Papers by Keyword: Tilt Angle

Abstract: Considering the dearth and limited supply of potable water for daily consumption globally, developing a desalination technique to produce water sufficient for the need has become imperative. This study examines the improvement of freshwater productivity in a single-slope solar still by incorporating a solar preheating system. The proposed design utilizes solar still distillation to preheat the feed water before it enters the distillation basin. This approach aims to increase the temperature gradient between the water surface and the glass cover, thereby accelerating the evaporation and condensation process. Experimental evaluations were conducted under varying climatic conditions and flow rates, with and without the preheater. We note that the productivity has improved at each flow rate as follows: at a flow rate of 1 L/min, the improvement percentage reached 96% (CLISS:130 g/hr and CLIPSS:170 g/hr), at a flow rate of 2 L/min, the improvement percentage reached 73% (CLISS:180 g/hr and CLIPSS: 220 g/hr), while the improvement percentage at 3 L/min became 61% (CLISS:240 g/hr and CLIPSS:290 g/hr.), and at a flow rate of 4 L/min, it reached 64% (CLISS:280 g/hr. and CLIPSS: 320 g/hr.), and up to a flow rate of 8 liters/minute, the productivity improvement percentage between the two systems reached 31% (CLISS:310 g/hr. and CLIPSS:340 g/hr.). The results showed that the preheated system significantly improved solar thermal performance and daily production, especially during the early morning and late afternoon hours. Compared to a conventional design, the preheated system achieved an overall productivity increase of 25% to 35%.

Abstract: In this paper, the flow of a shear thinning nanofluid in a mechanically stirred tank has been numerically analyzed. This tank is cylindrical with a flat bottom. It is filled with Al₂O₃ nanoparticles suspended in the base fluid and equipped with an anchor-type stirrer whose shape is tilted upwards at an angle α. The purpose of this research is to study the impact of the tilt angle (0≤α≤π/6) and the effect of the alumina nanoparticles concentration (0≤φ≤0.1) on the hydrodynamic behavior and energy consumption. In the new anchor design (α>0), the fluid volume that is swept during the rotation of the anchor is the same as that in the case of a standard anchor (α=0). The laminar flow of the nanofluid is governed by the continuity and momentum equations taking into account the physical properties of the nanofluid introduced through correlations cited in the literature. The results obtained have shown that the tilt angle significantly contributes to the reduction of the power number, and leads to a decrease in the intensity of the tangential flow at the level of the extreme transverse planes of the tank. However, this reduction in intensity is compensated by increasing the axial flow. The use of nanoparticles in this work aims to show the role of the new design of anchor in creating a vortex at the bottom of the tank and to avoid of particles sedimentation.

Abstract: Carbon fiber reinforced plastics (CFRP) has been widely used in various aircraft structural components. However, it is difficult for conventional methods such as drilling and helical milling to meet the requirements on high quality and efficient holes creation. Hence a so-called tilt helical milling (THM) method has been proposed. This new method is performed by replacing the revolving motion of the tool in conventional helical milling (CHM) with a conical pendulum motion, in which the tool axis is tilted towards the hole axis at a certain angle. As a step toward the establishment of the new method, in this work, the fundamental drilling characteristics of CFRP by the THM is elucidated by experimentally investigating the effects of tilt angle on thrust force and delamination factor. The obtained experimental results demonstrated that thrust force and delamination factor can be reduced with THM technique. In addition, THM can achieve better hole surface finish than CHM.

Abstract: This paper focuses on to evaluate technical performance of PV roof top system. This system totally consists of 168 polycrystalline modules in which 14 are connected in series and 12 are connected in parallel. The total capacity of the system is 50 kWp, in which each module has the rated power capacity of 305 Watt. This system is connected to three 20kW inverters and which intern is connected to grid. Tilt angle and orientation is obtained by MATLAB 7.10 and PVsyst software for each 15⁰ change in tilt angle, the variation in solar irradiance absorbed by the PV modules, variation in energy produced by the modules and the variation in the final yield are observed. MATLAB software is also used to find the curve fitting by using surface fitting tool. The result showed that at 15⁰ tilt and 45⁰ azimuth angles, the maximum yield and effective energy were obtained as 4.65 h/day and 1394 kWh/kWp/year respectively.

