Various Angles Of Inclination Research Articles

Functioning Features of Liquid Crystalline Cells Doped with CoFe2O4 Nanoparticles

The first experimental results on the functioning of liquid crystal cells doped with CoFe2O4 nanoparticles are presented. Transmission spectra in the visible and near-infrared range, dynamic parameters of the Fredericks effect, refractive characteristics, as well as wetting angles of the mesophase sensitized surfaces have been obtained. The measured surfaces were the K8 Crown glass, the conductive ITO and the ITO treated with a surface electromagnetic wave. The experiment was performed in order to establish the prospect of using such reliefs as a novel liquid crystal composite orientator sensitized with CoFe2O4 nanoparticles. A color change of the liquid crystal matrix, its refractive coefficients alterations, and the variation of inclination angle of the sensitized liquid crystal droplets on the considered reliefs were established. The time reaction parameters and the medium relaxation parameters were measured. It was proposed that the liquid crystal composition is a kind of an immersion medium that preserves properties of the introduced nanoparticles, which expands their application scope in optoelectronics and biomedicine.

The study of mixed mode fatigue crack growth mechanism of 25CrNiMo compact tensile specimens by experiment and finite element simulation

Fatigue cracking is the most common failure mode that endangers the safety and service life of parts. Initial manufacturing flaws are a critical factor affecting the growth of fatigue cracks. Currently, mixed-mode crack growth research frequently applies a simplistic two-dimensional finite element model, which cannot adequately represent the crack growth mechanism. An improved finite element method is proposed in this paper to overcome this drawback. Fatigue fracture propagation investigations on 25CrNiMo compact tensile specimens are conducted in this study, and the crack propagation rate is calculated using the Paris formula. Moreover, the special element modeling method and second-order Runge-Kutta integration method are utilized to perform finite element calculations on the 3D model. The results are highly consistent with the experimental test results. The propagation mechanism of cracks with varied initial inclination angles is explored depending on the finite element method. The relationship between the stress intensity measures KI, KII, and KIII is discovered to be competitive. The results have significant application value for the crack growth path prediction and crack life in parts with initial flaws.

Microgravity two-phase flow research in the context of vapor compression cycle experiments on parabolic flights

Research on two-phase channel flow in microgravity has extensively investigated flow regimes, pressure drop, and heat transfer during evaporation and condensation processes over several decades. This literature has been primarily motivated by the goal of enabling future space applications for two-phase thermal management systems, among them vapor compression refrigeration cycles. However, relative to the number of two-phase channel flow experiments, research on vapor compression cycles in microgravity has been almost non-existent. This paper reviews two-phase flow research and compares key outcomes with those from system-level measurements obtained from recent testing of a vapor compression cycle at varying inclination angles and on parabolic flights. Previous two-phase channel flow experiments have resulted in several microgravity-specific flow regime maps and have also generally found reduced condensation heat transfer coefficients in microgravity as compared to normal gravity. The flow pattern map of Jayawardena et al. (1997) and generally reduced condensation heat transfer are confirmed by the vapor compression cycle experiments. Regarding evaporation heat transfer coefficients and friction factors, there is not a consensus in the literature on the effects of microgravity in two-phase channel flows. Similarly, the system-level experiments do not show repeatable increases or decreases for those parameters. Lastly, the dependence of system-level behavior on orientation with respect to gravity was tested by performing dynamic inclination experiments, where the inclination angle was changed every 2 min by a 90-degree increment. These tests reveal an increased relative dependence of the vapor compression cycle to orientation with decreasing mass fluxes, in line with two-phase channel flow research that has generally shown that increasing the flow inertia acts to mitigate various flow instabilities and dependence on orientation. However, inclination testing with longer locking times per angle showed a constant relative dependence of the vapor compression cycle to orientation changes.

