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非流化移动床内颗粒的流动为柱塞流,颗粒间无相对运动,竖管传热主要靠颗粒间导热。由于导热热阻大,在管壁周围的颗粒吸热后不易传出,而在其周围形成一个热边界层,阻止了传热。利用在竖管上加上的扰流圈,使近壁处颗粒发生扰动,而使热颗粒传出,冷颗粒得以进入管壁周围,从而起到强化传热的作用。强化后的平均传热系数可增加20%左右。平均传热系数值可达220W/(m ̄2·K)。
Particle flow in the non-fluidized bed is plug flow, no relative movement between the particles, and standpipe heat transfer mainly depends on the thermal conductivity between the particles. Due to the large thermal conductivity of heat transfer, the particles around the tube wall are not easily released after absorbing heat, forming a thermal boundary layer around them, preventing the heat transfer. The use of turbulence on the riser increases the turbulence of the particles near the wall, allowing the hot particles to pass out and cold particles into the wall of the tube, reinforcing the heat transfer. After strengthening the average heat transfer coefficient can increase about 20%. The average heat transfer coefficient of up to 220W / (m ~ 2 · K).