Rotor Components Research Articles

Low-voltage ride-through capability in a DFIG using FO-PID and RCO techniques under symmetrical and asymmetrical faults

The power grid faults study is crucial for maintaining grid reliability and stability. Understanding these faults enables rapid detection, prevention, and mitigation, ensuring uninterrupted electricity supply, safeguarding equipment, and preventing potential cascading failures, ultimately supporting the efficient functioning of modern society. This paper delves into the intricate challenge of ensuring the robust operation of wind turbines (WTs) in the face of fault conditions, a matter of substantial concern for power system experts. To navigate this challenge effectively, the implementation of symmetrical fault ride-through (SFRT) and asymmetrical fault ride-through (AFRT) control techniques becomes imperative, as these techniques play a pivotal role in upholding the stability and dependability of the power system during adverse scenarios. This study addresses this formidable challenge by introducing an innovative SFRT–AFRT control methodology based on rotor components optimization called RCO tailored for the rotor side converter (RSC) within a doubly-fed induction generator (DFIG) utilized in wind turbine systems. The proposed control strategy encompasses a two-fold approach: firstly, the attenuation of both positive and negative components is achieved through the strategic application of boundary constraints and the establishment of reference values. Subsequently, the optimization of the control characteristic ‘beta’ is accomplished through the utilization of a particle swarm optimization (PSO) algorithm integrated within an optimization loop. This intricate interplay of mechanisms aims to optimize the performance of the RSC under fault conditions. To measure the efficacy of the proposed control technique, a comparative analysis is conducted. Fractional-order (FO) proportional–integral–derivative (PID) controllers are employed as an additional method to complement the novel approach. By systematically juxtaposing the performance of the proposed SFRT–AFRT control technique with the FO-PID controllers, a comprehensive evaluation of the proposed approach's effectiveness is attained. This comparative assessment lends valuable insights into the potential advantages and limitations of the novel control technique, thereby contributing to the advancement of fault mitigation strategies in WT systems. Finally, the paper highlights the economic viability of the proposed control method, suggesting its suitability for addressing broader power network issues, such as power quality, in future wind farm research.

Effects of magnet shapes on total harmonic distortion and cogging torque in a permanent magnet synchronous generator for wind turbines

Abstract This paper explores and theoretically reports the effects of different magnet structures on the cogging torque and the total harmonic distortion of the output waveforms from a permanent magnet generator. The generator is a radial flux machine and four different structures are considered for the magnet arrangement in the rotor component and modelled in the Ansys/Maxwell electromagnetic simulation program. This three-phase machine exhibits different behaviours towards various magnet structures, i.e. rectangular, inclined slotted rectangular, skewed double rectangular and inclined slotted skewed double rectangular, respectively. It has been proven by finite element analysis and Fourier analysis that both the cogging and total harmonic distortion values vary significantly for all models. The cogging torque values change in the range of 89.95 to 436.75 mNm and the lowest cogging torque is measured for the inclined slotted skewed double rectangular magnet geometry, while the conventional rectangular magnet geometry yields the worst value with 436.75 mNm. Furthermore, the total harmonic distortion values varies between 1.63 and 3.55 for different magnetic orientations. While the worst total harmonic distortion value is obtained from the inclined slotted rectangular magnet, the best total harmonic distortion is acquired from the skewed double rectangular magnet. All these results will provide scientists and engineers with important information in order to obtain more efficient machines.

