Effect Of Tilt Angle Research Articles

Effects of electrode placement position and tilt angles of a platform on voltage induced by NaCl electrolyte flowing over graphene wafer

The extraction of energy from water in the natural environment has attracted significant interest in energy-harvesting applications in recent years. This study investigates the effects of the electrode placement position and the tilt angle of a platform on the voltage induced by a flow of aqueous NaCl electrolyte solution over a two-dimensional graphene wafer. It is shown that an orthogonal arrangement of the electrodes relative to the electrolyte flow direction maximizes the induced voltage. Further experiments are performed in which the graphene wafers are positioned such that the electrolyte flows over the short and long sides of the electrodes, respectively. The results show that the higher voltage response is obtained when the electrolyte flows through the long side of the electrodes. Finally, an investigation is performed into the voltage induced for various tilt angles from 20° to 60° of the graphene wafers placed on a platform. The charging and discharging time are revealed from experiments for the first time for various tilt angles. Based on the cases studied, the 45° tilt angle induces the highest voltage. Overall, the results presented in this study provide a useful insight into the optimal electrode placement position and tilt angle of a platform for graphene energy harvesting from aqueous sodium chloride solutions.

Characterizations of weld defects, intermetallic compounds and mechanical properties of friction stir lap welded dissimilar alloys

This experimental investigation describes the effect of tilt angle and rotational speed on the characteristics of welding defects, intermetallic compounds, weld strength and micro-hardness in friction stir welding of thin sheets of AA6061-T6 and AISI304. Qualitative and quantitative assessments of the welding defects have been made by using X-ray micro computed tomography and metallographic study. Three-dimensional tomography and special distribution of internal voids (pores) have been discussed by correlating it to different values of tool rotational speed and tilt angle. Internal defects were localized in the stir zone. Welding at a tilt angle of 1° reduced both surface and internal defects. Non-uniform thickness of intermetallic compound (FexAly) layer has been found in the weld zone whose thickness varied with the values of process parameters. Higher weld porosity, bigger steel hook defect and increased layer thickness of intermetallic compound caused a significant reduction in the joint strength and elongation.

Effects of Tilt Angles on the Thermal Performance of a Solar Parabolic Trough Collector System

This paper studied the effects of tilt angles on the thermal performance of a solar parabolic collector system. This is the angle at which the beam solar radiation arriving from the sun will fall perpendicular to the solar collector surface. The quantitative assessments of radiation incident on a tilted plane are very important for designing solar collecting devices. The idea was to evaluate the thermal performance of the solar collector at the monthly optimal tilt angles in Bauchi (latitude 10°30’ North and 10°00’ East). Monthly mean daily global and diffuse components of the solar radiation for 10 years (January, 2009-December, 2019) were collected and used for the simulation using MATLAB software. Also used for the simulation are the developed energy balance equations for evaluation of thermal performances of solar collector. It was observed that, as the tilt angles decreases, both absorber tube and fluid temperatures together with the thermal efficiencies of the collector increased. Higher tilt angles were witnessed during January-February and September-December (20°-33°) and these months were having low temperatures of the absorber tube and the fluid (169°C-228°C and 130°C-117°C respectively). Low tilt angles between March to August (7°-16°) and with temperatures of the absorber tube and fluid between 220°C-235°C and 128°C-142°C respectively. Maximum thermal efficiency of 73% was obtained at the least optimal tilt angles (7°-8°). Thus, for efficient solar radiation collections, solar parabolic trough collector system should be maintained at optimal tilt angles between 7°-33° in Bauchi depending upon the seasonal variations.

