Dual Rotor Research Articles

Analysis of Airconditioning System Using Single-Rotor Wind Turbine Power, Dual Rotor Wind Turbine Power, and Ducted Dual Rotor Wind Turbine Power As Input to Compressor

As vapor compression refrigeration system is the best-suited system used in the present scenario due to its various advantages, in the present paper MATLAB analysis is done for the analysis of simple VCR to calculate COP and refrigeration effect.in the present paper R134a refrigerant is used as a refrigerant.as we know a certain amount of power is used to drive the compressor input in conventional VCR system uses electrical power to convert into mechanical shaft rotation with certain rotation, power and torque.in this paper specific power torque and rotation is given to the compressor without any electrical motor. the power obtains from an SRWT, DRWT, and DDRWT with specific torque power and rotation. then after analysis is carried out to get the COP and Refrigeration Effect.

Optimization of an angle between the deflector plates and its orientation to enhance the energy efficiency of Savonius hydrokinetic turbine for dual rotor configuration

ABSTRACT Many efforts have been made to enhance the hydrokinetic turbines’ energy efficiency, extracting the energy from the flowing water in the canal and river. Savonius hydrokinetic turbine is one of the turbines producing mechanical power output using renewable energy sources of flowing water. It has good starting characteristics but has low energy efficiency. In the present investigation, an attempt is made toward the enhancement of the energy efficiency and load-carrying capacity of the Savonius turbine. The two dual-rotor Savonius turbine designs with deflector plates are proposed termed as Dual Rotor with Diverging Deflector Plate (DR-DDP) and Dual Rotor with Converging Deflector Plate (DR-CDP). The investigations are carried out with numerical simulations. The experiments are also performed for the validation of the methodology adopted in the presented numerical simulations. The results indicate the improved performance of the turbine units with both deflector plate designs. The power coefficient with the Savonius turbine unit’s investigated design is enhanced from 0.135 of the conventional turbine to 0.16 with DR-DDP, and that up to 0.20 with DR-CDP.

Multi-physics design and analyses of dual rotor synchronous reluctance machine

Dual rotor topology of synchronous reluctance machine is here proposed to improve the motor torque density and reduce the torque ripple. Thus, allowing synchronous reluctance machine to merge into EV and HEV applications. This paper presents a multi-physics design and analyses of three double rotor synchronous reluctance machine, 24/4, 36/4 and 48/4 stator slot/rotor pole combinations, through electromagnetic, mechanical and thermal analysis. First, a genetic algorithm optimization process linked to magnetic FEA has been used. The optimization is set to target the highest torque, lowest torque ripple and core loss. Mechanical study and investigation of the magnetic and rotational forces on the rotor ribs and stator tooth-tip structure have been considered to guarantee the mechanical robustness. Furthermore, the design assembly structure to ease heat dissipation from the stator has been investigated thermally. Finally, a comparison with a conventional single-rotor synchronous reluctance machine having the same size and operating conditions have been made to highlight the advantages of the double rotor synchronous reluctance machine. From the comparison it has been concluded that the double rotor machine produced 45% higher torque and 40% less torque ripple compared to its single rotor counterpart. Synchronous Reluctance Machines, Double Rotor Machine, Structural Analysis, Double Airgap Machines. • The design of a novel double rotor synchronous reluctance machine is presented. • A multi-physics design process and genetic algorithm global optimization are used. • The double rotor machine showed higher power density when compared to the single rotor. • Lower torque ripple is found in the double rotor machine when compared to the single rotor. • The higher power density and lower torque ripple are essential for automotive application.

CFD Analysis of Torque and Power for Single Rotor, Dual Rotor, and Ducted Dual Rotor Wind Turbine

With the present advancement, a wind turbine needs a wind rotor with high torque and power. The present study aims to enhance the torque and power of wind turbine by employing the ducted dual rotor. In this regard, CFD analysis is performed to analyze the torque and power produced for horizontal axis single rotor bare wind turbine, dual rotor wind turbine, and convergent-divergent ducted type dual rotor wind turbine. The comparative study is conducted to enhance the power and torque for the aforementioned rotor type. The results highlight the maximum value of torque for a dual ducted wind turbine is 36.9% more than a dual rotor at 16 m/s of wind velocity and 92.2 % more than a single rotor at 16 m/s of wind velocity, and the maximum value of the power produced for a dual ducted wind turbine is 40.48% more than a dual rotor at 16 m/s of wind velocity and 139.66% more than a single rotor at 16 m/s of wind velocity. Therefore result suggested that a dual ducted wind turbine is better than a single rotor wind turbine.

