Harmonic Analysis of the High Speed Direct Coupled SCO2 Turbo-Generator

The rotordynamics and harmonic characteristics of the rotor assembly designed for 40-kW high-speed sCO2 direct-coupled turbo-generator pair have been evaluated numerically using finite element solver “ANSYS Mechanical”. First, the shaft geometry and dimensions have been optimized using lumped mass-inertia-based AxSTREAM RotorDynamics module followed by the bearing selection analysis using SKF SimPro expert to ensure enough separation margin from the nearby critical speeds. Equivalent 2D geometry has been used with an FEA-based ANSYS general axisymmetric model to reduce the computation time. The effect of the damping on the forces transmitting to the bearings and shaft deflection at the critical speeds are analyzed by performing harmonic analysis under various damped and undamped conditions (ζ = 0, 0.005, 0.01, and 0.02).

Application of Blocked Force Methodology in NVH development of Electrical Machines

To determine excitation forces of electrical machines from measurements, Transfer Path Analysis is commonly used. Transfer Path Analysis yields input forces indirectly utilizing measured responses and transfer functions. When conducting transfer function measurement, it is recommended that the source of excitation is mechanically isolated from the receiver structure. However, in practice this is difficult to achieve without affecting the transfer path itself. The concept of the Blocked Force method introduces blocked forces which are independent of the receiver structure, thus allowing measurement of transfer functions without isolating the source. In this research, a stator / rotor assembly is considered as the source. This assembly is bolted to a test-housing, considered as the receiver. Blocked forces are determined at the mounting locations between stator and test-canister. The correctness of the calculated blocked forces is verified by comparing the predicted and measured responses at selected target points which were not used for determining the blocked forces.

Model for evaluating the end runouts of a rotor with parallel connections of parts

The existing methods for calculating the assembly dimensional chains of aircraft engine rotors are analyzed. The factors that have a significant impact on the reliability of the calculation of the controlled assembly parameters of the product are identified. One of these factors is the existence of parallel connections of parts in the rotor. In the drum disk rotors, parallel rotor connections are formed by mating their parts along several end surfaces in the axial direction. A mathematical model is proposed that allows taking into account the parallel connections of the rotor parts. The form of relationship between rotor end run-outs and amplitudes of deviations of the shape of the mating surfaces of the parts and their angular positions in the unit is determined. The determined dependence includes many coefficients that allow taking into account the amplitudes of deviations of the shape of the mating surfaces, parallel connections of parts in the rotor, and their angular position. Determination of dependence coefficients values is solved as a problem of regression analysis. The initial data for obtaining the dependence are formed using the developed parameterized finite element model (FEM) of a part of the rotor of an aircraft engine high-pressure compressor (HPC). The results of research of end run-outs of control surfaces of disks of the considered HPC rotor assembly part are presented. The values of the dependence coefficients for assessing the end run-outs of the rotor are determined.

Monomer model: an integrated characterization method of geometrical deviations for assembly accuracy analysis

Purpose Assembly accuracy is the guarantee of mechanical product performance, and the characterization of the part with geometrical deviations is the basis of assembly accuracy analysis. Design/methodology/approach The existed small displacement torsors (SDT) model cannot fully describe the part with multiple mating surfaces, which increases the difficulty of accuracy analysis. This paper proposed an integrated characterization method for accuracy analysis. By analyzing the internal coupling relationship of the different geometrical deviations in a single part, the Monomer Model was established. Findings The effectiveness of the Monomer Model is verified through an analysis of a simulated rotor assembly analysis, and the corresponding accuracy analysis method based on the model reasonably predicts the assembly deviation of the rotor. Originality/value The Monomer Model realizes the reverse calculation of assembly deformation for the first time, which can be used to identify the weak links that affect the assembly accuracy, thus support the accuracy improvement in the re-assembly stage.

A Probabilistic Approach for Three-Dimensional Variation Analysis in Aero-engine Rotors Assembly

Rotor assembly is a core tache in the whole process of aero-engine manufacturing. Preventing out-of-tolerance of concentricity is one of the primary tasks. Conventional assembly approaches are based on a manual test with the dial indicator, depending on experience appraises, which lack systematic and quantitative precision design theory. As a result, two issues need to be solved: the modeling problem of complicated geometric variations in three-dimensions, as well as the abnormal distribution of ubiquitous actual deviations. This work attempts to propose a novel probabilistic approach for three-dimensional variation analysis in rotor assembly. Based on rotor’s revolving characteristics and multistage stacking process, Jacobian–Torsor model is adopted to establish the variation propagation, and Pearson distribution family is used to derive the probability density function, which can quickly determine the variation distribution pattern and efficiently perform statistical variation analysis. A real case of mechanical assemblies consisting of revolving axisymmetric components is concerned. The results show that the suggested method has a similar accuracy, but much higher efficiency than conventional methods. Calculations agree with the experimentations, and the probability distribution type of the part’s variation has an appreciable impact on the final assembly precision.

