free-air reduction 中文意思是什麼
free-air reduction
解釋
自由空氣衰減-
Electric cables - calculation of the current rating - thermal resistance - a method for calculating reduction factors for groups of cables in free air, protected from solar radiation
電纜.額定電流的計算.熱變電阻.室外避免太陽輻射的電纜組減縮系數的計算方法 -
Result of numerical simulation shows that the grads of continuous phase " s velocities decreases with the presence of microbubble of which the diameter is 100 / / w, the profiles of air volume fraction in the boundary layers is similar to triangle or echelon, affected by interaction among the particle, there is a saturated air fraction, within the scope of saturated air fraction, increasing the air injection ratio can accrete the friction reduction ratio, under the condition of same air injection ratio, the free - steam velocity is larger, the effect of friction reduction is worse
計算結果表明，直徑為100 m的微氣泡能減小近壁面連續相的速度梯度；微氣泡在邊界層中的濃度分佈近似為三角形或梯形分佈；受粒子間相互作用的影響，存在一飽和濃度；減阻率隨噴氣量的增大而增大，直至飽和噴氣量，此後，增大噴氣量，壁面摩擦阻力變化不大；相同噴氣量下，來流速度越大，減阻率越低。 -
Electric cables - calculation of the current rating - part 2 : thermal resistance - section 2 : a method for calculating reduction factors for groups of cables in free air, protected from solar radiation
電纜.額定電流的計算.第2部分:熱絕緣電阻.第2節:室外避免陽光照射的電纜組用計算簡化系數的方法
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