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A Numerical Study on the Effects of Viscosity on the Performance of CO_2 Gasdynamic Laser
https://jaxa.repo.nii.ac.jp/records/34506
https://jaxa.repo.nii.ac.jp/records/34506701520a0-cdfc-4e68-b620-452543835913
| 名前 / ファイル | ライセンス | アクション |
|---|---|---|
SA2401201.pdf (2.2 MB)
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| Item type | 紀要論文 / Departmental Bulletin Paper(1) | |||||||||
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| 公開日 | 2015-03-26 | |||||||||
| タイトル | ||||||||||
| タイトル | A Numerical Study on the Effects of Viscosity on the Performance of CO_2 Gasdynamic Laser | |||||||||
| 言語 | en | |||||||||
| 言語 | ||||||||||
| 言語 | eng | |||||||||
| 資源タイプ | ||||||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_6501 | |||||||||
| 資源タイプ | departmental bulletin paper | |||||||||
| 著者 |
KAWAMURA, Ryuma
× KAWAMURA, Ryuma
× MASUDA, Wataru
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| 出版者 | ||||||||||
| 出版者 | 東京大学宇宙航空研究所 | |||||||||
| 出版者（英） | ||||||||||
| 出版者 | Institute of Space and Aeronautical Science,University of Tokyo | |||||||||
| 書誌情報 |
en : ISAS report/Institute of Space and Aeronautical Science,University of Tokyo 巻 40, 号 8, p. 205-244, 発行日 1975-06 |
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| 抄録（英） | ||||||||||
| 内容記述タイプ | Other | |||||||||
| 内容記述 | CO_2 gasdynamic lasers (CO_2 GDL) make use of the flow through supersonic nozzles to produce the inversion from initially equilibrium CO_2-N_2-He mixtures by differential vibrational relaxation. The nozzle size is determined so that the characteristic flow time through the nozzle is large compared to the vibrational relaxation time of the lower laser level system in order to deexcite that system and short compared to that of the upper laser level system in order to freeze that system effectively. Therefore, very short nozzles are required to produce the inversion. For these small supersonic nozzles, the boundary layers and wakes generally occupy a considerably large portion of the total flow. In the present paper, the effects of viscosity on the performance of CO_2 gasdynamic laser have been studied numerically using the laminar boundary layer model and turbulent wake model. A finite-difference method was developed for the solution of the vibrational nonequilibrium boundary layer equations. To avoid the numerical instability associated with the very fast relaxation rates, production terms in the differential equations are linearized about an appropriate initial guess to the solutions, and then an implicit finite-difference scheme of Crank-Nicolson type is used to solve the resulting equations. Solutions are obtained by successively solving the equations in sequence until the original differential equations, in which the production terms are expressed as nonlinear, are satisfied within the desired accuracy. The forementioned numerical procedure could be used successfully to obtain the solution for the present problem. The effects of the nozzle wall conditions, specifically the wall temperature and catalysis, resevoir conditions and the throat Reynolds number on the performance of CO_2 gasdynamic laser have been studied. The numerical results show that the viscosity is an important parameter for determining the optimum nozzle size and that one should operate CO_2 gasdynamic lasers with uniformly cooled wall condition. The above conclusions hold for wide range of reservoir conditions of interest in CO_2 GDL's. | |||||||||
| ISSN | ||||||||||
| 収録物識別子タイプ | ISSN | |||||||||
| 収録物識別子 | 0372-1418 | |||||||||
| 書誌レコードID | ||||||||||
| 収録物識別子タイプ | NCID | |||||||||
| 収録物識別子 | AA00675986 | |||||||||
| 資料番号 | ||||||||||
| 内容記述タイプ | Other | |||||||||
| 内容記述 | 資料番号: SA2401201000 | |||||||||