Determination of Optimum Tilt Angle for Rooftop Solar Photovoltaic System Installation for KikuKinderhaus in Kumasi

The population growth in the Ghanaian urban areas and the high energy consumption per unit area compared to the low solar energy capture by Photovoltaic (PV) systems makes solar PV energy systems investment an unattractive venture for most urban settlers. Because building architectures mostly do not incorporate solar PV systems in facility planning, most building roofs pose challenges for solar PV array installation leading to lower PV energy output. The effects of tilt angle on the output of Solar Photovoltaic Systems were analyzed in this study using RETScreen 4. The optimum tilt angle and the corresponding PV output were estimated annually for three different PV systems. It was found that, the optimum tilt angle for all the systems that would give better yield and allow self-cleaning is 10°. The information presented in this study can serve as inputs for the development of grid-tied PV system without battery storage, grid-tied PV system with battery storage and stand-alone systems in Kumasi, Ghana.

Numerical analysis of thermal post-buckling strength of laminated skew sandwich composite shell panel structure including stretching effect

The computational post-buckling strength of the tilted sandwich composite shell structure is evaluated in this article. The computational responses are obtained using a mathematical model derived using the higher-order type of polynomial kinematic in association with the through-thickness stretching effect. Also, the sandwich deformation behaviour of the flexible soft-core sandwich structural model is expressed mathematically with the help of a generic nonlinear strain theory i.e. Green-Lagrange type strain-displacement relations. Subsequently, the model includes all of the nonlinear strain terms to account the actual deformation and discretized via displacement type of finite element. Further, the computer code is prepared (MATLAB environment) using the derived higher-order formulation in association with the direct iterative technique for the computation of temperature carrying capacity of the soft-core sandwich within the post-buckled regime. Further, the nonlinear finite element model has been tested to show its accuracy by solving a few numerical experimentations as same as the published example including the consistency behaviour. Lastly, the derived model is utilized to find the temperature load-carrying capacity under the influences of variable factors affecting the soft-core type sandwich structural design in the small (finite) strain and large deformation regime including the effect of tilt angle.

Ferromagnetic resonance frequency and spin wave mode of asymmetric strip nanomagnet

Recently, the operating frequency of nanomagnetic logic device has reached the spin wave frequency of nanomagnets. Therefore, the dynamic magnetic properties of nanomagnets, which are excited by microwave magnetic field, have been explored by many researchers. In this paper, the micro-magnetic model of asymmetric strip nanomagnets under microwave excitation is established. By using the anisotropic stress field (along the <i>x</i>-axis direction) that is generated by a constant voltage and the SINC function microwave magnetic field (along the <i>y</i>-axis direction) to excite the nanomagnets at the same time, the effects of tilt angle and defect angle on the ferromagnetic resonance (FMR) spectrum and spin wave mode of the asymmetric strip nanomagnets are studied. Spectral analysis is performed on the micromagnetic simulation data. Simulation results show that as the tilt angle of the asymmetric strip nanomagnet increases, the ferromagnetic resonance frequency increases. What is more, this phenomenon is independent of the defect angle of the nanomagnet. When the tilt angle is constant, there exists a monotonically increasing relation between the ferromagnetic resonance frequency of the asymmetric strip nanomagnet and the defect angle. The spin wave modes of the nanomagnets differ a lot as defect angle changes. The asymmetric strip nanomagnet is compared with the rectangle nanomagnet, and the spin wave mode of the asymmetric strip nanomagnet is localized. Specifically, the spin wave mode of the asymmetric strip nanomagnets is asymmetric and the high precession region exists at the edge, which is termed asymmetric edge mode. The changes of the tilt angle lead to the changes in the demagnetizing field inside the nanomagnet, which gives rise to the movement of the edge mode. However, the center mode is not sensitive to the change of tilt angle. Finally, the magnetic loss of the model under the excitation of high frequency microwave magnetic field is analyzed and the reliability of the model is verified. These findings indicate that the defect angle and tilt angle can be used to tune the spin wave mode and the ferromagnetic resonance frequency of nanomagnets, and thus providing an important theoretical basis for designing the tunable microwave nanomagnetic devices.

