Time-dependent measurements are essential to describe the temperature and heat transfer coefficient development lead to understanding the unsteady nature of tunnel kiln behavior during cooling. The present paper introduces experimental investigations in a brick tunnel kiln equipped with a U-shape guide vane to monitor its transient thermal behavior. The experimental test rig of scale 1:4 has been fabricated for this purpose. Three U-shape guide vanes have attack angles (θ = 120°, 135°, and 150°) positioned in the flow direction are used to direct the flow to the confined zone among bricks columns. Two settings with a Reynolds number range from 14285 to 25480 are used. The results revealed that in absence of vanes, the average heat transfer coefficient (AHTC) has low values compared to that with vanes. The highest values of AHTC are obtained at vane angle θ = 135° $,$ over the whole time. The Longitudinal middle bricks have the highest heat transfer coefficient for all vane angles due to high flow velocity with a good air-cooling rate. The maximum augmentation reached 48% at vane angle, θ = 135°, for setting 7. The guide vanes have beneficial features when used as a turbulence generator to improve the heat transfer rate from the brick setting.

The higher the process efficiency, the lower the fuel consumption, and the less impact carbon emissions have on the environment. The flow characteristics around brick settings are an important field of investigation to acquire control over the energy intake and production process. The current work is a numerical CFD investigation to demonstrate fluid flow characterization inside the cooling zone in a brick tunnel kiln for lattice settings (the number of bricks in each layer is identical). Four different lattice settings were examined, and three were validated with published experimental data (settings 1, 2 and 3). In the current study, the BSL κ-ω turbulent model agrees well with the published experimental results. The numerical investigation presents the flow characteristics through four different lattice brick settings (e.g., velocity vectors, velocity contours and streamlines) that could not be measured experimentally. The investigation also looks at the flow zones of the vortex formation upstream, downstream and through the brick column. It was discovered that for settings 1 and 11, the quick air flow in the wall channels is much greater than in the column channels. Setting 3 has a larger vortex formation region, whereas setting 1 has a weaker vortex than the other settings. The cooling of the lattice bricks in Setting 3 is superior to the cooling in the other settings.

This paper discusses the transport of granular materials through flighted rotary drums operated at the optimum loading. A mathematical model is derived from the force balance acting on a single traveling particle, to predict the mean residence time of transportation. Based on the available parameters of mean height of falling curtains and final discharge angle, this model can be helpful to estimate the appropriate solid feeding rate. Two steps were followed to implement the use of the model. Firstly, experiments were carried out on a batch rotary drum to obtain the needed input parameters. Then, a case study of a small capacity rotary dryer was considered. In both steps, the drum was operated at the optimum loading. The model results were compared with other correlation from the literature for two cases of solid and air flows: con-current and counter current. Based on the results, a factor is introduced for generalized correlation from literature.