JJF 1004-2004_English: PDF (JJF1004-2004)
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Metrological Terms and Their Definitions for Flow Rate
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JJF 1004-2004
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Standards related to: JJF 1004-2004
| Standard ID | JJF 1004-2004 (JJF1004-2004) | | Description (Translated English) | Metrological Terms and Their Definitions for Flow Rate | | Sector / Industry | Metrology & Measurement Industry Standard | | Classification of Chinese Standard | A53 | | Classification of International Standard | 17.120 | | Word Count Estimation | 41,451 | | Date of Issue | 2004-09-21 | | Date of Implementation | 2005-03-21 | | Older Standard (superseded by this standard) | JJF 1004-1986 | | Drafting Organization | China Institute of Metrology | | Administrative Organization | Flow capacity measured at the National Technical Committee | | Regulation (derived from) | National Metrology technical regulations (industrial metrology 2005 Volume 15 Number 1) enacted in 2004 | | Issuing agency(ies) | State Administration of Quality Supervision, Inspection and Quarantine | JJF 1004-2004
Metrological Terms and Their Definitions for Flow Rate
National Metrological Technical Specifications of the People's Republic of China
Terms and definitions of flow measurement
Published on.2004-09-21
2005-03-21 Implementation
Published by the General Administration of Quality Supervision, Inspection and Quarantine
Terms and definitions of flow measurement
Instead of JJG1004-86
This specification was approved by the General Administration of Quality Supervision, Inspection and Quarantine on September 21,.2004, and
Effective March 21,.2005.
Focal unit. National Flow Capacity Measurement Technical Committee
Drafting unit. Chinese Academy of Metrology
National Water Flow Metering Station
The central unit is entrusted with the interpretation of this specification
The main drafters of this specification.
Duan Huiming (Chinese Academy of Metrology)
Zhai Xiuzhen (Chinese Academy of Metrology)
Wang Zihe (National Water Metering Station)
Participating drafters.
Li Fang (Chinese Academy of Metrology)
table of Contents
1 General term (1)
1.1 flowrate (1)
1.2 pipeflow, ductflow (1)
1.3 Open Channel Flow (1)
1.4 flowmeter (1)
1.5 Flowmeter error characteristic curve (errorperformancecurveofflowmeter) (1)
1.6 metertube (1)
1.7 primary device (1)
1.8 secondary device (1)
1.9 outputsignal (1)
1.10 calibration factor of the primary device (1)
1.11 maximum flow-rate (1)
1.12 minimum flow-rate (1)
1.13 flow-raterange (2)
1.14 transitional flow-rate (2)
1.15 nominalflow-rate (2)
1.16 fullscale flow-rate (2)
1.17 pressureloss (2)
1.18 working conditions (2)
1.19 working temperature (2)
1.20 working pressure (2)
1.21 installation conditions (2)
1.22 straightlength (2)
1.23 wal (pressure) tapping (2)
1.24 drainholes (2)
1.25 ventholes (2)
1.26 swirling flow (2)
1.27 pulsating flow of mean constant flow-rate (2)
1.28 turbulentflow (3)
1.29 laminarflow (3)
1.30 steadyflow (3)
1.31 unstableflow (3)
1.32 multiphaseflow (3)
1.33 criticalflow (3)
1.34 velocity distribution (3)
1.35 Fully developed velocity distribution (fulydevelopedvelocitydistribution) (3)
1.36 regular velocity distribution (3)
1.37 flowprofile (3)
1.38 mean axial fluid velocity (3)
1.39 hydraulic diameter (3)
1.40 hydraulic radius (3)
1.41 Static Pressure (3)
1.42 absolute static pressure of the fluid (3)
1.43 gauge pressure (4)
1.44 dynamic pressure (4)
1.45 total pressure (4)
1.46 stagnation pressure (4)
1.47 Froude number (4)
1.48 Reynolds number (4)
1.49 Machnumber (4)
1.50 Strouhalnumber (4)
1.51 ratioofspecificheatcapacities (5)
1.52 isentropic exponent (5)
1.53 compressibility factor (5)
1.54 Coanda Effect (5)
1.55 Dopplereffect (5)
1.56 gauge (5)
1.57 bedslope (bottomslope) (5)
1.58 Surfaceslope (5)
1.59 Fal (5)
1.60 water level (stage; gaugeheight; liquidlevel) (5)
1.61 stage-dischargerelations (5)
1.62 benchmark (5)
1.63 Logging (gaugewel, stilingwel) (5)
1.64 head (5)
2 Measuring instruments and methods (6)
2.1 Differential pressure flowmeter (6)
2.2 Laminar Flowmeter (8)
2.3 critical flowmeter (criticalflowmeter) (8)
2.4 electromagnetic flowmeter (9)
2.5 Turbine Flowmeter (9)
2.6 vortex-sheddingflowmeter (9)
2.7 vortexprecessionflowmeter (10)
2.8 Ultrasonic Flowmeter (10)
2.9 Positive Displacement Flowmeter (11)
2.10 massflowmeter (11)
2.11 Rotameter (floatmeter) (11)
2.12 watermeters (12)
2.13 drygasmeter (12)
2.14 heatmeters (12)
2.15 Fuel Dispensers (12)
