Some standard content:
Introduction
National Standard of the People's Republic of China
Characteristics
Numbers
Characteristic numbers
GB3102.12—93
replaces GR3102.12- 86
This standard is equivalent to the international standard IS () 31-12: 1992 "Quantities and Units Part 12: Characteristic Numbers". This standard is one of a series of national standards that have been developed related to and. units. This series of national standards are: GB3100 International System of Units and their Applications;
GB3101 General principles of quantities, units and symbols: GB3102.1 Quantities and units of space and time; GB3102.2 Cycles and related phenomena Quantities and units of mechanics, mechanical sum units:
GB 3102. 3
GB3102.4 Thermal quantities and units;
GB 3102. 5
Electricity and Magnetism Quantities and units of acoustics;
GB3102.6 Bases and units of light and related electromagnetic radiation; GB 3102.7
Quantities and units of acoustics;
GB 3102.8 N||tt ||Bases and units of physical chemistry and molecular physics; GB3102.9 Quantities and units of atomic physics and nuclear physics; GB3102.10
Quantities and units of nuclear reactions and ionizing radiation; in physical science and technology Numerical symbols used; GB 3102. 11
GB3102.12 Characteristic numbers;
GB3102.13 Quantities and units of solid state physics. The above-mentioned national standards implement the "Measurement Law of the People's Republic of China", the "Standardization Law of the People's Republic of China", the "Order on the Unified Implementation of Legal Units of Measurement in my country" promulgated by the State Council on February 27, 1981, and the "Legal Units of Measurement of the People's Republic of China" . The tables of quantities list the most important bases and their symbols in the field of this standard, and in most cases give definitions of the quantities, but these definitions are only for identification and are not always complete. The quantitative properties of certain quantities, especially when definitions require it, are specified without any attempt to be complete or consistent. In most cases, each quantity is given only a name and a symbol. When a quantity is given two or more names or symbols without distinction, they are on equal footing. When two italic letters (e.g., , , Φ.9.g) are present, only one of them is given, but this does not mean that the other is not equally applicable. Generally, such variants should not be given different meanings, and the symbols in brackets are "backup symbols" for use when the main symbol is used with a different meaning in specific circumstances. Explanation on the units of quantities of dimension one:
The consistent unit of any quantity of dimension one is a number (1). When expressing the value of this quantity, the unit 1 is generally not explicitly written. Prefixes should not be added to the number 1 to form decimal multiples or fractional units of this unit. The prefix can be replaced by a power of 10. Example:
Refractive index n1.53×1=1.53
State Bureau of Technical Supervision approved on 1993-12-27 and implemented on 1994-07-01
339
GB3102. 12--93
Reynolds number Re=1.32×103
Considering that the plane angle is generally expressed as the ratio of two lengths, and the solid angle is expressed as the ratio of the area to the square of the length, International Metrology The Committee (CIPM) stipulated in 1980 that radian and steradian are dimensionless derived units in the International System of Units; this means that plane angles and solid angles are regarded as dimensionless derived quantities. In order to facilitate the identification of quantities with the same dimensions but different properties, the units radian and steradian can be used in the expression of derived units.
