Abstract
Magnalium (Mg/Al)-AP based composite propellant has been studied as an improved neutralized propellant. Mg in Mg/Al particles plays a role of neutralizing agent. Mg/Al enhances the burning rates of AP based propellants by 40% in the range from 1.0 MPa to 10.0 MPa. To clarify the cause of the high burning rate, the thermal balance at the burning surface was analyzed by the temperature profiles, the observation of the metal particle condition on the burning surface and the calculated characteristic values of the solid propellant.
From the results of the quenched burning surface observation, it was found that Mg/Al particles were ready to ignite on the burning surface different from Al particles. As Mg/Al particle ignites and burns closely to the burning surface, the temperature gradient of the gas phase near the burning surface became steep. The heat input from the gas phase to the burning surface was estimated quantitatively with the characteristic value of the propellants. It is considered that the high burning rate of the propellant with Mg/Al depends mainly on the high temperature gradient in the gas phase at the burning surface.
マグナリウム（Mg/Al）-AP系コンポジット推進薬は，金属燃料にマグネシウムを適用した中和型推進薬と同様の観点で金属燃料にMg/Alを適用し，Mg/Alに含まれるMg成分の塩素固定化とエネルギー損失抑制の両立を狙っている。当該推進薬の燃焼速度は，金属燃料にAlを用いた同組成の推進薬よりも1〜10 MPaの窒素雰囲気においておよそ40 ％高い値を示す。燃焼表面の熱バランス式に基づいて燃焼速度増加に影響を及ぼす要因について検討した。すでに知見として得ていた燃焼表面近傍気相側の温度勾配や燃焼表面におけるMg/AlおよびAlの状態等の解析結果から，当該推進薬の燃焼特性はMg/Al粒子の燃焼機構に強く依存していることが分かった。Mg/Al粒子はAl粒子よりも表面近傍で着火，燃焼するため燃焼表面近傍気相側の温度勾配が急になり，その結果燃焼表面への熱流入量が増大して燃焼速度が増大したことを定量的に明らかにした。
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