基于金属增材制造的密集纵向翅片套管换热单元 特性研究

Study on Characteristics of Double-Pipe Heat Exchanger Units with Densely Longitudinal Fins Based on Metal Additive Manufacturing

摘要:

为提高热管换热器的性能和紧凑度，设计并采用金属增材制造获得了直翅片型(DPHE-1)和周期排列翅片型(DPHE-2)两类密集纵向翅片套管换热单元。通过剖切及几何检测，总结了制造偏差分布特点，显示其内部结构完整。通过光学检测，显示出倾斜翅片两侧的粗糙度分布不均。采用稳态传热实验方法对四种密集纵向翅片套管换热单元进行了传热特性研究。结果显示，由于换热面积的增大和流动掺混作用的增强，在Re=2000~15000工况范围内，DPHE-2的平均传热努塞尔数是DPHE-1的1.3~1.4倍，DPHE-2的平均阻力系数是DPHE-1的12.6~28.6倍。对比综合传热性能，直翅片型中的长翅片结构，即DPHE-1-B具有相对最优的强化传热性能。

Abstract:

Aimed at improving the performance and compactness of the heat pipe heat exchangers, different forms of double-pipe heat exchanger units with densely longitudinal fins are obtained by metal additive manufacturing method. The manufacturing deviation is summarized, which shows that the internal structure is complete. The optical measurement shows that the roughness distribution on both sides of the inclined fin is not uniform. The steady state experiments are implemented to investigate the heat transfer characteristics of four densely longitudinal fins enhanced compact double-pipe heat exchanger units. The configurations are classified into two categories of straight fin type (DPHE-1) and periodically arranged fin type (DPHE-2). Within the Re ranging from 2000 to 15000, the tested results show that, due to the increase of heat transfer area and the enhancement of flow mixing effect, the DPHE-2 gives 1.3~1.4 folds averaged Nusselt number and 12.6~28.6 averaged friction factor than the DPHE-1. Comparing their overall heat transfer performance, the long fin scheme in DPHE-1 type performs best.