval system or otherwise, without the prior written permission of the publisher. The American Society of Mechanical Engineers Three Park Avenue, New York, NY 10016-5990 Copyright 2001 by THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS All Rights Reserved Printed in U.S.A. FOREWORD ASME

9、 Performance Test Code 6 on Steam Turbines (PTC 6-1996) states that numerical examples of corrections to test performance for the effect of deviations of operating condi- tions from those specified are given in a separate publication of the PTC 6 Committee. This Appendix, PTC 6A, Sample Calculations

10、, fulfills the Committees obligation as stated in the Code. The 1996 version of the Steam Turbines (PTC 6) incorporates the Interim Test Code for an Alternative Procedure for Testing Steam Turbines (PTC 6.1-1984) with the 1976 version of the Test Code. This Appendix provides sample calculations usin

11、g both methods for a reheat regenerative cycle turbine. In addition, sample calculations have been added for a non-reheat regenerative cycle turbine, an automatic extraction condensing cycle turbine, a refurbished low pressure turbine, and determination of the coefficient of discharge of a throat-ta

12、p nozzle. Instrumentation listed has been updated to reflect those currently used. This newly revised Appendix to the Test Code, now named Appendix A to Test Code for Steam Turbines, PTC 6A-2000, was approved by the Board on Performance Test Codes on July 14, 2000. It was approved as an American Nat

13、ional Standard by the Board of Standards Review on November 17, 2000. All ASME codes are copyrighted, with all rights reserved to the Society. Reproduction of this or any other ASME code is a violation of Federal Law. Legalities aside, the user should appreciate that the publishing of the high-quali

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17、x 2300, Fairfield, New Jersey 07007-2300, and ASME will expedite delivery of such copies to you by return mail. Please instruct your people to buy required test codes rather than copy them. Your cooperation in this matter is greatly appreciated. Intentionally left blank NOTICE All Performance Test C

18、odes MUST adhere to the requirements of PTC 1, GENERAL INSTRUCTIONS. The following information is based on that document and is included here for emphasis and for the convenience of the user of this Code. It is expected that the Code user is fully cognizant of Parts I and III of PTC 1 and has read t

19、hem prior to applying this Code. ASME Performance Test Codes provide test procedures which yield results of the highest level of accuracy consistent with the best engineering knowledge and practice currently available. They were developed by balanced committees representing all concerned interests.

20、They specify procedures, instrumentation, equipment operating requirements, calculation methods, and uncertainty analysis. When tests are run in accordance with this Code, the test results themselves, without adjustment for uncertainty, yield the best available indication of the actual performance o

21、f the tested equipment. ASME Performance Test Codes do not specify means to compare those results to contractual guarantees. Therefore, it is recommended that the parties to a commercial test agree before starting the test and preferably before signing the contract on the method to be used for compa

22、ring the test results to the contractual guarantees. It is beyond the scope of any code to determine or interpret how such comparisons shall be made. Intentionally left blank PERSONNEL OF PERFORMANCE TEST CODE COMMITTEE NO. 6 ON STEAM TURBINES (The following is the roster of the Committee at the tim

23、e of approval of this Appendix.) OFFICERS Bezalel Bornstein, Chair Edwin J. Brailey, Jr., Vice Chair Jack H. Karian, Secretary COMMITTEE PERSONNEL Paul G. Albert, General Electric Co. John A. Booth, General Electric Co. (retired) Bezalel Bornstein, Consultant Edwin J. Brailey, Jr., Stowe Engineering

24、 Corp. Thomas M. Brown, Ontario Power Generation Norman R. Deming, Westinghouse Electric Corp. (retired) Arturo J. Egli, ABB Alstom Power Generation Alfonso . Fajardo, Jr., Siemens Power Group Christopher J. Haynes, New England Power Co. Dale C. Karg, Santee Cooper Jack H. Karian, American Society o

