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GB/T 21188-2007 English PDF

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GB/T 21188-2007: Measurement of gas flow by means of critical flow Venturi nozzles
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GB/T 21188-2007English854 Add to Cart 5 days [Need to translate] Measurement of gas flow by means of critical flow Venturi nozzles Valid GB/T 21188-2007

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Basic data

Standard ID GB/T 21188-2007 (GB/T21188-2007)
Description (Translated English) Measurement of gas flow by means of critical flow Venturi nozzles
Sector / Industry National Standard (Recommended)
Classification of Chinese Standard N12
Classification of International Standard 17.120.10
Word Count Estimation 43,414
Date of Issue 2007-09-12
Date of Implementation 2008-05-01
Adopted Standard ISO 9300-2005, IDT
Regulation (derived from) China Announcement of Newly Approved National Standards No. 12 of 2007 (No. 112 overall)
Issuing agency(ies) General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China, Standardization Administration of the People's Republic of China
Summary This standard specifies the measurement of gas mass flow rate of the critical flow venturi nozzle geometry and use.

GB/T 21188-2007: Measurement of gas flow by means of critical flow Venturi nozzles

---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.
Measurement of gas flow by means of critical flow Venturi nozzles ICS 17.120.10 N12 National Standards of People's Republic of China GB/T 21188-2007/ISO 9300.2005 Flow Venturi nozzle Measurement of gas flow by critical (ISO 9300.2005, IDT) Posted 2007-09-12 2008-05-01 implementation Administration of Quality Supervision, Inspection and Quarantine of People's Republic of China Standardization Administration of China released

Table of Contents

Introduction Ⅲ 1 Scope 1 2 Terms and definitions 1 3 Symbol 4 4 Basic Equation 5 4.1 Equation of State 5 Under ideal conditions of flow rate 4.2 5 Under actual conditions Flow 4.3 5 4.4 Critical mass flux 5 5 possible applications 5 6 standard critical flow Venturi nozzle 6 6.1 General requirements 6 6.2 Structure 6 Installation Requirements 7 8 7.1 General 8 7.2 upstream line 9 7.3 upstream large space 9 7.4 Downstream Requirements 9 7.5 pressure measurement 9 7.6 vent 10 7.7 Temperature measurement 10 7.8 Density measurement 10 Calculate the gas density 11 7.9 8 Calculation 11 8.1 Mass Flow 11 8.2 discharge coefficient Cd '11 8.3 C critical flow function and the critical flow coefficient of real gas CR 12 12 8.4 measured in terms of pressure and temperature conditions of stagnation 8.5 The maximum allowable downstream pressure 12 Flow Measurement Uncertainty 9 13 9.1 General 13 The actual calculation of 9.2 Uncertainty 13 Appendix A (normative) critical flow venturi nozzle discharge coefficient 15 Appendix B (normative) various gas stream function C critical values in Table 17 Annex C (normative) gas mixture critical mass flux calculations 24 Mass flow in Appendix D (normative) atmospheric air correction factor 28 GB/T 21188-2007/ISO 9300.2005 Appendix E (normative) and upstream of the nozzle throat diameter of the pipe than β > critical flow nozzle critical mass of 0.25 Flux calculations 29 Appendix NA (informative) Inspection Rules 32 Appendix NB (informative) critical flow nozzle 34 References 35 GB/T 21188-2007/ISO 9300.2005

Foreword

This standard is identical with ISO 9300.2005 "with a critical flow Venturi nozzle Measurement of gas flow." This standard is equivalent translation ISO 9300.2005 (in English). In developing this standard according to GB/T 1.1-2000 "Standardization Guide Part 1. Standard structure and writing rules" and GB/T 20000.2-2001. the relevant provisions of "Standardization Guide Part 2 rules of international standards," made the following editorial modify. --- Remove the ISO 9300.2005 international standard foreword; --- To the "international standards" to "this standard"; --- The ISO 9300.2005 international standard as a decimal comma "," to the decimal point; "." --- Chapter 5 "(see 9.5)," corrected to "(see 7.5)"; --- Original E. 2 "correction factor" in the third sub-paragraph a "(β between 0.15 to 0.5)," corrected to "(β value Between 0.25 to 0.5) "; --- This standard is based on the specific circumstances of the country, increasing the appendix NA "inspection rules" and Appendix NB "critical flow nozzle." The Standard Appendix A, Appendix B, Appendix C, Appendix D, Appendix E is normative annex, appendix NA and NB for the informative Appendix appendix. The standard proposed by China Machinery Industry Federation. The standard measurement and control Standardization Technical Committee first points by the National Technical Committee of industrial processes. This standard is drafted by. China Institute of Metrology. Participated in the drafting of this standard. National Large Water flow metering stations, metering test Beijing, Zhejiang Yuyao City Yinhuan flow Instruments Inc. Secretary, Tianjin Runtai Automation Instrumentation Co., Ltd. Harbin first tool oilfield tool branch. The main drafters of this standard. Xu Yinghua, Wang and since, Wang Dongwei. Participate drafters of this standard. Yangyou Tao, Zhu Jiashun, children come again, Wang Yaoting. This standard is the first release. GB/T 21188-2007/ISO 9300.2005 Flow Venturi nozzle Measurement of gas flow by critical

1 Scope

This standard specifies the gas mass flow measurement of critical flow Venturi nozzle (CFVN) geometry and method of use (system Installation and working conditions), and given the required information to calculate traffic and uncertainty. This standard applies to gas flow in the throat is accelerated to critical speed (equal to the local speed of sound), and only the presence of the text single-phase gas unsteady flow in the throat Venturi nozzle. In the critical velocity, mass flow rate of gas flowing through the venturi nozzle is actually swim under conditions likely to reach the maximum flow. Critical flow Venturi nozzle can only be prescribed for use within the nozzle throat diameter ratio limits the inlet and throat Reynolds number. This standard Involving critical flow Venturi nozzle direct calibration has been done a lot of tests, to ensure the critical flow venturi nozzle flow coefficient given in a A predictable uncertainty within the limits. Information given in this standard are suitable for the following situations. critical flow Venturi nozzle upstream pipeline to pipeline circular cross-section; or critical Flow Venturi upstream of the nozzle, or into an upstream group to install a critical flow venturi nozzle can be seen as a large space. This group Configured for critical flow Venturi nozzle installed in parallel to provide the possibility, so you can get more traffic. For high accuracy measurement, it discusses this standard venturi nozzle for precise machining low Reynolds number of critical flow.

2 Terms and definitions

The following terms and definitions apply to this standard. 2.1 pressure measurement 2.1.1 Drilled holes on the wall, its edges flush with the inner surface of the pipe. Note. The pressure should be taken to the mouth of the duct static pressure at this point. 2.1.2 The actual pressure with a pressure gauge attached to the wall of taps of the measured flow of the gas. Note. The absolute value of static pressure are used in this standard. 2.1.3 When the flow of gas to the gas isentropic process to achieve a stationary state the existence of pressure. NOTE. The standard used in both absolute stagnation pressure only. 2.2 Temperature Measurement 2.2.1 The actual temperature of the flowing gas. Note. The absolute static temperature values are used in this standard. 2.2.2 Gas flow and other process comes to a standstill when the entropy state existed gas temperature. Note. The values are absolute stagnation temperature used in this standard. GB/T 21188-2007/ISO 9300.2005

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