Hydrodynamic Performance Analysis of Vertical Axis Water Turbine (VAWT) Gorlov Type With Hydrofoil Thickness and Inclination Angle Variables using Computational Fluid Dynamics (CFD) Approaches

The issue of renewable and eco-friendly energy has become the focus of research in several countries to encourage eco-friendly alternative energy. One of them is by using turbines to produce electrical energy. Vertical Axis Water Turbine (VAWT) can be an exciting research object because it has various advantages. VAWT has a simpler structure, can move at relatively slow currents and is famous for its tendency to move regardless of the water flow directions. In this study, the experimental turbine from secondary data numerically simulates using the Computational Fluid Dynamics (CFD) method with the help of ANSYS V18.1 software. The Gorlov turbine model is manufactured in 3 dimensions under steady-state flow conditions. Validation is carried out after obtained numerical results with the mean error rate being less than 10%. The variables in this research are the thickness of hydrofoil using NACA 0010, NACA 0016, NACA 0020, and variations in inclination angle of the blade for 25. After comparing the simulation results in the form of torque values is done, it is shown that the best turbine performance is given by water turbine using NACA 0016 with 60 and 60 of inclination angle.

Effect of Glass Cover Thickness and Inclination Angle on Distillate Efficiency of Single-Stage Solar Still

Solar desalination is one of many methods to separate excess salt from seawater. In this work, solar energy is applied because of its economical and environmental value. Additionally, solar energy is practical to use in the coastal region. To increase the distillate produced by the solar still, four variations of cover thickness and three variations of inclination angle are applied to the still. The cover thickness and inclination angle used in this work are 3 mm, 5 mm, 8 mm, 10 mm and 25°, 30°, 45°. The type of still that is used in this work is a rectangular-shaped single-stage solar still with an area of 0.8 m2. The desalination processes in this work were done from 09.00 until 16.00 and the data was collected every hour in the processes. The result of this work shows that the distillate efficiency produced by the solar still is 1.03% - 6.91%. The highest solar intensity is 1231.97 W/m2 and the lowest solar intensity is 101.03 W/m2. The most effective efficiency was obtained with the variation of 3 mm cover thickness and 25° inclination angle, while the lowest efficiency was obtained with the variation of 10 mm cover thickness and 30° inclination angle.

Development of electric vehicle with permanent magnet synchronous motor and its analysis with drive cycles in MATLAB/Simulink

The conventional fuel dominant automotive market has been challenged by electric vehicles (EVs) in both commercial and private vehicles segment. The rising fuel prices, stringent emission norms, government incentives, and increasing awareness towards global warming has publicized EV as the future of the automobiles. New rare earth permanent magnet materials and advanced electronic controllers have made the traction motors more compact and energy efficient. EV motors combined with the advanced battery technology has helped in ruling out range anxiety from people’s mind. Modeling and simulation of electric vehicle reduces cost and ramps up the development process. In this paper simulation model of electric vehicle is developed for traction application with model-based design approach using MATLAB/Simulink. This includes a dynamic vehicle model running on two different drive cycles, extra urban driving cycle (EUDC) and new european driving cycle (NEDC). The vehicle model takes velocity as input from the drive cycle and generates the required torque and power. The permanent magnet synchronous motor (PMSM) model takes this torque as input reference torque and produce the power and torque. The simulated results of vehicle model are validated by analytical calculated results. The error obtained are under 0.05%. The vehicle performance with variations in inclination angle and driving cycle is also observed and analysed. This model is used to observe torque, power, energy consumption and range of the vehicle.

THE INFLUENCE OF TILT ANGLE ON THE PERFORMANCE OF SOLAR PANELS AS A SMART HELMET POWER SUPPLY IN A MOTORCYCLE SAFETY SYSTEM

The performance of a solar panel module is strongly influenced by its orientation and tilt angle. Tests have been carried out to track variations in the performance of the solar panel module and electrical parameters at various angles of inclination in the conditions of Karawang and Bogor. There are two experimental modes: 1) a varying slope module under a constant irradiance level, 2) a varying irradiation intensity at the optimal tilt setting. For the former schematic, the irradiation levels were carried out at 2 different locations, and for the later setup, the angle of inclination of the module was varied from 90° and 180° by using a single axis tracer At 90° tilted angle in Karawang test place at rest condition, morning experiment give the result of 5,69V on average while in Bogor the experiment gives 5,46V on average. At 180° tilted angle in Karawang test place at rest condition, morning experiment give the result of 5,49V on average while in afternoon experiment afternoon 3.026V on average. In Bogor test place morning experiment give solar panel 5,2V on average and 3,33V at afternoon experiment. In the electrical parameters of the module, the open circuit voltage, short circuit current, maximum power point voltage and maximum power point current decrease substantially with increasing slope angle, while the charge factor decreases somewhat gradually. Tests in both Karawang and Bogor in the afternoon and afternoon confirmed that the optimal tilt angle on cloudy on with UV index between 1-2 in the morning and 3-4 in the afternoon on average is 180° tilted and directing the solar panel module at this angle will maximize the captured solar energy and thereby improve its performance.