Special instructions for this standard:
The name and symbol of each characteristic number in this standard consists of two letters. When these symbols are used as factors in a product, it is recommended that they be separated from other symbols by a space or by a multiplication sign or parentheses. The unit of all characteristic numbers is one (1). In the tables of this standard, unit 1 is not explicitly indicated. 1 Subject content and application scope
This standard specifies the names and symbols of some commonly used characteristic numbers used to describe transfer phenomena in various scientific and technological fields. This standard applies to all fields of science and technology. 2 Name and symbol
340
2.1
Characteristic number: momentum transfer
Term number
12-1
12-2| |tt||12-3
12-4
12-5
12-6
12-7
12-8||tt ||Symbol
Re
Eu
Fr
Gr
We
Ma
Kn
Sr
symbol
1
AT
Ap
g
a
f
C| |tt||Name
Reynolds number
Reynolds number
Euler number
Euler number
Froude number
Froude number
Grashof number
Grashof number
Weber number
Weber number
Mach number
Machnumber
Knu Knudsen number
Knudsen number
Strouhal number
strouhal number
GB 3102.12-93
Definition
Re pul_ | |tt||Eu=
Puz
Fr=www.bzxz.net
ig
Gr
gaAT
We-
a
Maa
C
Kn=
Sr=
8
The symbol used in the definition of 2.1
Name
Characteristic length
Characteristic speed
Characteristic temperature difference
Power difference
Volume mass
[Power] Viscosity|| tt||Kinematic viscosity: 7/0
Surface tension
Free fall acceleration
Body [swelling coefficient:
ldv
Mean free path| |tt||Characteristic frequency
Speed ??of sound
Remarks
Sometimes called Reech number
AeαAT
Refer to relevant entries in national standards
GB 3102.1—93,1-3. 1
GB 3102.1—93,1-10
GB3102.493,4-1
GB3102.3—93 ,3-15.1
GB 3102.3—93,3-2
GB3102.3---93,3-23
GB3102.3—93,3-24||tt ||GB3102.3—93,3-25
GB3102.1—93,1-11.2
GB3102.4—93,4-3.2
GB3102.8—93, 8-38
GB 3102.2—93,2-3.1
GB 3102.7—93,7-14,1
341
2.2
Feature number: Heat transfer
Item number
12-9
12-10
12-11
12-12
12-13
symbol
t
T
g
p
Cp
)
K
342
symbol
Fo
Pe
Ra
Nt
St|| tt||Name
Fourier number
Fourier number
Becklet number
Peclet number
Rayleigh number
Rayliegh number
Nusself number
Nusself number
Stanton number
Stanton number.
GB 3102.12--93
Definition|| tt||at
Fos
Pe=pepul_ nl
a
Rulan
pcgaAT
K
Nu -
Sta
K
poc
The symbol used in the definition of 2.2
The name of the quantity
Characteristic length||tt| |Characteristic velocity
Characteristic time interval
Characteristic temperature difference
Free fall acceleration
Volume mass
[Dynamic] viscosity
Kinematic viscosity ：7/p
Constant pressure mass heat capacity
dy
Body [expansion coefficient:
Thermal conductivity, (thermal conductivity)
Thermal diffusivity: A/pCp
Heat transfer coefficient: heat/(time × cross-sectional area × temperature difference) gaAT
va
Remarks
Pe=Re- Pr
Ra=Gr.Pr
When the Nusselt number is dedicated to convection
heat transfer, the definition formula can also be called
as Biot Number, symbol Bi
St=Nu/Pe
Sometimes called Margoulis
(Margoulis) number, symbol Ms
i=St·Pr2/3 It is called heat transfer
factor
Refer to the relevant items in the national standard
GB 3102. 1—93,1-3. 1
GB 3102. 1-- 93,1-10
GB 3102. 1—93,1-7
GB 3102.4—93,4-1
GB 3102. 1-93,1-11. 2
GB 3102. 3--93,3-2
GB 3102.3—93,3-23
GB 3102.3—93,3-24
GB 3102.4— 93,4-16.2
GB 3102. 4—93,4-3. 2
GB 3102. 4—93,4-9
GB 3102. 4--93, 4-14
GB 3102.4-93,4-10.1
2.3
GB 3102.1293
Characteristic number: mass transfer item number in two-component mixture||tt ||12-14
12-15
12-16
12-17
symbol
Fo
Pe||tt ||Gr
Nu
12-18
St
symbol
AT
Ar
g||tt ||p
β
D
Table
Name
Mass transfer Fourier number
Fourier numberformass transfer mass transfer Becker number
Péclet number for mass transfer Grashof number
Grashof number for mass transfer Nusselt number
Nusselt number for mass transfer Mass transfer Stein number| |tt||Stanton number for mass transfer definition
Definition
Fo*=Dt
Po-
Gr\Egpsx
Nu*=kl| |tt||OD
St'=k
p
The symbol used in the definition of 2.3
The name of the quantity
Characteristic length||tt ||Characteristic velocity
Characteristic time interval
Characteristic temperature difference
Characteristic mole fraction difference
Free fall acceleration
Volume mass
Motion Viscosity: \/p
8--(),
Diffusion coefficient
Mass transfer coefficient: mass/time × cross-sectional area × mole fraction difference) body [swelling coefficient ：
1dy
Remarks
Fo' =Fo/Le
Comparable with 12-9
Pe*-Re- Sc-||tt ||Pe·Le
Comparable to 12-10
Comparable to 12-4.