Sensitivity analysis of several operational parameters on gas temperature deviation in a tangential firing boiler

In this work, an integrated numerical model combining combustion and fluid heating was established for a 660 MW coal-fired boiler. To validate the accuracy of the developed model, related experiment was also conducted, and shows that the relative errors (REs) of several predicted parameters on both flue-gas side and water-steam side of the boiler are less than 7 %, which meets the requirement of analysis. The results indicate that the effect of SOFA tilt angle on gas temperature deviation (GTD) is greatest, and that of SOFA’s proportion follows; while GTD presents a smallest sensitivity to the concentration of O2. This is because O2 concentration mainly affects the average value of the gas temperature, but barely changes its distribution. By contrast, altering SOFA’s tilt angle and its proportion directly varies the shape, location, and area of the high-temperature and low-temperature regions at the entrance profile of the horizontal crossover pass, so these two factors play a more important role in the variation of GTD.

Phase-shifted gratings fabricated with femtosecond laser by overlapped two types of fiber Bragg gratings

A phase-shifted fiber Bragg grating (PS-FBG) fabricated by femtosecond laser phase mask technique is demonstrated. The PS-FBG fabricated by overlapped two types of fiber Bragg gratings (FBGs), which is a normal FBG and a titled fiber Bragg grating (TFBG). They are inscribed one over the other on the same section in a single-mode fiber. We researched the effect of different tilt angles to the Bragg wavelength of TFBG. The intensity and wavelength of PS-FBGs can be changed by controlling tilt angles. The method has advantages of simple and efficient fabrication as well as high-quality spectrum. Meanwhile it has a good repeatability. Additionally, the strain and temperature sensitivities of the 0° + 3° PS-FBG are experimentally measured, which are 0.867 pm/με and 14.91 pm/℃, respectively.

Assessing the Quality of Shortwave and Longwave Irradiance Observations over the Ocean: One Year of High-Time-Resolution Measurements at the Lampedusa Oceanographic Observatory

AbstractMeasurements of downwelling shortwave (SW) and longwave (LW) irradiance were carried out on an oceanographic buoy close to the island of Lampedusa (Italy), in the central Mediterranean Sea. Irradiance measurements on the buoy were acquired at high time resolution together with the radiometer pitch and roll angles. The measurements carried out during 2016 have been compared with ground-based observations made at the Lampedusa Atmospheric Observatory, about 15 km northeast of the buoy. The radiometers were compared before and after deployment on the buoy and are traceable to the World Radiometric Reference scale. The SW measurements were corrected for the thermal offset. A small bias (measurements over the sea are smaller than on land) of about −2 W m−2 is found in the daily mean SW, and a moderate bias of +6.2 W m−2 (irradiance over the sea is larger than on land) is found in the LW. Similar biases are found when instantaneous measurements obtained with horizontal radiometers, clean domes, and cloud-free conditions are selected, suggesting that impacts of the moving platform and poor dome cleaning are minor at this site. The effect of the mean tilt angle was also investigated. Deviations in the hourly mean SW irradiance are on the order of 20% for a mean offset of 4° with respect to the solar zenith angle; the effect of tilt angle on LW irradiance appears to be negligible. Radiative transfer calculations show that the observed biases may be ascribed to the differences in the instrument altitude (through radiation absorption, scattering, and emission by the atmospheric constituents in the lowest atmospheric layers) and in the SW surface albedo.

Study on the effects of tool tile angle, offset and plunge depth on friction stir welding of poly(methyl methacrylate) T-joint

The effects of tilt angle (TTA), plunge depth (TPD) and offset (TO) of tool in friction stir welding of poly(methyl methacrylate) T-joint were investigated. To understand better the effects of process parameter, thermomechanical simulation of joint was assessed. The results seem to show that at higher TPD and TTA, frictional heat increases. Woven tissue structure joint line forms after friction stir welding of poly(methyl methacrylate) sheets. The distance of woven layers was affected by TPD and TTA, while TO do not significantly affect heat generation of joint. The best material flow and adequate heat are generated at 0 mm TA, 2° TTA and 0.2 mm TPD, respectively. The highest flexural and tensile strength of friction stir welded joint were approximately 93% and 90% of as-received poly(methyl methacrylate), respectively. Crack forking was detected on the fractured surface of flexural samples and crack path was detected in the vicinity of shrinkage holes at fracture surface of tensile samples. These holes and degradation of poly(methyl methacrylate) during friction stir welding process decrease strength and hardness of the joint.