Process model of vibrating screen based on DEM and physics-informed machine learning

Vibrating screens are widely used in industry but it is difficult to consider the enormous controlling variables and complicated particle-particle interactions in current screen process models. This study develops a new process model for vibrating screens by the combination of discrete element method simulation and physics-informed machine learning. First, based on the assumption that the particle passing in a part of a screen is dependent on the local screen and flow conditions, the relationship between the passing flow rate and local conditions is established through machine learning of data generated by a series of controlled DEM simulations. In particular, a universal local passing function is developed to predict the passing flow rates of different size particles on a screen segment, according to the segment's vibration conditions, inclination angle, and the inlet flow. Then the process model for the whole screen is developed by connecting different segments based on mass continuity, which can predict overflow partition curves under various conditions in a much more efficient way than DEM. Moreover, the process model can be applied not only to the original simulated incline vibrating screen, but also to modified screens with varied inclination angles or vibration conditions in different segments. The model would be helpful to the smart design and control of industrial screens and other similar particle classification processes. • Combined DEM and physics-informed machine learning for process model of screen. • Local passing function established by machine learning of DEM data. • Local flow in segment predicted by ML and linked by mass conservation. • Process model accurately predicts partition curve but much more efficient than DEM. • Process model is versatile to banana screens and varied vibration screens.

Effect of inclination angle on the thermal performance of a three-phase closed thermosyphon containing SiC particles

Three-phase closed thermosyphon (THPCT) with variable inclination angle (0°–30°) is designed and built to investigate thermal performance by applying fluidized bed heat transfer technology to the two-phase closed thermosyphon (TPCT). Visual experiments were conducted to help explain the flow in THPCT. Water and silicon carbide (SiC) particles are selected as working media. The effect of solid holdup (0–20%) and input power (100–300 W) is also discussed. Results show that the addition of SiC particles can improve the thermal performance of the thermosyphon and reduce the overall thermal resistance under different inclination angles. The reduction rate of the overall thermal resistance fluctuates with the increase in inclination angle. The maximum reduction rates of the overall thermal resistance for the inclination angles of 0°, 10°, 20°, and 30° are 32.9%, 26.7%, 37.0%, and 30.5%, respectively. The maximum reduction rates of the overall thermal resistance exist at low input power, depending on the solid holdup. The overall thermal resistances of the TPCT and THPCT generally decrease with the increase in input power but fluctuate with the increase in inclination angle. In most cases, the minimum overall thermal resistance is obtained at the inclination angle of 0°. The convective heat transfer coefficient of the condensation section is obviously lower than that of the evaporation section under different inclination angles. The input power and particle addition have a more obvious influence on the heat transfer of the condensation section compared with the evaporation section. The results are beneficial to the application of the THPCT in some industrial fields, such as solar collector and frozen earth.

Pressure distribution on a flat plate in the context of the phenomenon of the Coanda effect hysteresis

As a result of the Coanda effect, a symmetrical free jet will flow as an asymmetrical wall jet. At the same time, at the obstacle along which the flow is observed, the wall jet generates pressure distribution. In this study, the obstacle located at the diffuser outlet is a flat plate with a variable inclination angle. The article presents results of the study on pressure distributions on a flat plate with a variable angle of inclination. In the experiment, the Reynolds number ranged from 16,192 to 42,240. A fixed geometry diffuser (Witoszyński nozzle) with a height of 0.60 m, width of 0.02 m and outlet velocity of 11.33–29.57 m/s was used. A plate with a length of 1.00 m and a variable inclination angle was installed at the diffuser outlet. What is new, however, is that the presented results of the experimental research include the influence of the Coanda effect hysteresis on the pressure distribution on the plate. The article shows how pressure distributions change on the plate depending on whether the initial angle of inclination was 0° and was increased gradually in the course of the experiment until a detachment of the jet flowing from the plate was observed, or the initial angle of inclination was close to 90° in the primal state and as the angle of the plate inclination was decreased, the jet flowing towards the plate reached the state of attachment to the plate surface. The study demonstrated that for a turbulent jet, pressure distribution on a flat plate is determined not only by the plate’s inclination angle, but also by the direction of its rotation.