COUNTER-ROTATING DUAL ROTOR WIND TURBINE LAYOUT OPTIMISATION

General energy demand is continuously increasing, thus the energy generating assets need to be optimised for higher efficiency. Wind turbines are no exception. Their maximum efficiency can be determined on a theoretical basis. The limit is approached by researches day by day, utilizing the latest developments in airfoil design, blade structure and new and improved ideas in conventional and unconventional wind turbine layouts. In this paper, we are reviewing the conventional and unconventional wind turbines and their place in smart cities. Then, an unconventional wind turbine design, the CO-DRWT (counter-rotating dual rotor wind turbine) is analysed with a CFD (computational fluid dynamics) code, varying the axial and radial distances between the two turbines. After the simulations, the power coefficients for the different turbine configurations is calculated. At the end of this paper, the simulations results are summarized and consequences are drawn for the CO-DRWT layouts.

Investigation of a Dual-Winding Dual-Flux-Concentrated Magnetic-Field-Modulated Brushless Compound-Structure Machine

In this article, a new dual-winding dual-flux-concentrated magnetic-field-modulated brushless compound-structure machine (DDMFM-BCSM) is proposed by combining the magnetic-field modulated brushless dual-rotor machine (MFM-BDRM) and permanent magnet synchronous machine (PMSM) into one. Proposed machine has two sets of windings in stator slots and spoke-type PMs on dual rotors. Besides, there are flux barriers on the inner rotor to improve the performance of MFM-BDRM part. Based on magnetic field modulation principle, the main harmonics of the flux density in inner and outer air gap are calculated by analytical method and simulated by finite element method (FEM). The performance of the proposed machine, including MFM-BDRM part, PMSM part, and the whole DDMFM-BCSM, is analyzed. In order to analyze the influence of flux barriers on the performance of DDMFM-BCSM, a DDMFM-BCSM without flux barriers is designed to compare their performance, including torque, loss, and power factor.

A comparative 3-D transient electromagnetic, thermal and powertrain study of single rotor BLPMSM and dual rotor machine for electric propelled vehicle

This article addresses the benefits of novel dual rotor machine for automobile sector. In case of traditional electric vehicle technology, the vehicle has a single rotor electric machine that can able to perform motoring or regenerative operation and can be possible according to the energy available in the battery. To overcome the above-mentioned problem, novel electric machine design topology with dual operation of motor and generator at same instances of time is proposed with improved electromagnetic, thermal and mechanical transmission losses. The design can be possible by adopting 7.2 kW claw pole alternator and 15 kW brushless permanent magnet synchronous machine as a dual rotor machine considering in-wheel concept. The performance analysis of the machine is done by using finite element analysis technique. The electromagnetic compatibility of machine is performed by three-dimensional transient solver in MagNet software. The electromagnetic analysis of machine is improved by introducing notches in the stator and permanent magnets in the rotor. Based on the electromagnetic results, thermal analysis of machine is calculated by coupling transient analysis using ThermNet software. The simulation results of machine are validated by using electric vehicle Powertrain blocks. The real-time performance of the machine is tested with real-world drive cycle using simulation software. The result substantiates the novelty of this design for improving the driving range of the vehicle for electric vehicle applications.

Nonlinear vibration response characteristics of a dual-rotor-bearing system with squeeze film damper

Rolling bearing and Squeeze Film Damper (SFD) are used in rotor support structures, and most researches on the nonlinear rotor-bearing system are focused on the simple rotor-bearing systems. This work emphasizes the comparative analysis of the influence of SFD on the nonlinear dynamic behavior of the dual-rotor system supported by rolling bearings. Firstly, a reduced dynamic model is established by combining the Finite Element (FE) method and the free-interface method of component mode synthesis. The proposed model is verified by comparing the natural characteristics obtained from an FE model with those from the experiment. Then, the steady-state vibration responses of the system with or without SFD are solved by the numerical integration method. The influences of the ball bearing clearance, unbalance, centralizing spring stiffness and oil film clearance of SFD on the nonlinear steady-state vibration responses of the dual-rotor system are analyzed. Results show that SFD can effectively suppress the amplitude jump of the dual rotor system sustaining two rotors unbalance excitations. As the ball bearing clearance or unbalance increases, the amplitude jump phenomenon becomes more obvious, the resonance hysteresis phenomenon strengthens or weakens, the resonant peaks shift to the left or the right, respectively. SFD with unreasonable parameters will aggravate the system vibration, the smaller the oil film clearance, the better the damping performance of the SFD, the larger the centralizing spring stiffness is, the larger resonance amplitudes are.