Effect of Tilt Angle and Pin Depth on Dissimilar Friction Stir Lap Welded Joints of Aluminum and Steel Alloys.

Automobile, aerospace, and shipbuilding industries are looking for lightweight materials for cost effective manufacturing which demands the welding of dissimilar alloy materials. In this study, the effect of tool rotational speed, welding speed, tilt angle, and pin depth on the weld joint were investigated. Aluminum 5052 and 304 stainless-steel alloys were joined by friction stir welding in a lap configuration. The design of the experiments was based on Taguchi’s orthogonal array for conducting the experiments with four factors and three levels for each factor. The microstructural analysis showed tunnel defects, micro voids, and cracks which formed with 0° and 1.5° tilt angles. The defects were eliminated when the tilt angle increased to 2.5° and a mixed stir zone was formed with intermetallic compounds. The presence of the intermetallic compounds increased with the increase in tilt angle and pin depth which further resulted in obtaining a defect-free weld. Hooks were formed on either side of the weld zone creating a mechanical link for the joint. A Vickers hardness value of HV 635.46 was achieved in the mixed stir zone with 1000 rpm, 20 mm/min, and 4.2 mm pin depth with a tilt angle of 2.5°, which increased by three times compared to the hardness of SS 304 steel. The maximum shear strength achieved with 800 rpm, 40 mm/min, and a 4.3 mm pin depth with a tilt angle of 2.5° was 3.18 kN.

Research on Impact of Nanofluids in Heat Pipes

The basic aim of this study is to study the impact of nanofluids such as (Al2O3+Distilled water) in complete liquid form by dispensing aluminium oxide (fluid form) in base fluidand also to investigate the thermal performance of heat pipe solar collector using nanofluids under real operating conditions by theoretically and experimentally.The experimental setup is made with heat pipes and real time temperatures are measured for experimental efficiency. The theoretical investigation is to be done by using Computational Fluid Dynamics (CFD).The main innovation done in this experiment is the nanofluid prepared in complete fluid form without particles suspension to avoid the settling of nanoparticles in thermo syphon setup.For long term applications, we opted this method of preparing the fluid. The operating parameters to be considered are solar intensity, effect of tilt angle and effect of working fluid. Finally, the experimental output is to be compared with the theoretical one (CFD). The efficiency of theoretical was higher than experimental because ofassumptions considered in CFD. The nanofluid filled with 25% of total capacity of heat pipe i.e. 25ml/pipe.Heat pipes are best energy conserving technology for solar energy conversion.

Cooling of high heat flux electronic devices using ultra-thin multiport minichannel thermosyphon

Studying multiport minichannels as thermosyphons are considered to be of great interest compared to cylindrical and flat shaped ones with single ports. In this study, a novel multiport minichannel (MPMC) thermosyphon (hydraulic diameter of 1.18 mm, length of 200 mm with 10 internal ports with thickness 0.1 mm each) with acetone as working fluid is experimentally investigated for cooling high heat flux electronic devices. Effect of heat load (10–50 W), filling ratio (40%, 50%, and 60%) and tilt angles (45°, 60° and 90°) on thermal resistance, convective heat transfer coefficients of evaporator and condenser, vapour velocity, flooding, sonic, boiling limits and efficiency are experimentally studied. Results showed 9.31% and 22.2% reduction in evaporator wall temperature and thermal resistance at optimum filling ratio (OFR) of 50%. Enhancement in evaporator heat transfer coefficient and thermal efficiency of 30.7% and 89.8% are respectively observed at OFR. Multiports present in minichannel acts as internal fins and increases the surface area and evaporation rate. Further multiports increases surface tension of condensate at right angles to the flow direction along with the effects of gravity enhancing the rate of condensation. Thus, the obtained experimental results will be useful in cooling of miniaturized high heat flux electronic devices..