aT+r
is sometimes called the Sherwood
(Sherwood) number, the symbol Sh
can be compared with 12-12
St'-Nu '/Pe*
can be compared with 12-13.
jm=St*·Sc2/3 is called the traditional
prime factor
Refer to the relevant entries in the national standard
GB 3102. 1—93,1-3 . 1
GB 3102. 1—93,1-10
GB 3102.1--93,1-1
GB 3102. 4--93,4-1||tt ||GB3102.8—93,8-15.1
GB3102.1—93,1-11.2
GB 3102.3—93,3-2
GB 3102.3—93,3- 24
GB3102.8-93,8-39
GB 3102. 4—93,4-3. 2
343
2.4
items
Characteristic number: physical property constant
symbol
12-19
12-20
12-21
symbol||tt| |p
7
D
C
in
a
2.5
No.
Pr
Se
Le
number
name
Prandtl number
Prandtl number
Schmidt number| |tt||Schrnidt number
Lewis number
Lewis number
GB 3102.12—93
Definition
Pr =
a|| tt||Se=
PD=
Le:
a
CDD
in 2.4 Symbols used in the definition
Quantity
Name
Volume mass
[Dynamic] viscosity
Kinematic viscosity: n/p||tt| |Diffusion coefficient
Constant pressure mass heat capacity
Thermal conductivity, (thermal conductivity)
Thermal diffusivity: ^/pc
Characteristic number: Magnetohydrodynamics
Item number
12-22
12-23
12-24
12-25
344
Symbol
Rm
Al
Ha
Co
Magnetic Reynolds number
Name
magnetic Reynolds number||tt ||Alfren number
Alfren number
Hartmann number
Hartmann nunber
Cowling number
Cowling number
|tt||Remarks
LeSc/Pr
Refer to relevant entries in national standards
GB 3102.3--93,3-2
GB 3102.3-93,3 -23
GB 3102. 3--93,3-24
GB 3102.8—93,8-39
GB 3102. 4-93,4-16. 2|| tt||GB 3102.4—93,4-9
GB 3102. 4—93,4-14
Definition
Rm-
o
=mat
1/
A
VA
Ha=Bi
B2
Co-
upe|| tt||11/2
Remarks
VA=B/(pμ)V is called Alfine
Speed
Co=(Ua/)=Al-2 It is usually called
as the "second" Cowling number, with the symbol Co2
. "The first\ Cowling number is usually defined as
Co,-Ha\/Re:||tt| |Co·Rm
Bo
pv
symbol
p
B
G
volume mass||tt ||Characteristic length
Characteristic speed
GB3102.12-93
The symbol used in the definition of 2.5
The name of the quantity
Refer to the national standard Related entries of
GB3102.3—93,3-2
GB3102.1—93,1-3.1
GB3102.1—93,1-10
Kinematic viscosity: n/p
Magnetic permeability
Magnetic flux [amount] density
Conductivity
Additional notes:
This standard is measured by the National It is proposed and coordinated by the unit standardization technical committee. GB3102.3—93,3-24
GB3102.5—93,5-24.1
GB3102.5—93.5-19
GB3102.5—93,5-36| |tt||This standard is drafted by the First Subcommittee of the National Technical Committee for Quantity and Unit Standardization. The main drafter of this standard is Chen Yeqin.
345
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