Abstract: Numerical simulation of fluid flow and heat transfer in the shell side of reticulation orifice-baffle longitudinal flow type heat exchanger is carried out with CFD software. Heat transfer enhancement principle of the reticulation orifice-baffle is summarized, and the influences of space between baffles (L), and open area ratio (y) on its heat transfer and pressure drop Dp analyzed, and correlations are developed for the models. The results indicate that jet flow and second flow appear after fluid leaves the reticulation orifice-baffle, which enhance heat transfer of fluid in the shell side. Compared with plate baffle heat exchangers within Reynolds number Re=2300~6300, Nusselt number (Nu) of the reticulation orifice-baffle heat exchanger is about 50% higher than that of the plate baffle heat exchanger, while its shell side pressure drop is about 2.5 times higher than that of the plate baffle heat exchanger. In the range of study, both Nu and pressure drop rise with L or y decreasing, and the influences of L or y on Nu and Dp increase with the increase of Re, but with L or y decreasing, increasing speed of Dp is obviously bigger than that of Nu.

Key words: longitudinal flow type heat exchanger, reticulation orifice-baffle, numerical simulation, heattransfer enhancement

摘要： 应用CFD软件对网状孔板换热器壳程流体流动及换热特性进行了数值模拟研究，揭示了网状孔板强化传热的机理，分析了孔板间距及开孔率对其换热、压降性能的影响，推导出网状孔板纵向流换热器壳程换热与流动的准数关系式. 结果表明，流体流过网状孔板产生射流及二次流现象，强化了壳程流体的传热；在Re=2300~6300范围内，网状孔板换热器比弓形折流板换热器的Nu数增大约50%，但压降比弓形折流板换热器高约2.5倍；在研究范围内，孔板间距减小、开孔率减小均能使壳程流体的Nu数及压降增大，且Re数越大，开孔率、折流板间距对Nu数及压降的影响越大；但随开孔率、折流板间距减小，流体压降增加的速度明显比Nu数快.

关键词: 纵向流换热器, 网状孔板, 数值模拟, 强化换热