Values Of Rotational Speed Research Articles

Contact Line Pinning and Depinning Can Modulate the Rod-Climbing Effect.

Our experiments on the rod-climbing effect with an oil-coated rod revealed two key differences in the rod-climbing phenomena compared to a bare rod. First, an enhancement in the magnitude of climbing height for any particular value of the rod rotational speed and second, a decrease in the threshold rod rotational speed required for the appearance of the rod-climbing effect were observed. Observed phenomena are explained by considering the contact line behavior at the rod-fluid interface. Transient evolution of the meniscus at the rod-fluid interface revealed that the three-phase contact line was pinned for a bare rod and depinned for an oil-coated rod. We modeled the subject fluid as a Giesekus fluid to predict the climbing height. The differences in the contact line behavior were incorporated via the contact angle at the rod-fluid interface as a boundary condition. Agreement was found between the observed and predicted climbing height, establishing that contact line behavior may modulate the rod-climbing effect.

Effect of dwelling time and plunge depth on the joint properties of the dissimilar friction stir spot welded aluminum and steel

Sound joints of a far apart property, pure aluminum and mild steel, dissimilar materials were obtained by friction stir spot welding (FSSW) solid state joining process. Sheets of 2 mm thickness were overlapped and fixed with a fixture device then welded. Welding parameters that produced the sound joint were identified. Joints microstructure and mechanical properties were investigated. A microstructural investigation has revealed a creation of mechanical interlocking and discontinuous formation of the intermetallic compounds found at the interface. The intermetallic compound (IMC) layer thickness ranged from 6 μm to 17 μm with the optimum condition specimen, 800 rpm and 5 Sec dwell time. Tensile–shear test showed that failure load has increased with increasing tool plunge depth and rotational speed. After the optimum value of rotational speed, the shear failure load decreased. The maximum shear failure load of 2.15 KN attained at 800 rpm and 2.4 mm plunge depth.

Experimental and thermal investigation with optimization on friction stir welding of nylon 6A using Taguchi and microstructural analysis

Friction stir welding is an environmentally friendly process of joining due to the non-usage of flux, or any shield gas. Therefore, this article proposes an experimental and thermal investigation with optimization technique for studying the process of FSW on nylon 6A or polycaprolactam polymer composite plates. Specifically, the influence of input operating process parameters such as tool rotational speed (TRS), feed rate, and pitch values on the output response parameters like ultimate tensile strength (UTS), and hardness of welded joints is examined. In addition, L27 orthogonal array of Taguchi approach is employed for the optimization of design experiments of FSW parameters. The experimental setup is carried out with various process parameter combinations like 500, 1000, and 1500 rpm as TRS, 30, 40, and 50 mm as feed rate by varying the pitch values as 1, 2, and 3 mm. Further, the analysis of variance (ANOVA) also employed for finding the significant parameters of input process using the regression analysis equations. Finally, microstructural analysis is used to assess the mixing or dispersing uniformity of composites effectively. The experimental and optimum FSW parameters for maximum UTS are obtained at a feed rate of 30 mm/min, tool pitch of 3 mm, and the TRS of 500 rpm.

Investigation of Factors Affecting Friction Stir Welding of Polyethylene by ANOVA Analysis

The variables that are effective in joining high density polyethylene sheets by friction stir welding (FSW) have been investigated. In order to understand the effects of welding parameters, using Taguchi optimization, tool rotation speed, feed rate, shoulder diameter and pin diameter values were selected in a wide range. The results obtained with Taguchi optimization method were evaluated according to the highest / the best signal-noise ratio. Macro photographs taken cross-sectional view taken the weld seam, SEM images and hardness measurements were used to evaluate. As a result of the evaluation, the accuracy of the optimization was found to be approximately 96 %. As a result, feed rate and shoulder diameter were determined as the most effective parameter affecting the welding quality and welding performance. These two parameters (shoulder diameter and feed rate) have found to effect of approximately 65 % on tensile strength, weld quality and hardness. Finally, it has obtained that the most effective welding parameter was the shoulder diameter with 40.81 %.

