Performance Parameters of Explosives: Equilibrium
and Non-Equilibrium Reactions

Fred Volk and Helmut Bathelt

Fraunhofer-Institut f¸r Chemische Technologie ICT, Joseph-von-Fraunhofer-Stra˚e 7,
D-76327 Pfinztal (Germany)

Dedicated to Professor Dr. Hiltmar Schubert on the Occasion of his 75

th

Birthday

Summary

For the calculation of the performance parameters of combus-

tion processes, equilibrium thermodynamic processes are taken
into account. On the other hand, non-equilibrium reactions occur,
mostly connected with low pressure burning. In this paper, several
explosives, explosive mixtures, solid and liquid propellants have
been calculated. It is shown how energy output and gas formation
depend on the oxygen balance and the enthalpy of formation. It
was found that the reason for the higher specific energy of liquid
propellants is due to the increased formation of gases consisting of
H

2

, N

2

and H

2

O, compared with conventional solid propellants

based on nitrocellulose and nitroglycerin, which produce more
CO and CO

2

. Non-equilibrium combustion of solid propellants

was found at very low loadingdensities or pressures lower than 1
to 2 MPa. In this case, the reaction products measured by mass
spectrometry, such as NO, N

2

O and HCN, are metastable and

highly toxic, producing a much lower heat of explosion compared
with equilibrium burningmeasured and calculated.

1 Introduction

A precise knowledge of the combustion processes of

energetic materials is important since the reaction process
determines the energy output and other parameters such as

*

Enthalpy of reaction

*

Specific energy

*

Specific impulse

*

Reaction temperature and pressure

*

Reaction products and gas formation and therefore the
degree of the toxicity of the products.

For the theoretical verification of the combustion behav-

ior of energetic materials computer codes are widely used,
which evaluate the reaction energy and products on the basis
of thermodynamic equilibrium calculations.

Under the aspect of a critical application of the codes, it is

possible to determine not only the combustion energy of a
number of explosives, but also the reaction products
quantitatively, especially by consideringthe freeze out
reactions of the products. On the other hand, it is possible to
avoid some toxic products by optimizingthe components of
the propellant or gas generator.

The followingcontribution shows under which precondi-

tions the thermodynamic calculations lead to a good agree-
ment between theory and experiment. But it also points out
the limit of the calculation of reactions, which are very
strongly dependent on the pressure, so that non-equilibrium
reactions occur. In this case we have to analyze the reaction
products usingexperimental methods, or we have to
measure the energy output with calorimetric methods.

2 Thermodynamic Calculations with the ICT-

Thermodynamic Code

The ICT-Thermodynamic Code is based on a method

developed by the National Space Administration (NASA)

(1,2)

.

This method uses mass action and mass balance expressions
to calculate chemical equilibria. Thermodynamic equilibria
can be calculated for constant pressure conditions as well as
for constant volume conditions.

In addition to the equation of state (EOS) for an ideal gas,

the virial EOS can be used and is necessary for the high-
pressure conditions of guns and closed vessels

(3, 4)

. The

calculation of the heat of explosion is of special interest,
because the experimental measurement of the heat using
the closed vessel technique is sometimes difficult due to high
temperatures and erosive reaction products.

Finally, the code can be used to determine the parameters

of gas detonations, e.g. pressure, temperature and detona-
tion velocity.

The enthalpies of formation, which are necessary for

thermodynamic calculations, are contained in the ICT-
Thermochemical Data Base

(5)

.

2.1 Calculated Results of Several Explosives at Constant

Volume Conditions

For the thermodynamic calculations of energetic materi-

als we usually need the composition and the enthalpy of
formation. Then it can be decided if the calculation should
be for conditions of a constant volume or of a constant
pressure. The main advantage for a constant volume

¹ WILEY-VCH VerlagGmbH, 69469 Weinheim, Germany, 2002

0721-3113/02/2701-0136 $ 17.50+.50/0

136

Propellants, Explosives, Pyrotechnics 27, 136 ± 141 (2002)

calculation is that we can evaluate the heat of explosion.
This holds for a loadingdensity of 0.1 g/cm

3

. This value

can also be measured experimentally in a calorimetric
bomb system at the same loadingdensity. This way it is
possible to compare measured and calculated heats of
explosion.