2.16 Gas Dispensers (12)
2.17 velocity-areamethods (13)
2.18 tracermethods (14)
2.19 weirflumemethods (14)
3 Flow standard device (16)
3.1 Liquid Flow Standard Facilities (16)
3.2 gasflow standard facilities (17)
3.3 Pipeprover (17)
3.4 mastermeter method (17)
4 Letter symbols (17)
Appendix A Chinese Index (19)
Appendix B English Index (27)
Terms and definitions of flow measurement
1 General term
1.1 flowrate
The amount of fluid flowing through a section is called flow. Flow is a collective term for instantaneous flow and cumulative flow. during one period
The amount of internal fluid flowing through a certain cross section is called cumulative flow, also called total. When the time is short, the fluid flows through a certain section
The quantity is called instantaneous flow, and in the case of no misunderstanding, instantaneous flow can also be referred to as flow. Volume meter for flow
When it is displayed, it is called volume flow, and when it is expressed by mass, it is called mass flow.
1.2 Pipeflow, ductflow
The fluid fills the flow of the pipe.
1.3 Open Channel Flow
The liquid has a free surface flow in the open channel.
1.4 flowmeter
Apparatus for measuring flow. It usually consists of a primary device and a secondary device.
Note. High accuracy and good stability. The flowmeter that can be used as a comparison standard for other flowmeters is called standard flowmeter.
1.5 Flowmeter error characteristic curve (errorperformancecurveofflowmeter)
The curve showing the relationship between the flow rate and the error of the flowmeter is a function of other quantities that are measured and affect the measurement error.
1.6 metertube
In all aspects, it meets the technical requirements in the standard, and a specially processed section of pipeline equipped with a flow measurement device.
1.7 Primary device
A device that generates a flow signal. Depending on the principle used, the primary device can be inside or outside the pipeline.
Note. For electromagnetic flowmeters, a primary device includes. a measuring tube, one or more pairs of radially opposed signals
Electrode and an electromagnet that generates a magnetic field in the measuring tube. For differential pressure flowmeters, the primary device includes a measuring tube,
Throttling device and pressure taking hole. For ultrasonic flowmeters, the primary device includes a measuring tube and an ultrasonic transducer.
1.8 secondary device
A device that receives a signal from a primary device and displays, records, converts, and/or transmits the signal to obtain a flow value.
1.9 output signal
Is the output of the secondary device. This signal is a function of flow.
1.10 calibration factor of the primary device
The quotient of the flow rate and the corresponding signal value sent by the primary device under the specified reference conditions.
1.11 maximum flow-rate
Maximum flow to meet metering performance requirements.
1.12 minimum flow-rate
Minimum flow to meet metering performance requirements.
1.13 flow-raterange
The range defined by the maximum flow and the minimum flow meets the measurement performance requirements within this range.
1.14 transitional flow-rate
The flow value between the maximum flow and the minimum flow, it divides the flow range into two areas, namely "high area" and "low area".
1.15 nominal flow-rate
At the nominal flow rate, the flow meter should be able to meet the measurement performance requirements during continuous operation and intermittent operation.
Note. For water meters, the nominal flow is called common flow.
1.16 fullscale flow-rate
Corresponds to the maximum output signal flow.
1.17 pressureloss
Unrecoverable pressure drop due to the presence of a primary device in the pipeline.
1.18 working conditions
The characteristic value of the physical property of the measured fluid flowing through the device and meeting the specifications of the primary device.
1.19 working temperature
The temperature of the measured fluid flowing through a primary device and meeting the primary device specifications.
1.20 working pressure
The absolute static pressure of the measured fluid flowing through a primary device and meeting the primary device specifications.
1.21 installation conditions
Physical environment that allows the use of flow meters (or flow measurement devices).
Note. The physical environment includes external conditions, fluid status, numerical range of fluid physical properties, and geometric configuration of pipelines and their corresponding accessories.