Abstract: This paper presents an investigation of research objectives on the effect of tilt angle on microstructure and mechanical properties of dissimilar aluminum alloy sheets between AA5083 and AA6061, 5mm plates by using Friction Stir Welding (FSW) process in butt joint. The base materials of AA5083 and AA6061 were located on the retreating side (RS) and advancing side (AS), respectively. The welding process and the welding parameters such as tool pin profile, tool rotation speed, welding speed and tilt angle influenced the mechanical properties of the Friction Stir Welding joints significantly. For this experiment, the Friction Stir Welding materials joined under five different tilt angles (from 0^oto 4^o) with 86mm/min of welding speed and 910 rpm of tool rotation speed which were set similarly. Microscopic examination on the weld samples showed significant variation in the microstructure especially in the region of heat-affected zone (HAZ), weld nugget or dynamically recrystallized zone (DXZ) and in the base metal.

Abstract: This paper demonstrates three-dimensional imaging of threading screw dislocations (TSDs) and threading edge dislocations (TEDs) in 4H-SiC using two-photon-excited photoluminescence (2PPL) band-edge emission. Three-dimensional (3D) images of TSDs and TEDs are successfully obtained as dark contrasts on a bright background of band-edge emission. The intensity inversion of a 2PPL 3D image yields a perspective to visually examine the propagation behavior of dislocations. The tilt angles of TEDs are also measured and shown to correlate with the directions of the extra half planes of TEDs.

Abstract: Electric mobility seems to be an innovative alternative to future urban transport. In this study, a steady-state cornering model of a three-wheel narrow electric vehicle is derived. The steady-state cornering analysis is conducted by varying the location of the vehicle center of gravity, speed and tilt angle. From this analysis, the center of gravity location and tilt angle that gives better cornering characteristics can be obtained. Therefore, this analysis helps and can be used as starting point to design the chassis and the tilting control system of the three-wheel narrow electric vehicle.

Abstract: Solar energy is the largest available renewable energy for enhancing the endurance of a solar-powered unmanned aerial vehicle (UAV). However, harnessing solar energy is a great challenge because the power output efficiency of solar module systems is only 15% to 30%. A solar-powered UAV has the potential to outperform a battery-powered UAV, particularly in tasks involving a pseudo satellite that requires long operating hours. Atmospheric conditions and geographical location are the main causes of the poor performance of solar modules. Despite the improvements in solar cell efficiency over the years, solar module systems can still barely convert half of the sun’s power into electricity. This limitation hinders the use of current solar module systems for harvesting solar energy. Recent studies have focused not only on the type of solar cells but also on the positioning system. However, understanding and research on the solar irradiance intensity, as well as on the effect of daylight duration on the power output, remain lacking. A comprehensive model was developed to address this gap and investigate how the movement of the sun movement affects the performance of solar module systems. This simulation model found that daylight duration is more important than available solar irradiance. Higher solar irradiance and daylight duration corresponds to a higher power output of the solar module system. Daylight duration also depends on latitude where higher latitudes lead to longer daylight duration. On the other hand, longitudinal coordinates and elevation have minor effects on the estimation of daylight duration. Therefore, the northern hemisphere has more advantages than southern hemisphere during summer and vice versa.

Abstract: The thesis deals with a manufacturing system water jet technological head tilt angle influence analysis. The search is performed for two tilt angles and three speeds of the technological head shift. Frequency envelope comparative graphs are created for the head tilt angles 45o and 90o and for each of three speeds using graphical records which show vibration acceleration amplitude relation to its frequency. For each of the tilt angles summary comparative frequency envelope graphs in all analyzed speeds are created, too. On the base of the comparative frequency envelope graphs a discussion focused on results and formulated conclusion are performed. The paper presents a thematically integrated part of previous research and complements recent knowledge on technological and material parameter impact to water jet technology manufacturing system vibration generation.

Abstract: The paper deals with an experimental analysis of a technological head tilt angle impact to vibration generation. The search of the technological head tilt influence is performed for three technological head shift speeds and for three abrasive water medium pressure values. From graphic records showing relation of vibration acceleration amplitude to its frequency, a group of 9 comparative frequency envelope graphs for two tilt angles and three technological medium analyzed pressures for each of three speeds of the head shift is created. On the base of the frequency envelope comparative graphs a discussion and formulated conclusion are stated. The paper presents a thematically integrated part of the thesis and complements recent knowledge on water jet technology manufacturing system working condition diagnosis.