最大馬赫數 的英文怎麼說
中文拼音 [zuìdàmǎhèshǔ]
最大馬赫數
英文
maximum mach number-
At the same time this paper calculates the effect of train velocity on noise propagation, when mach number is 0. 1, sound velocity less effects on noise level ; when mach number is 0. 4, the difference value is about 2db whether to consider the sound velocity. so when the train velocity is not very high, the effect of sound velocity may not be considered
本文同時計算了列車運行速度對噪聲傳播的影響，當馬赫數為0 . 1時，聲音的傳播速度對聲級的影響是很小的，當馬赫數為0 . 4時，考慮聲速與不考慮聲速影響的最大值的差值大約為2db左右，因此在列車速度不是很高的情況下可以不考慮聲速的影響。The main results are : supersonic region and subsonic region can co - exist in flow path simultaneously, subsonic flow is insignificance for engine performance ; total pressure of primary rocket should be decreased when mach number is increased. in the experimental aspect, some components of ejectorjet experimental system were improved, ejectorjet experiments using alcohol as secondary fuel were conducted
由數值計算獲得的結論為：引射火箭內的一般流態為超音速區與亞音速區共存，亞音速區不具備做功能力；飛行馬赫數增大，引射火箭內更易於產生壅塞；為了獲得最佳的性能，隨著飛行馬赫數的提高，應當降低一次火箭的工作壓強。Finally, the two dimensional flow in the diffuser is calculated, the results show that the change of ma makes an effect to the performance of the diffuser. owing to the accretion of ma, the action of oblique shock waves and the boundary layer pricks up, the flow separates from the wall where the shock waves impinge on the boundary layer more quickly, the cluster of diamond shock waves becomes larger. moreover, by comparing the change of flow field under different structure parameter, it is found that the augment of length of constant area section alter the structure of fluid field little, a smaller area ratio and larger angle of compression section make the diffuser working better
最後，針對擴壓器中的二維流場進行了數值模擬，結果表明馬赫數對擴壓器性能影響較大，隨著馬赫數的增大，擴壓器管道內激波-附面層干擾加劇，流動從附面層分離相應加劇，激波串數目增多;通過比較不同結構參數下的擴壓器內流場，發現等直段長度的變化幾乎沒有改變流場結構，只是對局部流場稍有影響，並且在其它參數不變的情況下，一定范圍內減小面積比a2 / a1和增大收縮角有利於擴壓器性能的提高。
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