Analyzing mechanical vibrations of an aircraft opposed piston engine

The paper presents the results of the bench tests to measure mechanical vibrations of a new aircraft opposed piston engine with reciprocating pistons. The PLZ-100 engine is a three-cylinder, six-piston, two-shaft drive unit with a two-stroke diesel cycle. This type of engine is dedicated for powering light aircraft, e.g. autogyros. The tests were carried out on a test bench at the Lublin University of Technology. The engine was loaded with constant torque, for several fixed values of rotational speed of a crankshaft. The angle of the start of diesel injection was changed for each of the rotational speeds. The mechanical vibrations that accompanied the operation of this drive unit were recorded with three measurement transducers and a National Instruments conditioning system. Each of the transducers was mounted on a different axis of the engine. The signals were analyzed from their courses with the DIAdem software. The results were the courses of effective speed and vibration acceleration to conduct a vibration-acoustic evaluation of the PLZ-100, detect and prevent various types of defects or failures.

Adaptive fixed-time sensorless maximum power point tracking control scheme for DFIG wind energy conversion system

This work investigates the adaptive fixed-time control scheme to the maximum power point tracking (MPPT) control of double-fed induction generator (DFIG) based wind energy conversion system (WECS). Firstly, a fixed-time observer is designed to estimate the aerodynamic torque without the wind speed sensors. Optimal torque control is employed to obtain the real-time value of the optimal rotation speed by the torque observer. Then, an adaptive fixed-time nonsingular terminal sliding mode controller is proposed to implement optimal rotation speed tracking for MPPT of DFIG based WECS without the upper bound information of disturbances and system uncertainties in advance. The complete proof process of the stability of system and fixed-time convergence characteristics of the observer and the controller based on the Lyapunov theorem is constructed. Finally, simulation studies verify the effectiveness and strong robustness of the proposed method by Matlab/Simulink.

Discrete Element Simulation Based on Elastic–Plastic Damping Model of Corn Kernel–Cob Bonding Force for Rotation Speed Optimization of Threshing Component

Current corn kernel-cob bonding mechanics models (LSD models) uniformly consider the bonding force changes during the maize threshing operation as an elastic change, resulting in computational errors of up to 10% or more in discrete element simulations. Due to the inability to perform high-precision discrete element simulation of the mechanics characteristics during the corn threshing operation, the core operating parameters of the corn thresher (rotation speed of the threshing component) rely mainly on empirical settings, resulting in a consistent difficulty in exceeding 85% of the corn ear threshing rate. In this paper, by testing the mechanics characteristics of corn kernels, the bonding force is found to have both elastic and plastic changes during the threshing process. An elastic–plastic (EP) damping model of the corn kernel–cob bonding force was established by introducing a bonding restitution coefficient e to achieve an integrated consideration of the two changes. By testing the relationship between the properties of the corn ear itself and the model parameters, the pattern of the effect of the corn ear moisture content and the loading direction of the ear by force on the EP model parameters was found. By establishing a model of the relationship between the corn cob’s own properties and the model parameters, the EP model parameter values can be determined by simply determining the moisture content of the ear. In this paper, the EP model was established and the high-precision simulation and analysis of the process of bonding force variation between corn kernel and cob is realized on the self-developed AgriDEM software. At the meantime, the optimal values of the threshing component rotation speed under different conditions of moisture content of corn ear were obtained by establishing an optimization model of threshing component rotation speed. The test results showed that the corn ear threshing rate could reach more than 92.40% after adopting the optimized speed value of the threshing component in this paper. Meanwhile, the test results showed that the discrete element simulation results based on the EP model did not significantly differ from the measured results of the thresher. Compared with the most widely used LSD model, the EP model can reduce the computational error by 3.35% to 6.05%.

Numerical study of drilling fluids flow in drilling operation with pipe rotation

As one of the major functions of drilling mud is to maintain pressure inside a wellbore to avoid any invasion of unwanted high-pressure, this makes the determination of this pressure loss a very complicated task in the petroleum drilling industry.The aim of this paper is to predict the behaviour of drilling fluid flowing inside rotating pipe then in a concentric annulus at various values of inlet velocity and rotation speed. The governing equations (continuity and momentum) are solved numerically using CFD simulation with FLUENT commercial code. The flow is laminar in three-dimensional steady-state with non-Newtonian fluid. The results are visualized as: contours, pressure drop and velocity. The results show that pressure drop is decreased when pipe rotational speed increase.At the conditions of rotation speed of 300 rpm and inlet velocity of 1.2 m/s, the pressure loss present a significant decrease compared to the other conditions, furthermore, an uniform distribution of velocity in the pipe and annulus, is indicated. Therefore we can considerate this conditions of rotation speed and inlet velocity as optimal conditions.

