the physical properties of the blast wave produced by a stoichiometric propane/oxygen explosion...
TRANSCRIPT
THE PHYSICAL PROPERTIES OF THE BLAST WAVE PRODUCED BY A STOICHIOMETRIC
PROPANE/OXYGEN EXPLOSION
MABS22 Bourges, France 2012
by
Maura C. Dewey & John M. Dewey
Dewey McMillin & Associates LtdVictoria, BC Canada
Operation DISTANT PLAIN 1966
MABS22 Bourges, France 2012
Operation DISTANT PLAIN 1966
MABS22 Bourges, France 2012
Air Blast Time-of-Arrival Detectors (ABTOADS)
Recorder
An array of switches was closed by the primary shock,and the signals sent via a single cable to a recorder
MABS22 Bourges, France 2012
Primary Shock Radius-Time Trajectory Analysis
Dewey (2005), J. Phys. D: Appl. Phys., 38, 4245-4251
MABS22 Bourges, France 2012
Propane+oxygen
Propane only
MABS22 Bourges, France 2012
The Piston Path – Random Choice Method (PP-RCM)G. I. Taylor (1946)
MABS22 Bourges, France 2012
Smoke Tracer Trajectory Used as the Piston Path
MABS22 Bourges, France 2012
MISERS GOLD
2.445 KT ANFO
SURFACE BURST
Use of an Arbitrary Piston Path
MABS22 Bourges, France 2012
Radius
Tim
e
ObservedShock trajectory
CalculatedShock trajectory
ArbitraryPiston Path
Use of an Arbitrary Piston Path
MABS22 Bourges, France 2012
Radius
Tim
e
ObservedShock trajectory
CalculatedShock trajectory
ArbitraryPiston Path.
Use of an Arbitrary Piston Path
MABS22 Bourges, France 2012
Radius
Tim
e
ObservedShock trajectory
CalculatedShock trajectory
ArbitraryPiston Path.
Comparison of Observed and Calculated Shock Trajectories
MABS22 Bourges, France 2012
Radius (m/kg^1/3)
0 5 10 15 20 25
Tim
e (ms/kg^1/3)
0
10
20
30
40
50
60
Propane/oxygen ABTOAD dataPP-RCM calculation
Propane/Oxygen ABTOAD DataPP-RCM Calculation
The PP-RCM Calculated the Physical PropertiesThroughout the Flow Field
MABS22 Bourges, France 2010
Scaled Radius – 2 to 20 m/kg^1/3 at NTP
The PP-RCM Calculated the Physical PropertiesThroughout the Flow Field
MABS22 Bourges, France 2010
Scaled Radius – 2 to 20 m/kg^1/3 at NTP
Scaled Time – 2 to 50 ms/kg^1/3 at NTP
The PP-RCM Calculated the Physical PropertiesThroughout the Flow Field
MABS22 Bourges, France 2010
Scaled Radius – 2 to 20 m/kg^1/3 at NTP
Scaled Time – 2 to 50 ms/kg^1/3 at NTP
Stored Properties
Hydrostatic Overpressure – OP (atm)
The PP-RCM Calculated the Physical PropertiesThroughout the Flow Field
MABS22 Bourges, France 2010
Scaled Radius – 2 to 20 m/kg^1/3 at NTP
Scaled Time – 2 to 50 ms/kg^1/3 at NTP
Stored Properties
Hydrostatic Overpressure – OP (atm)
Density – ρ (atm)
The PP-RCM Calculated the Physical PropertiesThroughout the Flow Field
MABS22 Bourges, France 2010
Scaled Radius – 2 to 20 m/kg^1/3 at NTP
Scaled Time – 2 to 50 ms/kg^1/3 at NTP
Stored Properties
Hydrostatic Overpressure – OP (atm)
Density – ρ (atm)
Particle Velocity – U/a0
The PP-RCM Calculated the Physical PropertiesThroughout the Flow Field
MABS22 Bourges, France 2010
Scaled Radius – 2 to 20 m/kg^1/3 at NTP
Scaled Time – 2 to 50 ms/kg^1/3 at NTP
Stored Properties
Hydrostatic Overpressure – OP (atm)
Density – ρ (atm)
Particle Velocity – U/a0
Calculated Properties
Dynamic Pressure, Temperature and Sound Speed
Results
MABS22 Bourges, France 2012
Overpressure (atm)
Time (ms/kg^1/3
0.0 0.5 1.0 1.5 2.0 2.5 3.0
Overpressure (atm
)
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
PP-RCM data at 2.5 m/kg^1/3
Data Fitted to Modified Friedlander Equation
MABS22 Bourges, France 2012
𝑃=𝑃𝑆𝑒−∝𝑡 ¿
Time (ms)
0 1 2 3
Overpressure (atm
)
-0.5
0.0
0.5
1.0
1.5
2.0
PP-RCM data at 2.5 m/kg^1/3Modified Friedlander Fit
Overdensity-Time History at 10 m/kg^1/3
MABS22 Bourges, France 2012
Time (ms)
0 2 4 6
Overdensity (atm
)
-0.02
0.00
0.02
0.04
0.06
0.08
0.10
0.12
PP-RCM DataModified Friedlander Fit
Particle Velocity Time History at 20 m/kg^1/3
MABS22 Bourges, France 2012
Time (ms)
0 2 4 6
Particle V
elocity (u/a0)
-0.01
0.00
0.01
0.02
0.03
0.04
0.05
PP-RCM dataModified Friedlander Fit
Integration of the Equation over the Positive DurationProvides Quantities such as Impulse
MABS22 Bourges, France 2012
Radius (m/kg^1/3)
1 10
Overpressure Im
pulse (atm.s)
0.1
1
Log-log Plot of Impulse versus Scaled Radius
Summary
MABS22 Bourges, France 2012
All of the physical properties of a stoichiometricPropane/oxygen explosion have been characterised
Summary
MABS22 Bourges, France 2012
All of the physical properties of a stoichiometricPropane/oxygen explosion have been characterised
It has been demonstrated that a hemispherical blast wave can be fully
characterised using a simple ABTOAD array