U.S. patent application number 14/648889 was filed with the patent office on 2015-10-22 for liquid propellant.
The applicant listed for this patent is CARLIT HOLDINGS CO., LTD.. Invention is credited to Keiichiro Iwai, Katsuhiko Nozoe.
Application Number | 20150299063 14/648889 |
Document ID | / |
Family ID | 50827972 |
Filed Date | 2015-10-22 |
United States Patent
Application |
20150299063 |
Kind Code |
A1 |
Iwai; Keiichiro ; et
al. |
October 22, 2015 |
LIQUID PROPELLANT
Abstract
The present invention addresses the problem of providing a
liquid propellant which has low toxicity, is easy to handle, and
has excellent specific impulse. The present invention provides a
liquid propellant characterized by comprising at least a
dinitramide derivative represented by general formula (1) and an
amine nitrate represented by general formula (2).
Inventors: |
Iwai; Keiichiro; (Gunma,
JP) ; Nozoe; Katsuhiko; (Gunma, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CARLIT HOLDINGS CO., LTD. |
Tokyo |
|
JP |
|
|
Family ID: |
50827972 |
Appl. No.: |
14/648889 |
Filed: |
November 29, 2013 |
PCT Filed: |
November 29, 2013 |
PCT NO: |
PCT/JP2013/082160 |
371 Date: |
June 1, 2015 |
Current U.S.
Class: |
149/45 |
Current CPC
Class: |
C06B 25/34 20130101;
C06B 47/00 20130101; F02K 9/425 20130101; C06B 25/00 20130101; C06B
31/00 20130101 |
International
Class: |
C06B 31/00 20060101
C06B031/00; C06B 25/00 20060101 C06B025/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 30, 2012 |
JP |
2012-263446 |
Claims
1. A liquid propellant, comprising at least: a dinitramide
derivative represented by the following general formula (1)
##STR00005## (where R.sub.1-R.sub.4, which may be the same or
different, are hydrogen atom or alkyl group having 1-8 carbon
atoms); and an amine nitrate represented by the following general
formula (2) ##STR00006## (where R.sub.5 is an alkyl group having
1-8 carbon atoms, and R.sub.6-R.sub.7, which may be the same or
different, are hydrogen atom or alkyl group having 1-8 carbon
atoms).
2. The liquid propellant of claim 1, wherein the dinitramide
derivative is ammonium dinitramide represented by the following
formula (A) ##STR00007##
3. The liquid propellant of claim 1, wherein the total amount of
the dinitramide derivative and the amine nitrate is 80 wt % or
more.
4. The liquid propellant of claim 1, wherein the amine nitrate is
monoalkylamine nitrate.
5. The liquid propellant of claim 1, further comprising: a urea
derivative represented by the following general formula (3)
##STR00008## (where R.sub.8-R.sub.11, which may be the same or
different, are hydrogen atom, alkyl group having 1-6 carbon atoms,
alkenyl group having 2-6 carbon atoms, aryl group having 6-10
carbon atoms, alkylamino group having 1-6 carbon atoms, or
dialkylamino group having 2-6 carbon atoms, or optionally two or
more of R.sub.8-R.sub.11 are bonded together to form a five- or
six-membered ring that may have halogen groups).
6. The liquid propellant of claim 5, wherein the amount of urea
derivative is 5-20 wt %.
7. The liquid propellant of claim 1, wherein the weight ratio of
the dinitramide derivative to the amine nitrate is 4/6 to 7/3.
8. The liquid propellant of claim 1, wherein the liquid propellant
is substantially free of hydrazine.
9. The liquid propellant of claim 1, wherein R.sub.1-R.sub.4 and
R.sub.6-R.sub.7 are all hydrogen atoms.
10. The liquid propellant of claim 3, wherein R.sub.1-R.sub.4 and
R.sub.6-R.sub.7 are all hydrogen atoms
11. The liquid propellant of claim 3, wherein the weight ratio of
the dinitramide derivative to the amine nitrate is 4/6 to 7/3.
12. The liquid propellant of claim 11, wherein R.sub.1-R.sub.4 and
R.sub.6-R.sub.7 are all hydrogen atoms.
13. The liquid propellant of claim 5, wherein the total amount of
the dinitramide derivative and the amine nitrate is 80 wt % or
more, and R.sub.1-R.sub.4 and R.sub.6-R.sub.7 are all hydrogen
atoms.
14. The liquid propellant of claim 13, wherein the liquid
propellant is substantially free of hydrazine.
