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Highly Reliable Plasma Igniter for Ram/Scramjet

用于冲压/超燃冲压发动机的高度可靠的等离子点火器

基本信息

批准号：
10555331
负责人：
MASUYA Goro
金额：
$ 8.51万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-10555331/
关键词：
Scramjet Supersonic Combustion Ignition Plasma Jet 着火・保炎

项目摘要

In order to realize the ramjet/scramjet engine which is one of the most promising candidates of the propulsion system of aerospace planes, reliable ignition of fuel in supersonic airstream is an important subject. Plasma torches have been developed and tested in direct-connect combustors as well as in a sub-scale engine. However, early results of these tests showed insuffficient durability and reliability of the plasma igniter. The present research project has been carried out to clarify the cause of malfunction of the igniter and to develop highly reliable plasma igniter with experimental, theoretical and numerical approaches.The feedstock of the torch was changed from oxygen to nitrogen. Detrition of the electrodes and the nozzle of the torch was significantly suppressed by this change. In addition, the coolant of the torch was changed from gas to water. This change lessened thermal load of the torch. Durability of the plasma torch was greatly improved by these changes.Experimental and theoretical studies confirmed that the ignition performance of the nitrogen torch was as good as that of the oxygen torch. Improvement of the ignition perfomance was achieved by use of nitrogen/hydrogen mixture as the feedstock, though the minimum input power for the torch was increased. The improvement of ignition perfomance was caused by combustion of hydrogen in the plasma jet.When fuel was injected upstream the plasma torch, experiment and numerical simulation showed that it is important to select the lateral and transverse locations of the injector to make collision of the fuel jet and the plasma jet. The streamwise location and the angle of injection showed minor influence. When the fuel was injected downstream the plasma torch, the streamwise location became important, too.Increase of airstream Mach number made ignition performance of the torch worse. The effect of the pressue of the airstream was not straight forward in the present experiment.

冲压/超燃冲压发动机是空天飞机最有希望的推进系统之一，为了实现冲压/超燃冲压发动机，燃料在超声速气流中的可靠点火是一个重要课题。等离子体焰炬已经在直接连接的燃烧室以及一个小规模的发动机中开发和测试。然而，这些测试的早期结果显示等离子点火器的耐久性和可靠性不足。本课题从实验、理论和数值分析三个方面研究了等离子点火器的故障原因，并研制了高可靠性的等离子点火器。通过这种改变，电极和焊炬喷嘴的脱落被显著抑制。此外，火炬的冷却剂由气体改为水。这一变化减少了火炬的热负荷。这些变化大大提高了等离子体火炬的耐用性，实验和理论研究证实，氮气火炬的点火性能与氧气火炬相当。采用氮氢混合气作为点火原料，虽然提高了火炬的最小输入功率，但点火性能得到了改善。等离子体射流中氢气的燃烧改善了点火性能，实验和数值模拟结果表明，在等离子体炬上游喷入燃料时，选择喷注器的横向和侧向位置对燃料射流和等离子体射流的碰撞至关重要。流向位置和喷射角度的影响较小。当燃料在等离子体炬下游喷射时，流向位置也变得重要，气流马赫数的增加使等离子体炬的点火性能变差。在本实验中，气流压力的影响不是直接的。