Additive manufacturing materials for structural optimisation and cooling enhancement of superconducting motors in cryo-electric aircraft

Superconducting electric motors offer the potential for low weight and high power in applications such as electric aircraft and high speed marine transport. Combined with renewably-sourced cryogenic fuels and advanced fuel cells they offer a path to zero-carbon mass transport. The proposed architectures of these extreme machines, operating at temperatures around 20 K–50 K and employing very high alternating magnetic fields, require materials for the stator that are not electrically conducting and at the same time have good cryogenic structural performance. Additively manufactured (AM) materials can play a key role in these designs, and a collaboration between the Robinson Research Institute and Auckland University of Technology is studying the performance of a range of composite polymers in superconducting machine applications. There are significant challenges to be met, including understanding the effect of the build process on material properties at low temperatures, and also the effect of formulation changes on thermal properties. AM metals can be employed in the rotor components, where the magnetic field fluctuations are very small for our synchronous designs. In this usage case, we can achieve dramatic reductions in the weight of the rotor assembly by minimising the number of joints and facilitating the design of multi-functional components in our helium cooled, vacuum cryostat architecture. Novel design solutions have been developed for several key components in our prototype machines and these are discussed, along with cryogenic testing results for selected AM polymers and composites.

Critical Feature and Seawater Testing of Cross-Flow Rotor Components Fabricated with Additive Manufacturing

Cross-flow tidal turbines are an attractive option for powering remote or off-grid applications because of their simplicity as compared to axial-flow turbines. For instance, when oriented vertically, they harvest power from any current direction with a single degree of freedom and no yaw mechanism. Additive manufacturing (AM) offers an opportunity to print parts out of a wide variety of materials that can result in components that are lighter, stronger and/or less expensive to produce than with traditional manufacturing techniques. When coupled with cross-flow turbine rotors, which require critical features (blade-strut, strut-shaft connections) to be both structurally stiff and hydrodynamically shaped, which can be challenging for typical fabrication processes, AM offers the ability to do both well. This paper describes work on the feasibility of using advanced AM techniques to fabricate small cross-flow turbine rotors for applications at sea and near remote coastal communities.
 AM materials were categorized into 3 classes – plastics, metals, and ceramics – and reviewed for suitability based on a set of engineering requirements and criteria related to turbine characteristics, material properties, and AM process capabilities. Two plastics and two metals were selected to undergo further testing: Essentium CF25, CarbonX Ult 9085, Titanium Ti-6Al-4V, and Inconel 718. Testing is conducted in three phases: the first is a long-term, 5-month submersion test in the seawater tanks at PNNL-Sequim to study corrosion, water uptake, and biofouling potential; in the second, materials are tensile tested on a load frame to find their failure parameters to compare to material standards; the third test is a fatigue test consisting of cyclically loading test parts with a known force on the order of that exerted on rotor blades in a 1.5 m/s current flow. These tests are designed to discern the suitability of AM materials since their properties from 3D printing processes are known to vary from published parameters. The test samples undergoing submersion testing will be tension tested and compared to control samples not subjected to extended seawater immersion. For fatigue life testing, a small rotor is expected to complete 100 million cycles over the course of a year-long lifespan, but for the case herein is restricted to 1 million for a preliminary performance evaluation. The first 10k cycles are run on an MTS 312.21 load frame at a rate of 0.2 Hz, with the remaining on a custom-built cyclic-deflection test rig at 0.8 Hz.

The modeling and cascade sliding mode control of a moving mass-actuated coaxial dual-rotor UAV

In this study, an attitude control scheme based on a three-track moving mass control mechanism is proposed to address the problems of the overcomplicated rotor components, low service life, and low reliability of coaxial dual-rotor unmanned air vehicles (UAV). The motion and aerodynamic models of a moving mass-actuated ducted coaxial dual-rotor UAV are derived. The rotational dynamic characteristics of a moving mass-actuated UAV (MAUAV) with different slider positions and mass ratios are analyzed. An attitude controller based on backstepping sliding mode control is designed to address the nonlinearity and uncertainty of the MAUAV rotation. Based on this, we developed a position controller using cascade sliding mode control. The simulation results demonstrate that the designed attitude controller can achieve a settling time of 1.438 s in the unit-step response and a steady-state error of less than 5% in the sinusoidal attitude-tracking experiment. Additionally, the designed position controller exhibited a better trajectory-tracking effect under different levels of gust disturbance than that of a linear quadratic regulator control-based position controller.

