국내 최대 기계 및 로봇 연구정보

기술보고서

기술보고서 게시판 내용
타이틀	Humidity management for the NAL 1.27m hypersonic wind tunnel
저자	Shinji Nagai, Shoichi Tsuda, Tadao Koyama, Noriaki Hirabayashi, Hideo Sekine
Keyword	Hypersonic flow, multi-phase flow, wind tunnel, efficiency
URL	http://send.nal.go.jp/send/jpn/dlpdf.php3/naltr0001436.pdf?id=NALTR0001436
보고서번호	NAL TR-1436
발행년도	2001.12
출처	NAL (National Aerospace Laboratory of Japan)
ABSTRACT	Variation of pitot pressure was observed in a Mach 10 nozzle calibration test of the National Aerospace Laboratory 1.27m hypersonic wind tunnel immediately after a humid combustion gas evacuation system was added to the air heater. The mix of humidity provided by condensed water inside the tunnel structure was evaluated using run-by-run variations of evacuated heater pressure and of measured humidity level in the working air. The calibration data were also examined and a non-isentropic condensing flow through the nozzle was believed to have occurred. Thus modifications to prevent condensing of water were carried out and constant pitot pressure was obtained in a further calibration test. A statistical assessment was made of the data obtained before and after these modifications, and the results were compared to confirm the existence of a repeatable isentropic flow. This allowed efficient humidity management within the operation cycle. The water-effect free flow was assured by monitoring the humidity level and nozzle exit wall pressure.