HAN based green propellant
- Application and its
Combustion Mechanism Toshiyuki KATSUMI
and Keiichi HORI(ISAS/JAXA)
HAN-based liquid propellant
Hydroxyl Ammonium Nitrate (NH2OH･HNO3)



High Oxidizability
Low Toxicity
High Deliquescent
Water Solution


High Density
Low Freezing Point


Liquid Oxidizer
Monopropellant
Comparison of HAN-based
solution with Hydrazine
Hydrazine
HAN-based propellant
(SHP163)
Specific Impulse Isp** [s]
1.0
1.4
233
1.4
-68
276
ρ･Isp** [×103 s*kg/m3]
233
386
Toxicity
High
Low
Density ρ [×103 kg/m3] at 20 ˚C
Freezing temperature [˚C]
* SHP163: HAN/Ammonium Nitrate/Water/Methanol=95/5/8/21 (mass ratio)
** Nozzle area ratio (Ae/At);50, CF;1.875, Combustion chamber pressure; 0.7MPa
ρ･Isp of HAN-based propellant is
approximately 70% higher than Hydrazine
Burning rate
Control HAN/AN/Water/Methanol = 95/5/8/0
SHP069 HAN/AN/Water/Methanol = 95/5/8/8
SHP163 HAN/AN/Water/Methanol = 95/5/8/21
1000
Sample #1 (95/5/8/0)
Control
Control
Sample #2 (95/5/8/8)
SHP069
Sample #3 (95/5/8/21)
SHP163
REGRESSION RATE / mm/s
Combustion mechanism has not
been clarified
100
AN and methanol are eliminated
10
• Hydrodynamic
instability triggers the jump of the
1
burning rate to very high rate region
• Methanol0.1addition shifts the critical pressure to
1
3
10
5
7
higher pressure.
PRESSURE / MPa
Burning rates of aq. solutions
1000
80mass%
82.5mass%
Linear burning rate [m m /s]
77.5mass%
64mass%*
100
95m a
85m a
64mass%
85mass%
The linear burning
rate has the10 peak at
approximately
80mass% of HAN
concentration
50mass%
82.5m
80m a
77.5m
64m a
50m a
C rys
Crystal*
64m s
95mass%
1
1
2
3
4
P ressure [M P a]
5
6
7 8 9 10
*B. N. Kondrikov, V. E. Annikov, V. Yu. Egorshev, and L. T. De Luca,
“Burning of Hydroxylammonium nitrate”, Combustion, Explosion and Shock waves, Vol.36,No.1 ,2000
High burning rate
The linear
burning rates
are classified
to three zones
Temperature T / K
800
0
700
600
1000
500
400
Linear burning rate [mm/s]
300
0
0
0
5
10
Distance x / mm
15
95mass%
100
95mass%
85mass%
Zone2
85mass%
82.5mass%
82.5mass%
80mass%
80mass%
77.5mass%
77.5mass%
Zone3
10
64mass%
64mass%
Zone1
50mass%
50mass%
Low burning rate
De Luca
CrystalCrystal
by De by
Luca
1
1
1
1
2
2
3
4
5
6
Temperature T / K
800
700
600
500
7 8 400
9 10
3
4
5 6 7 8 9 10
Pressure [MPa]
Pressure [MPa]
300
0
5
10
Distance x / mm
15
Objective
 Combustion model of HAN aqueous
solution
 Combustion Model of HAN-based
propellant solution
The combustion wave structure of
HAN aq. solution
95mass% solution
80mass% solution
Reaction zone
Tf
Tbp
Tbp
T
T
Liquid phase
Two-phase
Gas phase
Two-phase
Liquid phase
The combustion wave structure of
HAN aq. solution
95mass% solution
80mass% solution
Reaction zone
Reaction zone
Tf
Tbp
Tbp
T
T
Liquid phase
Gas phase
Two-phase
Two-phase
Liquid phase
Combustion wave structure
changes by the water content
Reaction zone
High rb mode
Two-phase region
1. Fine bubbles are generated in front of
the combustion wave
2. Chemical reaction starts in the bubble
Two-phase
Liquid phase
Reaction zone
High rb mode
Two-phase region
1. Fine bubbles are generated in front of
the combustion wave
2. Chemical reaction starts in the bubble
3. Significant superheat (dT) is generated
Two-phase
Liquid phase
dT
Reaction zone
High rb mode
Two-phase region
1. Fine bubbles are generated in front of
the combustion wave
2. Chemical reaction starts in the bubble
3. Significant superheat (dT) is generated
4. Rapid nucleation is caused by superheat
Two-phase
Liquid phase
dT
Reaction zone
High rb mode
Two-phase region
1. Fine bubbles are generated in front of
the combustion wave
2. Chemical reaction starts in the bubble
3. Significant superheat (dT) is generated
4. Rapid nucleation is caused by superheat
5. High rb mode is established
Liquid phase
Nucleation rate may determine
the burning rate
Two-phase
Superheat & Nucleation rate
