Experimental study on heat transfer enhancement by viscoelastic fluid pulsating flow in copper-based microchannel heat sinks

•Heat transfer and mass flow rate of viscoelastic fluids are enhanced by pulsating pressure.•The storage-release mode of viscoelastic fluid is proposed for the enhancement.•Scaling law describing the enhancement ratio induced by VFPF is obtained. Highly efficient technologies of heat dissipation are urgent with the hoard of high heat flux in shrinking and integrating electronic units. Besides, increasing numbers of simple-structured microchannel heat sinks (MHSs) are called for precise instruments due to their higher stability and easier fabrication. Against this backdrop, a novel technology on heat transfer enhancement (HTE) is proposed, which combines viscoelasticity and pulsating effects. Parametric effects on thermal performance of a 1 mm × 1 mm × 20 mm copper-based rectangular MHSs are analyzed, including concentration of CTAC/NaSal solution, pulsating frequency and Re (0.12 to 1.36). Comparing with cases without pulsating pressure, maximum enhancement ηmax of 312% in Nu and 287% in Re are achieved by adopting CTAC/NaSal solution driven by pulsating pressure. The optimal frequency where ηmax occurs decreases with concentration and larger flow rate. It is the balance between relaxation time of the elasticity and the pulsating period. The enhancement on Re is explained by the stored-release mechanism of the elasticity in viscoelastic fluid. Finally, the technology is conducted within two types of multi-channel MHSs which confirms the applicability of this technique and points out the direction toward corresponding optimizations.