空间双组元发动机离心式喷注器的喷注流场诊断技术研究

本文对空间双组元发动机核心部件喷注器的喷雾流场可视化诊断技术开展了研究，以有效地识别出传统分析手段所难以发现的雾化场缺陷，从而实现对发动机工作特性的早期诊断，以实现故障预防和设计优化的目的。离心式喷注器的雾化喷注流场中包含了大量的数据信息，可以通过高速摄影和图像分析进行数据挖掘分析。通过均值图像和余弦相似性计算对喷注流场的空间分布结构进行诊断，均匀雾化场的左右相似度可以达到0.99以上。对图像液滴进行追踪测速，可以得到雾化平均速度场的量化分布。对雾化图片进行本征正交分解可以提取雾化场前6阶脉动主模态和幅频信息，分析其动态特性以识别异常状态。通过与热试车结果的比对，证明了在喷注流场诊断中发现异常的发动机在点火过程中出现了不均匀燃烧或者局部高温的缺陷，与冷态的流场诊断结果相符，对该诊断方法进行了验证。

Diagnosis Technology Research of Injection Spray Field for Swirl Injector of Bipropellant Space Engine

The present research was investigated for spray field visual diagnosis of injector, which is the most critical component of bipropellant rocket engine for spacecrafts. Therefore, it can visually identify atomization defects that are difficult to detect with traditional methods. In this way, the early diagnosis for engine characteristics can be achieved, thus aiming for failure prevention and design optimization. Spray field diagnosis under cold flow conditions can indicate a large amount of data and information, which can be used for data mining by means of high speed photography and image analysis. The spatial distribution structure of spray field was diagnosed by using mean image processing and cosine similarity calculation, and the left and right similarity of uniform spray field could reach more than 0.99. The quantized distribution of mean velocity was obtained by tracking and measuring the velocity of droplets in spray images. The first 6 order main modes and amplitude-frequency information of spray field were extracted by using proper orthogonal decomposition of spray images, and the dynamic characteristics of spray field can be analyzed to identify anomalies. By comparison with results of firing test, these diagnosis methods are adequately testified that the engine with abnormalities in spray diagnosis suffered failures of non-uniform combustion and local high temperature. It shows a good agreement with the cold spray field diagnosis, so these diagnosis methods are verified to be effective.