Design and Analysis of Rotor Assembly of Hammer Mill Machine`

The project deals with the Manufacturing with Design and Analysis of Hammer Mill Machine and Rotor Assembly of Machine of Capacity of 200 Kg/hr. Which is due to providing the transmission power of 5 HP to the machine. In this project, the Hammer mill machine body structure, Angle Frame and foundation frame for machine is designed using Catia. Also each and every part or component is required for machine is designed. In the present work by using standard design procedures, Diameter of the rotor of shaft of machine has been designed. Theoretical calculations done by using PTC Mathcad software for new learning experience and ease. When the shaft of the rotor is rotated at the given speed (rpm i.e. 1728 rpm) and the load applied to the shaft it should not bend during rotation. When the shaft is rotated under free conditions deflections will be created due to critical speed of the shaft. After Designing process, some of required drawings are converted into Ansys supported format i.e. drawings are imported into Ansys for further analysis. Meshing of the shaft model was done and the loads, stresses that were applied for the shaft to be checked out that the design should be safe one. The design should be safe when the values obtained from the design procedure were compared with the standard values and result obtained from the analysis using Ansys. As per the designing, the required parts are fabricated such as side plates, bearing support, doors, hinge supports by using conventional methods like gas cutting, welding, drilling, shaft turning, slotting, milling, etc. and some hardware materials buy from stores which is used for further assembly process. At the final step all parts are assembled according as per requirements. At the end actual capacity of machine is calculated by using conventional method.

Research on Multistage Rotor Assembly Optimization Methods for Aeroengine Based on the Genetic Algorithm

The coaxiality and unbalance are the two important indexes to evaluate the assembly quality of an aeroengine. It often needs to be tested and disassembled repeatedly to meet the double-objective requirements at the same time. Therefore, an intelligent assembly method is urgently needed to directly predict the optimal assembly orientations of the rotors at each stage to meet the double-objective requirements simultaneously. In this study, an assembly optimization method for the multistage rotor of an aeroengine is proposed based on the genetic algorithm. Firstly, a spatial location propagation model is developed to accurately predict the spatial position of each rotor after assembly. The alignment process of the assembly screw holes of the adjacent rotors is considered for the first time. Secondly, a new assembly optimization strategy is proposed to select different assembly data for the specific values of the coaxiality and unbalance, respectively. Finally, a double-objective fitness function is constructed based on the coaxiality and unbalance. The simulation and experimental results show that the assembly optimization method proposed in this study can be utilized to achieve synchronous optimization of the coaxiality and unbalance of an aeroengine during preassembly.

Mooring Fatigue Verification of the WindCrete for a 15 MW Wind Turbine

LCOE reduction in FOWTs is heading to larger wind turbines in order to increase power production and capacity. NREL and DTU have recently developed a 15MW reference wind turbine, which can be used to validate the platform concepts for the next generation of wind turbines. Increasing the power of wind turbines leads to larger platforms due to the need to withstand the increase of the weight of the Nacelle Rotor Assembly, as well as the increase of the wind forces and pitching moment. Moreover, the larger the turbines and platforms the larger surge/sway and yaw unbalanced forces, which will need to be hold up by the mooring system. The mooring system has to be designed to balance the wind and wave forces and provide the stiffness needed to the FOWT for a proper behavior. Moreover, the mooring system has to achieve enough reliability to prevent line failure that could lead to a chain reaction within a floating wind farm, and thus huge loses. Then, a complete and detailed fatigue analysis should be performed in order to guarantee the performance of the FOWT during its service life. Within the CoReWind EU-2020 project, the Windcrete platform is upscaled to withstand the new EIA 15MW reference wind turbine. As concrete is used as a main material, the mass and inertia are larger than steel counterpart which leads to stiffer and more loaded mooring system. In this paper, the fatigue analysis of the Windcrete mooring system is assessed and compared using different methods.