High-speed PIV investigation of the flow created by the model rotor in hover mode

A study of the instantaneous and average velocity and vorticity fields in the flow created by the model helicopter rotor in the hover mode was carried out. The velocity fields of the flow generated by the model rotor were obtained by a two-dimensional TR PIV system, which provided two components of the velocity vector in the diagnostic light plane. The processing of the obtained raw images was carried out using a two-frame algorithm with adaptive interrogation windows. The experiments carried out have shown the possibility of using the PIV technique to visualize the tip vortex structure descending from the rotor blade. This possibility seems to be especially interesting as one of the means of validation of the numerical methods for calculating rotor aerodynamics and acoustics.

PENGUJIAN EKSPERIMENTAL UNTUK MEMPELAJARI KARAKTERISTIK GETARAN PADA MODEL ROTOR GANDA KIT MENGGUNAKAN ANALISIS PETA SPEKTRUM DAN ORBIT

In modern technology, vibration signal is to be utilized in predictive maintenance application,more often when Dynamic Signal Analyzer (DSA) is invented. Unballance in rotor cause significantdeflection on rotated shaft and possible damage the machine. DSA is used in monitoring a condition ofbig rotation machines such as turbin, compressor, pump and generator. This research used double rotorsshaft system which was supported with journal bearing as a modification from the real rotation machines.Two of vibration characteristic as a sign of abnormal condition in rotation machine are unballance andoil whirl phenomenon. Meanwhile, oil whirl is seen in many rotation machines that use journal bearingas support its shaft. For rotation machine with high speed, oil whirl phenomenon can cause resonance inthe system, and then become the oil whip. Based on this condition that is very reasonable for makingearly detection, identification, and looking for the solution to prevent not wanted incident.

Investigation on the aerodynamic interaction between a rotor and ship with opened hangar door

Unsteady aerodynamic interference between a rotorcraft and a ship occurs during shipboard launch and recovery operations and has a negative impact on the safety. An experiment of a reduced-scale model rotor and a CFD analysis in hover was carried out to investigate the performance and flow field of a rotor approaching a ship. In this paper, the thrust and pitching moment of the rotor hovering above the ground, deck were tested, and the influence of hangar door on the thrust, pitching moment, and flow field was also measured. A CFD method based on RANS and overset technology was used to investigate the flow field of the rotor operating on the model-scale ship. As the rotor approaches the deck, its thrust first decreases induced by a recirculation near the deck, and then increases induced by the effect of deck, and finally obviously decreases caused by the recirculation near hangar door. The deck and hangar door also affects the flow field to yield an intensive nose-down pitching moment. The status of the hangar door has a significant influence on the rotor thrust and pitching moment. The recirculation is weakened with an opened hangar door resulting in recovery of the rotor thrust and decrease of the nosed down pitching moment.

Study on Wear form of Split Cone of Vertical Shaft Impact Crusher

The three-dimensional model rotor of vertical shaft impact crusher was established by using the three-dimensional software Solidworks and it was imported into the discrete element software EDEM for dynamic simulation. The force of the split cone, the motion trajectory and force of the particles were analyzed in rotor by using the post-processing function of EDEM. The results show that the split cone was mainly affected by the normal action of particles. According to the definition of impact wear, it was finally determined that the wear form of the split cone is impact wear.

Reduced-Order Model of Unsteady Flows in a Turbomachinery Fan Modeled Using a Novel Proper Orthogonal Decomposition

This paper presents a novel, more efficient reduced-order model based on the proper orthogonal decomposition (POD) for the prediction of flows in turbomachinery. To further reduce the computational time, the governing equations were written as a function of specific volume instead of density. This allowed for the pre-computation of the coefficients of the system of ordinary differential equations that describe the reduced-order model. A penalty method was developed to implement time-dependent boundary conditions and achieve a stable solution for the reduced-order model. Rotor 67 was used as a validation case for the reduced-order model, which was tested for both on- and off-reference conditions. This reduced-order model was shown to be more than 10,000 times faster than the full-order model.

Design Methodology for a Floating Offshore Wind Turbine Large-Scale Outdoor Prototype

This paper discusses the methodology introduced by the authors to design a large-scale wind turbine model starting from the DTU 10MW RWT. The wind turbine will be coupled with the model of a multi-purpose floating structure, designed within the EU H2020 Blue Growth Farm project, and it will be deployed at the Natural Ocean Engineering Laboratory (NOEL). In this paper the different strategies used to design the wind turbine model rotor, tower and nacelle are discussed, focusing on how it has been possible to reproduce the full-scale system aero-elastic response while ensuring the same functionalities of a real wind turbine.

Rotordynamic Morton Effect Simulation With Transient, Thermal Shaft Bow

The Morton effect (ME) is characterized by an asymmetric journal temperature distribution, slowly varying thermal bow and intolerable synchronous vibration levels. The conventional mass imbalance model is replaced by a more accurate thermal shaft bow model. Rotor permanent bow and disk skew are synchronous excitation sources and are incorporated in the dynamic model to investigate their influence on the ME. A hybrid beam/solid element finite element shaft model is utilized to provide improved accuracy for predicting the rotor thermal bow and expansion, with practical computation time. ME is shown to be induced by initial shaft bow and disk skew. The conventional mass imbalance approach is shown to have some limitations.