In this study, the drying of kiwi fruit in a convective dryer is examined experimentally. Air velocity, thickness of the slices and drying time are the varied parameters in drying process. In the experimental study, kiwi slices having thickness of 4 and 8 mm are dried in the dryer under the conditions of 45 °C temperature of the drying air, 10% relative humidity and 0.5–1.5 m/s drying air velocity. In addition to the tests, the effects of mentioned drying parameters on drying are analyzed by ANOVA (Analysis of Variance) method to find the contribution rate of each parameter. For this aim, an orthogonal array is arranged by using Taguchi design of experiment method. As the results of experiments and variance analysis, it has been determined that, drying air velocity plays a significant effect on total drying time. The minimum drying time (225 min) is achieved for 1.5 m/s for 4 mm slices, and the maximum drying time (750 min) is achieved for 0.5 m/s for the kiwi sample sliced 8 mm thick. It is also concluded that, working with the convective dryer at different velocities is advantageous in terms of preserving brightness and color quality.

The heat transfer of mixed convection in a horizontal channel filled with a porous medium has been studied in this article, given that it plays an extensive role in various technical applications, such as flow of fluid in geothermal resources, formations in chemical industries, the storage of radioactive nuclear waste material, and cooling. Those equations written in a dimensionless form have been solved using the finite difference method for different values of the parameters. The results obtained from the study have been presented through streamlines, isotherms, and both local and average Nusselt numbers. It has been observed that parameters such as the Rayleigh and Peclet numbers have an effect on flow and temperature fields.

In this study, a numerical and experimental analysis of a solar collector with roughness elements in the form of stainless-steel scourers on the absorber surface is presented. According to the location type and number of the stainless steel scourers, the absorber surfaces are referred to as the complex surface (C1), less complex surface (C2), and flat surface (C3). A Computational Fluid Dynamics (CFD) analysis was carried out using ANSYS-CFX-R18.2 commercial software. The results were verified with the experimental study. After the numerical study was confirmation with the experimental study, then the detailed investigation was performed by numerical simulations. The extracted results of the numerical and experimental analysis concerned the air temperature and velocity, and thermal efficiency, which varied with respect to the type of collector. As a result, the C1 type yielded the highest air velocity and air temperature, while the lowest values of air velocity and temperature were recorded for the C3 type, according to both the numerical analysis and experimental tests. This trend was similar for the efficiencies. The efficiency was nearly 80% for collectors with stainless-steel scourers, whilst it was 55% for the flat plate collector. The results showed that the experimental and numerical results agreed well.

In this study, the effects of drying air velocity on the organic apple and kiwi fruits that were sliced in same sizes were experimentally examined in a convective type dryer. In order to examine the effect of drying air velocity to drying process, drying air at 45?C and 10% relative humidity was applied to kiwi and apple fruit samples sliced in 4 mm thickness at 0.5, 1.0, and 1.5 m/s drying air velocities. It was observed from the experimental results that drying air velocity has a significant effect on the total drying time. The drying time of apple and kiwi slices under these conditions varied between 150-360 minutes. The lowest drying time (150 minutes) was obtained at 1.5 m/s for the apple sample with 4 mm slice thickness, and the highest drying time (360 minutes) was obtained at 0.5 m/s for the 4 mm thick kiwi sample. Freshly collected products were successfully dried in a convective dryer at different velocities.

In this study, the effect of various concentrations of Al2O3-water nanofluid on heat transfer in duct with a square cross-section, under conditions of continuous heat flux and laminar forced flow, investigated numerically. Reference experi-mental application parameters are accepted as reference, calculated with single phase homogeneous model (SPHM) and single phase Brownian model (SPBM) models, and the average heat transfer coefficient results of numerical models are compared with each other and reference experimental data. Numerical results obtained with SPHM and SPBM are in comparison to the relevant experimental data. For SPHM and SPBM results, 0.5%, %1.5, %2.5 Al2O3-water nanofluids, the average deviation rate for the average heat transfer coefficient is 3.35% and 2.36%, 5.24%, 3.43%, 7.74%, and 5.3% according to the reference experimental data respectively. 0.5%, %1.5, %2.5, 2.24%, and 3.81%, 5.86% and 7.47%, 9.58% and 11.6%, respectively, the average heat transfer coefficient is increased by using Al2O3-water nanofluid compared to water. It has been observed that, SPBM has closer results than SPHM model according the relevant experimental data.