T Tg  TSAT
Liquid
T; superheat
Bubble
Tg
TSAT
dn
 G ( r * ) kTg
 Ne
dt
  kTg / h,
4 *
G (r )  r 
3
*
2RT 
r 
i fg Mp f T
*
2
SAT
Tg; vapor temperature
TSAT; saturation temperature
dn/dt; nucleation rate
N; number of molecules
per unit volume
k; Boltzmann constant
h; Plank’s constant
r*; radius of the vapor nucleus
; surface tension
R; universal gas constant
ifg; latent heat of vaporization
M; molecular weight
pf; pressure in liquid space
Radiuses of vapor nucleuses
Parameter;
Pressure1~8MPa
1.E-08
Gas temperature
800~1300K
r* (m)
5E-09
Tg=1300K
Tg=900K
Tg=1200K
Tg=800K
Tg=1100K
Tg=1000K
r*min=2x10-9m
1.E-09
(10A) 1
2
3
4
Pressure (MPa)
5
6
7
8 9 10
Nucleation rate (dn/dt)
1E+30
Nucleation rate [m-3s-1]
1E+28
1E+26
8
1E+24
9
1E+22
1
1E+20
Tg=1300K
1
1E+18
1E+16
r*min=2x10-9m
Tg=1200K
1E+14
1E+12
1E+10
Tg=1100K
1E+08
1E+06
Tg=1000K
Tg=900K
Parameter;
Pressure1~8MPa
1
Gas temperature
800~1300K
#
Tg=800K
1E+04
1E+02
1E+00
1
2
3
4
Pressure [MPa]
5
6
1
7 8 9 10
#
#
1E+04
1E+01
1E-02
1E-05
1E-08
1E-11
1E-14
1E-17
1E-20
1E-23
1E-26
1E-29
1E-32
1E-35
1E-38
1E-41
1E-44
1E-47
1E-50
Linear burning rate
1000mm/s
1mm/s
In Zone2, bubble nucleation
rate governs the burning rate.
Tg=1300K
110
120
130
1000
Tg=1200K
80mass%
82.5mass%
77.5mass%
Linear burning rate [m m /s]
3
dv/dt (m /s)
dv/dt (4/3r*3dn/dt)
800
100
95m ass%
85m ass%
64mass%
Tg=1100K
82.5m ass%
Tg=900K
80m ass%
50mass%
77.5m ass%
Tg=800K
10
Tg=1000K
64m ass%
50m ass%
C rystalby D e Luca
64m saa% by D e Luca
1
900
1
2
1
3
4
2
3
Pressure
(MPa)
5
4
P ressure [M P a]
6
5
6
7 8 9 10
7 8 9 10
100
3
dv/dt (m /s)
dv/dt (4/3r*3dn/dt)
1E+04
1E+01
1E-02
1E-05
1E-08
1E-11
1E-14
1E-17
1E-20
1E-23
1E-26
1E-29
1E-32
1E-35
1E-38
1E-41
1E-44
1E-47
1E-50
Linear burning rate
95-80mass%; The gas temperature1000mm/s
in bubble
1mm/s
may be lower than 80 mass% aq. solution,
as the two-phase region is relatively short.
The nucleation
and apparent burning rates
Tg=1300K
becomeTg=1200K
lower.
110
120
130
800
80-50mass%；The gas temperature in
bubbles may
be lower
than 80 mass% aq.
Tg=1100K
Tg=900K
solution because
of higher
water content.
Tg=800K
Tg=1000K
The nucleation and burning rates become
lower.
2
3
4
5 6 7 8 9 10
1
Pressure (MPa)
900
100
Surface propagation
rateinincreases
Combustion
mode
Zone3
rapidly by the local disturbance
(2) Local disturbance
(3) Concentration of reactive
(1) Stable combustion
gas into concave area
wave
(4) Expansion into liquid phase
(5) Expansion stops
Comparison
of combustion
The jump mechanism
of burningwave
rate to
high rate structure
region is not clarified
High rb
1000
REGRESSION RATE / mm/s
1000
#1 (95/5/8/0)
Sample
Control
#2 (95/5/8/8)
Sample
SHP069
Sample #3 (95/5/8/21)
SHP163
Linear burning rate [mm/s]
Combustion
wave
structures
of
propellant
Zone2
solutions are similar to aqueous solution in
Zone3each burning rate zone
Zone1
100
100
95mass%
85mass%
82.5mass%
10
80mass%
77.5mass%
10
64mass%
50mass%
1
Crystal by De Luca
1
0.1
1
2
3
4
Pressure [MPa]
5
6
7 8 9 10
1
3
5
7
10
PRESSURE / MPa
Low rb
Aqueous solution
Propellant solution
Phenomena of Burning Rate Jumping
Transition Process
Hydrodynamic
instability isNewthe
Bubble
Liquid
Liquid
Liquid
(2) Brown bubble invade
(1)
Stable
combustion
trigger
to
jump
to
extremely
high
(3)
New
fine bubble
into
liquid
phase
wave propagates
are generated
burning rate region
Liquid
Liquid
(4) New bubbles develop (5) Extremely high burning rate
quickly
is established
Hydrodynamic instability - 1
◆Margolis model; extended model of Landau/Levich instability
Stable at high pressure,
Estimation result is
and at low methanol content
opposite tendencies to
Our results;
◆ Flame
stretchateffect
our results
Unstable
high pressure
Lewis and
number
effect;
out of content
consideration
at low
methanol
(Lewis number; no pressure dependency)
Markstein
Marksteinnumber（Ma）
number (by asymptotics)