Effect of Tilt Angle on PV Array Output Performance

Solar energy is an effective way to solve the world crisis for energy. In order to reduce cost research about solar energy is being done around the world. While searching about different techniques to increase efficiency and output, various methods present in recent researches. The numbers of factors are essentially important for the study. Tracing mechanism plays a vital role in that aspect. In this method, parameters such as width, height and other are considered. The best is obtained to setup the plant that promises maximum output and reduced cost. Locating the solar panels at different points of incidence to get the maximum power output is aimed in this article.

STUDY OF OPTIMUM GLASS TILT ANGLE ON OVERALL THERMAL TRANSFER VALUE (OTTV)

Glass Reflectance is the ability of the glass surface to reflect light when passing through the glass surface. All types of glass have this capability (Clear Glass, Tinted Glass, and Reflective Glass). With its ability, not all the light will be passed through the glass because the glass surface will reflect some of the light. The magnitude of reflection depends on the tilt angle of the glass against the light direction. It means if the glass is applied to the building façade and exposed to sunlight, not all sunlight and the heat forwarded into the building. To know the exact tilt angle of the glass when applied to the building, research on the effectiveness of light reflection by the tilt angle of the glass is necessary. This research uses a computer simulation method with hypothetical building objects. This research aims to test how effective the tilt angle of glass reflects the sunlight when applied as the building facade. The tilt angle tested in the simulation is a tilted and rotated glass. The tilt angle effect of the glass can be calculated using the building’s OTTV (Overall Thermal Transfer Value). Keywords: tilt angle glass, OTTV, simulation

Comparing the Effect of Rotor Tilt Angle on Performance of Floating Offshore and Fixed Tower Wind Turbines

The development of Floating Offshore Wind Turbines (FOWTs) aims to improve the potential performance of the wind turbine. However, a problem arises due to the angle of tilt from the wind flow and the floating platform, which leads to a vertical misalignment of the turbine axis, thereby reducing the available blade area and lowering the capacity to capture energy. To address this problem, this paper seeks to compare the influence of the rotor tilt angle on wind turbine performance between fixed tower wind turbines and FOWTs. The models used in the experiments have R1235 airfoil blades of diameter 84 cm. The experiment was analyzed using a wind tunnel and mathematical modelling techniques. Measurements were obtained using an angle meter, anemometer and tachometer. Testing involved wind speeds ranging from 2 m/s to 5.5 m/s, and the rotational speeds of the two turbine designs were compared. The study found that the rotational speeds of the FOWTs were lower than those of the fixed tower turbines. Moreover, at tilt angles from 3.5° – 6.1° there was a loss in performance which varied between 22% and 32% at different wind speeds. The tilt angle had a significant effect upon FOWTs due to the angle of attack was continuously changing, thus altering the optimal position of the turbine blades. This changing angle of attack caused the effective area of the rotor blade to change, leading to a reduction in power output at suboptimal angles. The study finally makes recommendations for future studies.

Effect of horizontal spacing and tilt angle on thermo-buoyant natural convection from two horizontally aligned square cylinders

Laminar natural convection heat transfer from two horizontally aligned square cylinders has been investigated numerically using a finite-volume method (FVM). Computations were performed to delineate the momentum and heat transfer characteristics under the following ranges of parameters: horizontal spacing between the cylinders (0 ≤ S/W ≤ 10), tilt angle of the square cylinder (00≤δ ≤ 600), and Grashof number (10 ≤ Gr ≤ 105) for some specific Newtonian fluids having Prandtl number (0.71 ≤ Pr ≤ 7). Computed results are presented in terms of temperature contours and streamlines, velocity and temperature profiles, the mass flow rate in the passage between the cylinders, local and average Nu, and the drag coefficient. The average Nu increases with decrease in the horizontal spacing up to a certain limit, whereas it significantly degrades with a further decrease in the spacing. The square cylinder having δ = 450 shows a higher heat transfer, whereas it is least for δ = 00. At higher Gr and Pr, the average Nu is found to be in excess of 22% at δ = 450 compared to at δ = 00. Overall, the average Nu has a strong dependence on both Gr and Pr, whereas it is a weak function of S/W and δ. Furthermore, the total drag coefficient (Cd) shows an adverse dependence on both Gr and Pr. The flow resistance is higher at the optimum horizontal spacing and decreases significantly with decrease in the spacing. The Cd is found to be lower for δ = 450 and in excess of 30% at δ = 00. Finally, a correlation for the average Nu has been developed, which can be useful for some engineering calculations.

