Levitation Concept Research Articles

Comparative study of passive magnetic bearing using four ring magnets: a critical review

Researchers on reducing energy losses caused by friction in small-scale wind turbines. This is crucial because a significant amount of energy is wasted due to friction in the main roller bearing. In order to overcome this, the concept of levitation has gained popularity. Levitation is achieved by employing the repelling forces between two opposing poles of a permanent magnet (PM), significantly reducing friction between the turbine stator and rotor. As a result, the overall energy production of the turbine increases. The use of passive permanent magnet bearings has several disadvantages, such as limited load-bearing capacity and rigidity. To address these limitations, we conducted numerical studies on four different configurations in order to enhance load-bearing capacity and stiffness. The results showed that the radial configuration outperformed the axial-type configuration in terms of stiffness and load-bearing capabilities in all four arrangements. Furthermore, it was revealed that radial passive magnetic bearings with adequate air gaps are not only more efficient but also less expensive than employing iron cores at the rear and between ring magnets for small-scale wind turbines.

Design of Solar Panel as Wind Turbine Blades

Abstract: The purpose of this system is to generate the green energy by using wind and solar technology. In conventional wind turbines friction losses due to bearings are more which affect the performance of the turbine. To reduce this friction loss we implement the concept of magnetic levitation in our project. We fabricate Hybrid wind Turbine which produces electricity on the principle of faradays law produced can be Stored of electromagnetic induction as well as solar technology. The electricity can be stored continuously for whole day. Keywords: Hybridized Power Generation, PV cells, Renewable energy systems.

Numerical and Experimental Investigation of the Performance of a Vertical Axis Wind Turbine Based on the Magnetic Levitation Concept

Abstract In this research, a vertical axis wind turbine (VAWT) with a Magnetic Levitation (Maglev) design was fabricated and tested. Numerical simulations were conducted to predict the magnetic flux distribution and generated voltage in the axial flux generator. Rare earth magnets were used to generate a repelling force to suspend the turbine rotor in order to minimize friction and increase rotational speed. Axially magnetized disc magnets and specific coils arrangements were set to produce voltage. The performance of the turbine was studied at various rotor rotational speeds ranging from 20 rpm to 200 rpm. Results show that the height of the gap between rotor and stator plates as well as the gap between coils and rotor magnets has a significant influence on the output voltage. The peak voltage was found to be increased by at least 1.3 V for each 1 mm reduction in the gap between coils and rotor magnets. The information provided in this paper may be beneficial for future researches related to efficiency optimization of Maglev wind turbines.

Design and implementation of positioning and control systems for capsule endoscopes

Wireless capsule endoscope (WCE) is a new diagnostic device that can be utilised for evaluating the whole digestive tract if effectively actuated. In this research, a new one degree of freedom (1DOF) actuation system based on a magnetic levitation concept is proposed for the capsule endoscope navigation system. The proposed system is used to move a permanent magnet inserted in WCE body by an arrangement of the current controlled electromagnetic actuator placed on a 3DOF movable frame. The aim of this study is to design a proportional–integral–derivative (PID) controller to suspend the capsule and keep it at a demand test region. DC and AC magnetic field-based positioning systems using the Hall effect sensor and the coil sensor, respectively are used to provide the controller by capsule position feedback. Improvement of the position feedback accuracy based on AC magnetic field using discrete Fourier transform is presented. Realistic simulation design of the system is implemented using Matlab/Simulink environment to validate the PID controller. The navigation scheme is implemented practically utilszing digital signal processor to verify the effectiveness of the controller. Finally, simulation and experimental results of the capsule navigation system are presented to show the performance of the proposed controller.

Rectification of Turbo lags in Turbocharger

A turbocharger is the most used component in an automobile. It is widely employing in marine engines and aircraft engines to provide dense air to the combustion chamber. Due to the friction between the bearings and the own impeller weight of the rotors of the turbine and compressor turbo lag is caused. To rectify the turbo lag, we proposed magnetic Levitation principle. The use of magnets can reduce friction to a great extent, further it increases the efficiency of the turbocharger. The implementation magnetic levitation concept in the conventional turbocharger reduces the friction to a greater extent and decreases the turbo lag since the shaft of the turbocharger levitates freely and so less power is required to drive the shaft. The bearings are replaced by levitation concept hence there is no requirement for lubrication of bearings thus reducing the weight, space occupied, and making the turbocharger more efficient than the present one.

