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
Solid Propellants HTPB/AP/AL PBAN/AP/AL 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 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) Isp275 s269 s density1770 kg/m^31772 kg/m^3 Regression Rate8.9 mm/s7.4 mm/s
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_ratio Me3.378 e P_0695,000 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 rops.htm rops.htm Industrial Solid propulsion Inc, Propellant Info different compositions Pressure vs. Altitude Relationships, S.E. Van Bramer 1/18/ 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