Paroxysmal impulse vibration phenomena and mechanism of a dual–rotor system with an outer raceway defect of the inter-shaft bearing

This paper focuses on the dynamic phenomena, physical mechanism and occurrence condition of paroxysmal impulse vibrations in a dual-rotor system with inter-shaft bearing defect. The equations of motion of the dual-rotor system are established considering the force model for the inter-shaft bearing with an outer raceway defect. The fourth order Runge-Kutta method is adopted to investigate the vibration acceleration signals of the rotor system. The results show that there are paroxysmal impulse vibration phenomena when the dual-rotor system reaches some special rotation speed ratios. The time-domain waveforms, Hilbert envelope spectrums and inter-shaft bearing contact force curves of paroxysmal impulse vibrations are markedly distinguished from those of general impulse vibrations. The physical reason of paroxysmal impulse vibration phenomena is that the inter-shaft bearing loading position and defect position are intermittently anti-phase. It is found that the paroxysmal impulse vibration phenomena will occur if the rotation frequency of the high-pressure rotor (HP rotor) is equal to the fractional or multiple defect frequencies of the dual-rotor system. Based on this finding, an analytical formula related to the rotation speed ratio is derived, which can well predict the occurrence condition of paroxysmal impulse vibrations. At last, according to the guidance of the analytical formula, 6 experimental cases are executed, proving the dynamic phenomena and occurrence condition of the paroxysmal impulse vibrations.

Modeling and Stability Analysis of Dual Rotor Axial Flux PMG for Wind Turbine Applications

This paper focuses on mathematical modeling and stability analysis of double rotor xil flux generator. The wind generator is modeled using dq reference frame theory. The cogging torque and gravitational force during starting time is considered for the modeling of the generator. There re several type of generators have been suggested for wind turbine applications out of which dual rotor PM generator having the lot of advantages than the other types of the permanent magnet generator based direct driven wind energy conversion system. Modeling of dual rotor PM generator is developed in the MATLAB. The simulated model is analyzed for various input and output variables. The stability of the proposed system is also analyzed by deriving small signal model of the wind turbine systems. The input wind velocity variations and grid fault conditions are considered for analysis of the system. The results of the proposed system is analyzed for various values of turbine speed.

Performance Improvement of Dual Stator Axial Flux Spoke Type Permanent Magnet Vernier Machine

This paper presents performance improvement of dual stator axial-flux spoke type permanent magnet vernier machine (DSAFST-PMVM), which has the capability to generate high torque at a lower speed due to magnetic gearing effect. Flux focusing effect is created by means of dual stator single rotor topology with spoke type permanent magnets. It is best suitable for high-performance industrial applications such as servo motors, robot arms, wind power, electric vehicles, and elevator applications. A PM shape is proposed in this paper which has notches in such a way that it produces discrete skew effect which reduces the cogging torque and torque ripples. Optimization of magnet shape is done to make the optimized model more competitive than the proposed and basic models. Main parameters such as back emf, cogging torque, torque ripples, electromagnetic torque, VTHD, airgap flux densities, flux density distribution, power factor, and power of the machine are compared among the basic model, proposed model, and optimized models. The comparative analysis is done by using the time stepped 3D finite element method.

Vibration Characteristics and Simulation Verification of the Dual‐Rotor System for Aeroengines with Rub‐Impact Coupling Faults

To study the rub‐impact fault between the dynamic and static parts of the rotor system of aeroengines, the dual‐rotor system of a typical aeroengine is introduced and taken as the research object. The analytical kinetic model is established based on the Lagrange equation considering the structural characteristics of the dual‐rotor system, the coupling effect of the intermediate bearing, and the rub‐impact fault between the high‐pressure turbine disc and the casing. The dynamic characteristics of the dual‐rotor system under the rub‐impact fault are analyzed, and the change rule of the rub‐impact shape is obtained. The vibration coupling and transfer among the high‐pressure rotor and the low‐pressure rotor are revealed. The influence of the unbalanced position and the speed of high and low rotors on the vibration response of the dual rotor is obtained. The sensitivity of the vibration response of the dual rotor at different test points to rub‐impact stiffness, clearance, and friction coefficient is compared. The simulation model is established based on the rigid‐flexible coupling multibody dynamic simulation platform. The analytical results and simulation results are compared, which have a good consistency. The theoretical research can deepen the understanding of the nature and law of aeroengine rotor operation, expose the possible faults and design defects, greatly improve the development efficiency and quality, reduce repeated physical tests, reduce the development risk and cost, and accelerate the development process. This study can provide a theoretical basis for the monitoring and diagnosis of engine rub‐impact faults and provide theoretical and practical reference for the establishment of the vibration fault test and analysis method system.