Superconducting Synchronous Motor Development for Airplane Applications - Mechanical and Electrical Design of a Prototype 100 kW Motor

A 100 kW, 4500 RPM synchronous superconducting motor is being built at the Paihau-Robinson Research Institute, Victoria University of Wellington, New Zealand. The motor has superconducting excitation field coils on the rotor and a conventional stator winding. To minimize mass the motor is an air-core type, meaning no ferromagnetic materials are employed inside the motor. Some of the salient features of this motor include: 1) field winding coils employing REBCO CORC conductor; 2) field coils powered with a contactless superconducting dynamo exciter; 3) an EM shield on the rotor for protecting the field coils from high frequency magnetic fields due to stator harmonics and the switching of the drive electronics; 4) a unique single-layer winding design for the stator winding, where the stator coils are made with copper Litz wire and are liquid-cooled. This paper describes the electrical design and 3D simulation of the motor including the superconducting dynamo, and highlights stator and rotor coil developments that will be validated in the prototype. Sensitivity to critical design parameters has been assessed in simulation and initial sub-system prototypes manufactured for testing. Preliminary design is projecting this motor diameter and axial length as 360 mm and 550 mm respectively, with an efficiency of 96.4 % at the rated load. These numbers may be comparable with permanent magnet motors of similar rating, but this motor is being built to serve as a test-bed for evaluating different technologies for rotor and stator components. The ultimate goal for this program is a 3.0 MW machine with superconducting armature and field windings. In comparison with the permanent magnet motor in 2.5 - 3.0 MW range, the superconducting motors are expected to be 4 to 5 times smaller in size and mass with efficiency exceeding 99 %.

Study on Delay Release Time of Fuze Based on ADAMS

In order to study the arming process of electromechanical fuze security mechanism, a dynamic simulation method using ADAMS software is proposed; The simulation model of the security mechanism is established, and the existence of complex factors such as contact and collision between the rotor and adjacent components is considered in the calculation process. The time of the horizontal rotor is simulated, and the flexibility and rapidity of the rotor rotation are verified, as well as the reliability of the locking mechanism; The simulation results are compared with the statistical results of high-speed camera test, and the correctness of ADAMS software simulation results is verified.

Superalloy—Steel Joint in Microstructural and Mechanical Characterisation for Manufacturing Rotor Components

The structure of energy rotor components includes different structural materials in the sections, which are subjected to varying levels of thermal loading. The first component section has to include a precipitation-hardened nickel-based alloy, while the second one may be manufactured from other materials. Due to the installation cost, the use of expensive nickel-based materials is not recommended for applications in sections with a lower degree of thermal loading. Therefore, this aspect is still actually from an engineering point of view and is discussed in the paper by means of manufacturing and experimental approaches. The paper follows the welding problems related to a hybrid joint made of superalloy (Alloy 59) and hard rusting steel (S355J2W+N steel). The problem is solved using the MIG process at various parameters. With respect to the joint quality, microstructural features and mechanical parameters of the examined zone are presented. In the case of microstructure analysis, the dendritic and cellular natures of austenite were dominant elements of the joint. Mechanical tests have expressed a 50% reduction in elongation of the steel and alloy steel weld and lowering mechanical parameters. Mechanical parameters of the joint were on the level of their values observed for the steel, while the hardening coefficient followed the hardening curve of the alloy. Decohesion of the steel and mixed weld has reflected the constant proportion of values of axial and shear stress components up to the total separation. It is noted the tensile curves of the alloy and alloy steel joint follow a very similar shape, reporting the same response on the monotonic tension. The materials can be analysed by applying constitutive equations at very similar values of their coefficients. The obtained results enabled elaborating and examining the MIG welding process for thick-walled structures (not smaller than 8 mm) in detail giving all parameters required for technology. Finally, the technology for producing a hybrid joint using difficult-to-weld materials with different physical and mechanical properties, such as nickel alloys and low-alloy steels, is proposed. Results have shown it possible to develop a technology for producing of hybrid joints (supper alloy + hard rusting steel) with assumed physical and mechanical properties for rotors applied in the power boiler. This solution was proposed instead of previously used elements of rotors from expensive materials. It was assumed that the newly proposed and utilised method of welding will allow for obtaining good properties in terms of energy devices.