Influence of tidal turbine control on performance and loads

Tidal stream turbines (TST) are subject to large unsteady hydrodynamic loads which will result in fatigue of components and potentially failure. Control algorithms, if used effectively, have the ability to reduce these unsteady loads without affecting overall performance. To examine the effect of control strategy on performance and loads, experimental tests were carried out using a 1:15 scale TST in a combined wave–current facility. Loose and stiff speed controllers were developed and implemented, in addition to torque control, and tested for a range of tip-speed-ratios in a fixed inflow velocity. The speed controllers are additionally tested under regular, irregular and focused wave conditions. Through time and frequency-domain analysis, it is demonstrated that looser controllers, through larger speed variations, induce larger variations in the streamwise forces (rotor thrust and root bending moment), but smaller variations in torque. Similarly, larger extremes are recorded for streamwise forces under looser controllers. Mean values and hence overall turbine performance is found to be unchanged. It is noted that for the wave cases tested the controllers do not significantly affect the streamwise forces; likely a result of the large wave-induced velocities dominating the resulting blade angles-of-attack. Additionally, for some rotational speed values significant amplification of mechanical vibrations are observed. These results highlight the complexities associated with controller choice; considering the trade-offs in torque and thrust variations, potential mechanical resonance, and varying performance depending on the flow conditions. Proper appreciation of these considerations will be vital as we move towards commercial arrays of devices which must be controlled optimally to maximise performance whilst minimising loading and associated O&M costs.

Rheology, Morphology and Thermal Properties of a PLA/PHB/Clay Blend Nanocomposite: The Influence of Process Parameters

The effect of process parameters on the final properties of a poly-lactic acid (PLA) and polyhydroxybutyrate (PHB) polymer blend filled with nanoclays was evaluated. To this aim, the nanofilled blend was processed in a co-rotating twin screw extruder, considering three different screw profiles and different values of the screw rotation speed, and the thermal and thermo-mechanical properties of the so-obtained materials were investigated. Furthermore, XRD analyses, SEM observations and rheological characterization were exploited to infer the coupled effect of the process parameters and nanoclay presence on the microstructure of the filled blend. Preliminary thermodynamic calculations allowed predicting the preferential localization of the nanoclay in the interfacial region between the polymeric phases. The relaxation mechanism of the particles of the dispersed phase in nanofilled blend processed, by rheological measurements, is not fully completed due to an interaction between polymer ad filler in the interfacial region with a consequent modification of the blend morphology and, specifically, a development of an enhanced microstructure. Therefore, by varying the screw configuration, particularly the presence of backflow and distribution elements in the screw profile, high shear stresses are induced during the processing able to allow a better interaction between polymers and clay. This finding also occurs in the thermo-mechanical properties of material, as an improvement of storage modulus up to 20% in filled blend processed with a specific screw profile. Otherwise, the microstructure of filled blend processed with different screw speed is similar, according to the other characterizations where no remarkable alterations of materials were detected.

INVESTIGATION OF SUBSTRATE MIXING PROCESS IN ROTATING DRUM REACTOR

The results of the research on the influence of the drum type reactor design-technological parameters and the substrate`s physical-chemical parameters on the substrate`s components mixing evenness, that influence the quality of the received compost, are presented in this paper. By the method of the multifactor experiment rational values of the drum rotation speed, the blades (mounted on the inner drum surface) angle and the substrate`s moisture content are defined at which the components distribution homogeneity in the substrate reaches maximal value. The abovementioned, in turn, provides high compost quality by the agrichemical indices. The recommendations are given to pick the design parameters and operational modes of the drum type reactor.

Increasing Wind Turbine Drivetrain Bearing Vibration Monitoring Detectability Using an Artificial Neural Network Implementation

The highest costs due to premature failures in wind turbine drivetrains are related to defects in the gearbox, with bearing failures being overrepresented. Vibration monitoring has been identified as the primary tool to detect and diagnose these types of failures. However, late or no signs of the failures are still being reported. Artificial neural networks (ANNs) has been shown to favourably be used as a classifier of bearing failures to increase the detection and diagnosis performance, which requires labelled data when training for all types of considered failures. However, less work has been done with an ANN used to create descriptive functions of the vibration and turbine operation data relationship and thereby negating inherent variance in the vibration data and increasing the detectability when a defect appears. Therefore, this study utilizes the relationship between the rotational speed recorded during a vibration measurement and the calculated condition indicator values of specific bearing failures in three wind turbine gearbox failures. An ANN establishes a function between the rotational speed and condition indicator values with healthy training data collected before the failure occurred. Thereafter, whole datasets leading up to the changing of the gearboxes is used to predict the condition indicator values without the failure influence. The difference between the predicted and true values show an increased sensitivity of the detection in two cases of gearbox output shaft bearing failures as well as indicating a planet bearing failure which with the previous data had gone undetected.