Design and Performance Analysis of a Novel Outer-Rotor Consequent Pole Permanent Magnet Machine With H-Type Modular Stator

In this paper a novel outer-rotor consequent pole permanent magnet machine (OR-CPPMM) with H-type modular stator core is proposed for higher average torque ( $T_{avg}$ ), flux linkage ( $\Phi$ ) and efficiency ( $\eta$ ) whereas low cogging torque ( $T_{cog}$ ), torque ripple ( $T_{rip}$ ) and harmonics content in flux linkage ( $\Phi _{THD}$ ) and back-EMF ( ${\mathrm {EMF}}_{THD}$ ). The proposed OR-CPPMM is investigated with different stator flux gaps width for static and dynamics electromagnetic performances. Analysis reveals that flux gaps in H-type stator core not only improve electromagnetic performance i.e., $\Phi $ is enhanced by 10.23%, $\Phi _{THD}$ is suppressed by 80.65%, diminished ${\mathrm {EMF}}_{THD}$ by 59.37%, truncate $T_{rip}$ by 44.37% and improve $T_{avg}$ by 15.99% but also exhibits better flux focusing effect to enhance flux linkage and diminish harmonic contents. In addition, H-type modular stator structure provide physical isolation of adjacent phase that de-couple the adjacent phase coupling flux which enhance self-inductance and weaken mutual-inductance and hence improve fault tolerant capability. In addition, to elaborate effectiveness of the proposed design and justification of OR-CPPMM novelty with H-type modular stator, electromagnetic performance is extensively compared with existing state of the art including E-core and C-core structure. Analysis and comparison with state-of-the-art reveals that proposed OR-CPPMM enhanced $\Phi $ by 65.35%, diminish $\Phi _{THD}$ by 67.24%, truncate $T_{cog}$ by 96.72%, suppresses ${EMF}_{THD}$ by 44.40%, diminish $T_{rip}$ by 77.23% whereas $T_{avg}$ is enhanced by 91.69%. Furthermore, the proposed design novelty is justified with comparison of OR-CPPMM with inner rotor and dual rotor permanent magnet flux switching machines. Comparison and analysis unveil that OR-CPPMM exhibits $T_{avg}$ higher up to 35.16%, truncate $T_{rip}$ up to 32.88%, enhanced $\Phi $ up to 22.13% and boost $T_{den}$ to 3.41 times at the cost of 2.58% increase in $T_{rip}$ .

Two-level DPC strategy based on FNN algorithm of DFIG-DRWT systems using two-level hysteresis controllers for reactive and active powers

In this paper, a novel switching table (ST) of the twelve sectors direct power command (DPC) strategy of doubly-fed induction generator (DFIG) based dual rotor wind power (DRWP) is proposed using two-level hysteresis controllers for reactive and active power and feedforward neural networks (FNNs) algorithms. This intelligent technique was used to replace the conventional ST in order to reduce rotor flux ripple, active power ripple, total harmonic distortion (THD) of stator voltage, torque and reactive power undulations. The simulation and modeling of the proposed strategy were carried out in Matlab software. The DFIG is tested in association with a DRWP systems. The simulation results show that the DPC with FNN controller (DPC-FNN) reduced the THD value of stator voltage, rotor flux undulation, active/reactive power undulation, and electromagnetic torque ripple compared to conventional DPC strategy. It was found that the current waveform becomes purely sinusoidal with a reduction in the THD rate to 0.64%.

Investigation on transient dynamics of rotor system in air turbine starter based on magnetic reduction gear

As an auxiliary mechanical device, Air Turbine Starter (ATS) uses compressed air as power source to start and drive the engine. It withstands the impact of high-pressure airflow during operation, which may cause collision between key components. For this reason, it is necessary to investigate the transient dynamics of ATS rotor system. However, different from the traditional dual rotor structure, ATS uses magnetic reduction gear (MRG) as a reduction unit, which involves multiple physical fields such as magnetic field and stress field, bringing challenges to transient dynamics analysis. In this paper, the magnetic interaction forces between various rotors are innovatively simplified into the form of springs, and added to the solution model to achieve the decoupling of multiple physical fields. On this basis, the transient displacement response of MRG-ATS has been analyzed using transient dynamics theory. The results indicate that the transient displacement of the rotor system has obvious characteristics of oscillation attenuation. The study reveals the feasibility of MRG-ATS application under transient shock.

