Research on the Rotor of a Ducted Fan Propulsion System of MOSUPS Aircraft Taking into Account Self-Balance during Operation

2015 ◽  
Vol 240 ◽  
pp. 191-197
Author(s):  
Dominik Głowacki ◽  
Krzysztof Bogdański ◽  
Miroslaw Rodzewicz
Keyword(s):  
Complex Geometry ◽  
Dynamic Properties ◽  
Propulsion System ◽  
Term Operation ◽  
Ducted Fan ◽  
Modeling Analysis ◽  
Statically Unbalanced Rotor ◽  
Aerial Vehicle ◽  
Joined Wing

The work concerns the research of a propulsion system for an unmanned aerial vehicle MOSUPS in joined wing configuration. Modeling, analysis and experimental research of a statically unbalanced rotor of a ducted fan propulsion system has been conducted.The aim of the analysis was to determine the critical rotational speeds of the rotor due to the probable excitation of oscillations. Due to the complex geometry, Finite Element Method has been used for the calculations. In the study, the critical frequencies (and also rotational speeds) of the rotor as well as precessional instability, flexibly mounted in the bearings have been calculated. Campbell and SAFE diagrams have been presented.Furthermore, the paper presents the idea for a device for automatic dynamic balancing of the mentioned rotor. A mechanism for changing the position of the correction weights has been developed, allowing for a long term operation of rotating parts without the need to stop the unit and correcting the unbalance.The main motivation for work was to fully understand the working conditions of the propulsion system and dynamic properties of the rotor in order to carry out a proper assessment of their impact on the safe operation of the aircraft.

scholarly journals Health-Conscious Optimization of Long-Term Operation for Hybrid PEMFC Ship Propulsion Systems

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3813
Author(s):  
Chiara Dall’Armi ◽  
Davide Pivetta ◽  
Rodolfo Taccani
Keyword(s):  
Polymer Electrolyte Membrane ◽  
Lithium Ion ◽  
Propulsion System ◽  
Optimization Strategy ◽  
Energy Management Strategy ◽  
Propulsion Systems ◽  
Hybrid Propulsion ◽  
Term Operation ◽  
Electrolyte Membrane

The need to decarbonize the shipping sector is leading to a growing interest in fuel cell-based propulsion systems. While Polymer Electrolyte Membrane Fuel Cells (PEMFC) represent one of the most promising and mature technologies for onboard implementation, they are still prone to remarkable degradation. The same problem is also affecting Lithium-ion batteries (LIB), which are usually coupled with PEMFC in hybrid powertrains. By including the combined degradation effects in an optimization strategy, the best compromise between costs and PEMFC/LIB lifetime could be determined. However, this is still a challenging yet crucial aspect, rarely addressed in the literature and rarely yet explored. To fill this gap, a health-conscious optimization is here proposed for the long-term minimization of costs and PEMFC/LIB degradation. Results show that a holistic multi-objective optimization allows a 185% increase of PEMFC/LIB lifetime with respect to a fuel-consumption-minimization-only approach. With the progressive ageing of PEMFC/LIB, the hybrid propulsion system modifies the energy management strategy to limit the increase of the daily operation cost. Comparing the optimization results at the beginning and the end of the plant lifetime, daily operation costs are increased by 73% and hydrogen consumption by 29%. The proposed methodology is believed to be a useful tool, able to give insights into the effective costs involved in the long-term operation of this new type of propulsion system.

Pipe Performance in Long Term Operation Framework: Ageing Issues

2021 ◽  
Author(s):  
S. A. Cancemi ◽  
R. Lo Frano
Keyword(s):  
Nuclear Power ◽  
Complex Geometry ◽  
Management Strategies ◽  
Safety Margin ◽  
Nuclear Industry ◽  
Term Operation ◽  
2Nd Generation ◽  
Class 1 ◽  
Bent Pipe