Quadratic Polynomial Velocity Profile in Laminar Boundary Layer Thickness

Motion of uid elements can be described by the Navier-Stokes equations. They arise from the use of Law of motion to a uid. In this investigation, two dimensional Navier-Stokes have been engaged. Then they are applied to an incompressible viscous uid movement down an inclined plane with net ow. These leads to examining the effects to the velocity of the motion at various angles of inclination and finding the boundary layer thickness. Viscous laminar incompressible fluid ow also ow on an inclined position which makes it necessary to investigate the ow on an inclined plane. Results that have been achieved are of the ow over horizontal at plate. Solution that has been obtained involves a at photographic film being pulled up by a processing bath by rollers at an angle \(\theta\) to the horizontal. Quadratic polynomial function approximate velocity profile has been obtained under initial boundary layer conditions. This velocity profile has been used in momentum integral equation for ow over an inclined plane to get the boundary layer thickness. Boundary layer thickness is one of the parameters that is used to obtain the ow velocity down inclined plane.

Experimental study of light sphere motion in liquid in rotating tilted cylinder

The motion of a light spherical body in a rotating tilted cylindrical cavity with liquid is studied experimentally. The rotation rate and angle of inclination of the cuvette, the viscosity of the liquid and the characteristics of the body vary. It is shown that with an increase in the rate of the cell rotation, the velocity of the body’s ascent decreases. An increase in the angle of inclination of the cylinder relative to the vertical also leads to a decrease in the ascent rate of the body. A paradoxical behaviour of the body is demonstrated: with an increase in the viscosity of the liquid, the velocity of the body’s ascent increases while maintaining other parameters (rotation rate, size, density of the body and the angle of inclination). The results of investigations at various angles of inclination, properties of liquid and the body are generalized on the plane of two control dimensionless parameters. Comparison with theory and with experimental results of other authors in the case of vertical orientation of the cavity demonstrates good agreement. It was found that during ascent, the body performs differential rotation relative to the cavity, the rate of which depends on the axial coordinate of the body.

Passive enhancement of heat transfer in a microchannel by an adjoint system of cylinder and flexible beam

Based on passive heat and mass transfer enhancement technology, a control method combining a cylindrical obstacle and a flexible beam was proposed to improve heat transfer performance in a microchannel. The optimal layout of a flexible beam was investigated under varying inclination angles of the beam and its spacing distances to the cylindrical obstacle through two-dimensional simulations of heat transfer, fluid and solid interaction. The control mechanism of the flexible beam was qualitatively analyzed from views of flow pattern and structural vibration. It was found that the pressure loss and heat flux should be considered simultaneously, to achieve the best performance of the heat transfer. Results showed that optimal performance occurred when the inclination angle of the beam and its spacing distance to the cylinder took specific values. In such circumstances, the flexible beam’s vibration was amplified by the periodic vortex shedding from the upstream cylinder, without introducing too large a blocking effect. The appropriate control strategy of fluid-structure interaction can enhance the disturbance of the thermal boundary layer and result in the largest thermal enhancement factor.

Thermal Analysis of Cooling Channels on Electromechanical Actuator During Actual Flight

