Rotor Assembly Research Articles

Measurement and optimization method for aero-engine rotors based on binocular multi-line laser sensing and virtual assembly

During the assembly of aero-engine rotors, eccentricity and tilt errors along the radial and axial direction result in uneven loading along the mating surface, which significantly impacts the operational lifespan of the rotor. This paper proposes a three-dimensional contour measurement system based on binocular multi-line laser sensing and conducts an aircraft engine rotor stacking virtual assembly technology system, to response the practical requirements of aircraft engine rotor unit production assembly engineering. We combine multi-line structured light active projection device with the binocular stereo vision model to construct the contour measurement system, which enhances the surface features of the projected object by adhering to the common constraint of structured line and stereo vision. Furthermore, the error propagation model for multi-stage rotor assembly to investigate the mechanism of error impact is established aiming to facilitate quantitative research on virtual assembly mechanisms. By manipulating the rotor phases and evaluating the coaxiality under various conditions, effective prediction of phase variation can be achieved, the multi-objective benchmark virtual assembly method based on the error propagation model of multi-stage rotor coaxiality is presented. The experimental results indicate that the proposed measurement system achieves the maximum disparity between the spatial data points procured by the proposed measurement system and the predetermined value of 2.1 μm, and the maximum disparity between the target plane’s average movement distance and the preset value of 3.7 μm. The precision provided by this system effectively meets the objective of assembly phase optimization for multi-stage rotors. In the empirical experiment conducted on the three-stage rotors, both systems yielded identical optimized phases: 0° for the first-stage rotor, 270° for the second-stage rotor, and 120° for the third-stage rotor, thereby validating the efficacy of the proposed measurement and optimization method for aero-engine multi-stage rotors with virtual assembly.

A comprehensive study of recent studies on the efficiency of axial flow turbines with an investigation on blade profile modifications in stator and rotor assemblies

Axial flow turbines are crucial in energy production and propulsion across diverse applications. As global energy needs rise, optimizing turbine efficiency is paramount. This review delves into the aerodynamic design of turbine blades, specifically examining blade profile modifications in both stator and rotor assemblies of state-of-the-art models proposed in the studies from 2019 to 2024. The focus is on mitigating performance discrepancies between idealized simulations and real-world applications, which present significant challenges such as inconsistencies in computational fluid dynamics (CFD) predictions and manufacturing constraints. Key findings from this review highlight a potential efficiency gain of 1%–3% through optimal blade designs that reduce incidence losses, secondary flows, and tip vortex formation. Advanced modeling techniques, including high-fidelity, multi-objective optimization with machine learning, are evolving to better predict and enhance turbine performance. However, gaps remain in system-level integration and the limited experimental data restricts comprehensive validation of these new designs. The insights from this review will aid the research community by identifying critical areas for future investigation, such as integrating blade aerodynamics with heat transfer and structural mechanics. Further, it emphasizes the need for exploring combinations of passive and active flow control strategies to fully harness the benefits of blade profile enhancements. These efforts are crucial for achieving substantial improvements in turbine efficiency, which are essential for meeting the growing demands for sustainable and efficient energy production.

Machine learning algorithm functional on environmental sustainability assessment in turbomachinery sector: Application on centrifugal compressors

The current government directives have focused industries' attention on environmental sustainability issues in products and processes. There is indeed a growing demand from customers to conduct environmental impact assessments of the products they purchase. This work presents the implementation of a predictive model developed in an industrial context to evaluate the environmental sustainability of a centrifugal compressor rotor assembly. The development of the predictive model arises from the objective of overcoming the limitations of the traditional Life Cycle Assessment approach, which is based on a retrospective evaluation of the product life cycle. The functionality of predictive models is to estimate product environmental sustainability to meet customer demands and guide them toward choices that aim for carbon neutrality. The implementation of the model has been conducted in parallel with a tailored measurement campaign of the primary inventory flows involved in various manufacturing operations. The article details the methodological approach that led to the development of the predictive models and their respective functionality in supporting the design engineer in evaluating the eco-profile of the assembly. In addition to the methodological aspect, the work also includes a case study through which the functionality of the models can be illustrated.