CFD Analysis of a Transient Rotor-Stator Axial Steam Turbine Stage

An axial steam turbine stage has both stationary and rotating components, which are coupled together in a CFD model by multiple frames of reference. There are three types of interface techniques available to exchange the information between the different frames of reference namely frozen rotor, stage, transient stator rotor. Both frozen rotor and stage interfaces are used in steady state analysis. The operation of axial turbine is inherently an unsteady process. The aerodynamic interaction between the rotating part and the stationary parts are the important contributor to the unsteadiness of the flow present in the turbine. Neither of the two interfaces implemented in the steady state CFD analysis is capable of predicting the unsteady effects resulting from the rotor-stator interaction due to their relative position change. The third type of interface, the transient stator-rotor interface, is available to simulate the fluid motion caused by the relative movement between a rotor and stationary components in axial turbine. Although enormous computer resources are needed for this modelling, it simulates real flow physics best of all, while steady or quasi-steady numerical approaches only approximate the real flow, because they neglect important effects of blade row interactions. The paper presents the CFD analysis carried out for an axial steam turbine stage with three different interface techniques and compares the results.

Effect of Fiber–Matrix Interface Friction on Compressive Strength of High-Modulus Carbon Composites

Carbon-fiber-reinforced polymers (CFRPs) enable lightweight, strong, and durable structures for many engineering applications including aerospace, automotive, biomedical, and others. High-modulus (HM) CFRPs enable the most significant improvement in mechanical stiffness at a lower weight, allowing for extremely lightweight aircraft structures. However, low fiber-direction compressive strength has been a major weakness of HM CFRPs, prohibiting their implementation in the primary structures. Microstructural tailoring may provide an innovative means for breaking through the fiber-direction compressive strength barrier. This has been implemented by hybridizing intermediate-modulus (IM) and HM carbon fibers in HM CFRP toughened with nanosilica particles. The new material solution almost doubles the compressive strength of the HM CFRPs, achieving that of the advanced IM CFRPs currently used in airframes and rotor components, but with a much higher axial modulus. The major focus of this work has been understanding the fiber-matrix interface properties governing the fiber-direction compressive strength improvement of the hybrid HM CFRPs. In particular, differences in the surface topology may cause much higher interface friction for IM carbon fibers compared to the HM fibers, which is responsible for the interface strength improvement. In situ Scanning Electron Microscopy (SEM)-based experiments were developed to measure interface friction. Such experiments reveal an approximately 48% higher maximum shear traction due to interface friction for IM carbon fibers compared to the HM fibers.

Flow Field Explorations in a Boundary Layer Pump Rotor for Improving 1D Design Codes

Boundary layer pumps, although attractive due to their compactness, robustness and multi-fluid and phase-handling capability, have been reported to have low experimental efficiencies despite optimistic predictions from analytical models. A lower-order flow-physics-based analytical model that can be used as a 1D design code for sizing and predicting pump performance is described. The rotor component is modelled by means of the Navier–Stokes equations as simplified using velocity profiles in the inter-disk gap, while the volute is modelled using kinetic-energy-based coefficients inspired by centrifugal pumps. The code can predict the rotor outlet and overall pump pressure ratio with an around 3% and 10% average error, respectively, compared to the reference experimental data for a water pump. Moreover, 3D RANS flow-field explorations of the rotor are carried out for different inter-disk gaps to provide insights concerning the improvement of the 1D design code for the better prediction of the overall pump performance. Improvements in volute loss modelling through the inclusion of realistic flow properties at the rotor outlet rather than the detailed resolution of the velocity profiles within the rotor are suggested as guidelines for improved predictions. Such improved design codes could close the gap between predictions and experimental values, thereby paving the way for the appropriate sizing of boundary layer pumps for several applications, including aircraft thermal management.

