Development Study of High-response Hydrogen Concentration Probe for Supersonic Flows

超声速流高响应氢气浓度探头的研制

• 批准号: 12450390
• 负责人: NAGATA Harunori
• 金额: $ 4.61万
• 依托单位: HOKKAIDO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12450390/
• 关键词: Scramjet Engine; Supersonic Combustion; Mixing in Share Layer; Catalytic Reaction

Scramjet engine is a strong candidate for use as thrusters for space planes and supersonic civil transporter in the next generation. Supersonic mixing is a key challenge to in realizing scramjet engines. Regarding this, the main purpose of this research is to develop a simple method to evaluate hydrogen concentration in a supersonic mixing layer without the need for costly apparatus. The investigators have proposed a hydrogen concentration probe using catalytic reaction on Pt wire surface. To use this probe to detect a concentration change in a supersonic mixing layer, the response of the catalytic heat release rate must depend only on concentration change around the probe. Catalytic heat release rate on the Pt wire surface in unsteady state is measured using a constant temperature type hotwire anemometer technique and a shock tube to investigate the relation of the response of the catalytic heat release rate and Pt wire temperature. The increasing rate of the catalytic heat release depends on the Pt wire temperature when the wire temperature is low. However, the dependence is very weak when the wire temperature is over about 680 K. This shows that not the catalytic reaction but moleculartransfer from the flow to the Pt wire surface is the controlling step when Pt wire temperature is high enough. As a conclusion, catalytic reaction rate on the Pt wire is high enough comparing with the molecular transfer rate with the temperature over about 680 K, yielding high response frequency as hotwire anemometers(over a hundred kHz).

超燃冲压发动机是下一代太空飞机和超音速民用运输机推进器的有力候选者。超音速混合是实现超燃冲压发动机的关键挑战。为此，本研究的主要目的是开发一种简单的方法来评估超音速混合层中的氢浓度，而不需要昂贵的设备。研究人员提出了一种利用铂丝表面催化反应的氢浓度探针。为了使用该探针检测超音速混合层中的浓度变化，催化放热速率的响应必须仅取决于探针周围的浓度变化。采用恒温式热线风速计技术和激波管测量非稳态铂丝表面催化放热速率，研究催化放热速率响应与铂丝温度的关系。当铂丝温度较低时，催化放热的增加速率取决于铂丝温度。然而，当丝温度超过约 680 K 时，相关性非常弱。这表明，当 Pt 丝温度足够高时，控制步骤不是催化反应，而是从流动到 Pt 丝表面的分子转移。综上所述，与温度超过 680 K 时的分子转移速率相比，Pt 线上的催化反应速率足够高，产生与热线风速计一样高的响应频率（超过 100 kHz）。