Shuangshuang Meng , Zhihao He , Tianbiao He , Ning Mao
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引用次数: 0
Abstract
The falling film flow and heat transfer characteristics are critical to improve the performance of spray heat exchangers in a sewage source heat pump (SSHP), which is influenced by the operating and structural parameters. Therefore, considering the unique flow patterns of wastewater falling film caused by the oily content, and the influence of heat exchange tubes with surface structures on flow and heat transfer, two types of heat exchanger tubes with axial and circumferential ribs were designed and the falling flow over tubes were investigated through CFD method using VOF model. The falling film flow pattern, liquid film coverage and heat transfer coefficient (HTC) outside the ribbed heat exchange tubes were investigated, and the influence of rib structures and Re were analyzed. It was found that oily wastewater liquid film spreaded differently depending on the rib structures, and circumferential ribs of case 2 improved the flow pattern by increasing film coverage, which obviously affected the tube HTC. At higher Re, the ribbed tubes displayed higher potential in better heat transfer performance. Therein, the circumferential ribbed tubes showed highest average HTC, with up to 31.9 % higher than smooth tubes, which can be further enhanced by increasing Re. This study provides a foundation for enhancing the heat transfer performance of spray heat exchangers in sewage source heat pumps through the design and modification of tube surface structures.
期刊介绍：
The International Journal of Thermal Sciences is a journal devoted to the publication of fundamental studies on the physics of transfer processes in general, with an emphasis on thermal aspects and also applied research on various processes, energy systems and the environment. Articles are published in English and French, and are subject to peer review.
The fundamental subjects considered within the scope of the journal are:
* Heat and relevant mass transfer at all scales (nano, micro and macro) and in all types of material (heterogeneous, composites, biological,...) and fluid flow
* Forced, natural or mixed convection in reactive or non-reactive media
* Single or multi–phase fluid flow with or without phase change
* Near–and far–field radiative heat transfer
* Combined modes of heat transfer in complex systems (for example, plasmas, biological, geological,...)
* Multiscale modelling
The applied research topics include:
* Heat exchangers, heat pipes, cooling processes
* Transport phenomena taking place in industrial processes (chemical, food and agricultural, metallurgical, space and aeronautical, automobile industries)
* Nano–and micro–technology for energy, space, biosystems and devices
* Heat transport analysis in advanced systems
* Impact of energy–related processes on environment, and emerging energy systems
The study of thermophysical properties of materials and fluids, thermal measurement techniques, inverse methods, and the developments of experimental methods are within the scope of the International Journal of Thermal Sciences which also covers the modelling, and numerical methods applied to thermal transfer.
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