AAE 450 Spring 2008

Ricky HintonFebruary 6th, 2008Propulsion Group

Solid Propellant Research and Optimum Expansion Ratio Code

Additional help from:Dana Lattibeaudiere and Stephanie Morris

Solid Propellants HTPB/AP/AL 14-68-14 PBAN/AP/AL 12.5-69.9-16 Integrate these numbers into

Dana’s prop code to replace the historical figures

Allows us to solve for rockets ve, mass flow rate, Pe /P0, Me, ε

Sample Results

ve 2697 m/s

m_dot 16.5 kg/s

Pe /P0 0.00845

Me 3.38

ε 15.53

AAE 450 Spring 2008

HTPB/AP/AL PBAN/AP/AL

Molecular Weight 27.4 g/mol 27.8 g/mol

T_c 3329 K 3480 K

γ (gamma) 1.142 1.18

Isp 275 s 269 s

density 1770 kg/m^3 1772 kg/m^3

Regression Rate 8.9 mm/s 7.4 mm/s

MATLAB Code: Solve for optimum expansion ratio (ε) and chamber pressure (P0) given stage altitude

Input from Trajectory: – Altitude at stage deployment(s)– Number of stages

Input from Prop code: – Mass flow rate– Exit velocity– Molecular Weight (propellant)– Chamber Temperature

Assumes that 2/3 of the stage altitude is where the Optimum thrust is located (Pe = Pa)

Uses altitude vs. Pa equation to find ambient pressure

Exit pressure known, chamber pressure can be calculated

Preliminary code but it works!!!!! Currently it runs as an m-file, but it

will be a function Sample case: same inputs as

above

AAE 450 Spring 2008

Output

p_ratio 0.0085

Me 3.378

e 15.513

P_0 695,000 Pa

Future Work

Continue to develop the Altitude/optimization code that I'm writing Develop Solid propellants for Dana’s code further Work with MAT team this Saturday to run inputs Help prop group with cost modifiers

AAE 450 Spring 2008

Additional Slides Naming Convention

– HTPB = Hydroxyl-terminated polybutadine

– AP = Ammonium Perchlorate

– AL= Aluminum

– PBAN = Polybutadiene Acrylonitrile

AAE 450 Spring 2008

References Solid rocket propellants and their properties

http://www.sis.lr.tudelft.nl/Propulsion_details/Data/Propellant_properties_files/Solid_props.htm 

Industrial Solid propulsion Inc, Propellant Info different compositions http://www.specificimpulse.com/images/ISP_Portfolio.pdf

Pressure vs. Altitude Relationships, S.E. Van Bramer 1/18/1998 http://science.widener.edu/~svanbram/chem332/pdf/press_alt.pdf

Additional HelpDana Lattibeuadiere – Original Propulsion code

Stephanie Morris – Help writing the new code and researching propellants

Elizabeth Harkness – Provided preliminary numbers for trajectory altitude

AAE 450 Spring 2008