WU Xuhui ¹, ZHANG Ping ¹, HUANG Yichen ²
(1. Mechanical and Electrical Engineering, Guilin University Of Electronic Technology, Guilin 541004, Guangxi, China; 2. College Materials Science and Engineering, Jingdezhen Ceramic University, Jingdezhen 333403, Jiangxi, China)

Abstract: Energy saving and carbon reduction in the ceramic industry are of great significance for environmental protection and sustainable development, while waste heat recovery is an effective way to realize energy saving and carbon reduction. In order to enhance the utilization rate of flue gas waste heat recovery in ceramic furnaces, Al₂O₃-water nanoceramic fluids composed of nanoceramic alumina powder and water with ribbed columns were combined to synergistically strengthen the heat transfer performance of microchannel heat exchangers. The non-orthogonal multiple relaxation (MRT) lattice Boltzmann method (LBM) was used to investigate the flow heat transfer characteristics of the Al₂O₃-water nanoceramic fluid in the microchannel with ribbed columns, while the accuracy and reliability of the model were verified by comparing with the results of previous work. Specifically, the effects of rib heights hi and nanoparticle volume fractions φ on flow heat transfer characteristics of the microchannels were examined with constant total heat transfer area of the ribbed columns. The incorporation of rib columns significantly enhanced the heat transfer performance of the microchannel as compared with a flat straight runner. In addition, the microchannel heat transfer performance was enhanced as φ increases. With the same total heat transfer area of the ribbed columns, the microchannel heat transfer performance decreased with increasing hi, but the thermal performance factor TPF was the largest at hi = 0.3125 and the combined heat transfer performance with pressure loss was optimized. Although the addition of ribs improved the microchannel heat transfer performance, the combined pressure loss and heat transfer performance were less than those of flat surface. The results could be used as reference for structural design and optimization within the microchannel heat exchangers.
Key words: microchannel heat exchanger; lattice Boltzmann method; nanofluid; ribbed column; flow heat transfer characteristics