Experimental investigation of mass transfer in 90° pipe bends using a dissolvable wall technique
Experimental investigation of mass transfer in 90° pipe bends using a dissolvable wall technique
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使用可溶壁技术进行 90° 弯管传质实验研究
DOI：
10.1016/j.ijheatmasstransfer.2013.06.001
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发表时间：
2013
影响因子：
5.2
通讯作者：
C. Ching
中科院分区：
文献类型：
--
作者：
H. Mazhar;D. Ewing;J. Cotton;C. Ching
90°角弯道的传质采用石膏浇铸的可溶解壁技术进行了测量。该方法允许表面形态演变，产生粗糙的表面，以模拟实际传质情况。在施密特数为1280、雷诺数为4万~ 13万的范围内，对直径为2.54 cm、曲率半径为1.5的标准90°弯头进行了实验。在靠近入口的弯道内壁、大部分弯道的侧壁以及靠近出口的弯道外壁，都观察到相对于上游管道的传质增强。在靠近弯道出口的弯道外壁处，最大传质增强约为1.85倍，与雷诺数无关。高传质位置的舍伍德数按re0.92进行标度计算。上游管道和弯道的表面粗糙度随雷诺数的增加而减小。对于不同雷诺数，粗糙度标度+估计约为30-70。
The mass transfer in 90° angle bends was measured using a dissolvable wall technique using test sections cast from gypsum. The method allows the surface morphology to evolve producing a roughened surface to mimic practical mass transfer situations. The experiments were performed for standard 90° pipe bends, with a diameter of 2.54 cm and radius of curvaturer/D= 1.5 at a Schmidt number of 1280 and Reynolds number in the rangeRe= 40,000–130,000. A mass transfer enhancement relative to the upstream pipe was observed on the bend inner wall near the inlet, on the side walls throughout much of the bend and on the bend outer wall near the outlet. A maximum mass transfer enhancement of approximately 1.85 times was observed on the bend outer wall near the bend outlet, which was independent of Reynolds number. The Sherwood number at the high mass transfer locations is found to scale asRe0.92. The surface roughness in the upstream pipe and in the bend is found to decrease slightly with Reynolds number. The roughness scalee+is estimated to be approximately 30–70 for the different Reynolds numbers.