Usually, combustion reactions not only depend on the

enthalpy of formation. In many cases, the oxygen balance of
the energetic component or the mixture influence much
more the energy-output and the gas formation. Table 1
contains the results of the calculations of several explosive
substances with different oxygen balances.

The oxygen balance is defined as the amount of oxygen

expressed in weight percent liberated as a result of a complete
conversion of the explosive material to CO

2

, H

2

O, SO

2

, Al

2

O

3

etc. (positive oxygen balance). If the amount of oxygen is
insufficient for the complete oxidation reaction (negative
oxygen balance), the deficient amount of oxygen needed to
complete the reaction is reported with a negative sign.

Only a few explosives exhibit a positive oxygen balance,

such

as

nitroglycerin

(

‡3.5%), ammonium nitrate

(

‡19.98%) or ammonium dinitramide (ADN) with

‡25.8%. For glycoldinitrate, the oxygen balance is zero.

In Table 1 the highest values for the specific energy, the

heat of explosion and even the adiabatic temperature are
produced duringthe combustion of substances havinga
positive or a small negative oxygen balance. But with the
more negative oxygen balance, the energy decreases and the
mole number increases. This means that the gas formation of
a more negative oxygen balance is higher than for a better
oxygen balance.

Therefore, it can be understood that the combustion of

substances with a very negative oxygen balance such as
benzene derivatives cannot be complete: The more CO and
H

2

is formed, with a decrease of CO

2

, the higher is the

probability of a formation of free carbon (see Table 1). In
the same direction, temperature, pressure and both energy
parameters are also decreasing.

The specific energy (E

S

) can also be evaluated from

measurements in a ballistic vessel. Its definition is:

E

S

ˆ n R T

EX

Table 1. Influence of oxygen balance on energy parameters of explosives.

Explosive

DH

f

kJ/kg

O

2

-Balance

%

Temperature
K

Pressure
MPa

Specific
Energy
J/g

Heat of
Explosion
J/g

Mole
number
mol/kg

Carbon
weight%

ADN

1 207.

‡25.8

2 514

92.6

843

3 337

40.30

±

Nitroglycerin

1 632.

‡3.5

3 887

124.0

1 125

6 671

31.91

±

Glycol dinitrate

1 596.

0.0

3 941

131.3

1 190

7 289

32.88

±

Hexanitrobenzene

‡420.7

0.0

4 509

128.3

1 154

7 203

25.85

±

Nitropenta

1 705.

10.1

3 953

133.3

1 205

6 306

34.79

±

CL-20

‡921.

10.9

4 347

147.9

1 323

6 312

34.22

±

Pentanitrobenzene

162.9

13.2

4 469

134.5

1 206

6 094

29.69

±

BTTN

1683.

16.6

3 917

139.0

1 254

6 022

37.28

±

TNAZ

‡189.5

16.7

4 263

151.5

1 358

6 343

36.39

±

RDX

‡301.4

21.6

4 000

154.1

1 375

5 647

40.26

±

NTO

775.

24.6

2 956

106.4

945

3 148

38.12

±

NC 13.4%N

2 390.

29.2

3 388

121.8

1 094

4 409

38.30

±

Nitroguanidine

893.

30.7

2 335

105.7

932

3 071

46.47

±

1,2,3,5-Tetranitrobenzene

‡142.8

31.0

4 298

143.1

1 277

4 941

34.73

±

1,2,3,4-Tetranitrobenzene

‡300.2

31.0

4 374

146.1

1 304

5 098

34.73

±

TAGN

287.9

33.5

2 593

132.1

1 159

3 974

51.90

±

NC 12.6%N

2 598.

34.5

3 085

115.7

1 037

3 983

39.69

±

Metriol trinitrate

1 666.

34.5

3 497

140.9

1 260

5 053

42.19

±

Nitromethane

1 853.

39.3

3 043

139.7

1 245

4 821

47.25

±

DEGN

2 227.

40.8

3 083

132.0

1 178

4 566

44.20

±

NC 11.6%N

2 859.

41.2

2 683

106.3

949

3 480

41.17

±

PVN

1 152.