Introduction and realization of four fractional-order sliding mode controllers for nonlinear open-loop unstable system: a magnetic levitation study case

The concept of magnetic levitation attracts the attention of researchers and developers on the global platform for its serviceability in both industrial and research applications. Sliding mode controller is a nonlinear and robust control strategy to provide efficient control over variable structure systems. This paper is initiating with nonlinear modelling of magnetic levitation system dynamics. Various sliding mode controllers for controlling the current through electromagnetic coil to levitate the ferromagnetic ball are presented. This paper is mainly focusing on design robust and energy-efficient fractional sliding mode controller for a nonlinear system. Four novel controllers called fractional static sliding mode controller, fractional integral static sliding mode controller, fractional dynamic sliding mode controller and fractional integral dynamic sliding mode controller are proposed. Stability proof of Lyapunov criteria for the proposed controller has been done. Performance of the proposed controllers is analysed in comparison with the existing sliding mode controllers. Experimental validation is done on a benchmark Feedback 33–210 magnetic levitation system.

Review of hydro-instability experiments with alternate capsule supports in indirect-drive implosions on the National Ignition Facility

Hydrodynamic instability growth of capsule support membranes (or “tents”) has been recognized as one of the major contributors to the performance degradation in high-compression plastic capsule implosions at the National Ignition Facility (NIF) [E. M. Campbell et al., AIP Conf. Proc. 429, 3 (1998)]. The capsules were supported by tents because the nominal 10-μm diameter fill tubes were not strong enough to support capsules by themselves in indirect-drive implosions on NIF. After it was recognized that the tents had a significant impact of implosion's stability, new alternative support methods were investigated. While some of these methods completely eliminated tent, other concepts still used tents, but concentrated on mitigating their impact. The tent-less methods included “fishing pole” reinforced fill tubes, cantilevered fill tubes, and thin-wire “tetra cage” supports. In the “fishing pole” concept, a 10-μm fill tube was inserted inside 30-μm fill tube for extra support with the connection point located 300 μm away from the capsule surface. The cantilevered fill tubes were supported by 12-μm thick SiC rods, offset by up to 300 μm from the capsule surfaces. In the “tetra-cage” concept, 2.5-μm thick wires (carbon nanotube yarns) were used to support a capsule. Other concepts used “polar tents” and a “foam-shell” to mitigate the effects of the tents. The “polar tents” had significantly reduced contact area between the tents and the capsule compared to the nominal tents. In the “foam-shell” concept, a 200-μm thick, 30 mg/cc SiO2 foam layer was used to offset the tents away from the capsule surface in an attempt to mitigate their effects. These concepts were investigated in x-ray radiography experiments and compared with perturbations from standard tent support. The measured perturbations in the “fishing pole,” cantilevered fill tube, and “tetra-cage” concepts compared favorably with (were smaller than) nominal tent perturbations and were recommended for further testing for feasibility in layered DT implosions. The “polar tents” were tested in layered DT implosions with a relatively-stable “high-foot” drive showing an improvement in neutron yield in one experiment compared to companion implosions with nominal tents. This article reviews and summarizes recent experiments on these alternate capsule support concepts. In addition, the concept of magnetic levitation is also discussed.

Design and Analysis of a Permanent Magnetic Bearing for Vertical Axis Small Wind Turbine

An interest toward zero frictional losses for small wind turbine is gaining popularity because of a considerable portion of the energy is lost due to friction in the ball bearing. The concept of levitation caused by repulsion of opposite pole in the permanent magnet reduced the friction between the stator and wind turbine rotor, so that the net power output of the turbine increases. The problem associated with usage of this kind of Passive magnetic bearing is its low load carrying capacity and low stiffness. To improve the load carrying capacity and stiffness, numerical simulation has been done for four different configurations. It is found that the stiffness is improved by stacking the magnet in the special combination of different radial cum axial direction of magnetization. The best configuration based on this analysis is fabricated and tested in the vertical axis wind turbine.

Multisurface HTS-PM Levitation for a Flywheel System

In this paper, a multisurface levitation concept using three permanent magnets (PMs) and one high temperature superconductor (HTS) ring in a levitation configuration is studied to improve stiffness in a superconducting magnetic bearing system. A geometrical rule is defined to select the size of second and third PMs placed over and under the ring HTS to overlap the frozen images of all PMs. For different combinations of the PMs, experiments are realized and levitation forces are measured. Three levitation surfaces case with attractive polarization of the PMs provided the largest levitation force in the experiments.

