Author: Fares

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 TiO2 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 TiO2 nanoparticle concentration of 0.5% M. The highest improvement rate in Nusselt was about 26%, achieved with TiO2 Nanoparticle, when S = 3 cm, H = 6 cm and TiO2 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 TiO2 nanosolution was done and studied. ► The heat transfer rate could be increased by surface coating with TiO2 nanoparticle. ► The heat transfer could be improved by the impingement jet technique with suitable adjustments. DOI Link: https://www.mdpi.com/1996-1073/14/3/595

Energy storage systems are essential as the world works to minimize its dependency on fossil fuel energy for environmental and economic reasons. Because of their high capacity for latent heat storage. The numerical study of benchmark cases of solidification and melting was undertaken, and the results of these investigations are presented in this project. Numerical analysis is conducted to examine the brief solidification process of a pure liquid phase-change material within a rectangular enclosure when natural convection is present. The horizontal boundaries are both taken to be adiabatic, with one vertical barrier maintained at a temperature below the material’s melting point and the other above. In this work, a numerical investigation of the melting of wax (namely N-octadecane) is presented. The numerical simulations of the experiments were carried out using STAR CCM+, and the results were compared with the results of other numerical simulations (FLOW 3D). The numerical simulations of gallium melting were carried out with a commercial code, STAR CCM+, which captures the solid-liquid interface with a fixed grid. This software captures the solid-liquid interface for phase change simulations in complex geometries with the enthalpy formulation technique. In addition, it demonstrates that computational fluid mechanics has reached a state of development where it permits reliable flow computations with solidification and melting. Casting with metal melts can be studied to provide information to engineers during the design process of new casting tools. The available simulation tools can also be used to predict existing casting processes. DOI Link: https://semarakilmu.com.my/journals/index.php/CFD_Letters/article/view/1772

Hydraulic jumps produce so much turbulence that hydraulic energy is effectively converted to heat. The speed, form, and volume of obstructions in an open channel have a considerable impact on the characteristics of a fluid stream. To create a hydraulic leap, a numerical analysis of water flow was done for a two-dimensional open channel over three different forms of obstruction, each with three volumes. Because of the impact of the air, it is possible to think of the emulsion of air and water as a compressible fluid with a vacancy percentage (a second fluid). The volume of fluid model (VOF), linked with the turbulent model, has been used to study each type of obstruction. The second-order upwind technique incorrectly solves the two-dimensional Reynolds-averaged Navier-Stokes equations. The numerical technique is implemented using the straightforward approach that was devised using control volumes. A wide range of Reynolds numbers (Re), corresponding to various flow patterns, were calculated for. The results demonstrate that when the Reynolds number increases, the effect of the gas phases on the liquid phases increases. The boundary layer thickness in the upstream zone from the obstacle decreases with increasing Re, whereas downstream from the obstruction, the height of the recirculation zone rises. Profiles of the empty fraction reveal two zones that are consistent with a diffusion equation. This article observed an inversion of the pressure gradient in the pressure field, which caused the boundary layer to separate; this is known as the “back flow phenomenon.” The results of the current work have been verified by comparison with those of related research projects, and the comparison has shown a commendable degree of agreement. Additionally, pressure in various areas of the obstacle and velocity were similar. DOI LINK: https://semarakilmu.com.my/journals/index.php/fluid_mechanics_thermal_sciences/article/view/2129