Heat transfer potentials of ZnO/water nanofluid in free impingement jet

Abstract

Heat transfer represented by jet impingement was considered due to the grown demand for such applications in the industry such as heat exchangers, metal cutting, and electronic's component cooling. Hence, ZnO/water nanofluid is embraced to enhance the heat exchanged by impinge nanofluid through a square jet. Five nanofluid were prepared thoroughly with different ZnO concentrations range of (0.1–0.5%) besides a plain de-ionized water for comparison. Validation was performed by comparing the outcome with comparable analogous studies and exhibited a content deviation. The parameter (H/Dh) which denotes the (exit of nozzle-to-hot plat spacing over the hydraulic jet diameter) was varied to be 2–8. The acquired results showed that the adoption of nanofluid in such an arrangement gives further magnification in heat transfer (Nu = 113.9%) at high Reynold's number and nanoparticle concentration (φ = 0.5%, Re = 17500, and H/Dh = 2). Whereas the minimum gained heat (Nu = 43.8%) was detected at nanoparticle concentration of (ɸ = 0.1%), Reynold's number of (Re = 5000), and H/Dh spacing of 8 respectively. It was found that applying excessive heat flux on the target plate causes rapid evaporation once the flow hits the surface plate, which leads to poor thermal performance. Eventually, the gained data were correlated and the empirical correlation is proposed.

Keywords

• Nanofluid
• Heat transfer
• Experimental
• ZnO Nanoparticle concentration
• Square jet
• Nusselt number