1.22 straight length
Pipe sections installed upstream and downstream of the flowmeter to achieve a certain level of flow field. Its axis is straight and
The area and shape of the internal cross-section is constant, the cross-sectional shape is usually circular or rectangular, but it can also be circular or any other
Has a regular shape.
1.23 Pipe wall pressure tap [wal (pressure) tapping]
The edge of the circular hole in the pipe wall is flush with the inner surface of the pipe. The pressure taking hole is used to measure the static pressure of the fluid in the pipeline.
1.24 drainholes
Holes for discharging undesired solid particles or fluids with a density greater than the fluid being measured in the pipeline.
1.25 ventholes
Holes for venting undesired gases in pipes.
1.26 swirling flow
Flow with axial and peripheral velocity components.
1.27 pulsating flow of mean constant flow-rate
Although the flow in the measurement section is a function of time, when averaged over a sufficiently long time interval, it has
A constant average flow.
Note. There are two types of periodic pulsating flow and random pulsating flow.
1.28 turbulentflow
Compared with viscous force, inertial force plays a major role in flow, also called turbulence.
Note. Turbulence is the flow in which the irregular (random) velocity fluctuations in time and space are superimposed on the average flow.
1.29 laminarflow
Compared with inertial forces, viscous forces play a major role in the flow.
Note. Laminar flow is the layered movement of the fluid particles, and no mixed flow occurs between the stratospheres.
1.30 steady flow
Speed, pressure, and temperature do not change over time, and do not affect the flow of measurement accuracy, also known as steady flow.
Note. The observed steady flow is actually that its speed, pressure, and temperature will all have small changes around the average, but not
Affects the flow of measurement uncertainty.
1.31 unstable flow
Flows in which one or more parameters of velocity, pressure, density, and temperature fluctuate over time, also known as unsteady flows.
Note. The time interval considered should be long enough to exclude the random component of the turbulence itself.
1.32 multiphase flow
Two or more fluids of different phases flow together. It is also called two-phase flow when only two-phase fluid flows together.
1.33 critical flow
The fluid flows through the throat of the throttle, and the ratio of the absolute pressure of the downstream to the upstream is less than the critical value. Critical flow upstream
When the fluid state (pressure, temperature, and velocity distribution) is constant, the mass flow rate remains constant.
1.34 velocity distribution
The distribution pattern of the axial component of the fluid velocity over the cross section of the pipe.
1.35 Fully developed velocity distribution (fulydevelopedvelocitydistribution)
Velocity distribution that does not change from one cross-section to another in the flow direction. it
It usually forms at the end of a long enough straight pipe section.
1.36 regular velocity distribution
Very similar to the fully developed velocity distribution, accurate flow measurement can be performed.
1.37 flowprofile
Graphical representation of velocity distribution.
1.38 mean axial fluid velocity
The ratio of the instantaneous volume flow (the integral of the axial component of the local fluid velocity over the pipe section) to the cross-sectional area.
1.39 hydraulic diameter
Quotient of four times the wet cross-sectional area and wet circumferential length.
Note. For circular pipes filled with fluid, the hydraulic diameter is equal to the inside diameter of the pipe.
1.40 hydraulic radius
Equal to the quotient of wet cross-sectional area and wet circumferential length.
1.41 Static Pressure
A pressure value measured in a fluid without being affected by the flow rate.
1.42 absolute static pressure of the fluid
The static pressure of the measured fluid relative to a complete vacuum.
1.43 gauge pressure
The difference between the absolute static pressure of a fluid and the atmospheric pressure at the measurement site at the same time.
1.44 dynamic pressure
1.44.1 Dynamic Pressure Offluid Element
For elementary stream bundles in a pipeline, the kinetic energy of the fluid is all isentropically converted into pressure energy which produces a pressure higher than the static pressure
force. For incompressible fluids, the dynamic pressure of the fluid element is
Note. The meaning of each letter symbol in the formula is shown in Table 1, the same applies hereinafter.
1.44.2 Mean dynamic pressure in cross-section
The ratio of the power of a fluid flowing through a section to the volumetric flow in the form of kinetic energy. For incompressible fluids, the
The average dynamic pressure is the sum of the gauge pressure and the dynamic pressure.
Note. For stationary unit fluid, the gauge pressure and total pressure have the same value.
1.46 stagnation pressure
A pressure characterizing an energy state in which the kinetic energy of a fluid is fully converted into pressure energy. Its value is equal to the sum of absolute static pressure and dynamic pressure.
Note. For static unit flow, absolute static pressure and stagnation pressure have the same value.
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