Simulation analysis of multi-ring interference assembly of large capacity composite flywheel rotor

Simulation analysis of multi-ring interference assembly of large capacity composite flywheel rotor

Compensating thermal bending of the runner disk in hydrodynamic thrust bearings: Simple approach for passively improving the performance of gas bearings

This paper presents a method for passively compensating thermal bending distortions of the thrust disk in gas thrust bearings by passive approaches. Thermal bending displays a prominent problem in hydrodynamic thrust bearings, especially in connection with air bearings. Axial temperature gradients cause the rotor disk to dish which in turn diminishes the lubricating gap topology and reduces the load capacity of the bearing. Consequently, the bearing performance is decreased and the bearing may even fail. The here proposed straightforward solutions are small changes in the rotor and runner disk design and are therefore rather simple and inexpensive to adopt. They comprise asymmetric mass distributions, recesses, disk cuts, and dual-material rotor disks. In order to show the benefit for the thrust bearing performance, detailed multiphysical numerical simulations of a representative rotor assembly with a foil thrust bearing are presented. The fully coupled finite element model calculates the deformations of the foil package (2D Reissner–Mindlin type shell equations), lubricating air film pressure (2D compressible Reynolds equation), air film temperatures (3D energy equation), and thermo-elastic deformations of the rotor and rotor disk (2D Navier-Lamé equations including centrifugal forces and thermal stresses). When the proposed design changes are applied, the model predicts reduced thermal bending, marked improvements in load capacity as well as decreased temperatures. The load capacity increase ranges up to 43% for an optimized design when compared against a standard symmetric design. Also, the sensitivity of different design parameters is discussed in detail. The suggested disk design changes may be applied to a broad variety of rotor-bearing systems. However, the design has to be tailored to the specific and individual machine operating conditions.

Study on the Speed Control and Heat Dissipation Performance of Cone-tube Permanent Magnet Governor

The speed regulation range, output torque, and heat dissipation performance are important performance indicators of permanent magnet speed regulators. Enhancing the speed regulation range and output torque, and reducing the heat generation power are of significant importance for expanding the application range of permanent magnet speed regulators. To address the issues of a single adjustment process, insufficient heat dissipation space, and inadequate torque transmission capability of the traditional straight-barrel permanent magnet speed regulator, a cone-barrel permanent magnet speed regulator with a magnetic rotor assembly structure was designed through the analysis of the structure and transmission characteristics of the traditional straight-barrel permanent magnet speed regulator. Using the ANSYS Maxwell finite element analysis software, the output torque characteristics of the cone-barrel structure were studied. Considering the effect of eddy current heating, a conjugate heat transfer model for the permanent magnet speed regulator was developed, and the heat dissipation performance of the cone-barrel structure was explored through ANSYS Fluent simulation analysis. The results indicate that compared to the traditional straight-barrel permanent magnet speed regulator, the cone-barrel regulator can provide greater output torque when fully coupled; at maximum power consumption, the air velocity over the surface of the cone-barrel permanent magnet speed regulator conductor is higher, resulting in better heat dissipation and thus a lower operating temperature.

Concentricity control for multistage rotor assembly based on contour vectorization

Concentricity control for multistage rotor assembly based on contour vectorization

Nonlinear Dynamic Analysis for a Jeffcott Rotor Considering Varying Connection Stiffness of Bolted Joint

Bolted joints have been widely used in rotor assemblies of aircraft engines. A typical bolt joint is composed of two metal parts connected mechanically with pre-tensioned bolts. During operations, the bolting pretensions can vary with the changing contacting relationship between the parts, which makes the connection stiffness of the joint nonlinear on the macroscopic scale. The fundamental problems of the dynamical analysis for bolted joints are (1) to identify the transition of the change of the connection stiffness and properly model the overall connection stiffness and (2) to investigate the influence of such variable stiffness on the rotor vibration. In this paper, an analytical model is proposed considering the effect of bolted joints. The bolt of the joint is simplified as a two-node spring-like connection element considering different axial tension and compression stiffness, non-uniform preload of bolts and the contact interface friction described based on Coulomb friction. The dynamic equations of the rotor system are established based on the lumped mass modeling and the proposed connection element, and numerically solved through the Runge–Kutta method. The results indicate that the rotor system exhibits a variety of states, such as period-1 motion, multi-period motion, quasi-periodic motion and chaotic motion. The effects of friction coefficient and preload of the bolts on the nonlinear dynamic behaviors of the bolted rotor system are demonstrated in detail.

