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