Design of Dual Copter for Surveillance Applications

In this paper, an innovative design model of autonomous aerial vehicle is designed and fabricated with dual rotor setup. Nowadays, innovative unmanned aerial vehicles (UAVs) are widely required for surveillance, monitoring, data collection, reconnaissance and generally in places where humans face hazardous. In this model and design of UAVs, aero dynamic principles are adopted through reasonable design considerations and assumptions. Most of the researchers and academicians are currently pursuing research on AVs with various structures, wing designs, fabrication methods, controllers and materials to increase the efficeincy as well as for various applications. In this proposed work, an effort is made to design and fabricate the dual copter with wide moving ranges for surveillance applications in military intelligence system. This proposed design will be suited for all environmental conditions to collect the data as well as monitoring the system. Dual copter chassis are fabricated using 3D printer after the validation and analysis the proposed design using Solidworks CAD tool. The chassis are fabricated with the provision of space where the required sensors, actuators and controllers can be assembled. Lithium polymer batteries are employed to achieve the better performance for copter. The fabricated setup is integrated with radio frequency controller to achieve the flight control through RF transmitter. Hence the performance of the fabricated device is validated and analyzed through various performance measures of dual copter.

A drone with a combination of dual rotors and fixed wings

The idea of tiltrotor has been proposed and pushed forward since people's first work in the direction originated in 1902. Successful works such as Bell Boeing V-22 Osprey are still on active military duty in the US and showing its remarkable efficiency in transportation and cargo handling, which is also served as one of the reference prototypes in this drone project. Tiltrotor aircraft shares desirable merits from fix wing and rotor aircraft, enabling it to take off and land vertically, hover at low speed in the air, while achieving a faster cruise speed than a rotor one. To be specific, the technique of vertical launching and landing allows a low request to the size of landing place, which is helpful when the design is utilized in extreme conditions (lack of landing space); The technique of tilted propeller provides extra propulsion to the aircraft, enabling it to keep a relatively high cruise speed. The capacities of hovering and other functions shared by rotor aircraft are also useful depending on purpose. This project aims to design a tiltrotor drone which shares all the merits of tiltrotor aircraft above and keeps the advantage of drones such as remote control, small size, and flexibility. The design achieves those merits by adding 2 remotely controlled rotating propellers. In other words, when the launch altitude meets the expectation, rotors, or the propellers are controlled to rotate 90 degrees reaching horizontal to provide forward propulsion. When used in application, this design is capable of handling similar tasks that can be done by normal rotor drone with a higher efficiency because of its high cruising speed. For example, when using it in aerial photography, people will spend less time waiting for drone traveling to the desired viewpoint.

Reduction of Cogging Torque in AFPM Machine Using Elliptical-Trapezoidal-Shaped Permanent Magnet

The reduction in cogging torque enables smooth operation and an increase in the torque density of the machine. This research aims to minimize cogging torque in dual rotor single stator axial flux permanent magnet (AFPM) machine. Reduction in cogging torque makes the back EMF sinusoidal and reduces the torque ripples in AFPM machine. In this paper, an elliptical trapezoidal-shaped permanent magnet (PM) is proposed to minimize torque ripples of the AFPM machine. The 3D finite element analysis (FEA) is used for the analysis of AFPM machine. The optimization of AFPM machine is done by employing the asymmetric magnet-overhang along with the parameters of elliptical-shaped PM using Genetic algorithm (GA).

Optimization of Air Gap for Axial Flux Machine

The analyses the axial flux permanent magnet generator (AFPMG) dual stator single rotor structure. For the valuation of analytical results, the electromagnetic design of AFPMG is done and compared with various air gaps to flux density and power density. In the axial flux design air gap to flux density is improvement for different air gap are analyzed. This machine is gauge with certain criteria such as the cost, the copper loss, the eddy current losses and the flux density.

Active and Passive Control of a Dual Rotor Wind Turbine Generator for DC Grids

This paper proposes a vector and a linear control strategy for wind turbines connecting to a DC collector grid. Two conversion schemes are considered for the wind turbine, (i) an active scheme where a dual rotor generator (DRG) is connected to a voltage source converter (VSC), and (ii) a passive scheme where a DRG is connected to a passive uncontrolled rectifier. The vector controller is implemented on VSC and DRG where the turbine rotor speed and output power are controlled via a VSC, and the wind turbine generator (WTG) rectified output DC voltage is controlled via a DRG DC filed current. A load-angle control and analytical modeling is discussed for the vector controller and evaluated via simulation results. In the passive scheme where the VSC is replaced with an uncontrolled rectifier the control is entirely shifted to DRG where a linear controller is implemented that controls the turbine rotor speed, power and voltage. A comparison of the vector and linear control is presented, and simulation results verify the effectiveness of the control strategy in steady-state and when turbine transitions between different wind velocities.