Rotordynamic analysis of non-uniform rotor assembly and prediction of failures due to abrupt using Xlrotor technique

Rotordynamic analysis of non-uniform rotor assembly and prediction of failures due to abrupt using Xlrotor technique

Research on the Influence of Disc–Drum Connection Bolt Preloading Rotor Assembly Modal Characteristics and Diagnosis Technology

The drum rotor of an aero-engine is connected by one or multiple mounting edges through bolts, and their dynamics are significantly influenced by the preload state of the bolts. Long working hours in challenging environments can result in the deterioration of bolt pre-tightening during assembly or service, which impacts the rotor’s dynamic stability and overall performance. Currently, there are no available methods for detecting the dynamic characteristics of the drum connection components. This paper analyzes the impact of the natural characteristics of the drum composite structure of a high-pressure aero-engine turbine based on the refined finite element method when the preloading state changes. Two conditions of deviation and uneven stiffness distribution were applied to the connected components of the drum. The analysis focused on the impact of the pre-tightening state on its natural frequency. After analyzing the feasibility of identifying the pre-tightening state, two methods are proposed. These methods focus on changes in natural frequency and mode shape, specifically the sensitive natural frequency change method and the mode step change method. The methods proposed in this paper can serve as a reference for evaluating the quality of assembling complex disc–drum structures with multiple bolt connections.

Computational flow field analysis of a Vertical Axis Wind Turbine

The present work has used Computational Fluid Dynamics (CFD) to obtain the flow field characteristics of a novel Vertical Axis Wind Turbine (VAWT). The turbine used in this study features a multi blade design where both a stator and rotor blade array is used. The computational model is three-dimensional and contains full-scale turbine geometry measuring 2.0m in diameter and 1m in height. The pressure field across the wind turbine has been computed for operating conditions of λ=0 and λ=0.4 where it is shown to be non-uniform. The velocity field across the turbine has been obtained at λ=0 and λ=0.4 and has highlighted the presence of a jet flow passing through the central core of the turbine as it exits the rotor assembly. It is evident that under dynamic conditions and due to the direction of this jet flow a strong flow interaction occurs with the downstream rotor blades. This interaction results in rotor blades 5, 6 and 7 generating an opposing torque that acts against the direction of motion. Furthermore, it is noticed that rotor blades 10, 11, 12 and 1 contribute to the majority of overall rotor torque, which is a characteristic of this machines design.

Fast‐Moving and Highly Adaptable Hollow Piezoelectric Miniature Robot

Fast motion and high adaptability are crucial for the practical applications of miniature robots. However, combining these capabilities into a single robot skillfully is challenging, particularly in the domain of miniature structural design. Inspired by the amphibious motion of crocodiles in nature, a hollow piezoelectric miniature robot (HPMR) is proposed. The key benefit of the HPMR is to concurrently output the oscillating motion of the driving foot (oscillating mode) and the rotating motion of the internal rotor (rotating mode). That is, the mode of single‐energy‐input‐multimotion output allows the robot to balance the requirements of speed and adaptability. In the oscillating mode, HPMR can run at speeds of up to 12.3 BL s−1 and realize a displacement resolution of 0.3 μm. Following the conical rotor assembly, the rotor can operate at a speed of 890 rpm, with a displacement resolution of 7.28 mrad. In the rotating mode, the robot demonstrates its multitasking ability in moving amphibiously, carrying loads, running on surfaces with varying roughness, crossing obstacles, and resisting shocks. The results show that the HPMR is capable of fast, high‐resolution moving combined with high adaptability, opening up the possibility of using it for mobile detection tasks in real‐world settings.

2D hexagonal assembly of a dipolar rotor with a close interval of 0.8 nm using a triptycene-based supramolecular scaffold.

