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title半導体レーザ吸収法によるExpansion Tube気流の計測
Other TitleExpansion tube flow diagnostics using laser diode absorption spectroscopy
Author(jpn)中北, 和之
Author(eng)Nakakita, Kazuyuki; Jeffries, Jay B.; Hanson, Ronald K.
Author Affiliation(jpn)宇宙航空研究開発機構総合技術研究本部風洞技術開発センター; スタンフォード大学機械工学科高温気体力学研究室; スタンフォード大学機械工学科高温気体力学研究室
Author Affiliation(eng)Wind Tunnel Technology Center, Institute of Aerospace Technology, Japan Aerospace Exploration Agency (JAXA); High Temperature Gasdynamics Laboratory (HTGL), Department of Mechanical Engineering, Stanford University; High Temperature Gasdynamics Laboratory (HTGL), Department of Mechanical Engineering, Stanford University
Issue Date2008-02-29
PublisherJapan Aerospace Exploration Agency (JAXA)
Publication titleJAXA research and development report
Publication date2008-02-29
AbstractAn expansion tube flow diagnostics was conducted to identify its flow static temperature as a research topic of the visiting researcher from JAXA. The expansion tube has constructed at High Temperature Gasdynamics Laboratory (HTGL), Department of Mechanical Engineering, Stanford University since July, 2005. As the expansion tube flow diagnostics, it was necessary to measure flow static temperature, however, it could not apply the conventional thermo sensors, which have poor time response, or theoretical estimation using incident Mach number of shock wave, which may cause error. The tunable laser diode absorption spectroscopy was applied because of its merits of fast and direct temperature measurement. The target seed of the tunable laser diode absorption spectroscopy was water vapor. This article includes followings as the description of the measurement system preparation and construction; (1) theory of absorption spectroscopy and temperature calculation. (2) line selection program to select best lines for the expansion tube tests. (3) test model for expansion tube test. (4) measurement system of the tunable laser diode absorption spectroscopy for expansion tube. HITRAN2004 was utilized to apply line selection and construct the data reduction software as the database of the absorption line. The expansion tube flow diagnostics was conducted using the constructed measurement system. Its scanning frequency was 50 kHz, measuring temperature every 20 microseconds. The data acquisition rate was 50 MHz ; 1000 data points on every one scan of absorption spectroscopy. At first, test gas duration was measured using single line setup. Then, the system was extended to two line setup and applied the static temperature measurement of the expansion tube flow.
2005 年3 月からの1年間、長期在外研究員として滞在したStanford大学機械工学科(Department of Mechanical Engineering)高温気体力学研究室(High Temperature Gasdynamics Laboratory; HTGL)において、2005年7月に完成したばかりのStanford 6 inch Expansion Tube気流の静温計測のための研究を行った。expansion tubeの気流持続時間は数10μs~数msと非常に短く、通常の温度センサによる温度計測は時間応答性の面から不可能であり、衝撃波速度を介した推定も誤差が大きい。このため高速の直接温度計測が可能な半導体レーザ吸収法を用いて気流静温の計測を行った。半導体レーザ吸収法の対象計測種としては気体水分子を用いた。吸収法の原理と温度算出手法、多数の水分子吸収線から試験条件に最適なラインを選択する最適吸収線選定プログラムの構築、吸収量及び温度計測のデータ処理ソフトの作成、expansion tubeでの計測用模型及び計測システムの製作の概要を紹介する。吸収線選定及びデータ処理にあたっての吸収線データベースとしてはHITRAN2004 を活用した。構築したシステムを用いてexpansion tube気流の計測を行った。半導体レーザ吸収法のスキャン周波数はexpansion tube気流の持続時間を考慮し50kHz(20μs毎に1点の温度を算出)とし、吸収量データの取り込みは50MHz、1スキャンあたり1000点のデータを使った。まず吸収線1本のシステムでシステムの動作確認も含めたexpansion tubeの試験時間の同定試験を行い、次に2本の吸収線を同時に計測するようシステムを拡張し、expansion tube気流の静温の時間履歴を計測した。
Description形態: カラー図版あり
KeywordsAbsorption Spectroscopy, Temperature Measurement, Expansion Tube
Document TypeTechnical Report
JAXA Category研究開発報告
Report NoJAXA-RR-07-045

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