Numerical investigation of the scale effects of pump-jet propulsor with a pre-swirl stator

In this study, the performance of a pump-jet propulsor (PJP) with pre-swirl stator in open water is numerically investigated. Both full-scale and model-scale configurations are considered. The Reynolds-averaged Navier–Stokes equations and shear stress transport k−ω turbulence model are used in the numerical calculation. The computational domain is discretized using structured grids, and a rotating grid is affixed to the rotor to deal with the relative motion between the rotor and stationary components. The mesh quality is determined based on a grid uncertainty analysis. The numerical method is validated using model-scale experimental data. The simulation results reveal the influences of the scale size on the hydrodynamic performance and the distributions of the velocity, pressure and vorticity under three advance coefficients. With the increase in the advance coefficients, the scale influences on the efficiency become more obvious, and the efficiency of the full-scale PJP is always higher than that of the model-scale PJP. The full-scale configuration is found with a more significant instability in the gap vortex development, because it presents larger interaction between tip leakage vortex (TLV) and the inner wall of the duct. As the main velocity increases, the TLV shedding is delayed. Finally, the development process of gap vortices is analyzed for the difference operation conditions.

Functionally integrated additive manufactured rotor components for torque-dense aircraft electric motors

In dealing with emissions targets worldwide, fundamental questions about the future arise for commercial aviation. The resulting consequences for aviation require efforts to make air traffic CO2 neutral. In this context, electrification is an important building block to enable the aviation industry to provide transport in the future with increasing traffic volumes. To achieve this goal, electric motors for flight operation must have a high power and torque density and operate as energy-efficiently as possible. The PM synchronous motors predominantly proposed for such applications have above average efficiencies but could provide higher peak powers if they could be thermally more loaded. In particular, the sensitive permanent magnets lose efficiency as the operating temperature of the electric motor increases, reducing the maximum possible torque of the motor. Since conventional rotor construction methods limit the design, additive manufacturing is used to develop a rotor design that allows the rotor magnets to be cooled in close range to their contours. In addition, by selective laser melting mechanical, thermal, and magnetic functions are integrated. A process for hybrid manufacturing of novel rotor topologies is proposed. For this purpose, the rather conventional rotor topology is replaced by an additive function-integrated component for a reference electric motor. By means of an FEM analysis, it was shown that the mechanical strength of the alternative fixation method is maintained. Using adequate design guidelines, the AM structural components were fabricated in aluminum and an iron-nickel alloy and the permanent magnets were secured on it using 1K-epoxy adhesive. CFD analysis was used to simulate the flow conditions and heat transfer to the coolant in the internal structures of the AM components. Finally, the effect of the integrated cooling function was verified with an experimental setup. The results show that the torque influencing factor of the magnetic induction can be increased.

Study on residual stress evolution of laser cladding low chromium carbon alloy on low-pressure rotor

