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ISSN Печать: 2150-766X
ISSN Онлайн: 2150-7678
Indexed in
ZERO-DIMENSIONAL UNSTEADY INTERNAL BALLISTIC MODELING
Краткое описание
Design of solid rocket motors requires theoretical models for prediction/test analysis having particular characteristics of effectiveness and short computation time, especially when these models are used for statistical calculations as scattering analysis or thrust imbalance evaluation between two coupled flight boosters. To this purpose, a specific internal ballistic model was developed and it is under validation at Fiat Avio-BPD with the following requirements: 1) the flow field solution in the propellant grain channel is obtained considering mass adduction, port area change, erosive burning, and different burn rate for each motor segment; 2) the motor ignition transient is described under unsteady conditions in the simplest way taking into account igniter mass flow rate, flame spreading, and chamber filling. These two requirements were properly combined through: 1) a steady-state solution of the propellant grain flow channel with a convenient linear combination of simple one dimensional flow in integral form (thus allowing Mach number, pressure, propellant mass flow rate, burn rate, etc. along the motor axis to be calculated); 2) unsteady internal ballistic model based on zero-dimensional operating conditions. Pressure, temperature, burn rate, and chamber volume are integrated in time taking into account the effective pressure and burn rate values obtained from the previous point 1 by means on iterative process. A good match was obtained during ignition transient and steady-state phase comparing the obtained results with more sophisticated models, and also with experimental measurements.