DESIGN AND FABRICATION OF MAGLEV TURBINE FOR AC POWER GENERATION USING FIRE

The paper depicts a system which has used the unwanted and waste heat energy as a source of renewable energy for the production of electricity. This heat energy can be used for the production of alternating current, with the help of an AC turbine. The absorbed heat will be used to generate steam using condenser which works as the de-condenser. The turbine works on the concept of magnetic levitation for the production of current. This following work can change the present scenario of power production and distribution, also making optimum and efficient use of energy. Following project can be used for domestic as well as for industrial application.

Acoustic levitator for contactless motion and merging of large droplets in air

Large droplet transport in a line-focussed acoustic manipulator in terms of maximum droplet size is achieved by employing a driving voltage control mechanism. The maximum volume of the transported droplets in the order of few microliters is thereby increased by three orders of magnitude compared to the constant voltage case, widening the application field of this method significantly. A drop-on-demand droplet generator is used to supply the liquid droplets into the system. The ejected sequence of picoliter-size droplets is guided along trajectories by the acoustic field and accumulates at the selected pressure node, merging into a single large droplet. Droplet movement is achieved by varying the reflector height. This also changes the intensity of the radiation pressure during droplet movement, which in turn could atomise the droplet. The acoustic force is adjusted by regulating the driving voltage of the actuator to keep the liquid droplet suspended in air and to prevent atomisation. In the herein presented levitation concept, liquids with a wide range of surface tension (water and tetradecane were tested) can be transported over distances of several mm. The aspect ratio of the droplet in the acoustic field is shown to be a good indicator for radiation pressure intensity and is kept between 1.1 and 1.4 during droplet transport. Despite certain limitations with volatile liquids, the presented acoustic levitator concept has the potential to expand the range of analytical characterisation and manipulation methods in applications ranging from chemistry and biology.

Outward transport of CAIs during FU‐Orionis events

Abstract— Evidence from meteorites shows that the first solids to form in the solar system, calcium‐aluminum‐rich inclusions (CAIs), were transported outward from the Sun by several AU in the early solar system. We introduce a new concept of levitation and outward transport of CAIs at the surface of protoplanetary disks. Thermal radiation from the disk and the Sun can cause particles to levitate above the disk and drift outward through a process known as photophoresis. During normal conditions this process only works for dust‐sized particles but during high luminosity events like FU‐Orionis outbursts, the process can provide an efficient lift and transport of CAIs from within the inner 1 AU to a distance of several AU from the Sun. This might explain why CAIs, believed to have formed close to the Sun, are common in meteorites believed to come from the outer asteroid belt but are rare or absent in samples from the inner solar system. Since the process only works during the FU‐Orionis event and only for particles up to cm‐size, it may also explain why the CAIs we find in meteorites appear to have formed within a short period of time and why they rarely exceed cm size.

Devices as destination therapy

The use of circulatory support as destination therapy has been a goal for the treatment of endstage heart failure for several decades. Current investigations are evaluating several circulatory pumps with that particular objective. With continued modification of design, the current and future pumps will become more reliable and provide improved quality of life to patients in need of mechanical circulatory assistance. The new pumps on the horizon specifically address reliability, size, and cost, and are based on the centrifugal system. These devices use the Maglev (Magnetic Levitation) concept that allows for frictionless pumping, low thrombogenicity, minimal noise, and increased durability. Further research with this goal in mind and support from the federal government will be the key to the future use of circulatory assistance as destination therapy for heart failure patients. In addition, the cost-effectiveness of these devices will need to be maintained as the technology improves, as in any new technology that confronts a more intuitive option like the native heart.

Rotation losses in the superconducting bearing based on magnetic gradient levitation concept

Magnetic bearings using bulk superconductors as field shaping materials have been under development for several years. The magnetic bearings need only a steel component on the rotor side for stable operation. In this system, using a bulk superconductor as a field shaping material generates a magnetic gradient that is stable against both vertical and radial displacement. Several tests were performed to better understand the loss mechanisms during rotation. Results from rotation tests using an iron rotor or a ferrite rotor indicate eddy current loss is the dominant cause of rotational losses.

Attractive levitation for high-speed ground transport with large guideway clearance and alternating-gradient stabilization

The author describes an attractive levitation concept that results in large guideways clearance and low magnetic drag and requires no feedback for stability. Dynamic stability is achieved by establishing alternating gradients of force in which the spatial dependence of the attractive force between the superconducting coils on the vehicle and the iron rails in the guideway is altered by periodic changes in the rail configuration. For a vehicular velocity of 500 km/h, the appropriate lengths for each configuration are in the range of 5 to 40 m, and the guideway clearance is in the range of 50 to 100 mm, depending on the details of the rail and vehicle magnet design.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>