44.9

3 388

143.0

1 269

4 781

42.76

±

Tetryl

69.9

47.4

3 468

137.0

1 208

4 271

40.27

2.2

TATB

541.4

55.8

2 218

96.1

838

3 062

43.85

4.9

Trinitroaniline

368.1

56.1

2 663

109.6

960

3 589

42.26

5.8

1,3,5-Trinitrobenzene

204.2

56.3

3 017

119.6

1 050

3 963

41.18

6.33

1,2,3-Trinitrobenzene

‡25.5

56.3

3 193

126.6

1 112

4 193

41.18

6.4

Triethyleneglycol dinitrate ( TEGN )

2 619.

66.6

2 025

102.5

899

3 317

47.50

±

2,4,6-TNT

295.3

74.0

2 512

103.3

908

3 766

46.13

11.2

Z-Tacot

‡1188.

74.2

3 086

103.6

924

4 121

45.68

16.2

1,3-Dinitrobenzene

161.8

95.2

2 304

88.1

782

3 519

50.82

19.2

Isopropyl nitrate

2 187.

99.0

1 723

92.7

803

3 126

53.86

4.1

Nitrobenzene

‡78.9

162.4

1 771

59.0

537

2 871

66.12

40.0

Propylene oxide

2 111.

220.4

1 371

56.6

517

2 415

74.67

35.2

Performance Parameters of Explosives

137

Propellants, Explosives, Pyrotechnics 27, 136 ± 141 (2002)

This means that the specific energy is proportional to the

gas formation n and the adiabatic temperature T

EX

.

2.2 Energy of CL20 with Different Amounts of PB-Binder

The relationship between the oxygen balance and the

energy parameters on the one hand and the gas formation on
the other hand will be much more clear when the calculated
results of the energetic substance hexanitrohexaazaisowurt-
zitane (CL20) with different amounts of a polybutadiene
binder (PB) are compared.

Table 1 and Table 2 show that pure CL20 is more

energetic than RDX regarding the temperature and the
heat of explosion. On the other hand, combustion pressure
and specific energy of RDX are higher. The reason for this
behavior is the oxygen balance, which is much more
negative for RDX. Therefore, RDX produces more gas
than CL20, which increases the product n

R T

EX

to a

higher value of the specific energy, despite the fact that the
adiabatic temperature of RDX is lower.

Together with the PB-binder, the oxygen balance and the

enthalpy of formation decrease more and more connected
with a decrease in pressure, temperature and the energy
parameters. Only the mole number and therefore the gas
formation increase. In addition, startingat an oxyg

en

balance of about

57 %, the combustion reaction produces

more and more carbon soot.

This behavior is typical for the combustion of energetic

materials: In many cases it is known from experimental
investigations that carbon soot is formed from materials
with an oxygen balance more negative than

55 %. But the

combustion of energetic materials is very different from
detonation processes

(6)

. In the case of a detonation, much

higher pressures will occur. They are about 34 GPa for RDX
and about 19 GPa for TNT. Therefore, a lot of the produced
carbon monoxide (CO) reacts accordingto the Boudouard
equilibrium under the formation of carbon soot and CO

2

:

2 CO

, CO

2

‡ C

DH ˆ 172.4 kJ/mol

Therefore, the carbon soot formation in detonation

processes is much higher than in combustion processes.
Because of the high energy output of the Boudouard
reaction, also the detonation heat is higher than the heat of
combustion.

2.3 Energy of Solid Propellants

In connection with the performance of solid propellants,

the energy output of some gun propellants is shown in
Table 3. With decreasing oxygen balance, the energy and the
gas formation of four conventional propellants are com-
pared with two nitramine containingpropellants.

Table 2. Energy parameters of CL20 with different amounts of PB.

Explosive
CL20/PB
(weight %)

DH

f

kJ/kg

O

2

-Balance

%

Temperature
K

Pressure
MPa

Spec. Energy
J/g

Heat of Explosion
J/g

Mole number
mol/kg

Carbon
weight %

100/0

920.5

10.95

4 347

147.9

1 323

6 312

34.22

±

95/5

898.9

26.4

4 206

156.5

1 392

5 453

38.52

±

90/10

877.4

41.8

3 751

155.0

1 366

4 780

41.28

±

85/15

855.8

57.2

3 167

145.0

1 263

4 579

44.66

3.8

80/20

834.3

72.7

2 695

125.3

1 091

4 435

48.23

8.3

75/25

812.8

88.1

2 517

116.5

1 018

4 288

51.70

12.6

70/30

791.2

103.5

2 355

108.3

949

4 138

55.08

16.8

65/35

769.7

119.0

2 210

100.5

884

3 985

58.37

20.9

60/40

748.1

134.4

2 083

93.3

824

3 829

61.58

24.9

55/45

726.6

149.8

1 973

86.7

769

3 670

64.71

28.9

Table 3. Energy output of different solid propellants.