Description
TECHNICAL FIELD
[0001] The present disclosure relates to a liquid propellant, and
more specifically, relates to a liquid propellant using a
dinitramide derivative and an amine nitrate.
BACKGROUND ART
[0002] In general, a liquid propellant is used as a propelling
source for a flying object, such as a rocket, and the like. In the
space rocket field, thrust can be controlled by suspending
combustion and re-ignition, and therefore, a liquid propellant is
utilized in posture control for an artificial satellite and the
like using a thruster, as well as a main engine of a rocket.
[0003] In general, there are two types of liquid propellants, that
is, a two-component mixture type and a one-component type. The
two-component mixture type can achieve large thrust by being burned
using a liquid oxidizer and a liquid fuel but, since a supply
device requires two systems, a complicated system is needed. The
one-component type may be burned by a contact with a catalyst or
external energy, and therefore, has a characteristic in which the
system may be simplified.
[0004] Examples of a liquid oxidizer used for a two-component
mixture type liquid propellant include liquid oxygen, dinitrogen
tetroxide, and the like, and examples of a liquid fuel used
therefor includes liquid hydrogen, and the like. Although these are
propellants that satisfy a certain performance requirement, liquid
oxygen and liquid hydrogen have to be handled at extremely low
temperature, dinitrogen tetroxide has high toxicity, and therefore,
a protective suit or the like has to be used to ensure safety, thus
resulting in a problem in handling.
[0005] For one-component type propellants, propellants using
hydrazine, an aqueous solution of hydroxylamine nitrate have been
developed and studied.
[0006] Hydrazine has high toxicity and is easily evaporated, and
therefore, in handing hydrazine, wearing of a special suit and an
air supply equipment therefor are needed. Furthermore, specified
working staff and medical staff are needed, parallel work is
prohibited during filling work, and like problems, which notably
reduce work efficiency in launching, arise.
[0007] Hydroxylamine nitrate has many problems in safety and
technical aspects, including, for example, a problem in which
hydroxylamine nitrate has detonation, which was a cause of an
explosion accident in a row material plant, and the like.
[0008] PATENT DOCUMENT 1 describes a liquid oxidizer using one or
more oxidizers selected from a group consisting of hydroxylamine
nitrate, hydrozinium nitroformate, ammonium dinitramide, ammonium
nitrate, and a hydrogen peroxide, and a hybrid propellant using the
liquid oxidizer. By using, as the liquid oxidizer, an aqueous
solution of hydroxylamine nitrate, hydrozinium nitroformate,
ammonium dinitramide, ammonium nitrate, and a hydrogen peroxide, a
system at extremely-low temperature and toxicity, which may be
problems of liquid oxide and dinitrogen tetroxide that are
conventional liquid oxidizers, are improved and specific impulse
equivalent to that achieved by a conventional technique can be
achieved, but noticeable increase in specific impulse has not been
achieved.
[0009] PATENT DOCUMENT 2 describes a propellant using, as an
oxidizer, a salt using dinitramide anion. As the fuel, monohydric
alcohol, dihydric alcohol, trihydric alcohol, or polyhydric alcohol
(specifically, glycerol (glycerine), or glycine) is useful, and
ammonium dinitramide (ADN), water, glycerol are described as
examples of specifically preferable compounds. Even when a mixture
of ADN and glycerol or glycine is used, water is indispensable in
using the mixture as a liquid propellant, and as a result, specific
impulse is disadvantageously reduced.
[0010] In view of the foregoing, there have been demands for a
liquid propellant with excellent specific impulse, which has low
toxicity and can be easily handled.
PATENT DOCUMENT
[0011] PATENT DOCUMENT 1: JP2002-020191 A
[0012] PATENT DOCUMENT 2: JP 2002-537218 A
SUMMARY OF THE INVENTION
Technical Problem
[0013] An object of the present invention is to provide a liquid
propellant with excellent specific impulse, which has low toxicity
and can be easily handled.
Solution to the Problem
[0014] As a result of keen examinations, the present inventors
found that the above-described object can be resolved by using a
liquid propellant containing at least a dinitramide derivative
represented by general formula (1) and an amine nitrate represented
by general formula (2) and completed the present invention.
[0015] That is, the present invention is as follows.
[0016] A first invention is directed to a liquid propellant
characterized by containing at least a dinitramide derivative
represented by the following general formula (1) and an amine
nitrate represented by the following general formula (2).
##STR00001##
[0017] In the general formula (1), R.sub.1-R.sub.4, which may be
the same or different, are hydrogen atom or alkyl groups having 1-8
carbon atoms.