Effect of tool tilt angle on weld joint properties of friction stir welded AISI 316L stainless steel sheets

The effect of tool tilt angle on mechanical and metallographic characteristics of friction stir welded AISI 316L austenitic stainless steel joints was investigated. Three experimental trials were performed between 0° to 3° in steps of 1.5°, while keeping the other primary FSW parameters constant (tool rotational speed of 600 rpm, welding speed of 45 mm/min and axial load of 11 kN). The experimental findings prove that the tool tilt angle has significant effect on dynamic volume of the stir zone, peak temperature and the intensity of the shear band formation in the weld zone. The weld joint made at 1.5° was the best tool tilt axis that exhibited higher strength and superior microstructural features leading to onion ring formation at the weld stir zone. 0° tilt angle resulted in slight shoulder plunge whereas, 3° tilt angle paved the way to the formation of void in the weld zone.

Effect of tool tilt angle on strength and microstructural characteristics of friction stir welded lap joints of AA2014-T6 aluminum alloy

Abstract Friction stir welding (FSW) has been extensively adopted to fabricate aluminium alloy joints by incorporating various welding parameters that include welding speed, rotational speed, diameters of shoulder and pin and tool tilt angle. FSW parameters significantly affect the weld strength. Tool tilt angle is one of the significant process parameters among the weld parameters. The present study focused on the effect of tool tilt angle on strength of friction stir lap welding of AA2014-T6 aluminium alloy. The tool tilt angle was varied between 0° and 4° with an equal increment of 1°. Other process parameters were kept constant. Macrostructure and microstructure analysis, microhardness measurement, scanning electron micrograph, transmission electron micrograph and energy dispersive spectroscopy analysis were performed to evaluate the lap shear strength of friction stir lap welded joint. Results proved that, defect-free weld joint was obtained while using a tool tilt angle of 1° to 3°. However, sound joints were welded using a tool tilt angle of 2°, which had the maximum lap shear strength of 14.42 kN and microhardness of HV 132. The joints welded using tool tilt angles of 1° and 3° yielded inferior lap shear strength due to unbalanced material flow in the weld region during FSW.

Temperature distribution in a photovoltaic module at various mounting and wind conditions: A complete CFD modeling

In this study, a complete three-dimensional computational fluid dynamics simulation of fluid flow and heat transfer from a Photovoltaic (PV) module is developed. Since the electrical efficiency of photovoltaic modules is a function of its temperature, the present research tries to calculate the temperature distribution in the module by numerically solving the governing momentum and energy equations with the finite element method. The three dimensional wind flow field around the system is simulated in different geometrical and ambient conditions to account for realistic and nonuniform convection heat transfer from the module surfaces. The electrical output power is calculated as a function of PV module temperature and is modeled as a negative source term in the energy equation. Results show that the present method is very successful in predicting the temperature distribution and output power of photovoltaic modules at various geometrical and environmental conditions. Specifically, the effect of wind direction and tilt angle of the PV module is investigated. By increasing the tilt angle at wind velocities higher than 1 m/s, the average PV temperature increases by about 4 K; as a result, its efficiency decreases. The most favorable wind direction is 90° as a 3 K cooling in the average PV module temperature can be achieved. The proper choice of mounting orientation is also important, and it depends on the wind direction. In most cases, the horizontal mounting (i.e., the longer side of the panel is parallel to the ground) results in better cooling.