Numerical Investigation of Convective Heat Transfer Performance of Hybrid Nanofluid Flowing Through Square Channel in PWR Fuel Rod Assembly

Abstract The invention of hybrid nanofluid provides a better cooling ability than the ordinary nanofluid. Its convective heat transfer performance and thermal conductivity foster a new opportunity for reducing thermal hydraulic challenges of nuclear reactor. This work investigates the effect of Reynold’s number (1.5 × 104 ≤ Re ≤ 2.8 × 104) and concentration of nanoparticle (0 ≤ VR ≤ 2%) on cladding wall temperature, average Nusselt number, pressure drop and performance evaluation criterion of copper-alumina hybrid water based nanofluid flowing through square sub channel of nuclear fuel rod assemblies in typical pressurized water reactor. The flow of turbulent hybrid nanofluid in square channel PWR nuclear fuel rod assembly was modeled using single phase and the k-ϵ turbulent models. The results are compared with existing correlations and give good agreement. The result shows that the addition of very moderate copper-alumina hybrid nanoparticles into water causes significant augmentation in heat transfer performance of about 40% than ordinary water. Also, copper-alumina hybrid nanofluid gives better heat enhancement ranging from 10% to 30 % compared to ordinary alumina nanofluid. with higher volume fraction. This implies that usage of hybrid nanofluid should be considered instead of mono nanofluid. since hybrid nanofluid has capability to increase the performance evaluation criteria (PEC) and lower the cladding wall temperature than water and mono nanofluid.