ДСТУ EN ISO 9300:2022 Вимірювання витрати газу за допомогою сопел у режимі критичного потоку (EN ISO 9300:2022, IDT; ISO 9300:2022, IDT)



ДСТУ EN ISO 9300:2022
(EN ISO 9300:2022, IDT; ISO 9300:2022, IDT)

Вимірювання витрати газу за допомогою сопел у режимі критичного потоку

 
   
 
 
     
Не є офіційним виданням.
Офіційне видання розповсюджує національний орган стандартизації
(ДП «УкрНДНЦ» http://uas.gov.ua)

Contents

Foreword

1 Scope

2 Normative references

3 Terms and definitions

3.1 Pressure

3.2 Temperature

3.3 Nozzle

3.4 Flow

3.5 Flow rate

3.6 Gas

4 Symbols and abbreviations

5 Basic equations

5.1 Gas behaviour

5.1.1 Isentropic process

5.1.2 State equation

5.2 Isentropic flow of a perfect gas

5.2.1 Flowing area

5.2.2 Static pressure

5.2.3 Static temperature

5.3 Theoretical variables at the critical point

5.3.1 General

5.3.2 Critical pressure

5.3.3 Critical temperature

5.3.4 Critical density

5.3.5 Critical velocity

5.4 Theoretical mass flow rates

5.4.1 General

5.4.2 Theoretical mass flow rate of a perfect gas

5.4.3 Theoretical mass flow rate of real gas

5.5 Mass flow rate

6 General requirements

7 Applications for which the method is suitable

8 CFN

8.1 General requirements for both the standard CFN types

8.1.1 General

8.1.2 Materials

8.1.3 Contraction and throat

8.1.4 Diffuser

8.2 Requirements for each standard types of CFN

8.2.1 Standard CFNs

8.2.2 Toroidal-throat CFN

8.2.3 Cylindrical-throat CFN

9 Installation requirements

9.1 General requirements for both the standard configurations

9.1.1 Standard configurations

9.1.2 Upstream pressure tapping

9.1.3 Downstream pressure tapping

9.1.4 Temperature measurement

9.1.5 Density measurement

9.1.6 Drain hole

9.1.7 Downstream condition

9.2 Pipe configuration

9.2.1 General

9.2.2 Upstream pipe

9.2.3 Pressure measurement

9.2.4 Temperature measurement

9.3 Chamber configuration

9.3.1 General

9.3.2 Upstream chamber

9.3.3 Pressure measurement

9.3.4 Temperature measurement

9.3.5 Back-pressure ratio

10 Calculations

10.1 General

10.2 Calculation of mass flow rate, qm

10.3 Calculation of discharge coefficient, Cd

10.4 Calculation of critical flow function, C* or C*o

10.5 Conversion of measured pressure into stagnation pressure

10.6 Conversion of measured temperature into stagnation temperature

10.7 Calculation of viscosity

11 Estimation of critical back-pressure ratio

11.1 For a traditional diffuser at Reynolds numbers higher than 2 x 10^5

11.2 For any diffuser at low Reynolds numbers

11.3 For CFNs without diffuser or with very short diffuser

12 Uncertainties in the measurement of flow rate

12.1 General

12.2 Practical computation of uncertainty

12.3 Correlated uncertainty components

Annex A (informative) Discharge coefficient values

Annex B (informative) Critical flow function

Annex C (informative) Critical flow function values — Pure gases and air

Annex D (informative) Computation of critical mass flux for critical flow nozzles with high nozzle throat to upstream pipe diameter ratio, β > 0,25

Annex E (informative) Diameter correction method

Annex F (informative) Adjustment of discharge coefficient curve on a data set

Annex G (informative) Discharge coefficient

Annex H (informative) Critical back pressure ratio

Annex I (informative) Viscosity values - Pure gases and air

Annex J (informative) Supplement

Bibliography