Experimental and numerical approach to resolve particle deposition on dimpled heat transfer surfaces locally and temporally
Experimental and numerical approach to resolve particle deposition on dimpled heat transfer surfaces locally and temporally
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DOI：
10.1016/j.ces.2020.115840
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发表时间：
2020-12
影响因子：
4.7
通讯作者：
Hannes Deponte;R. Kasper;S. Schulte;W. Augustin;J. Turnow;N. Kornev;S. Scholl
中科院分区：
文献类型：
--
作者：
Hannes Deponte;R. Kasper;S. Schulte;W. Augustin;J. Turnow;N. Kornev;S. Scholl
当优化热交换器的性能时，在表面上引入诸如凹坑或肋的结构可能是有利的。在热-水力效率方面的一个特别有利的解决方案是使用具有球形凹坑的表面，其中传热仅以较小的压力损失增加而增加。然而，这种表面结构化也影响颗粒在水性悬浮液中的沉积。由此产生的结垢是热交换器的设计和操作的严重问题，并且可以导致显著的经济和生态破坏。尽管了解结垢的重要性和由此产生的缺点，但这种知识尚未系统地纳入设计过程中，并且在热交换器的设计期间，最大化传热和减少水力损失的标准仍然是最重要的。在这项研究中，深径比为0.18，0.26和0.35的酒窝表面进行了评估，通过测量和比较他们的传热能力和压力损失，并没有发生颗粒污垢的水悬浮液。污垢阻力用于评估由于颗粒沉积而导致的传热效率的降低，局部和时间分辨。首次定量评估了一排凹坑在污垢条件下的传热效率，并通过实验确定了其热工水力效率。结果与数值研究相匹配。研究了水悬浮液中微凹表面的湍流结构、传热和颗粒污垢的相互作用。
When optimizing the performance of heat exchangers, it can be advantageous to introduce structures, such as dimples or ribs on the surface. One especially advantageous solution in terms of thermo-hydraulic efficiency is to use surfaces with spherical dimples, where heat transfer is increased at an only minor pressure loss increase. However, this surface structuring also influences the deposition of particles in aqueous suspensions. The resulting fouling is a serious problem for the design and operation of heat exchangers and can cause significant economic and ecological damage. Despite the knowledge of the importance of fouling and the resulting disadvantages, this knowledge has not been incorporated systematically into the design process, and the criteria of maximizing heat transfer and reducing hydraulic losses remain in the foreground during the design of heat exchangers. In this study, dimpled surfaces with a depth to diameter ration of 0.18, 0.26 and 0.35 were evaluated by measuring and comparing their heat transfer ability and pressure loss with and without the occurrence of particulate fouling from aqueous suspensions. The fouling resistance is used to assess the reduction in heat transfer efficiency due to particulate depositions, both local and time resolved. For the first time, a row of dimples is quantitatively assessed regarding its heat transfer efficiency under fouling conditions, and the thermo-hydraulic efficiency is determined experimentally. The results are matched against numerical investigations. The interactions of turbulent flow structures, heat transfer and particulate fouling in aqueous suspension are determined for dimpled surfaces.