Possibilities of Energy Harvesting from the Suspension System of the Internal Combustion Engine in a Vehicle

The automotive industry faces huge challenge in environmental protection by reducing fossil fuels and energy consumption by developing various practical solutions in energy harvesting. The current analysis is related to the diesel engine power supply system in a passenger off-road vehicle for application of the piezoelectric energy harvesting system. Experimental tests were carried out for the three constant rotational speed values - 800, 1000 and 1500 rpm. The results pertained to operational and simulation tests of available power supply options from the engine suspension system in the vehicle, e.g. to power sensors supervising the engine’s operation or other small electrical devices in the vehicle. The simulations of output voltage were conducted by means of a nonlinear model with a resonator coupled to a piezoelectric elastic beam deformed in the magnetic field to improve the band of frequency transducing kinetic mechanic energy into electric energy.

Surface Finish Analysis in Single Point Incremental Sheet Forming of Rib-Stiffened 2024-T3 and 7075-T6 Alclad Aluminium Alloy Panels.

The article presents the results of the analysis of the interactions between the single point incremental forming (SPIF) process parameters and the main roughness parameters of stiffened ribs fabricated in Alclad aluminium alloy panels. EN AW-7075-T6 and EN AW-2024-T3 Alclad aluminium alloy sheets were used as the research material. Panels with longitudinal ribs were produced with different values of incremental vertical step size and tool rotational speed. Alclad is formed of high-purity aluminium surface layers metallurgically bonded to aluminium alloy core material. The quality of the surface roughness and unbroken Alclad are key problems in SPIF of Alclad sheets destined for aerospace applications. The interactions between the SPIF process parameters and the main roughness parameters of the stiffened ribs were determined. The influence of forming parameters on average roughness Sa and the 10-point peak–valley surface roughness Sz was determined using artificial neural networks. The greater the value of the incremental vertical step size, the more prominent the ridges found in the inner surface of stiffened ribs, especially in the case of both Alclad aluminium alloy sheets. The predictive models of ANNs for the Sa and the Sz were characterised by performance measures with R2 values lying between 0.657 and 0.979. A different character of change in surface roughness was found for sheets covered with and not covered with a soft layer of technically pure aluminium. In the case of Alclad sheets, increasing the value of the incremental vertical step size increases the value of the surface roughness parameters Sa and Sz. In the case of the sheets not covered by Alclad, reduction of the tool rotational speed increases the Sz parameter and decreases the Sa parameter. An obvious increase in the Sz parameter was observed with an increase in the incremental vertical step size.

Effect of Friction Stir Process Parameters on Mechanical Properties of Al/Eggshell/SiC Composite Material

The rise in pollution is a serious matter of concern for all nations. Industries are mainly responsible for damaging the balance of the cycle of pollution. In this paper, the mechanical properties of Aluminum have been enhanced by reinforcing it with eggshell wastes and SiC as reinforcement particles. Ball-milling technique has been applied for up to 75 hours for making the densities of Aluminum, Eggshell and SiC equal. The prime focus of this work is to improve the hardness value of Aluminium-based final composite material. Friction Stir Process (FSP) technique has been used to develop the composite and the driving parameters of FSP like rotational speed, transverse speed etc. are optimized with the help of the Box-Behnken Design approach. The optimized value of rotation speed was 966.14 rpm as well as transverse speed was 23.18 mm/min. Hardness and tensile strength of composite developed at an optimum combination of parameters were found to be 72.2 BHN and 194.48 MPa respectively. Results showed that tensile strength and hardness were enhanced by about 44.05% and 64.09% respectively.

Design of 6S8P axial flux permanent magnet brushless DC motor with double-sided rotor

Electric motors developed rapidly in this decade. That is because electric motors have many advantages over conventional engines. The types of electric motors also vary, from low rated power to high rated power. Electric motors become an essential part of many sectors, such as industry and transportation. Brushless Direct Current Motor (BLDC) is one of the electric motors that has been developed because it has advantages compared to BDC motors. Low-power BLDC motors are widely used in several fields, such as computer construction, robots, and aviation. Research on the form of BLDC motor construction needs to be done to find out the maximum performance of a BLDC motor. Testing of a small motor axial flux permanent magnet brushless direct current with the double-sided rotor (AFPM BLDC DR) was carried out to determine the values of rotational speed, torque, mechanical power, and efficiency. Based on the test, a maximum rotational speed of 2365 rpm, the torque of 0.055 Nm, and the effectiveness of 70.34% are obtained.

