冲量法固体推进剂燃速测试原始数据有效性判定

Determination of Validity of Original Data of Burning Rate Test of Solid Propellant by Impulse Method

关键词:  固体推进剂  燃速测试  冲量法  点火同步性  原始数据

Key words:  Solid propellant  Burning rate test  Impulse method  Ignition synchronization  Raw data

摘要:

为了定义并明确冲量法燃速测试的应用边界，通过对“推进剂药柱点火不同步”、“存在侵蚀”、“推进剂药柱同心度不好”3种情况下终了燃面偏离设计值的分析，提出以最大压强尤其是最大推力处的下降速率作为冲量法燃速测试数据有效性的判据，该判据同时解决了“裸露的推进剂药柱表面同步点火”无法评判的问题。根据燃烧室在无加质条件下燃气质量的变化规律，计算获得燃烧室压强随时间的改变趋势，与试验压强-时间曲线进行对比，提出数据有效性因子K，给出了原始数据有效性的数值判定方法。研究表明，当数据有效性因子K=1~1.2时，冲量法燃速测试结果与恒压发动机燃速测试结果一致性较好，数据有效。同时验证了喷管烧蚀会影响冲量燃速测试的压强范围，但不影响燃速测试结果。

Abstract:

In order to define and clarify the application boundary of the impulse burning rate test， the descending rate at the maximum pressure， by analyzing the deviation， which comes from “inconsistent ignition” “erosion combustion” or “propellant eccentricity”， between the final combustion surface and design value， is proposed as the criterion for the validity of the burning rate test data of impulse method. Besides， the criterion is capable of judging whether the surface of bare propellant grain has been ignited synchronously. Based on the principle of conservation of mass， a numerical method to determine the validity of the original data is given. The data validity factor K is obtained by calculating the ratio of the theoretical pressure drop time to the actual value. The research shows that when the data validity factor K=1~1.2， the combustion rate test results of the impulse method are in good agreement with those of the constant pressure engine. Furthermore， it is verified that nozzle ablation can affect the pressure range of impulse burning rate test， but does not affect the burning rate test result.