##STR00002##
[0018] In the general formula (2), R.sub.5 is an alkyl group having
1-8 carbon atoms, and R.sub.6-R.sub.7, which may be the same or
different, are hydrogen atom or alkyl group having 1-8 carbon
atoms.
[0019] A second invention is directed to the liquid propellant
described in the first invention, characterized in that the
dinitramide derivative is ammonium dinitramide represented by the
following formula (A).
##STR00003##
[0020] A third invention is directed to the liquid propellant
described in the first or second invention, characterized in that
the amine nitrate is monoalkylamine nitrate.
[0021] A fourth invention is directed to the liquid propellant
described in any one of the first to third inventions,
characterized by containing a urea derivative, which will be
described later, and in that the amount of urea derivative is
preferably 5-20 wt %.
[0022] A fifth invention is directed to the liquid propellant
described in any one of the first to fourth inventions,
characterized in that the weight ratio of the dinitramide
derivative to the amine nitrate is 1/9 to 9/1, and preferably, 4/6
to 7/3.
[0023] A sixth invention is directed to the liquid propellant
described in any one of the first to fifth inventions,
characterized in that the total amount of the dinitramide
derivative and the amine nitrate is 80 wt % or more.
[0024] A seventh invention is directed to the liquid propellant
described in any one of the first to sixth inventions, in which the
liquid propellant is substantially free of hydrazine.
Advantages of the Invention
[0025] According to the present invention, a liquid propellant with
excellent specific impulse, which can be easily handled, and
preferably, has low toxicity, can be provided.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1 is a graph illustrating the relationship for specific
impulse of a liquid propellant using ammonium dinitramide and
monomethylamine nitrate.
DESCRIPTION OF EMBODIMENTS
[0027] The present invention is directed to a liquid propellant
characterized by containing at least a dinitramide derivative
represented by the above-described general formula (1) and an amine
nitrate represented by the above-described general formula (2).
[0028] The term "liquid propellant" herein means a propellant that
has fluidity when the liquid propellant is supplied and ejected in
a rocket engine system. As long as fluidity is not lost, the liquid
propellant may contain a solid material.
[0029] In the above-described general formula (1), R.sub.1-R.sub.4,
which may be the same or different, are hydrogen atom or alkyl
group having 1-8 carbon atoms.
[0030] Preferably, as the alkyl groups having 1-8 carbon atoms,
alkyl groups having 1-6 carbon atoms are preferable, and
specifically, examples of the alkyl groups having 1-8 carbon atoms
include a methyl group, an ethyl group, a propyl group, a butyl
group, a pentyl group, a hexyl group, and the like, and among
these, a methyl group is specifically preferable because the methyl
group has excellent solubility.
[0031] Examples of a cationic part of ammonium dinitramide
represented by the general formula (1) includes an ammonium cation,
a tetramethylammonium cation, a tetraethylammonium cation, a
tetrapropylammonium cation, a tetraisopropylammonium cation, a
tetrabutylammonium cation, a trimethylethylammonium cation, a
triethylmethylammonium cation, a dimethyldiethylammonium cation, a
dimethylethylmethoxyethylammonium cation, a
dimethylethylmethoxymethylammonium cation, a
dimethylethylethoxyethylammonium cation, a trimethylpropylammonium
cation, a dimethylethylpropylaminium cation, a
triethylpropylammonium cation, and the like.
[0032] Among these, the ammonium cation is specifically preferable
because the ammonium cation has excellent specific impulse. That
is, it is preferable to use the ammonium dinitramide represented by
the formula (A), that is, a compound in which R.sub.1-R.sub.4 are
all hydrogen atoms.
[0033] As a method for producing ammonium dinitramide, a known
production method (JP1997-500795 A, WO91/19669 A, and the like) may
be used. Ammonium dinitramide of the above-described general
formula (1) can be obtained by preparing a corresponding cation in
accordance with the production method.
[0034] In the general formula (2), R.sub.5 is an alkyl group having
1-8 carbon atoms and R.sub.6-R.sub.7, which may be the same or
different, are hydrogen atom or alkyl group having 1-8 carbon
atoms. At least one of R.sub.6 and R.sub.7 may be an alkyl group
that is the same as that of R.sub.5 or different from that of
R.sub.5.
