Pintle-controlled solid rocket motor research

Paper number

IAC-08.C4.3.12

Author

Mr. yuan wu, Northwestern Polytechnical Univ., China

Year

2008

Abstract

The test system of the pintle-controlled solid rocket motor was developed. PLC was triggered by firing signal, regulating command was issued by PLC, electrical servo mechanism was actuated, the pintle position was changed, throat area was changed, finally the interior ballistics of the motor was changed?and the velocity of pintle could be controlled real-time by servo system. 
Two experiments were carried out in this paper. The feasibility of the motor interior ballistics through controlling the pintle movement, the reliability of the dynamic seal, the work match of servo mechanism and motor were proven by the experiment. Four regulations of the pintle were mainly carried on in experiment ?and a pressure turndown ratio in excess of 3.756:1 was obtained. The test results show that the run pressure curve agrees well with the prediction curve. In experiment ?,the follow-up of the interior ballistics of the motor with the pintle movement velocity and frequency were tested. The results show that the follow-up of the interior ballistics is well while the frequency of pintle is one Hz, it become worse when following velocity and frequency of pintle is higher, and it will not change when the velocity and frequency of pintle exceed the range to the given propellant. 
The results show that the change of the interior ballistics is delay to the pintle movement, and the response time will be increased with advancing pressure ratio, and the response time of the pressure step-down process is shorter to the pressure step-up. The essential of the delay phenomenon is the process that the inner flow field adapts to the choked throat, and mutual couple to the combustion of the propellant. The delay-time of the experiments agrees well with the theoretical delay time in the magnitude.
For better predicting of the regulation characteristic of the motor interior ballistics, based on the dynamic mesh methods, the unsteady numerical simulation of the two experiments were carried on, the result of the unsteady numerical simulation ?is well with the experiment ?, but the result of the numerical simulation ? is not prefect to the experiment, the quick change characteristic of the interior ballistics under high frequency regulation is indicated in the unsteady numerical simulation. The possible reason is that single gas phase was calculated in numerical simulation without considering the influence of the propellant combustion and multi-component reaction.

Abstract document

IAC-08.C4.3.12.pdf

Manuscript document

IAC-08.C4.3.12.pdf (🔒 authorized access only).

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