Liquid methane is regarded as a potential cryogenic propellant that can be used as coolant for regenerative cooling channels of high-power electrical devices, in addition to the oxygen/methane thrust chamber, owing to its moderate working temperature. This study examines the thermal performance of supercritical methane in cooling channels of the electromechanical actuator of a flight vehicle at varying angles of inclination and flight acceleration overloads. The main effects of overload and attitude at various angles of inclination on heat transfer are shown as variation in buoyancy force, which can be classified into gravitational and centrifugal buoyancy forces. Both forces can disturb the turbulent structure and complicate heat transfer under the influence of the drastically variable properties of the supercritical fluid. The authors also discuss conjugate impacts of the two kinds of buoyancy forces on the thermal performance of the cooling channel at various angles of inclination and flight acceleration overloads. The physical model was constructed as a helically coiled tube with angles of inclination varying from 0 to 90 deg, and flight overload was implemented as and (where is the gravitational acceleration). The analysis shows that both the flight attitude and overload played an essential part in the thermal performance of supercritical methane in the cooling channel. Some novel findings were obtained; an enhancement and a deterioration in local heat transfer could occur at large overloads with inclined orientations. The gravitational buoyancy force leading to secondary flow was an essential factor in the deterioration of local heat transfer but was inconspicuous under the gravity of Earth. Moreover, the trends of development of and were consistent, implying that the buoyancy force generated by gravity and centrifugal forces was not isolated.

Numerical scrutinization of dropwise condensation heat transfer on an inclined surface

AbstractRecently, achieving an ameliorated heat transfer rate in dropwise condensation (DWC) has attracted the attention of many researchers. Several parameters, including chemical and physical properties of the substrate, inclination, and interfacial characteristics influence DWC heat transfer rate. The variation of inclination angle is followed by the change in droplet shape and consequently, the heat transfer rate are changed. In this study, the effect of droplet shape variation on diverse inclined substrates is simulated. Moreover, three‐dimensional mass, momentum, and energy equations considering the desired boundary conditions on the unstructured grid are utilized for the scrutinization of flow behavior and heat transfer for static and sliding droplets. For the sake of validation, the outcomes obtained from the simulation were compared with existent data in the literature and a proper agreement was attained. Regarding the outcomes, it was of concern that the influence of inclination angle on the droplet shape is more distinct at higher droplet volume; while no considerable change was seen on heat flux of small droplets by increasing the inclination angle. Furthermore, a higher heat transfer rate was noted by exceeding the inclination angle beyond a definite angle. Additionally, the increased heat transfer rate was affirmed by increasing the Marangoni number .

Numerical and Experimental Modal Analyses of Inclined Supported Bridge Wing Structures

This paper studies ship bridge extensions called "bridge wings", which are one of the most critical areas of importance in ship vibration. These extensions, which have been modeled at the laboratory scale, have been analyzed using both experimental and finite element analysis methods. Bridge wing models have been constructed with varying inclination angles, and the natural frequencies and mode shapes obtained, both experimentally and numerically, have been compared. In this way, the effects of design properties on the results have been emphasized. Besides, the natural frequency discrepancies between the experimental and finite element analyses have been found to be very low. Another important result of this study has been obtained such that a certain support angle has been detected which the mode shape transition occurs in resonance. Natural frequency and mode shape analyses of the plates which have been supported with beams with varying inclination angles and achievement of mode shape transition phenomenon can be considered as the novelty about the contribution of this study to the state-of-the-art.

Experimental study on control of flame inclination in a thermal flow reversal reactor with extra lean premixed methane/air intake

Combustion instability is a basic obstacle to the wide application of porous media combustion devices in industry. However, the investigation about it with extremely dilute gas fuel issorelylacking due to the limitation of laboratory test conditions. In this study, inclinational instability of extra lean-premixed flame (with volume fraction below 1%) in a thermal flow-reversal reactor with honeycomb ceramic packings is investigated experimentally. The effects of inlet methane concentration on the flame inclination are studied. Then the flame inclination is restrained through electronically controlled adjustment on the valve opening and switch time. The experimental results show that the intake methane concentration has a remarkable effect on the flame inclination angle variation in each semi cycle. When the intake concentration decreases from 0.6 vol% to 0.2 vol% and the flow direction is downward, the growth of the flame inclination angle in each semi cycle gets lower. The adjustment on the scale of the high temperature zones in two half parts of the packed bed through the valve opening has a great influence on the flame front position and flame inclination angle. The setting of asymmetric switch time for the reverse flow also has obvious effect on the evolution of the flame inclination. Finally, the flame inclination angle drops firmly for approach of the two high temperature zones in size and height. The synchronous adjustment of valve opening and switch time fastens the convergence of the two high temperature zones in two half parts of the packed bed. This work is beneficial to the development of thermal flow-reversal reactor technique for better dealing with ventilation air methane and other lean gaseous fuel streams.

