Finned heat exchangers made of TiB₂–SiC–graphene composites with enhanced heat transfer performance

Designing high efficient heat exchangers, which are capable of working in high temperatures, is an important issue in many engineering processes and areas of technology. Improving the thermal performance of these devices enables industrial processes to diminish waste of energy and operational expenses. Ceramic and composite-made heat exchangers can be appropriate alternatives to raise efficiency and extend the life of devices at high temperatures. In the present work, TiB₂–SiC and TiB₂–SiC–GNP (GNP: graphene nano-platelets) composites are introduced as suitable candidates to be utilized in the plates of finned heat exchangers. SiC with the 25 vol% of matrix and GNP with 2 wt% of the matrix were used in the combination of these composites. The dimensions of the channels in the investigated heat exchanger are changed. The effect of using composite materials and the channels’ dimension variation on the thermal and hydraulic performances of the heat exchanger is studied. For further investigation, the length of the heat exchanger is reduced by about 15%, and the heat transfer and hydraulic performance of the device is examined in this length. A numerical simulation is performed to examine the thermal characteristics of the heat exchangers and to find the Colburn and friction factors correlation. The temperature distribution and heat transfer efficiency of TiB₂–SiC and TiB₂–SiC–GNP heat exchangers are presented and compared to the reported data for Al₂O₃-made one. Based on numerical simulation, the utilization of TiB₂–SiC and TiB₂–SiC–GNP instead of alumina resulted in 3% and 8.2% enhancements in the heat transfer (q) and relative efficiency index (η) of the device (at the mass flow rate of 7.2 × 10^–5 kg/s), respectively. By reducing the length of the mentioned heat exchanger, not only the overall performance of the device is significantly improved (about 6.7%), but also the amount of raw materials for manufacturing heat exchangers made of these advanced composites are reduced to a large extent. Graphical abstract: [Figure not available: see fulltext.]