[0035] Preferably, as alkyl groups having 1-8 carbon atoms, alkyl
groups having 1-6 carbon atoms are preferable, and specifically,
examples of the alkyl groups having 1-8 carbon atoms include a
methyl group, an ethyl group, a propyl group, a butyl group, a
pentyl group, a hexyl group, and the like, and among these, the
methyl group is specifically preferable because the methyl group
has excellent solubility.
[0036] Examples of amine of the amine nitrate represented by the
general formula (2) include monoalkylamine, dialkylamine, and
trialkylamine
[0037] Examples of monoalkylamine include monomethylamine,
monoethylamine, monopropylamine, monobutylamine, monopentylamine,
monohexylamine, and the like.
[0038] Examples of dialkylamine include dimetylamine, diethylamine,
dipropylamine, dibutylamine, dipentylamine, dihexylamine,
methylethylamine, methylpropylamine, methylbutylamine,
ethylpropylamine, ethylbutylamine, and the like.
[0039] Examples of trialkylamine include trymethylamine,
triethylamine, trypropylamine, tributylamine, tripentylamine,
triheptylamine, dimethylethylamine, diethylmethylamin, and the
like.
[0040] Among these, monoalkylamine is preferable because
monoalkylamine has excellent specific impulse, and specifically,
monomethylamine is preferable. In other words, both of R.sub.6 and
R.sub.7 in the general formula (2) are preferably hydrogen atoms,
and specifically, R.sub.5 is preferably a methyl group. As amine
nitrate represented by the general formula (2), commercially
available amine nitrate may be used and amine nitrate obtained by a
known production method may be used. As the production method, for
example, a method in which corresponding amine and a nitric acid
are caused to react may be used, and specific examples will be
described later as Examples.
[0041] The liquid propellant using the dinitramide derivative
represented by the general formula (1) and the amine nitrate
represented by the general formula (2) does not need to use
hydrazine and has lower toxicity than a liquid propellant using
hydrazine, so that the liquid propellant may be easily handled even
without ensuring safety with a protective suite, and the like, and
also, has more excellent specific impulse than that of a liquid
propellant that has been used up until now. Therefore, preferably,
the liquid propellant according to the present invention is
substantially free of hydrazine. The expression "substantially free
of hydrazine" means, for example, that a content thereof is 1 wt %
or less. Preferably, the total amount of the dinitramide derivative
represented by the general formula (1) and the amine nitride
represented by the general formula (2) in the liquid propellant
according to the present invention is 75 wt % or more, more
preferably, 80 wt % or more, and further more preferably, 90 wt %
or more.
[0042] Regarding the ratio between the dinitramide derivative
represented by the above-described general formula (1) and the
amine nitrate represented by the above-described general formula
(2), (the weight of the dinitramide derivative)/(the weight of the
amine nitrate) is preferably 10/90 to 90/10, more preferably, 20/80
to 80/20, and further more preferably, 40/60 to 70/30. Specifically
excellent specific impulse may be achieved by setting the ratio in
the above-described ranges.
<Freezing Point Depressant>
[0043] The liquid propellant according to the present invention may
contain a urea derivative, which will be described below, in order
to depress the freezing point of the liquid propellant. In the
present invention, "a urea derivative" may be "urea" itself. The
liquid propellant according to the present invention preferably
contains 5-20 wt % of a urea derivative.
[0044] The urea derivative is a compound represented by the
following general formula (3), which has a urea bond in a
molecule.
##STR00004##
[0045] In the general formula (3), R.sub.8-R.sub.11, which may be
the same or different, are hydrogen atom, alkyl group having 1-6
carbon atoms, alkenyl group having 2-6 carbon atoms, aryl group
having 6-10 carbon atoms, alkylamino group having 1-6 carbon atoms,
or dialkylamino group having 2-6 carbon atoms. Optionally, two or
more of R.sub.8-R.sub.11 may be bonded together to form a five- or
six-membered ring, and these groups may further have halogen
group(s).
[0046] Specific examples of the urea derivative represented by the
general formula (3) include urea, N-methyl-N'-methylurea,
N-methyl-N'-ethylurea, N-methyl-N'-propylurea,
N-methyl-N'-butylurea, N-metyl-N'-pentylurea,
N-methyl-N'-hexylurea, N-methyl-N'-phenylurea,
N-methyl-N'-stearylurea, N-ethyl-N'-ethylurea,
N-ethyl-N'-propylurea, N-ethyl-N'-butylurea, N-ethyl-N'-pentylurea,
N-ethyl-N'-hexylurea, N-ethyl-N'-phenylurea,
N-ethyl-N'-stearylurea, N-butyl-N'-pentylurea,
N-butyl-N'-hexylurea, N-butyl-N'-phenylurea,
N-butyl-N'-stearylurea, and the like, and among these, urea, that
is, a form in which R.sub.8-R.sub.11 are all hydrogen, is
specifically preferable because urea has an excellent advantage of
depressing the freezing point.