Name

O

2

-Balance

%

T
K

P
MPa

E

S

J/g

n
mol/kg

Q

EX

J/g

JA-2

30.35

3 397

127.1

1 141

40.39

4 622

A 5020

39.67

2 916

113.1

1 011

41.70

3 759

M 1

50.52

2 494

103.9

921

44.40

3 247

P 544

51.88

2 009

90.7

799

47.83

2 841

KHP 305

35.49

3 522

151.5

1 338

45.69

4 828

KHP 168

55.61

2 180

107.3

933

51.46

3 281

RDX

21.6

4 000

154.1

1 375

40.26

5 647

TNAZ

16.6

4 263

151.5

1 358

36.39

6 343

CL 20

10.9

4 347

147.9

1 323

34.22

6 312

138

F. Volk and H. Bathelt

Propellants, Explosives, Pyrotechnics 27, 136 ± 141 (2002)

Conventional propellants

*

JA-2

Double base propellant

*

A 5020 Single base propellant

*

M1

Single base propellant

*

P544

Triple base propellant with nitroguanidine (Nigu).

Nitramine containingpropellants

*

KHP 305 79% RDX, 8.0% TAGN, 13.0% GAP binder,

*

KHP 168 42.5% RDX, 42.5% Nigu, 4% KNO

3

,

11% Polybutadiene binder (PB).

In addition, the energy parameters of RDX, TNAZ (1,3,3-

Trinitroazetidine) and CL20 are listed in Table 3.

With the decrease of the temperature and of the specific

energy the gas formation (mole number n) increases. It is of
interest that the nitramine propellant KHP 305 containing
RDX and a GAP binder exhibits a much higher specific
energy (1 338 J/g) than the double base propellant JA-2
(1 141 J/g). On the other hand, the same composition with
respect to RDX and TAGN, but with a polybutadiene binder
instead of the GAP binder, produces a much lower specific
energy and heat of explosion. The reason for this behavior is
that the Glycidylazide Polymer (GAP) has a better oxygen
balance ( 121.1%) and a more positive enthalpy of
formation (H

f

ˆ ‡141.0 kJ/mol), compared with the poly-

butadiene HTPB: oxygen balance

ˆ 317.6% and H

f

ˆ

‡2.93 kJ/mol.

So, nitramine propellants with GAP-binders exhibit a

quite high energy, much higher than the conventional
propellants based on nitrocellulose, nitroglycerin or nitro-
guanidine.

Even for explosives with the highest energy output, such

as 1,3,3-Trinitroazetine (TNAZ) or Hexanitrohexaazaiso-
wurtzitane (CL20), the specific energies of the pure
substances are quite similar to the GAP containingnitr-
amine propellant KHP 305, as it is shown in Table 3.

2.4 Energy of Liquid Propellants

It is well known that liquid propellants increase the energy

output markedly (Table 4). High specific energies and heats
of explosion are produced from the hypergolic liquid
propellants with hydrazine (N

2

H

4

) and unsymmetric dime-

thylhydrazine H

2

N N(CH

3

)

2

(UDMH) as fuels and nitrogen

tetroxide (N

2

O

4

) as an oxidizer.

The followingspecific energies are calculated:

50% N

2

H

4

/

50% N

2

O

4

: 1 636 J/g

35% UDMH/50% N

2

O

4

: 1 536 J/g.

These energy values are higher than the highest energies

from solid propellants. It may be reminded that the rocket
motor of the Apollo 11 Spacecraft Vehicle landingon the

Table 4. Liquid explosives.