25、f Mechanical Engineers Charles H. Kostors, Elliott Turbomachinery Co., Inc., Ebara Group Joseph S. Lamberson, Dresser-Rand Co. Randall W. Moll, Alternate, Dresser-Rand Co. James B. Nystrom, Alden Research Laboratory Surinder S. Sandhu, Consultant Charles Bo Scharp, Baltimore Gas and Electric Co. (re

26、tired) Kevin Stone, Alternate, General Electric Company Einar J. Sundstrom, Dow Chemical USA (retired) Leif Svenson, Alternate, Santee Cooper Jason A. Zoller, Black ewaer.u. onensae s (a) Turbines Operating Predominantly in the Superheated Steam Region Steam / 1 generator / / / I Feedwater heating 1

27、0/ Feedwater pump _ separator 8 / COndensate heating / Condensate pump 6 /7 s b) Turbines Operating Predominantly in the Wet-Steam Region Without Reheat Steam / generator /- tars 10/ Feedwater heating 9 / _l F(;edwater pump MsO S; rra o r 8 / / I Condensate heating - / t Condensate pump /7 6 s (c) T

28、urbines Operating Predominantly in the Wet-Steam Region With Reheat FIG. 2.1 TEMPERATURE-ENTROPY DIAGRAMS APPENDIX A TO PTC 6, THE TEST CODE FOR STEAM TURBINES ASME PTC 6A-2000 2.4 DEFINITIONS Term Definition Units U.S. Customary Steam rate Heat rate Valve-loop curve Mean of the valve loops Valves w

29、ide open (VWO) Valve points Locus curve Power Steam consumption per hour per unit output in which the turbine is charged with the steam quantity supplied. Heat consumption per hour per unit output. The turbine is charged with the aggregate enthalpy Note (2) of the steam supplied plus any chargeable

30、aggregate enthalpy added by the reheaters. It is credited with the aggregate enthalpy of feedwater returned from the cycle to the steam generator. Turbine-generator performance may be defined on the basis of the gross power output at the generator terminals less the power used by the minimum electri

31、cally driven turbine auxiliaries and excitation equipment, supplied as part of the turbine-generator unit, required for reliable and continuous operation. The continuous curve of actual heat rate for all values of output over the operating range of the unit. For partial admission turbines, a smooth

32、curve which gives the same load-weighted average performance as the valve-loop curve. Maximum control valve opening obtainable under nor- mal turbine control system operation. Valve positions that correspond to the low points of the valve-loop curve. The continuous curve connecting the valve points.

33、 The useful energy, per unit of time, delivered by the turbine or turbine-generator unit. Ibm/kWhr Ibm/hp-hr Btu/kWhr Btu/hp-hr hp-hr/hr or kWhr/hr kg/kJ kg/kWh Note (1) kg/kJ kg/kWh Note (1) kJ/kWh Note (1) J/J kJ/kWh Note (1) kWh/hr NOTES: (1) These are tolerated non-SI units. (2) Aggregate enthal

34、py: Product of enthalpy, Btu/Ibm(kJ/kg) and flow rate, Ibm/hr(kg/h); Btu/hr(kJ/h). ASME PTC 6A-2000 APPENDIX A TO PTC 6, THE TEST CODE FOR STEAM TURBINES 2.5 SI UNITS CONVERSION TABLE Quantity SI Units Conversion Factor Heat rate J/J 2.9307 x 10 -4 x (Btu/kWhr) kJ/kWh Note (1) 1.05506 x (Btu/kWhr) S

35、team rate kg/kJ 1.260 x 10 -4 x (Ibm/kWhr) kg/kWh Note (1) 0.4536 x (Ibm/kWhr) Mass flow rate kg/s 1.260 x 10 -4 X (Ibm/hr) Pressure kPa 6.8948 x (psi) bar Note (1) 0.068948 x (psi) Temperature K (F + 459.67)/I.8 C Note (1) (F - 32)/I.8 Differential temperature K F/1.8 Density kg/m 3 16.018 x (Ibm/f

