Nomeclature - Intergraph Smart Instrumentation - Reference - Hexagon

A

Required effective discharge area, inch2

A1

Exposed surface area, inch2

Ad

Root diameter of thermowell, m

B

Diameter at tip, in

b

Fillet radius at root, m

bs

Fillet radius at base for stepped thermowell, m

C

Discharge coefficient

CV

Valve flow coefficient, US gallon per minute of water (60 ºF) at 1 psi pressure drop

Cr

Coefficient for critical flow equation, dimensionless

Cs

Speed of sound, m/s

Cp

Speed of sound in pipe wall, m/s

D

Internal pipe diameter (upstream) at flow temperature, mm

D0

Internal pipe diameter (upstream) at ambient temperature, mm

Dt

Nominal size of sensing element, in

D1

Inlet internal diameter of the pipe, mm

D2

Outlet internal diameter of the pipe, mm

Dd2

Outlet outside diameter of the pipe, m

DP

Pressure differential, P1-P2 , or differential pressure transmitter range, bar

DPA

Maximum allowable pressure drop, bar

DPloss

Pressure loss, bar

DPn

Differential pressure at normal flow rate, bar

Dbh

Bleed/Vent hole diameter, mm

Dj

Diameter of the jet, m

d

Valve inlet diameter or orifice (throat) diameter at flow temperature, mm

db

Bore diameter of thermowell

d0

Orifice (throat) diameter at ambient temperature, mm

E

Module of Elasticity at 70 °F, psi-g

Ef

Acoustical efficiency factor, dimensionless

Eref

Reference value for module of elasticity, Pa-g

Eps

Gas expansion factor, ratio of flow coefficient for a gas to that for a liquid at the same Reynolds number, dimensionless

F

Environment Factor, dimensionless

F1

Heat Absorption Factor, dimensionless

F2

Coefficient for subcritical flow equation, dimensionless

Fd

Valve style modifier, dimensionless

Fe

Environmental factor for thermowell calculation, dimensionless

FF

Liquid critical pressure ratio factor, dimensionless

Fk

Ratio of specific heats factor, 1/K, dimensionless

FL

Liquid pressure recovery factor, dimensionless

FLP

Product of the liquid pressure recovery factor of a valve with attached fittings and the piping geometry factor, dimensionless

Fp

Piping geometry factor, dimensionless

FR

Reynolds number factor, dimensionless

Fs

Correction factor for steam quality, dimensionless

fp

Peak frequency, Hz

fo

Coincidence or Natural frequency, Hz

fr

Ring frequency, Hz

fw

Wake frequency, Hz

Gf

Liquid specific gravity (ratio of density of liquid at flowing temperature to density of water at 15.6 °C), dimensionless

Gg

Gas specific gravity (ratio of density of flowing gas to density of air with both at standard conditions, which is equal to the ratio of molecular weight of gas to the molecular weight of air), dimensionless

Hc

Mounting factor, dimensionless

HS

Segmental height at flow temperature, mm

HS0

Segmental height at ambient temperature, mm

HV

Heat of vaporization, J/kg

K

Specific Heat Ratio, Cp/Cv dimensionless

K1,K2,Kb1,Kb2

Effective velocity head coefficients, dimensionless

KC

Cavitation index, dimensionless

KCD

Relative capacity, CV/d2

KCV

Valve cavitation index, dimensionless

Kb

Capacity correction factor due to back pressure, dimensionless

Kcc

Combination capacity factor for rupture disk at the relief valve inlet, dimensionless

Kd

Effective coefficient of discharge, dimensionless

Kf

Constant for thermowell calculation, dimensionless

Kn

Correction factor for Napier equation, dimensionless

Kp

Correction factor for overpressure, dimensionless

Ksh

Superheat steam correction factor, dimensionless

Kv

Correction factor for viscosity, dimensionless

Kw

Correction factor for back pressure, dimensionless

L

Maximum thermowell length or unsupported length of thermowell, in

La

"A"-weighted sound level, dB(A)

Lg

Correction for pipe Mach number dB

Lpi

Internal sound pressure level dB

Ls

Length of reduced-diameter shank for stepped thermowell, m

M

Molecular weight, atomic mass units

MN

Mach number in pipe, dimensionless

MN0

Mach number in valve outlet, dimensionless

Mj

Mach number in the jet, dimensionless

No

Number of flow passages , dimensionless

Ns

Strouhal number

Nsc

Scruton number

P

Absolute static pressure, bar

PC

Absolute thermodynamic critical pressure, bar

PV

Absolute vapor pressure of liquid at inlet temperature, bar

PVC, PVCC

Absolute pressure in vena contracts at subsonic and critical flow conditions, Pa

P2c, P2b, P2ce

Border pressures for different noise regimes, Pa

Pa

Absolute outside pipe pressure, Pa

Pb

Total back pressure, psi-g

Pb1

Constant back pressure, psi-g

Pb2

Variable back pressure, psi-g

Pb3

Built-up back pressure, psi-g

Pcf

Critical flow throat pressure, psi-a

Pover

Overpressure, %

Ps

Set pressure, psi-g

Pup

Upstream relieving pressure, psi-a

R

Limitation on Wake to Natural frequency ratio, dimensionless

RO

Density at flow conditions (upstream), kg/m3

ROm

Density of well material at ambient temperature, kg/m3

ROp

Density of pipe material, kg/m3

ROs

Density of the thermowell sensor at ambient temperature, kg/m3

Rf

Ratio of frequency at fluid temperature to frequency at 70 °F, dimensionless

RS0

Segmental radius at ambient temperature, mm

Re

Valve (pipe) Reynolds number, dimensionless

Remax, Ren

Pipe Reynolds number at maximum and normal flow rate, dimensionless

Rq

Radius of upstream profile of Quarter of Circle (Quadrant Edge) orifice, mm

S

Maximum allowable working stress, Pa-g

Sf

Fatigue endurance limit, Pa-g

SRF

Scale reading factor, 10´Wn/Wmax

St

Water in steam, %wt

T

Flow temperature, K

T1

Gas temperature at relieving conditions, °R

T0

Ambient temperature, K

Tc

Thermodynamic critical temperature, K

TL

Transmission loss, dB

TLfo

Transmission loss at coincidence frequency, dB

TLfr

Transmission loss across the pipe wall at the ring frequency, dB

Tw

Vessel Wall Temperature, °R

t

Minimum tip thickness of thermowell, m

U

Velocity, m/s

V

Velocity, ft/s

W

Flow rate, kg/h

Wmax, Wn

Maximum and normal flow rate, kg/s

Wa

Sound power, W

Wm, Wms

Stream powers, W

wall

Pipe wall thickness, m

X

Ratio of pressure drop to absolute inlet pressure (DP/P1), dimensionless

XT

Pressure drop ratio factor, dimensionless

XTP

Value of XT for valve-fitting assembly, dimensionless

Z

Compressibility at operating conditions, dimensionless

Zb

Compressibility at base conditions, dimensionless

ap, ape

Linear expansion coefficient of pipe and primary element material, 1/ºC

b

Diameter ratio of orifice or throat and inside diameter of line

DLf

Correction value for cavitating flow, dB

DTLfp

Correction for ratio of peak frequency and coincidence frequency, dB

h

Acoustic efficiency factor, dimensionless

m

Absolute (dynamic) viscosity, Pa×s

n

Kinematic viscosity, centistokes

ξ

Damping factor, dimensionless

0

First estimate

1

Upstream conditions

2

Downstream conditions

VC

Vena Contracta