异型管管翅式换热器性能研究

管翅式换热器的翅片优化为研究热点,而对管型的研究较少.本文提出一种与圆管相同水力半径的异型管的设计方法,建立了异型管管翅式换热器空气侧换热的数值计算模型,研究了管型、迎风方向和翅片间距对异型管管翅式换热器性能的影响.结果表明:对于双排的异型管换热器,第一排管大圆迎风,第二排管小圆迎风时,空气流动最均匀,压降最低,是综合...

Study on Performance of Special-shaped Tube-fin Heat Exchanger

Fin optimization of tube-fin heat exchangers is a research hotspot, and there are few studies on tube types. A design method for a special-shaped tube with the same hydraulic radius as a circular tube is proposed. A numerical calculation model of the air-side heat transfer of the special-shaped tube-and-fin heat exchanger was established. The effects of tube shape, windward direction, and fin spacing on the performance of special-shaped tube-and-tube-fin heat exchangers were investigated. The results showed that for the double-row special-shaped tube heat exchanger, when the first row of tubes exposed to the air is larger than the second row, the air flow is the most uniform and the pressure drop is the smallest, delivering the best overall performance in the upwind direction. When the round tube, elliptical tube, special-shaped tube, and flat tube-fin heat exchangers are compared, the best resistance characteristic and comprehensive performance is the special-shaped tube at a air velocity of 4 m/s. The pressure drop is lower than that of the round tube by 31.86%, the value of performance enhancement evaluation index (Nu/Nu0)/(f/f0) is 1.456, mainly due to the large net flow area of the air between the tubes, and there is less disturbance when flowing through the heat exchanger. In addition, the larger the fin spacing, the greater the influence of the tube type on the air-side flow and heat transfer. The large fin spacing has better improvement effects on the resistance performance and overall performance of the heat exchanger than the small fin spacing.