Abstract:

Rhombus heat transfer surface with staggered circular tubes bundles (CTB)performed high heat transfer capacity, large fluid flow resistance and high efficiency in ash blowing.Based on that, a new rhombus heat transfer surface with staggered elliptical tube bundles (ETB)was proposed.The new heat transfer surface maintained the high heat transfer coefficient and efficiency in ash blowing of CTB, which also showed lower resistance characteristic.2D numerical simulations of rhombus heat transfer surface with CTB and ETB were presented to conduct improving the performance in heat transfer and fluid flow.The effects of different upwind angels (-45°, 0°, 45°)of ETB were discussed.To obtain an understanding of the physical behavior of thermal and fluid flow, different Reynolds numbers ranging from 3000 to 21000 were calculated.Entropy generation principle was used to investigate the heat transfer performance.Results showed that compared with CTB and other ETB, ETB with 0° upwind angel had higher heat transfer coefficient and lower flow resistance, comprehensive properties of which was better.

Key words: elliptical tube bundles, fluid flow, heat transfer, numerical simulation

摘要：

圆形管束菱形受热面在流动与传热方面表现出传热能力强、流动阻力大、吹灰方便等特点。以此为基础，提出了一种基于椭圆管束的菱形受热面。椭圆管束菱形受热面保持了圆形管束菱形受热面传热能力强和吹灰方便的特点，同时显著降低了烟气侧流动阻力。采用数值模拟方法，分析了叉排椭圆管束不同迎风角下的流动传热特性，与叉排圆形管束进行了对比，给出了各特征参数随Reynolds数的变化规律。模拟结果表明，迎风角为0°的叉排椭圆管束菱形受热面较圆形管束传热效果好，流动阻力小，综合性能高。

关键词: 椭圆管束, 流动, 传热, 数值分析