Heat transfer enhancement with nanofluids under laminar pulsating flow in a trapezoidal-corrugated channel

摘要

>In this study, the heat transfer characteristics of CuO-water-based nanofluids in a trapezoidal-corrugated channel under pulsating inlet flow conditions are investigated numerically. The simulations are performed for different Reynolds numbers, pulsating frequencies and amplitudes via a control volume-based CFD solver. The nanoparticle volume fraction and the other parameters are kept constant. The flow develops both thermally and hydrodynamically while the corrugated-channel walls are kept at a constant temperature. The results indicate a good potential in promoting the thermal performance enhancement by using the nanoparticles under pulsating flow. Because of the flow periodicity, the secondary flow structures occur in the corrugated walls, and improve the mixture between hot and cold fluids. Furthermore, the pulsating flow has the advantage of preventing the sedimentation of nanoparticles in the base fluid. A comparison is presented between the heat transfer coefficients for nanofluids under steady flow conditions and the existing results. The use of nanoparticles under the pulsating flow conditions increases the heat transfer rate compared with the steady flow case. The obtained results are given as a function of dimensionless parameters.