Controlling the rotation of carbon-carbon bonds, which is ubiquitous in organic molecules, to create functionality has been a subject of interest for a long time. In this context, it would be interesting to explore whether cooperative and collective rotation could occur if dipolar molecular rotors were aligned close together while leaving adequate space for rotation. However, it is difficult to realize such structures as bulk molecular assemblies, since molecules generally tend to assemble into the closest packing structure to maximize intermolecular forces. To tackle this question, we examined an approach using a supramolecular scaffold composed of a tripodal triptycene, which has been demonstrated to strongly promote the assembly of various molecular and polymer units into regular "2D hexagonal packing + 1D layer" structures. We found that a molecule (1) consisting of a dipolar 1,2-difluorobenzene rotor sandwiched by two 10-ethynyl-1,8,13-tridodecyloxy triptycenes, successfully self-assembles into the desired structure, where the dipolar rotor units align two-dimensionally at a close interval of approximately 0.8 nm while having a degree of freedom for rotational motion. Here we describe the self-assembly behavior of 1 in comparison with the general trend in molecular self-assembly, as well as the motility of the two-dimensionally aligned molecular rotors investigated using solid-state 19F-MAS NMR spectroscopy.

Design and Analysis of Horizontal Axis Small Wind Turbine for Low Wind Velocity Using QBlade

Renewable energy systems are of high importance considering the present day energy requirement. In Wind energy systems design and analysis of wind turbines for enhanced efficiency at low at wind speed is studied in this paper. Aero foil shape is the one of the key aspects which determines the efficiency of the turbine. In this paper airfoil G4510, NACA 0018 and NACA 4412 are considered for the study with a blade length of 0.762 m. General Public Licensed Software QBlade is used for the simulation which uses Blade Element Method (BEM). Comparison of performance parameters for different aero foil is presented and blade is designed using G4510 airfoil nomenclature. Using these blades, a three bladed rotor is assembled and structural analysis is performed to know the pressure distribution on different areas of the blade. Finally, a tower is attached to the rotor assembly and simulation is carried on the small wind turbine. Graphical relationship between power, tip speed ratio, velocity and coefficient of pressure is obtained for analysis.

A Decoupling Algorithm-Based Technology for Predicting and Regulating the Unbalance of Aircraft Rotor Assembly Considering Manufacturing Errors

Rotor unbalance is the most important factor affecting the dynamic performance of aircraft engines. The existing unbalance prediction and control methods are insufficient for multi-stage rotors. The post-assembly unbalance of rotors in aircraft engines is a critical factor affecting their dynamic performance. In order to predict and reduce the unbalance of multi-stage rotors after assembly, this paper establishes a measurement model for the center-of-mass offset of aircraft engine rotors through decoupled calculations of the unbalance. Furthermore, it constructs an unbalance prediction model using the spatial transfer mechanism of combined rotor offset centers under the influence of manufacturing errors. Additionally, a method for measuring rotor unbalance during the assembly phase is proposed. The experimental results of the unbalance in multi-stage combined rotor assembly indicate that the degree of agreement between the predicted results and the experimental results is 91.3%, resulting in a reduction in the mean error of 15.3% compared to before the correction. The study also investigates the impact of manufacturing errors on unbalance. This research provides robust support for controlling the unbalance in multi-stage combined rotor assembly.

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.

Design, Manufacture and Testing of an Open-Source Benchmark Composite Hydrokinetic Turbine Blade

In a trend towards clean energy alternatives, recent years have seen great strides in the marine energy space. This has resulted in a pressing need for the design, development, and validation of novel energy harvesting technologies such as hydrokinetic devices, which capture kinetic energy from waves, tides, and currents. However, these devices span numerous concepts and designs that often lack solid benchmark research that can be freely referenced. This work focuses on the design process of an open-source composite hydrokinetic turbine blade for a three-bladed marine turbine rotor assembly with a diameter of 2.5 m. The proposed blade consists of two structural composite skins that are bonded with an adhesive and filled with a foam core. This study will explore and contrast the efficiency and resolution of low-fidelity rapid design methodologies and comprehensive high-fidelity approaches for the blade design, modeling, and analysis efforts, a key objective in this research. Blade hydrodynamic loads were modeled and applied to finite-element blade models to study deformations and potential failure. Ongoing efforts will result in blade manufacture and structural testing at the National Renewable Energy Laboratory. In future work, multiple blades will be deployed at the Living Bridge site at the University of New Hampshire and will be compared to rigid aluminum blades of the same geometry, developed by Sandia National Laboratories. Ultimately, this research will lay foundational groundwork for researchers and manufacturers, establishing a baseline composite blade design that will serve as a benchmark in the development of future hydrokinetic turbine blades.

