1. AAE 450 Spring 2008 Ricky Hinton February 6 th, 2008 Propulsion Group Solid Propellant Research and Optimum Expansion Ratio Code Additional help from: Dana Lattibeaudiere and Stephanie Morris

2. 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 v e, mass flow rate, P e /P 0, M e, ε Sample Results veve 2697 m/s m_dot16.5 kg/s P e /P 0 0.00845 MeMe 3.38 ε15.53 AAE 450 Spring 2008 HTPB/AP/ALPBAN/AP/AL Molecular Weight27.4 g/mol27.8 g/mol T_c3329 K3480 K γ (gamma)1.1421.18 Isp275 s269 s density1770 kg/m^31772 kg/m^3 Regression Rate8.9 mm/s7.4 mm/s

3. MATLAB Code: Solve for optimum expansion ratio (ε) and chamber pressure (P 0 ) 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 (P e = P a )  Uses altitude vs. P a 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_ratio0.0085 Me3.378 e15.513 P_0695,000 Pa

4. 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

5. Additional Slides  Naming Convention –HTPB = Hydroxyl-terminated polybutadine –AP = Ammonium Perchlorate –AL= Aluminum –PBAN = Polybutadiene Acrylonitrile AAE 450 Spring 2008

6. References  Solid rocket propellants and their properties http://www.sis.lr.tudelft.nl/Propulsion_details/Data/Propellant_properties_files/Solid_p rops.htm http://www.sis.lr.tudelft.nl/Propulsion_details/Data/Propellant_properties_files/Solid_p rops.htm  Industrial Solid propulsion Inc, Propellant Info different compositions http://www.specificimpulse.com/images/ISP_Portfolio.pdf 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 http://science.widener.edu/~svanbram/chem332/pdf/press_alt.pdf Additional Help Dana 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