柱面梯形翼强化直接空冷凝汽器换热及其流阻性能的数值模拟

Numerical Simulation on the Performance of Heat Transfer and Flow Resistance of Direct Air-cooled Condenser With Cylindrical-shell Trapezoidal Winglet

通过数值模拟的方法,利用综合因子（j/j0）/（f/f0）1/3研究Re=600~1 800范围内,柱面梯形翼（攻角、位置、布置方式、排数）对直接空冷凝汽器单排蛇形翅片扁管空气侧换热和阻力的影响。结果表明：在所研究的范围内,攻角β=30°、距管壁c=2 mm、距入口b=50 mm、前低后高近管壁的柱面梯形翼以及三排错列和前沿间距11mm的1对柱面梯形翼对单排扁管的强化换热和流阻的综合性能最好。根据计算结果拟合Nu数与Re数、倾角、攻角、距管壁距离和距翅片入口距离的无量纲关联式,为布置柱面梯形翼的单排蛇形翅片扁管工程设计和优化提供了依据和参考。

With dimensionless number（j/jo）/（f/f0）^1/3, the parameter analyses were performed to numerically investigate the effect of cylindrical-shell trapezoidal winglet on pressure drop and heat transfer of single-row wavy-finned flat tube of direct air-cooled condenser. The parameters included the angle of attack, position, installation modes and rows with Re ranged from 600 to 1 800. The results show that the cylindrical-shell trapezoidal winglet has best overall performance under the considered conditions, with the angle of attack fl=30~, away from tube c=2mm, away from entrance b=50mm, low-tail close to tube, three staggered rows and leading edges spacing 11 mm. The dimensionless correlation was developed based on the calculated results. The correlation includes Nnsselt number, Reynolds number, angle of inclination, angle of attack, distance from the tube and distance from the entrance. This correlation can be referred for designing and optimizing the single-row wavy-finned flat tube with cylindrical-shell trapezoidal winglet.