结构特征对螺旋管换热器性能的影响

目的研究结构特征对螺旋管换热器换热性能的影响,为换热器设计和结构优化提供理论依据。方法在CFD软件Ansys的FLUENT模块中模拟螺旋管换热器内流体的流动换热过程。在相同边界条件下,不改变总换热面积,通过改变换热器的换热管直径和壳体长度,研究几何参数对换热性能的影响。通过对比单管单螺旋、单管双螺旋、双管双螺旋和内外双螺旋等4种不同缠绕方式换热器中流体的温度分布云图,研究螺旋管的结构对换热器换热性能的影响。结果保持总换热面积不变,减少换热器的管径,增大壳体的长度,都能有效提高换热效率。与单管单螺旋结构的换热器相比,单管双螺旋结构换热器的流体出口温度下降了9.74%,平行双螺旋结构换热器的出口温度下降了5.05%,内外双螺旋结构换热器的出口温度上升了10.11%。结论在螺旋管换热器的设计和优化过程中,可以通过减小换热管径,增大壳体长度,采用内外双螺旋结构,以实现提高传热效率的目的。

Effect of Structural Characteristics on Heat Transfer Performance of Spiral Shell-tube Heat Exchangers

The work aims to provide a theoretical basis for the design and structural optimization of spiral shell-tube heat exchanger by studying the effect of structural characteristics on heat transfer performance of spiral shell-tube heat exchangers. The flowing and heat transfer process of fluid in the spiral shell-tube heat exchanger was simulated in the Ansys FLUENT module of CFD software. Firstly, the tube diameter and shell length of the heat exchanger were changed without changing the total heat transfer area under the same boundary condition to investigate the effect of geometric parameters on heat transfer performance. Secondly, the temperature distribution contours of four spiral shell-tube heat exchangers with different structures (namely, single-tube-single-spiral, single-tube-double-spiral, double-tube-double-spiral, and internal-external-double-spiral) were compared to investigate the effect of spiral tube structure on heat transfer performance of the heat exchanger. The results indicated that, when the total heat transfer area remained unchanged, the heat transfer efficiency increased effectively with the decrease of tube diameter and the increase of shell length. Compared with single-tube-single-spiral heat exchanger, the outlet fluid temperature of single-tube-double-spiral heat exchanger declined approximately 9.74%, the outlet fluid temperature of parallel-double-spiral heat exchanger declined approximately 5.05%, and the outlet fluid temperature of internal-external-double-spiral heat exchanger increased by 10.11%. Based on these results, the heat transfer efficiency of spiral shell-tube heat exchangers will be improved by decreasing tube diameter, increasing shell length, and using internal-external-double-spiral structure in the process of designing and optimizing spiral shell-tube heat exchangers.