The in-service behavior of low-pressure rotor components can potentially be impacted by the residual stress distribution of cladding layers. To predict the evolution of residual stress in a multi-pass multi-layer cladding, a thermal-metallurgical-mechanical model that incorporates the effect of solid-state phase transformation (SSPT) is proposed. In the multi-pass case, high longitudinal tensile stress peaks were generated in the former pass, reaching 588 MPa. With multi-pass deposition, the maximum transverse and longitudinal stresses in the substrate increased to 282 and 523 MPa, respectively, which were adjacent to the heat-affected zone (HAZ). In the multi-layer case, multiple thermal cycles had a significant effect on increasing the longitudinal stress of the substrate plate. The maximum of longitudinal stress reached 634 MPa. In the case of the multi-pass multi-layer, the fluctuation of residual stress was generated inside and on the top surface of the cladding layers. The transverse tensile stress changed from 110 to 10 MPa, and the longitudinal tensile stress decreased from 385 to 173 MPa. The interval of high tensile stress was related to the hatch space of the laser beam. In the simulation of the cladding process on a low-pressure rotor, the residual-stress distributions were not uniform along the cladding sequence. Owing to the heat accumulation and scanning strategy, a compressive stress zone adjacent to the endpoint of the cladding sequence, emerged in the cladding layers and substrate. From the simulation results, to estimate the high residual stress and ease the non-uniform residual stress, the laser scanning strategy should be changed in the actual manufacturing process.

Polar localization of CheO under hypoxia promotes Campylobacter jejuni chemotactic behavior within host.

Campylobacter jejuni is a food-borne zoonotic pathogen of worldwide concern and the leading cause of bacterial diarrheal disease. In contrast to other enteric pathogens, C. jejuni has strict growth and nutritional requirements but lacks many virulence factors that have evolved for pathogenesis or interactions with the host. It is unclear how this bacterium has adapted to an enteric lifestyle. Here, we discovered that the CheO protein (CJJ81176_1265) is required for C. jejuni colonization of mice gut through its role in chemotactic control of flagellar rotation in oxygen-limiting environments. CheO interacts with the chemotaxis signaling proteins CheA and CheZ, and also with the flagellar rotor components FliM and FliY. Under microaerobic conditions, CheO localizes at the cellular poles where the chemosensory array and flagellar machinery are located in C. jejuni and its polar localization depends on chemosensory array formation. Several chemoreceptors that mediate energy taxis coordinately determine the bipolar distribution of CheO. Suppressor screening for a ΔcheO mutant identified that a single residue variation in FliM can alleviate the phenotype caused by the absence of CheO, confirming its regulatory role in the flagellar rotor switch. CheO homologs are only found in species of the Campylobacterota phylum, mostly species of host-associated genera Campylobacter, Helicobacter and Wolinella. The CheO results provide insights into the complexity of chemotaxis signal transduction in C. jejuni and closely related species. Importantly, the recruitment of CheO into chemosensory array to promote chemotactic behavior under hypoxia represents a new adaptation strategy of C. jejuni to human and animal intestines.

Modelled optimisation approaches for laser cutting sheets simultaneously applied to EV component production.

This paper proposes that laser cutting has potential as a viable alternative to stamping for mass manufacture of thin steel components such as stator and rotor components in the electric automotive sector. Current laser cutting processes are much less efficient than stamping. However, laser cutting is much more flexible and is used for small batches and one-off production. This paper assesses the potential of performing laser cutting operations of multiple sheets or layers simultaneously. This method is referred to herein as polystromata cutting. A numerical model is used to assess the manufacturing performance of stamping, traditional laser cutting and polystromata laser cutting. Polystromata laser cutting is shown to be capable of producing parts at 37% less cost than stamping. However, polystromata remains slower than stamping, taking 79% more time to produce each stator stack. Through this research it has been identified that optimisation of polystromata processes is more complex and performance efficiency varies wildly dependent on manufacturing set-up. This work aims to provide a best practice optimisation methodology for polystromata laser cutting by assessing results using different manufacturing objectives.