Abstract The Long-Term Operation (LTO) process involves a full screening of structures, systems, and components (SSCs), for ageing assessment in order to verify their residual safety margin is still acceptable. At today, 46% of the operating Nuclear Power Plant (NPP) has lifetime between 31 and 40 years, while 19% is in operation since more than 40 years. LTO currently represents the highest priority for all the nuclear industry. To propose and plan suitable management strategies, first step is to intensify the efforts for studying phenomena that influence the performance of SSCs and, in turn, may threat the plant safe operation. This study deals with the investigation of the performance of a primary piping (Class 1 component of a 2nd Generation PWR) subjected to the effects of alteration of material properties as caused by ageing. In this study it is proposed a numerical investigation of a piping characterized by a complex geometry. Numerical analyses were performed by means of MSC©MARC FE code. The (quantitative) influence of ageing and corrosion processes onto bent pipe are so studied. Particularly, corrosion effects generated from an operation of beyond 35 years are considered. The methodology and results may have an influence on future issues about LTO of NPPs.

scholarly journals Towards dynamic property control of bridge spans

2021 ◽  
Vol 23 (6) ◽  
pp. 201-219
Author(s):  
V. M. Kartopoltsev ◽  
A. V. Kartopoltsev ◽  
S. A. Kukharenko
Keyword(s):  
Dynamic Load ◽  
Dynamic Properties ◽  
Frequency Characteristics ◽  
Load Bearing ◽  
Term Operation ◽  
Bridge Span ◽  
Vehicle System ◽  
Property Control ◽  
Bridge Spans

Regulation of the dynamic properties of bridge spans is a priority field of this research, which solves the problem of increasing the obsolescence and physical periods of bridge structures manifested both at the design stage of the load redistribution in the load bearing and during long-term operation.Over the past 40 years, technical bridge diagnostics has shown that the durability and safe long-term operation can be ensured by the improved calculations, operation and stress and strain control under the excess and over-calculated live loads.The aim of this work is to control the dynamic deformation and amplitude-frequency characteristics of bridge spans under harmonic random (non-stationary) oscillations of the span-vehicle system due to changes in the energy and stress state of the structure. The dynamic behavior of the span-vehicle system is based on the control for the amplitude-frequency characteristics of random oscillations by averaged values, the required spectral density being provided.The use of dynamic dampers for the system element control and the rigidity of junctions provide antiphase oscillations of the bridge span elements such as beams and decks, that leads to the unaccounted inertial forces.Another important element of the joint work imbalance of the bridge span elements during the dynamic load, are various defects, both in the deck design and load-bearing elements. It is assumed that the deck is a transfer layer (element) of vibrations induced by a vehicle in the beams. It is shown that the control for the dynamic properties is required in the case of a coincidence between the vehicle and beam stiffness and mass at the center of the system rigidity.The attention is paid to the conditions and dependencies between the dynamic load parameters and the stress-strain state of the bridge beams at the elastic and elastoplastic stages, with respect to the additional inertia of the system. This approach is the pilot in the Russian and foreign bridge construction in terms of experimental studies and testing of bridges for continuous random traffic.The dynamic testing of bridge spans for random traffic flow contributes to the creation of vibration diagnostic express laboratories necessary for the operation and maintenance of bridges.

Analysis of crystallite size changes in a hematite and magnetite formed on steel used in the power idustry

2017 ◽  
Vol 1 (21) ◽  
pp. 65-73
Author(s):  
Monika Gwoździk
Keyword(s):  
Elevated Temperature ◽  
Oxide Layer ◽  
Cross Section ◽  
X Ray ◽  
Term Operation ◽  
Diffraction Line Profile ◽  
Crystallite Sizes ◽  
Scherrer Formula ◽  
Pipe Outlet

The paper presents results of studies on the crystallite sizes of oxide layer formed during a long-term operation on 10CrMo9-10 steel at an elevated temperature (T = 545° C, t = 200,000 h). This value was determined by a method based on analysis of the diffraction line profile, according to a Scherrer formula. The oxide layer was studied on a surface and a cross-section at the outer and inner site on the pipe outlet, at the fire and counter-fire wall of the tube. X-ray studies were carried out on the surface of a tube, then the layer’s surface was polished and the diffraction measurements repeated to reveal differences in the originated oxides layer.

Sign in / Sign up

Export Citation Format

Share Document