Discrete element modeling of rock-concrete bi-material discs under dynamic tensile loading

As the most fragile component in a bi-material, the performance of the rock-concrete interface can greatly affect the stability and durability of the concrete structures founded on the rock masses. In this study, a range of numerical simulations using the discrete element method (DEM) have been conducted to identify the failure mechanism and mechanical property of the rock-concrete bi-materials under the dynamic flattened Brazilian disc (FBD) tests using the modeled split Hopkinson pressure bar (SHPB) system. There are four groups of bi-material specimens that differ in the aspects of rock type (i.e. limestone and sandstone), interface inclination (i.e. 0°, 15°, 30°, 45°, 60°, 75°, and 90°), and specimen configuration (i.e. intact and hollow). The numerical results show that the nominal tensile strength depends on the rock type, and the intact specimen has a higher loading capacity than that of the hollow specimen. The failure modes are classified into three main types in intact limestone-concrete bi-materials according to the degree of the interface angle, which is in good agreement with the previous experimental results. Such transition from interface failure to tensile failure can be observed as well in the bi-material specimens with a hole inside, while the varying inclination angle has a minimal effect on the failure pattern of the sandstone-concrete bi-material specimens. The cracking process of the specimens is visualized using the evolution of acoustic emission (AE) activities. The moment tensor inversion interprets that more energy is required for cracks to propagate from concrete to limestone. The overall AE magnitude is the lowest in limestone-concrete specimens with a pre-cut opening due to the deteriorated specimen bearing capacity.

Dynamic melting of encapsulated PCM in various geometries driven by natural convection of surrounding air: A modelling-based parametric study

Encapsulated phase change material (PCM) has a great potential to reduce the fluctuation of indoor air temperature and subsequent building energy consumption through ceiling applications in air-conditioning systems. However, the effects of capsule geometry on the dynamic melting performance remain unknown when the melting is driven by natural convection. In this work, we modelled the melting behavior of PCM encapsulated in six different capsule shapes subject to natural convection of surrounding air, which was validated by our measurement results. The model considers the conjugate heat transfer through the surrounding air, capsule shell and PCM, enabling the prediction of a three-stage dynamic melting process. The melting process of the encapsulated PCM were further studied for varying inclination angles (with respect to the vertical axis), temperature differences (between the surrounding air and PCM), and capsule sizes. The results show that the capsule geometry plays a dramatic role in the time of phase change. At the ambient temperature of 22°C, the short cylindrical capsule with a horizontal axis takes the longest time to complete phase change (162 min), whilst the pyramidal capsule with a horizontal base takes the shortest time (120 min). We also quantified the heat transfer between capsules and surrounding air for varying temperature difference and capsule size, and found that the pyramidal and tetrahedral capsules with a horizontal base melt faster than capsules of other shapes due to the higher heat transfer rate caused by larger surface area. For cases with a medium capsule size and low temperature difference, early termination of melting at 80% liquid fraction is recommended since more than 30% of melting time can be saved with only 20% reduction in cold storage capacity. This work provides a validated model that is able to predict the dynamic melting process of PCM of different geometries, which will enable informed design of PCM panels for improving thermal management and comfort in buildings.

Increasing the Efficiency of Food Material Cutting during Inclined and Shear Movements of Knife.

Mathematical models for predicting the resistance forces that are developed during the inclined and sliding cutting of food materials have been developed. The dependence of the actual cutting angle on the angle of inclination and sliding speed of the cutting edge at various sharpening angles have been investigated. For the inclined cutting mode, the dependence of the useful resistance force on the cutting speed has been determined at various angles of inclination of the cutting edge and designed sharpening angles. For the sliding cutting mode, the dependence of the useful resistance force on the feeding speed has been demonstrated at various sliding speed values and designed knife sharpening angles. The dependence of the transformed dimensionless sharpness of the knife on the angle of inclination of the cutting edge and the sliding speed has been established for different constructional sharpness values of the knife. The results of the study indicate that the useful resistance force is significantly reduced during the inclined and sliding cutting processes when compared with the normal cutting process, and a change in the pattern of fiber destruction, which significantly increases the cutting efficiency of cutting tools, is obtained.