Instrumentation & Automation

Windows ⁄ Android

Orifice Plate - Gas Mixtures

Example Of Gas Flowrate
Flowrate - Volume Std. Cond.
Calculation of the flowrate [q] for a given differential pressure [Δp].
1. Input values

Calculated values	Symbol	Unit	Value
Device diameter at 20 °C	d20	mm	84,000
Pipe diameter at 20 °	D20	mm	150,000
Device material	steel AISI 321, S32100
Pipe material	steel 1030, 1034, 1035, 1038
Arithmetical mean deviation of the roughness profile (Steel new, seamless hot drawn)	Ra	mm	0,0300
Uniform equivalent roughness	Rk	mm	0,1000
Tapping	Corner
Operating temperature	t	°С	2,00
Atmospheric pressure	p_a	kPa	100,50
Upstream pressure	p_u	kPa	1200,00
Differential pressure	Δp	kPa	16,00
Operating conditions
Dynamic viscosity	μ	μPa·s	10,4961
Density, standard conditions	ρ_s	kg/m³	0,6800
Compressibility factor	K	-	0,97170
Adiabatic index	k	-	1,31174

2. Calculation of intermediate values

Calculated values	Symbol	Unit	Value
Absolute pressure	p	kPa	1300,50
Thermodynamic temperature	T	°K	275,15
The temperature coefficient of change in the diameter of the device, caused by temperature deviations from 20 °C	K_d	-	1,000000
Device diameter at operating temperature	d	mm	84,0000
The temperature coefficient of change in the diameter of the pipe, caused by temperature deviations from 20 °C	K_p	-	1,000000
Pipe diameter at operating temperature	D	mm	150,0000
Diameter ratio	β	-	0,560000
Input rate factor	E	-	1,05312
Density, operating conditions	ρ	kg/m³	9,5695
Expansibility factor	ε	-	0,99638

3. Final calculations

Calculated values	Symbol	Unit	Value
1-st approximation
Reynolds number	Re	-	1000000
Discharge coefficient	C	-	0,605036
The roughness coefficient of the internal surface of the pipe	Kr	-	1,00102
Volume flowrate, standard conditions	q_vs	m³/s	2,86610
2-nd approximation
Reynolds number	Re	-	1576127
Discharge coefficient	C	-	0,604617
The roughness coefficient of the internal surface of the pipe	Kr	-	1,00140
Volume flowrate, standard conditions	q_vs	m³/s	2,86519
Deviation	Δ	%	0,0003188
3-d approximation
Reynolds number	Re	-	1575624
Discharge coefficient	C	-	0,604617
The roughness coefficient of the internal surface of the pipe	Kr	-	1,00140
Volume flowrate, standard conditions	q_vs	m³/s	2,86519
Deviation	Δ	%	0,0000002