DH

f

kJ/kg

O

2

-Balance

%

Temperature
K

Pressure
MPa

Spec. Energy
J/g

Heat of Explosion
J/g

Mole number
mol/kg

N

2

H

4

/N

2

O

4

50/50

683.6

15.15

3 725

183.5

1 636

6 822

52.10

UDMH/N

2

O

4

35/65

151.6

29.33

3 818

172.6

1 536

6 246

46.87

MMH/HNO

3

35/65

1384

19.51

3 496

157.2

1 414

6 076

48.03

TEA/HNO

3

35/65

3362

20.7

3 159

125.5

1 137

4 973

43.0

NOS 365
HAN/IPAN/H

2

O

60.7/19.3/20.0

6144

0.01

2 480

98.1

916

4 647

44.28

Table 5. Combustion products of MMH/HNO

3

compared with the gun propellant JA-2 ( Loading density: 0,1 g/l).

MMH/HNO

3

JA-2

Analysis

Calculation

Calculation

Oxygen balance in %

30.0

30.0

30.35

Composition in Vol%
H

2

21.5

22.3

13.6

N

2

26.1

25.9

12.6

CH

4

0.7

0.9

0.6

CO

10.4

10.2

31.8

CO

2

4.7

5.6

18.8

H

2

O

36.6

34.8

22.5

Heat of Explosion Q

EX

( J/g)

5 583

4 609

Spec. Energy E

S

( J/g)

1 403

1 139

Mole number n (mol/kg)

52.52

40.39

Mean molecular weight (g/mol)

19.04

24.76

Enth. of Formation (kJ/kg)

1 209

2 290

Performance Parameters of Explosives

139

Propellants, Explosives, Pyrotechnics 27, 136 ± 141 (2002)

moon in July 1969 used UDMH and N

2

O

4

as rocket

propellants.

The specific energies of these liquid propellants are even

higher than those of gun propellants with a similar oxygen
balance because of the higher amount of reaction products
such as H

2

, N

2

and H

2

O, and less carbon dioxide. In addition,

a less negative enthalpy of formation leads to a higher heat
of explosion (Table 5).

Also other fuels such as monomethylhydrazine (MMH)

and triethanolamine (TEA) together with nitric acid
(HNO

3

) as an oxidizer develop quite high energies, see

Table 4.

The last liquid propellant system in Table, 4 NOS 365,

consistingof hydroxylammoniumnitrate (HAN), isopropyl-
ammonium nitrate (IPAN) and water is of interest, because
it was tested for a longtime as a liquid gun propellant

(7, 8)

.

This fuel combination has the main advantage that only CO

2

,

N

2

and water are produced duringthe combustion, without

formation of toxic CO.

2.5 Optimization of Gas Generators for Airbag Systems

Gas generators for airbag systems have to fulfill special

requirements with respect to the quality of the combustion
products. Especially, the amount of toxic components has to
be minimized and it has to correspond to the official limits.
Therefore, it is very helpful to reduce those toxic products,
which can be calculated very accurately such as the CO and
NO

X

by optimization of the fuel/oxidizer ratio at the

manufacturingprocess

(9)

.

Table 6 makes clear, how the CO content in the reaction

products of an airbagpropellant consistingof 5-amino-
tetrazole (5-ATZ) and potassium nitrate (KNO

3

) can be

minimized only by changing the fuel/oxidizer ratio. The
oxygen balance is of great influence on the formation of CO,
H

2

and NO. Increasingof the KNO

3

content, i.e. improving

the oxygen balance, the content of CO and H

2

decreases

very strongly. After attaining the minimum of CO a further
increase of the oxygen balance to positive values increases
the formation of NO.

Therefore, it is very important to meet special limits with

regard to the fuel/oxidizer ratio during the manufacturing of
the propellants for gas generators. Nevertheless, it is very
important to measure all the toxic products experimentally
by usingspecial trace analysis detectors.

3 Non-Equilibrium Combustion Reactions

Contrary to equilibrium reactions, it is not possible to

calculate non-equilibrium processes usingthermodynamic
codes, and for the reaction kinetic procedures, there are not
enough correct data for the many reaction rate constants,
which we need for a complete calculation of the reaction
products. Therefore, it is necessary to analyze the combus-
tion products.

A lot of investigations have been carried out at the

Fraunhofer ICT to learn about the products of propellants,
especially formed by low pressure burning

(10)

. As an

example, the reaction behavior of the double base propel-
lant JA-2 was investigated by burning under different
pressures (Table 7), first by burningin a closed vessel with
a loading density of 100 g/l (high pressure burning), then by
burning with a low loading density of 0.66 g/l. The high
loadingdensity of 100 g/l leads to a reaction pressure of
more than 120 MPa (see also Table 3), compared with only a
few MPa for the loadingdensity of 0.66 g/l. As a result, very
different reaction products have been analyzed.

