optimum velocity ratio 中文意思是什麼
optimum velocity ratio
解釋
最佳速比-
The design method of double crank mechanism and optimum transmission double crank mechanism are presented according to the conditions of minimum transmission angle, the time ratio, the factor of velocity variety or the minimum size
摘要研究了按照最小傳動角、速度變化系數、行程速比系數以及尺寸和最小等條件設計雙曲柄機構以及最佳傳動雙曲柄機構的方法。 -
For shutters, the results show : 1 ) according to the formula p =, the theoretical value of is calculated by the effective velocity of the flow, and its engineering value is calculated by the arriving velocity of the flow, the relationship between the theoretical value of and its engineering value is 2 ) the smaller value of declining angle will result in the smaller pressure loss and smaller outlet velocities. as a result, the declining angle of 30 擄 or less is recommended in some places which need small wind velocity, such as broadcasting studio and library, and the declining angle of 45 擄 or less is recommended in places which need big wind velocity, such as cinema and office ; 3 ) the larger value of ratio between the wide of the shutter b and the space between two boards h ( b / h ) will result in the larger pressure loss and smaller outlet velocities. the range of b / h from 0. 8 to 2. 0 and the optimum value 1. 2 is recommended ; 4 ) the range of b from 10 mm to 50 nun and the optimum value 40 mm is recommended ; 5 ) the proper thickness of the boards 8 of the shutters is 1. 5 mm ; 6 ) cuneiform boards should replace the rectangle inlet boards of the shutters in order to obtain better ventilation
數值模擬採用fluent軟體，計算結果用excel進行處理，通過對大量數值工況進行數值模擬計算，結果表明：對于單側百葉風口，計算表明： 1 ）對于公式p = （ ~ 2 ） 2 ，的理論計算值中定義為流體流經百葉風口內部時的速度，即有效速度，而工程上常使用流體的來流速度來計算，計算表明，的理論計算值與工程應用值的關系為（ _ （理論） ） （ _ （工程） ） = 0 . 813 ； 2 ）當來流速度一定時，擋板傾斜角度越小，壓力損失越小、出口速度越小；因此在要求進口風速比較小的場所，如播音室、圖書館等，宜採用擋板角度30的百葉風口；在要求進口風速比較大的場所，如電影院、辦公室等，百葉擋板的角度應選45 ； 3 ）當來流速度一定時，百葉擋板的擋板寬度b與擋板間距h的比值b h越大，壓力損失越大，出口速度越小，計算表明，鑒于壓力損失、出口風速、板間形成渦流區的大小，百葉擋板的b h值取0 . 8到2 . 0之間， b h = 1 . 2為最佳值； 4 ）當來流速度一定時，在計算的條件下，當百葉擋板寬度b = 40mm時，百葉擋板的阻力系數最小，考慮到渦流區等的影響，建議選用10mm b 50mm的百葉擋板；西安建築科技大學碩士學位論文5 ）百葉擋板的厚度取為1 . sinln為好; 6 ）百葉擋板的入口側可選用具有傾斜度的楔形擋板來代替矩形擋板，利用其較好的導流作用，可得到更好的出流效果。
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