右旋形態 的英文怎麼說
中文拼音 [yòuxuánxíngtài]
右旋形態
英文
d-form-
In this thesis hydraulic experimental studies and theoretical analyses on the vortex - flow drop shaft were conduced and the following results were accomplished : ( 1 ) in the model test some hydraulic characteristics including the shape of air core in the center of the drop shaft, the radial distribution of water flow velocity and the distribution of pressure on the wall of the drop shaft were measured under the condition of high water head above 250m and large discharge above 1400m3 / s. ( 2 ) a kind of computational method for the spiral water flow in the air core region of drop shaft was discussed and applied and the results agree the experimental data well. ( 3 ) the total ratio of energy dissipation in the drop shaft can reach 90 % and the energy dissipation in every region was discussed quantitatively
本文通過試驗研究與理論分析對旋流式豎井泄洪洞應用於高水頭、大泄流量情況時存在的一些水力學問題進行了研究和探討，取得以下主要成果：一、結合小灣工程導流洞改建，對高水頭（ 252m ） 、大泄流量（ 1400m ~ 3 s ）條件下旋流式豎井中的水流運動特徵進行了比較全面的測量，包括空腔形態、徑向流速分佈及井壁壓強等；二、提出了豎井空腔段螺旋水流水力計算方法，其計算結果與實測值吻合良好；三、利用試驗與計算結果，對旋流式豎井的消能機理進行了探討，對豎井各部分的消能能力有了總體認識；四、對豎井下部消力井的合理井深進行了優化試驗研究，發現消力井合理深度為0 . 9d左右；五、通過試驗研究，歸納出豎井水流總摻氣量估算方法，為導流洞排氣方案的設計提供了參考依據；六、在高水頭、大流量條件下，豎井空腔段下部流速很高，盡管水流螺旋運動引起的離心力可以確保井壁壓強保持正壓，但空化數依然較低，因此豎井的空化空蝕始終是工程界關注的重大問題。The results indicated that, the fabrication process of ultra - fine grain material is mainly determined by the stress, rotate speed and the flux of cooling water. the grain refining and the hardening effect are mostly affected by the rotate speed and the flux of cooling water. compared with commercial ly12, the invalidate strength and the prolongation rate of the ultra - fine grain material are properly improved in the measurement of compression property ; and the abrupt change of the dilatability of the ultra - fine grain material at 500c is found ; also the phenomena of which the grain size of these microstructures is stable when annealed under 300c is observed
研究表明，採用本文提出的摩擦壓扭強變形區轉移法可以得到棒狀的超細晶材料，軸向壓力、扭轉速度和溫度是採用該方法制備超細晶材料的主控參數；試件的旋轉轉速和冷卻速度對變形區晶粒細化和硬化效果影響顯著；超細晶ly12的壓縮性能與淬火+自然時效狀態的ly12壓縮性能相比，斷裂強度和延伸率均有一定程度的增強；超細晶ly12的熱膨脹系數在550左右發生明顯的變化。
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