Of special interest is the analysis of the product gas, which

was done by mass spectrometry and gas chromatography.
The low-pressure products are very different from the high
pressure burning, which is very similar to the calculated gas
composition: A high concentration of NO (18.9 mol%),
HCN (1.1 mol%), and carbon soot (13.5 mol%), which are

Table 6. Gas generator optimisation.

5-ATZ/KNO

3

( Weight%)

O

2

-Balance

%

Temperature
K

Heat of Explosion
J/g

Mole number
mol/kg

CO
mol%

H

2

mol%

NO
mol%

47.00/53.00

10

2 070

3 290

32.73

6.90

13.25

±

42.28/57.72

5

2 184

3 536

30.46

3.86

7.34

±

38.49/61.51

1

2 291

3 739

28.59

0.85

1.59

±

37.54/62.46

0

2 300

3 790

28.13

0.001

0.001

0.001

36.59/63.41

‡1

2 207

3 664

27.85

±

±

0.027

32.80/67.20

‡5

1 843

3 161

26.44

±

±

0.061

28.05/71.95

‡10

1 780

2 473

22.51

±

±

0.085

Table 7. Reaction products of double base GP JA-2.

( O

2

-Balance:

30.2%)

Experiment

Calculation

LoadingDensity [g/l]

0.66

100

100

Combustion Condition

0.1 MPa

Closed
Vessel

±

Products [mol%]:
H

2

3.5

14.0

13.6

CH

4

1.0

±

0.7

CO

24.9

32.7

31.2

CO

2

7.0

17.0

19.0

N

2

1.3

12.4

12.6

NO

18.9

0.025*

±

HCN

1.1

±

0.004

NH

3

0.8

±

0.08

H

2

O

28.0

23.4

22.9

C

solid

13.5

0.5

±

Q

EX

[ J/g]

2 488

4 550

4 719

* ( NO )

X

-Analyzer

140

F. Volk and H. Bathelt

Propellants, Explosives, Pyrotechnics 27, 136 ± 141 (2002)

typical for non-equilibrium products. There is also a large
difference in the heats of explosion: 2 488 J/gcompared with
4 550 J/g. These values have been calculated from the
difference of the enthalpies of the reaction products and
the propellant components.

A similar influence of the combustion pressure on the

reaction products was found for other propellants and
explosives such as single base and triple base propellants,
but also for all the nitramine containingpropellants

(11)

.

An example of non-equilibrium combustion of the nitr-

amine containingpropellant KHP 305 with a GAP binder is
recorded in Table 8. Also in this case, metastable reaction
products such as NO and HCN have been produced under
the low combustion pressure of the loadingdensity 0.67 g/l,
whereas the high pressure burning with 100 g/l exhibits only
main products such as H

2

, N

2

, CO, CO

2

and H

2

O, which are

typical products of the water gas equilibrium

CO

‡H

2

O

, CO

2

‡ H

2

DH ˆ 41.03 kJ/mol

In another study with the aim to evaluate the combustion

behavior of propellants as a function of the loadingdensity,
it was found that the equilibrium burningstarted at loading
densities higher than 10 to 20 g/l. This result is also in
agreement with experimental results of Andrejev

(12)

who

found that the equilibrium burningof nitric esters starts at
pressures higher than 1 to 1.5 MPa.

4 Conclusion

Several explosives have been calculated thermodynami-

cally by usingthe ICT-Code. It was shown that oxygen
balance and enthalpy of formation are the most important
parameters, which influence combustion temperature, spe-
cific energy, heat of explosion and gas formation.

Comparingthe reaction products of liquid propellants

and solid propellants havingthe same oxygen balance, the

investigated liquid propellants exhibit a higher specific
energy than the conventional solid propellants based on
nitrocellulose and nitroglycerin. The reason was the in-
creased formation of H

2

, N

2

and H

2

O producingmuch more

gas with a lower mean molecular weight.

It was also shown that the ICT-Code is very useful for the

optimization of gas generators for airbag systems, especially
to avoid toxic products.