 Le  1 1  1 ln1  x 
Ma 
ln  
dx rate of stretched flame
Su
; Burnign

(s)
Su(l)-Su
0
1 (s)
2
 1
x
 Ma

Ka
Su(l); Laminar burning arate


T
T

T
d
ad
0
  Su

; Zel'dovich Number Le  ; Lewis Number
u (l)
b,
2
Ka; Flame stretch ratio
D
Ts
By Clavin P., Energy Combust. Sci., vol.11, pp.1-59, 1985
1000
Control#1 (95/5/8/0)
Sample
SHP069
Sample #2 (95/5/8/8)
SHP163
Sample
#3 (95/5/8/21)
REGRESSION RATE / mm/s
Unstable
at high pressure,
Hydrodynamic
instability
-3
M arkstein N um ber
Hydrodynamic and at low methanol content
Our results;
instability
of propellant
7.5
Unstable at high pressure
solutions is affected by
and at low methanol content
7
flame stretch and Estimation results
6.5
determines the jumpsupports our results
pressure.
6
100
10
1
0.1
1
3
5
PRESSURE / MPa
5.5
Ma=Ma,cr
5
3.3MPa
5.0MPa
4.5
6.6MPa
4
0
2
4
6
P ressure [M P a]
8
10
7
10
C ontrol
S H P 069
S H P 163
Application to thruster
Objective
Development of HAN-based Monopropellant Thruster
Propellant; SHP163
Catalyst; S405
Propellant
Catalyst
Heater
Burning process
1.Monopropellant is injected into the preheated catalyst bed.
2.Chemical reaction of monopropellant occurs at the catalyst bed.
3.Gas products burn thoroughly in the combustor.
4.Combustion product gas is exhausted through the nozzle.
Free fall test 1/2
HAN-based thruster
system
Sequence
Separation@37.5km
Y=0 sec
Y+20 sec
Start
Ｙ+50 sec
Finish
Launch
Thrusters burn
for 30 seconds
Objective
Pretest of supersonic vehicle test flight
• Balloon operation
• Attitude control by N2 gas jets
• HAN thrusters help the acceleration at free fall
Supersonic vehicle
mock-up
Free fall test 2/2
Flight system
Thruster
Diameter; 75 mm
Length; 992.5 mm
Nozzle
Thruster
Valve
Pressure
sensor
Thermocouple
Propellant Tank
Combustion
chamber
Injector
Catalyst bed
Static firing test
Simulated environmental test (Vacuum and Low temperature)
• Thruster burned stably for 30 seconds in simulated condition
Static firing test (movie)
Result of free fall test
Specific impulse; 230 sec
Combustion efficiency; 0.88
• Thruster burned well for 30 seconds in the flight
• Density*Isp is approximately 1.46 times higher than the hydrazine
• This results show the potential for the application to space programs
Summary
-Combustion mechanism• Bubble nucleation rate by superheat
governs the apparent linear burning rate in
very high burning rate zone.
• The water content dominates the burning
rate zone in the case of aqueous solutions.
• The hydrodynamic instability determines the
burning rate zone in the case of propellant
solutions.
Summary
-Application to thruster• Flight system is developed and burnt
for 30 seconds successfully in vacuum
and -50 C
• Isp is approximately 230 seconds
• The high potential of HAN-based
thruster for the application to space
programs was shown