36、t 3) Enthalpy kJ/kg 2.3260 x (Btu/Ibm) Entropy kJ/(kgK) 4.1868 x (Btu/IbmR) Specific heat kJ/(kgK) 4.1868 x (Btu/IbmR) Length m 0.3048 x (ft) Area m 2 0.092903 x (ft 2) Volume m 3 0.028317 x (ft ) Velocity m/s 0.3048 x (ft/sec) GENERAL NOTE: For temperature differentials “K“ must be used. NOTE: (1)

37、This value is a tolerated non-SI unit. APPENDIX A TO PTC 6, THE TEST CODE FOR STEAM TURBINES ASME PTC 6A-2000 SECTION 3 GUIDANCE FOR A TEST RESULTS COMPARISON OF 3.1 INTRODUCTION Section 5 of the Code contains a general descrip- tion of the computation of test performance for the various types of tu

38、rbines. It recognizes the necessity to correct test performance for the effect of deviations from specified operating conditions so the as-tested turbine performance can be compared to the design or specified turbine performance on the basis of equivalent cycle and steam conditions. Reference to thi

39、s Appendix for numerical examples of the corrections involved is made in para. 5.1 of the Code. The purpose of this Section is to provide a better understanding of the numerical examples by describ- ing how the corrections to test results are made. 3.2 CORRECTION OF THE TEST RESULTS TO SPECIFIED CON

40、DITIONS This procedure corrects the test performance for the influence of off-design steam and cycle condi- tions so that the test turbine performance can be compared to the specified turbine performance on the basis of an equivalent cycle. The calculated test performance is recalculated, substituti

41、ng specified steam and cycle conditions for test steam and cycle conditions while maintaining test turbine efficiency. The corrected test cycle is now comparable with the specified cycle. The specified performance remains unchanged, which is particularly appropriate when the specified performance is

42、 associated with a turbine performance guarantee. Some of the steam and cycle conditions that are apt to differ from specified values during a test of a fossil-fueled unit, despite efforts to influence the controllable ones, are as follows: (a) Controllable Items (1) Pressure of steam supplied to th

43、e turbine (2) Temperature of steam supplied to the turbine (3) Temperature of reheated steam returned to the turbine (4) Low pressure turbine exhaust pressure (un- controllable if higher than the specified value) (5) Make-up feedwater flow rate (b) Uncontrollable Items (1) Pressure drop of steam thr

44、ough the reheater system(s) (2) Reheater desuperheating water flow rates (3) Superheater desuperheating water flow rate, of no concern if taken downstream from the top heater (4) Steam flow rate for some auxiliary uses (5) Extraction line pressure drops and heat losses (6) Feedwater heater terminal

45、temperature differ- ences (7) Feedwater heater drain-cooler-approach dif- ferences (8) Feedwater enthalpy rise through condensate and feedwater pumps (9) Cycle losses (usually assumed to be zero in design) (10) Additional uncontrollable items for units operating predominantly in the moisture region

46、are (a) Moisture content (percent) of the steam supplied to the turbine (b) Temperature of the reheated steam re- turned to the turbine Each of these items has some degree of influence on measured turbine performance, making the use of appropriate corrections necessary. It should be noted that the r

47、eheat temperature of a light-water-moderated reactor unit influences the position of the low pressure turbine expansion line and, therefore, the amount of moisture existing in the blade path. A correction for deviation from specified reheat temperature is appropriate only to the extent that the test

48、 reheat temperature has been affected by differences from specified values of pres- sure drop in the heating steam supply line to the final stage reheater, assuming that the reheater has been supplied as a part of the turbine-generator contract. An appropriate correction for the effect of pressure d

49、rop differences can be made when drawing the expansion line for the heat balance used to determine the Group I corrections. This correction is applied by changing the test efficiency of each separate expansion (between extraction points) by ASME PTC 6A-2000 APPENDIX A TO PTC 6, THE TEST CODE FOR STEAM TURBINES Locus of test points Line of constant corrected to specified es hrottle fl w . o Uncorrected test heat rate with steam and cycle cond bons Test efficiency