In addition, it was explained that the limits of thermody-

namic calculations are burningreactions at low pressures. In
this case, a non-equilibrium burningis responsible for the
formation of toxic metastable reaction products, such as NO,
N

2

O, HCN etc. These products are the reason that the

energy output is much lower than in the case of an
equilibrium burningat pressures higher than 1 to 2 MPa.

5 References

(1) F. J. Zeleznik, S. Gordon, ™An Analytical Investigation of

Three General Methods of Calculating Chemical Equilibrium
Compositions∫, NASA-TN D-473, 1960.

(2) F. J. Zeleznik, S. Gordon, ™A General IBM 704 or 7090

Computer Program for Computation of Chemical Equilibri-
um Compositions, Rocket Performance, and Chapman-Jou-
guet Detonations∫, NASA-TN D-1454, October 1962.

(3) F. Volk, H. Bathelt, and H. Hornberg, ™Application of the

Virial Equation of State in CalculatingInterior Ballistics
Quantities∫, Propellants and Explosives 1, 7 ± 14 (1976).

(4) ™The ICT-Thermodynamic Code (ICT-Code), User×s Man-

ual∫, Report 200626-7, June 2000, Fraunhofer-Institut f¸r
Chemische Technologie (ICT), D-76318 Pfinztal.

(5) H. Bathelt, F. Volk, and M. Weindel, ™The ICT-Database of

Thermochemical Values, Sixth Update, 2001∫, Fraunhofer-
Institut f¸r Chemische Technologie (ICT), D-76318 Pfinztal.

(6) F. Volk, F. Schedlbauer, ™Analysis and Post Detonation Products

of Different Explosive Charges∫, IVth Seminar New Trends in
Research of Energetic Materials, University of Pardubice, Faculty
of Chemical Technology, April 11 ±12, 2001, pp. 352-359.

(7) C. S. Leveritt, N. Klein, ™The Physical Properties and

Molecular Structure of the HAN-Based Liquid Gun Propel-
lants∫, 22nd Int. Annual Conference of ICT, Karlsruhe,
Germany, July 2 ± 5, 1991, pp. 74/1 ± 10.

(8) N. Klein, C. S. Leveritt, ™The Ignition and Combustion of

Liquid Gun Propellants∫ 22nd Int. Annual Conference of
ICT, Karlsruhe, Germany, July 2 ± 5, 1991, pp. 49/1 ± 10.

(9) F. Volk, ™Utilization of Propellants for Inflator and Belt

Restraint Systems∫, 4th International Symposium on Special
Topics in Chemical Propulsion: Challenges in Propellants and
Combustion 100 Years After Nobel, Stockholm, Sweden, May
27 ± 31, 1996, pp. 457 ± 464.

(10) F. Volk, ™Analysis of Reaction Products of Propellants and

High Explosives∫, 3rd Symposium on Analysis and Detection
of Explosives, July 10 ± 13, 1989, Mannheim-Neuostheim,
Organized by Fraunhofer-Institut f¸r Chemische Technologie
(ICT), pp. 12/1 ± 18.

(11) F. Volk, ™Reaction Products of Nitrocellulose and Nitramine

ContainingPropellants∫, 22nd Int.Pyrotechnics Seminar, Fort
Collins, CO, USA, 15 ± 19 July 1996, pp. 717 ± 724.

(12) K. K. Andrejew, ™Thermische Zersetzungs- und Verbren-

nungsvorg‰nge bei Explosivstoffen∫, Erwin Barth Verlag
KG, Mannheim, 1964, p. 92.

(Received March 13, 2002; Ms 2002/008)

Table 8. Reaction products of KHP 305.

( O

2

-Balance:

36.3%)

Experiment

Calculation

LoadingDensity [g/l]

0.67

100

100

Combustion Condition

0.1 MPa

Closed
Vessel

±

Products [ Mol %]:
H

2

17.8

23.3

21.79

CH

4

0.3

0.3

±

CO

24.5

28.6

27.45

CO

2

5.3

5.4

6.01

N

2

27.9

30.9

31.01

NO

3.6

±

±

HCN

4.7

±

0.02

C

2

H

2

0.1

±

±

NH

3

0.1

±

0.32

H

2

O

15.7

11.5

13.39

Q

EX

[ J/g]

4 108

4 409

4 642

Performance Parameters of Explosives

141

Propellants, Explosives, Pyrotechnics 27, 136 ± 141 (2002)