The decrease in length-diameter ratio may lead to some technical problems in shell-and-tube heat exchangers, such as fluid flow maldistribution, sharp increase of pressure drop, and performance deterioration. In order to solve above problems, two techniques are proposed in this study, application of a novel structure of multi-parallel-channel inlet/outlet (MPC) and installation of fluid flow distributors (FDBs) in the region of inlet/outlet in shell-side. The shell-side fluid flow is simplified according to its structural characteristics and the unit duct model is established. By employing commercial CFD software of FLUENT 6. 3, the numerical investigation on shell-side fluid flow was carried out. The numerical model and method were confirmed by experiment. Without FDBs and with FDBs of different punching ratios, both shell-side velocity distribution and resistance were investigated with different values of Reynolds number and number of tube rows (N). Without FDBs, as N decreases, the distribution of shell-side is effectively improved and the resistance is reduced sharply, with more than 70% of total pressure drop reduced when N decreases from 11 to 7 at the same Re. FDBs improve the shell-side fluid distribution effectively, but increase the shell-side pressure drop. The comparison shows that the fluid flow distributor with the best fluid flow distribution gives the largest pressure drop, about 10%-12% larger than that without FDB and about 4%-6% larger than that with other two FDBs. The largest pressure drop of shell side is generated in the regions of inlet and outlet.%对一种新型并流多通道进出口结构(MPC)轴流管壳式换热器壳程流场分布与阻力性能进行全面研究,分别研究了管排数、Reynolds数、不同挡板对壳程流场分布、阻力性能的影响,并且采用实验方法对数值模型与方法的正确性进行论证.研究结果表明,在无挡板的情况下,随着管排数的减小,壳程流场分布不均现象得到有效的遏制,压降大幅降低,最大降幅达到70％以上;挡板能够有效促进流场的二次分布,但是同时亦使阻力增大较为显著.
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