Numerical Analysis of Surface Integrity in Parallel Turning Process Part II: Influence of Cutting Tool Rake Angle

Parallel turning is one among the advanced unconventional turning process. It employs two turning tools operating concurrently to cut the material from the workpiece. For turned rotary components, surface integrity is a major quality indicator that determines the fatigue life of the finished workpiece. Tool parting distance, rake angle and edge radius affects surface integrity. Part I dealt with numerical analyses to determine the effect of parting distance on surface integrity using finite element based commercial software Abaqus 6.14. Here in Part II, the impact of rake angle over surface integrity for various cutting speeds and feeds are numerically analyzed. It was observed that with the rise in negative rake angle the negative residual stresses decreased for the machined surface of leading and lagging cutting tool. When the rake angle is increased from-10 ̊ to-2 ̊, percentage reduction of negative residual stresses is same for the turned surfaces of both tools. The cutting velocity was 250 m/min and feed 0.2 mm/rev. With the rise in rake angle, the friction angle reduced but shear angle raised. When the cutting velocity increased, the shear angle of the leading and lagging cutting tool reduced. Lower shear angle causes higher stagnation region which further causes higher compressive surface residual stress.

Structural acoustics analysis of automobile parts by using finite element method

A modal analysis of the electric motor automotive component is presented in this study. The frequency responses for the rotor component of the electric motor were computed using finite element method. Comparison of the stator and rotor components of the electric motor's overall deformation frequency findings from modal analysis is done.CATIA V5 is used as a tool to design the electric motor parts; it also helped in making complicated parts easier to assemble. The electric motor is discredited using ANSA, which transforms the domain into a mesh and instantly displays the failure element. The numerical approach is used to calculate modal vibrations. Rigid body and natural frequencies are computed and displayed in different modes to avoid resonance. The ANSYS finite element (FE) code is used to investigate the system.

Manufacture and Testing of a Magnetically Suspended 0.5-kWh Flywheel Energy Storage System

This article presents crucial issues regarding the design, manufacture, and testing of a steel rotor for a 0.5-kWh flywheel energy storage system. A prototype was built using standard industrial components. The rotor has a maximum operating speed of 24 000 min <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−1</sup> and is magnetically suspended. The introduced critical issues regarding the manufacture include the thermal stress during the rotor hardening process, the fixation for the rotor components of the drive machine and the magnetic bearings, etc. The rotor strength was validated by the overspeed testing according to the standard <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">IEC 60034-1</i> . A rotation of up to 28 800 min <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−1</sup> (120% of the maximum speed) was realized and maintained for 2 min. The proved rotor was suspended by commercial magnetic bearings in the flywheel system. Despite simple decentralized control, the rotor was successfully driven up to the designed maximum speed. The rotor dynamic behavior is analyzed by analytical calculation, simulation, and measurements. Different eigenmodes are identified. The results prove the possibilities to build and operate a flywheel system using standard industrial components, showing potential for cost-effective designs.

Performance study of savonius style wind turbines in a solar chimney power plant under guided flow environment

With the uprise in global population and rapid industrialisation in developing nations, increasing energy demand to compensate for societal and industrial needs is inevitable. However, popular energy resources such as gas, petroleum, and coal, on which the global energy mix is heavily reliant, induce environmental pollution and global warming. Thus, clean energy sources, such as wind and solar, are increasingly sought to mitigate these adverse environmental effects and identify alternative sustainable and renewable energy technologies. The existing literature suggests minimal research has been conducted on the turbine component of the solar chimney power plant (SCPP). The present research proposes the study of a vertical axis wind turbine (VAWT), namely the Savonius-style wind turbine (SSWT), for power augmentation in the SCPP under the influence of guide vanes and shields that are installed in the solar collector area. A two-dimensional numerical analysis is performed using the ANSYS Fluent software. The SSWT and SCPP models used in the simulations were validated using numerical and experimental results from previous literature data. The angle of the guide vanes was varied while the dimensions of the SCPP model and the energy extractor considered were kept constant. The optimum turbine performance was identified based on the flow analysis and the power output of the rotary component from different guide vane configurations. The present study shows an overall improvement in the turbine’s performance coefficient and power output under the influence of the guide vane and shield in the SCPP. The turbine with the guide vane and shield at an angle of 45° enhanced the performance by 22.22% and power output by 22.25% compared to the turbine without the guide vane and shield.