Assessment of TiO 2 Nanoconcentration and Twin Impingement Jet of Heat Transfer Enhancement—A Statistical Approach Using Response Surface Methodology

Impinging jets are considered to be a well-known technique that offers high local heat transfer rates. No correlation could be established in the literature between the significant parameters and the Nusselt number, and investigation of the interactions between the correlated factors has not been conducted before. An experimental analysis based on the twin impingement jet mechanism was achieved to study the heat transfer rate pertaining to the surface plate. In the current paper, four influential parameters were studied: the spacing between nozzles, velocity, concentration of Nano solution coating and nozzle-plate distance, which are considered to be effective parameters for the thermal conductivity and the heat transfer coefficient of TiO 2 nanoparticle, an X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) analysis were done, which highlighted the structure and showed that the nanosolution coated the surface homogenously. Moreover, a comparison was done for the experimental results with that of the predicted responses generated by the Design Expert software, Version 7 User’s Guide, USA . A response surface methodology (RSM) was employed to improve a mathematical model by accounting for a D-optimal design. In addition, the analysis of variance (ANOVA) was employed for testing the significance of the models. The maximum Nu of 91.47, where H = S = 1 cm; Reynolds number of 17,000, and TiO 2 nanoparticle concentration of 0.5% M. The highest improvement rate in Nusselt was about 26%, achieved with TiO 2 Nanoparticle, when S = 3 cm, H = 6 cm and TiO 2 nanoparticle = 0.5 M. Furthermore, based on the statistical analysis, the expected values were found to be in satisfactory agreement with that of the empirical data, which was conducted by accounting for the proposed models’ excellent predictability. Multivariate approaches are very useful for researchers, as well as for applications in industrial processes, as they lead to increased efficiency and reduced costs, so the presented results of this work could encourage the overall uses of multivariate methods in these fields. Hypotheses : A comparison was done for the predicted responses generated by the Design Expert software with the experimental results and then studied to verify the following hypotheses: ► Preparation of three concentrations of TiO 2 nanosolution was done and studied. ► The heat transfer rate could be increased by surface coating with TiO 2 nanoparticle. ► The heat transfer could be improved by the impingement jet technique with suitable adjustments.