Retracted] Experimental Investigation and Optimization on Friction Stir Welding of Nylon 6A Using Taguchi and ANOVA with Microstructural Analysis

Friction stir welding is an environmentally friendly process of joining due to the nonusage of flux, or any shield gas, and it does not produce any harmful gases when compared to the joining process of fusion. Therefore, this article proposes an experimental investigation and optimization technique for studying the process of FSW on nylon 6A or polycaprolactam polymer composite plates. Specifically, the influence of input operating process parameters such as tool rotational speed (TRS), feed rate, and pitch values on the output response parameters like ultimate tensile strength (UTS) and hardness of welded joints is examined. In addition, L27 orthogonal array of Taguchi approach is employed for the optimization of design experiments of FSW parameters. The experimental setup is carried out with various process parameter combinations like 500 rpm, 1000 rpm, and 1500 rpm as TRS, and 30 mm, 40 mm, and 50 mm as feed rate by varying the pitch values as 1 mm, 2 mm, and 3 mm. Further, the analysis of variance (ANOVA) is also employed for finding the significant parameters of input process using the regression analysis equations. Finally, microstructural analysis is used to assess the mixing or dispersing uniformity of composites effectively.

A re-investigation of mechanical properties of aluminium-based surface composites prepared by friction stir processing

The properties of the alloys and metal matrix composites processed by friction stir processing are significantly affected by some fundamental parameters like; type of reinforcement, weight or volume % of reinforcement, number of passes, rotational speed, etc. The current study was done to explore the effect of these parameters on the mechanical properties of aluminium-based materials processed by friction stir processing. It was observed during the literature survey that the strength and hardness increased by 30%–40% after processing Al-based materials up to 3–4 friction stir processing passes. The wear rate decreased by 25%–30% after processing the Al-based materials up to 3–4 friction stir processing passes. The wear rate gets reduced on increasing the value of rotational speed (about 60%–70% reduction in wear rate after processing the aluminium based materials at a rotational speed 1300 rpm–1500 rpm). As the grain size increases on increasing the tool rotational speed, strength and hardness decreases. On increasing the transverse speed, there is a reduction in the grain size. Hence, the strength and hardness increase with an increase in the transverse speed.

Desain Turbin Angin Horisontal untuk Area Kecepatan Angin Rendah dengan Airfoil S826

This research aims to determine performance of turbine rotor performance with a single rotor blade model with a diameter of 0.6 m that has been developed by NORCOWE, while for turbine rotor blades used is the NREL S826 airfoil series. The wind turbines are operated at wind speed intervals of 1-5 m / s. This parameter will also present data in the form of the optimal point of wind turbine rotation and rotor rotation speed. The pitch angles used are 25 °, 30 °, and 35 °. The pitch angle that affects the value of the ideal rotational speed with the highest optimization for the horizontal airfoil turbine S826 is 30 ° with a wind speed of 5 m / s and a rotation of 570 RPM. This is because the greater the pitch angle of the installation, the easier it will be to experience speed trimming but is vulnerable to too large an angle of attack that causes a stall.

Magneto-Free Convectiveof Hybrid Nanofluid inside Non-Darcy Porous Enclosure Containing an Adiabatic Rotating Cylinder

ABSTRACT Magneto-free convective of hybrid nanofluid with an inner adiabatically rotating cylinder and a hot side wall was analyzed in a non-Darcy-permeable cavity. The Darcy-Forchheimer model has been used for the permeable domain. The solutions of employing equations are obtained by the Finite Element Method. The role of different Rayleigh (103≤ Ra≤106) for various angular velocity (0 ≤≤6000), Darcy (10−5≤ Da≤10−2), and Hartmann number (0≤ Ha≤100) are illustrated. The obtained data were compared with already cited researches, and a great degree of accuracy and compatibility were found symmetric. The implications of relevant parameters on velocity, stream functions, isotherms and mean Nusselt number are graphically examined. Estimations demonstrate that the mean improvement in heat transfer is more pronounced with the enhancement in Darcy number, the angular velocity, Rayleigh number, and decays through the rise of Hartmann number. It is also observed that an increment in Ra leads to an apparent incremental increase in the stream function outcome. A significant enhancement was also noticed in Nu number with augmentation in the Da and Ra numbers, but certain decline occurred for augmented values of Ha number and rotation speed.