Blade sequencing optimization of aero-engine based on deep reinforcement learning

The unreasonable sorting of single-stage rotor blades leads to the over-tolerance of rotor unbalance, which is the main cause of excessive engine vibration. Aiming at the problems of long search time, poor repeatability, weak adaptability and difficulty in obtaining global optimum by using heuristic algorithm for blade sorting, this paper presents a deep reinforcement learning method is proposed to solve the blade ordering problem. A pointer network model including an encoder and a decoder structure is established. For the case where the blade data cannot be obtained, the unbalance of the single-stage rotor is used as the reward function, and the pointer network model is trained by the Actor Critic reinforcement learning algorithm. The experimental results show that the trained enhanced pointer network model can directly perform end-to-end reasoning on the input sequence, avoiding the iterative solution process of traditional heuristic algorithms, and has high solution efficiency. Using the enhanced pointer network blade sorting optimization model in this paper to sort a set of blade sequences, the unbalanced value of the rotor after sorting is 14.78 g.mm, which is 84.8% better than the genetic algorithm, and the search speed is increased by 95.9%. The results show that the method can quickly and accurately give the arrangement order of the leaves, and the proposed model has generalization. It can provide a reliable measurement method for rotor assembly measurement of large engine manufacturing enterprises such as China Aero-Engine Company.

Effect of Stem Diameter, Cutting Speed and Moisture Content on Cutting Torque for Green Gram Harvesting

The study was conducted during November, 2021 at Department of FMPE, CAET, OUAT, Bhubaneswar, Odisha, India to investigate the torque requirement and ascertain optimum peripheral cutting velocity of rotary cutting disc based on varying stem diameter and moisture content of green gram . The cutting operation was simulated to find the cutting torque in the instrumented soil bin, which comprises of test trolley, processing trolley and vertical rotor assembly with vertical shaft having serrated cutting disc. Sample plant stems of green gram were firmly fixed in the plant stem holder, and buried beneath the soil to simulate the natural standing of the crop as in the actual field condition. The cutting torque required to cut the stem of green gram at different crop moisture content (39.2, 41.4 and 42.9% (wb)), peripheral cutting velocity (20, 25, 30, and 35 ms-1) and plant stem diameter (2.95, 3.97 and 4.96 mm) was measured. It has been observed that peripheral cutting velocity of disc, stem diameter and moisture content of plant affected cutting torque at 1% level of significance. The cutting torque increased with decrease in moisture content and increase in diameter of plant stem of green gram. The cutting torque increased with an increase in peripheral cutting velocity up to the critical velocity of 30 ms-1, but the value decreased after critical peripheral velocity.

Determination of Mechanical Properties for Laser Welded Turbine Rotor Assemblies for Automotive Turbocharger Applications

To meet the demands of higher speeds, higher power density and the ability to adapt to harsh operating environments over a long period of time, structural designers use various materials to fabricate rotor parts for turbine assemblies. This introduces high requirements for stable rotation and rotor life. It is therefore important to analyse and determine the mechanical properties for a turbine rotor taking into account the manufacturing process. This paper focuses on laboratory mechanical testing for determination and analysis of turbine components consisting of a rotor, from 42CrMo4 (DIN EN 10083-3) and a turbine, made from Inconel 713C in laser welded assembly. The tests carried out consists of tensile testing for the turbine – rotor assembly, microhardness measurements, macro and microscopic examinations of the welded joint. The obtained results stand as a validation for the welding process technology used for this type of application ensuring the superior mechanical characteristics required for operation in harsh enviornments.