[0047] Whether or not water is used as a solvent, the liquid
propellant according to the present invention is in a liquid state,
and therefore, water is not necessarily used, but in order to
depress the freezing point of the liquid propellant or the like,
water may be added, as appropriate.
[0048] For the liquid propellant according to the present
invention, in order to adjust various performances, a fuel may be
used. Examples of the fuel include alcohols, aminos, ketones, and
the like.
[0049] Examples of alcohols include methanol, ethanol, ethanediol,
propanol, isopropanol, propanediol, propanetriol, butanol,
butanediol, and the like.
[0050] Examples of aminos include glycine, alanine, valine,
leucine, isoleucine, and the like.
[0051] Examples of ketones include acetone, methylethylketone,
methylpropylketone, methylisobutylketone, dimethylketone,
diethylketone, methylamylketone, cyclohexanone, isophorone, and the
like.
<Additives>
[0052] As the liquid propellant according to the present invention,
a liquid propellant may contain an additive and thus be used.
Examples of the additive include a combustion catalyst, a
combustion aid, and the like.
[0053] A combustion catalyst is a catalyst that promotes
combustion, and more specifically, increases reaction activity,
enables ignition at low temperature, and can be used in a wide
range. Examples of the combustion catalyst include rhodium,
ruthenium, platinum, palladium, iridium, and the like.
[0054] A combustion aid is an additive that increases specific
impulse of a liquid propellant, and examples of the combustion aid
include aluminum, magnesium, boron, titanium, graphite, and the
like, in a powder form.
[0055] As for a conventional liquid propellant, such as dinitrogen
tetroxide, and the like, the average density at 23.degree. C. was
about 1.44 g/cm.sup.3 or less. On the other hand, the average
density for the liquid propellant according to the present
invention at 23.degree. C. is preferably 1.45-1.52 g/cm.sup.3. As
described above, excellent specific impulse, which will be
described later, may be achieved by increasing the average
density.
<Specific Impulse>
[0056] Specific impulse is a measure of fuel efficiency of a rocket
engine, and represents the magnitude of thrust with respect to a
propellant flow rate. As a calculation formula, "specific
impulse=thrust/(propellant flow rate*gravitational acceleration)"
is used and the units are seconds. In other words, specific impulse
is "seconds for which the generation of unit thrust can be
continued by a propellant of a unit weight". Specific impulse is
related to the pressure and temperature of the inside of an engine,
the composition and thermodynamic characteristic of a combustion
product, an atmospheric pressure, and an expansion velocity.
[0057] Vacuum specific impulse of a liquid propellant can be
calculated using NASA CEA2 chemical equilibrium calculation program
(Chemical Equilibrium with Application, NASA-Glenn chemical
equilibrium program CEA2, May 21, 2004, by Bonnie McBride and
Sanford Gordon). The results calculated for the specific impulse of
a liquid propellant using ammonium dinitramide and monomethylamine
nitrate by the program are given in FIG. 1.
[0058] The specific impulse calculated using the above-described
chemical equilibrium calculation program at a chamber pressure of
10 bar with an opening area ratio of 100 is preferably 240 sec or
more, more preferably, 260 sec or more, and specifically, even more
preferably, 280 sec or more.
[0059] The liquid propellant according to the present invention can
achieve specific impulse of, for example, 240 sec or more, and more
preferably, 240-320 sec. Therefore, the liquid propellant according
to the present invention may be optimally used as a liquid
propellant for rockets.
EXAMPLES
[0060] The present invention will be described below with reference
to Examples, but the present invention is not limited to the
Examples.
Examples 1-10, Comparative Examples 1-5
[0061] For Examples 1-10 and Comparative Examples 1-5, a component
1, a component 2, an additive, and a solvent corresponding to Table
1 were used. For ammonium dinitramide, urea, hydrazine, glycerol,
and ammonium nitrate, commercially available reagents were used.
For monomethylamine nitrate, monomethylamine nitrate produced in
the following manner was used.
