conceptual design is a bridge between what is in our mind and what could be in market,the hybrid motor uses propellants in different physical phases and which is more advantageous than solid propellant engines.

1. SUB: Technical Seminar SUB CODE:17AE
NAME: ABHIJEET
USN: 1SJ17AE002
Topic
“Conceptual design of space hybrid motor”

2. Content
• What is conceptual design?
• What is hybrid motor?
• Components of hybrid motor
• Why hybrid motor is required?
• Hybrid motor advantages and challenges
• How to proceed in conceptual design?
• Conceptual design : case study
• Conclusion
• Reference

3. What is conceptual design ?

4. What is hybrid
motor?
• Hybrid motors in chemical
propulsion refers to a type
of motor which has
propellants in different
physical phases.
• Also referred as HRE
• working
• Many components of HM
are having similarities with
solid and liquid propellant
engines
• Despit such similarities the
nature and performance of
an HM is fundamentally
different

5. Components of hybrid motor

6. Why hybrid motor is required?
• The solid propellant motor have some
disadvantages like low Isp ,throttling , difficult
to stop and restart and some safety issues
• To overcome these disadvantages hybrid
motors can be used
• These are controllable and advantageous in
restart and throttling capability and it is easier
than liquid propellant engines

7. Hybrid motor
• Advantages :
 Use of energetic propellant
grids
 Handling is easy
 Eco friendly
 Fuel verstality
 Oxidizer control
 Good throttling
• Challenges or limitation
 Scalability
 stability
 low fuel regression rates
Disadvantages:
 Lower density – Specific
impulse
 Some fuel sliver in the
combustion chamber at the
end of burning
 Oxidizer to fuel ratio shift

8. How to proceed in conceptual design
space hybrid motor?
• Conceptual design has 3 steps:
1. Design determination: Assigns combination of
propellants , number of grain ports and
configuration of such ports to satisfy the
propulsive system requirements
2. Performance estimation: Is required to validate
the compatibility of results with requirements
3. Sizing :sizing the system and subsystem satisfy
the requirements.

9. Conceptual design: case study
• If we want to design a propulsion system for
the upper stages of an expandable launch
vehicle ,the mission requirements are as
follows:

10. Conceptual design
• Design determination:
Specific values for variables are a basic selection
& During design iteration they will be modified.
Design variables limit the response and allow
finding the results for specified condition and
with scanning the response surface for
acceptable values
For this consider some variables:

11. Conceptual design
• ….some basic parameter values like
• Grain port-8
• grain-wagon wheel with isolated core port
• Propellant combination: HTPB/Lox
• O/F ratio=1.2, CCP=30 bar
• Structure material= Al Alloy,
• pressurized He for oxidizer pressurization
• After choosing of parameters the specification and size
of the subsystem are evaluated
• The next step is preliminary design of components and
simulation of performance to validate results

12. CCP and feeding system
• Initial ccp =30 bar , Pamb=0 (assumed)bar
,Pe=0.01bars and other pressures are evaluated
as follows:
Pressure type formula Calculated values
Injector pressure loss P inj =0.2Pc 600, 000 (Pa)
Pressure loss of feeding
system
P feed(sutton,2010 )=0.016Pc 50000(Pa)
Dynamic pressure of oxidizer P dynamic=1/2(ρv^2) 57, 100 (Pa)
Cooling system pressure P cool=0.05Pc 150000(Pa)
Minimum required pressure
of oxidizer (OX) tank
PTank = Pc+Pdynamic+Pfeed
+Pinj
3, 707, 100(Pa)

13. Gas dynamic parameter calculation
• Nozzle exit pressure, Pc and Me
relation
• Exit mach number
• Expansion ratio
• Specific velocity
• Specific impulse

14. Initial mass flows
• Thrust
• Total exit mass flow
• Initial mass flow of fuel
and oxidizer

15. Determination of propellants and
allowed dry masses
• Ideal and actual specific impulse
• Ideal rocket equation detemines
the final mass
• Propellant mass
• Fuel mass
• Oxidizer mass

16. Fuel grain configuration
The number of ports and initial oxidizer flux are two desired input parameters to
evaluate fuel grain configuration. As mentioned before, a wagon wheel-shaped grain
with eight triangular ports was selected
• Oxidizer initial flux
• Initial c/s of port
• Initial c/s of fuel flux
• Throat dia and length of the
chamber

17. Sizing and configuration of subsystem
Throat area and exit area of
the nozzle
Throat dia and length of the chamber and
Length of converging and diverging
section of
nozzle

18. Conclusion
• By these calculation one can estimate required pressure
levels , gas dynamic parameters , required thrust , mass
flux ,propellant mass ,fuel grain configuration ,sizing of
system as per required by the perticular mission.
• One can do iteration and modification so that
improvisation can be done
• Coupling this conceptual design method with other
design disciplines can be used in multidisciplinary
design of space vehicles.
• Results of this study are useful for feasibility study and
developing HMs for space missions.

19. Reference
• https://www.researchgate.net/publication/2707
44808
• Aircraft Engineering and Aerospace
Technology: An International Journal
Conceptual design and performance simulation
of a space hybrid motor Article in Aircraft
Engineering and Aerospace Technology ·
January 2015