Numerical simulation of CaSO4 crystallization fouling in a rectangular channel with vortex generators
Numerical simulation of CaSO4 crystallization fouling in a rectangular channel with vortex generators
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DOI：
10.1016/j.icheatmasstransfer.2018.12.014
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发表时间：
2019-02
影响因子：
7
通讯作者：
Zhiming Xu;Z. Han;Jingtao Wang;Yanfeng Li
中科院分区：
文献类型：
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作者：
Zhiming Xu;Z. Han;Jingtao Wang;Yanfeng Li
被动式涡流发生器是一种高效的强化传热技术，它利用一种特殊的延伸表面，主要产生平行于流动方向的涡流，既能提高换热器的传热性能，又能防止污垢的形成。为了研究不同涡流发生器对矩形通道内污垢生长的影响，采用数值模拟方法，研究了3种相同前缘面积的涡流发生器对硫酸钙污垢沉积过程的影响。首先，研究了入口流速从0.5 ~ 0.8 m/s、CaSO 4浓度从2.0 ~ 3.5 kg/m3、表面温度从320 ~ 350 K变化对污垢特性的影响。然后，采用性能评价准则（PEC）对不同类型涡流发生器的通道换热特性和污垢特性进行了评价。结果表明，三种类型的气相沉积物的污垢热阻变化趋势基本一致。渐近污垢热阻随流速的增大而减小，随浓度的增大而增大，随表面温度的增大而增大。对于3种不同类型的涡流发生器的矩形通道，当考虑流阻时，半圆柱涡流发生器的带污垢性能评价准则（PECf）在3种不同类型的涡流发生器中最优。
Use of passive vortex generators (VGs) is an efficient heat-transfer enhancement technique, which utilizes a special type of extended surface that mainly generates vortices parallel to the flow direction to not only improve the heat transfer performance of the heat exchangers, but also prevent the formation of fouling. In order to study the growth characteristics of fouling on the rectangular channel with different VGs, three types of VGs with the same frontal area were used in the present study and the deposition process of calcium sulfate (CaSO4) fouling was studied by numerical simulation method. First, the effects of the changes in inlet velocity from 0.5 to 0.8 m/s, concentration of CaSO4from 2.0 to 3.5 kg/m3, and surface temperature from 320 to 350 K on fouling characteristics were investigated. Then, the Performance Evaluation Criterion (PEC) was used to evaluate the heat transfer characteristics and fouling characteristics on a channel with different types of VGs. The results showed that the fouling resistance of the three types of VGs followed the same trend. The value of asymptotic fouling resistance decreased with the increase of the velocity, and increased with the increase of the concentration and surface temperature, respectively. For the rectangular channels with three different types of VGs, when the flow resistance was taken into account, the Performance Evaluation Criterion with fouling (PECf) of the half-cylinder VG was found to be the best among the three different types of VGs.