<Synthesis of Monomethylamine Nitrate>
[0062] Reaction was caused by dropping 187.6 parts of 70% nitric
acid to 146.5 parts of a monomethylamine 40% aqueous solution and
stirring the obtained mixture at 10.degree. C. or less. After
reaction, water was distilled away from the obtained aqueous
solution under the conditions of 60.degree. C. and 30 mmHg to
obtain a saturated aqueous solution of monomethylamine nitrate. The
saturated aqueous solution of monomethylamine nitrate was added to
280 parts of isopropyl alcohol and the obtained mixture was stirred
to precipitate a crystal of monomethylamine nitrate. The obtained
crystal was filtered, was washed with isopropyl alcohol, and was
dried, and thus, 186.4 parts of monomethylamine nitrate was
obtained.
TABLE-US-00001 TABLE 1 Liquid Propellant Component 1 Component 2
Additive Solvent (wt %) (wt %) (wt %) (wt %) Example 1 ADN MMAN --
-- 25 75 Example 2 ADN MMAN -- -- 50 50 Example 3 ADN MMAN -- -- 57
43 Example 4 ADN MMAN -- -- 75 25 Example 5 ADN MMAN Urea -- 52 39
9 Example 6 ADN MMAN -- Water 52 39 9 Example 7 ADN MMAN Urea 50 30
20 Example 8 ADN MMAN Urea 40 40 20 Example 9 ADN MMAN Urea 40 50
10 Example 10 ADN MMAN Urea 60 30 10 Comparative ADN GLU -- Water
Example 1 61 13 26 Comparative N.sub.2H.sub.4 -- -- -- Example 2
100 Comparative ADN AN -- -- Example 3 60 40 Comparative ADN AN
Urea -- Example 4 50 40 10 Comparative ADN AN -- Water Example 5 50
40 10
[0063] Abbreviated words in Table 1 represent as follows.
ADN: ammonium dinitramide (compound A) MMAN: monomethylamine
nitrate Urea: urea GLU: glycerol (glycerine) N.sub.2H.sub.4:
hydrazine AN ammonium nitrate
[0064] In order to obtain vacuum specific impulse of a liquid
propellant, calculation was performed using NASA CEA2 chemical
equilibrium calculation program (Chemical Equilibrium with
Application, NASA-Glenn chemical equilibrium program CEA2, May 21
2004, by Bonnie McBride and Sanford Gordon). As initial conditions,
heat of formation of each component was input as follows, 10 bar
was input for the chamber pressure, and 100 was input for the
nozzle opening area ratio, and thus, calculation was performed.
[0065] The heat of formation (cal/mol) of each component input for
use in the above-described calculation is as follows.
[0066] Ammonium dinitramide (N.sub.4H.sub.4O.sub.4): -35,500
[0067] Monomethylamine nitrate (CH.sub.6O.sub.3N.sub.2):
-80,981
[0068] Urea (CH.sub.4ON.sub.2): -79,679
[0069] Hydrazine (N.sub.2H.sub.4): +12,103
[0070] Glycerol (C.sub.3H.sub.8O.sub.3): -159,775
[0071] Water (H.sub.2O): -68,315
[0072] The state of the liquid propellant at ambient temperature
was evaluated by visual examination. A liquid that does not contain
a solid state material at all, a liquid that partially contains a
solid state material, and a perfect solid are labeled as A, B, and
X, respectively. The vacuum specific impulse and the state of the
liquid propellant at normal temperature are summarized in Table
2.
TABLE-US-00002 TABLE 2 Vacuum Specific State of Liquid Impulse Isp
Propellant at (sec) Normal Temperature Example 1 284.9 B Example 2
306.8 B Example 3 311.3 B Example 4 285.3 B Example 5 293.7 A
Example 6 283.8 A Example 7 280.0 A Example 8 273.7 A Example 9
281.3 A Example 10 299.4 A Comparative Example 1 256.5 A
Comparative Example 2 237.5 A Comparative Example 3 221.1 X
Comparative Example 4 245.3 B Comparative Example 5 234.2 B
[0073] According to Table 2, it is understood that the specific
impulse is better for Examples 1-10 than for Comparative Examples
1-5. Also, in Examples 1-10, since the freezing point depressed,
and therefore, it is understood that the liquid propellant fully
contains a liquid at normal temperature.
INDUSTRIAL APPLICABILITY
[0074] A liquid propellant according to the present invention does
not have toxicity, is easy to handle, and has excellent specific
impulse, and therefore, can be used not only for a liquid
propellant for rockets but also for various applications.
[0075] The present invention is based on Japanese Patent
Application No. 2012-263446 filed on Nov. 30, 2012, in Japan, the
entire disclosure of which is incorporated by reference herein and
forms a part of the present specification.
* * * * *