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Content available Analysis of model-scale open-water test uncertainty
EN
Within the frame of CTO’s standard procedure, a propeller open-water test is preceded by a reference measurement, which is taken for a reference propeller model (P356). The results of these measurements are assembled to conduct an open-water test uncertainty analysis. Additional material was gathered from open-water tests that were conducted throughout several research projects on the CP469 model, which is a model of the Nawigator XXI propeller. The latter is a controllable pitch propeller; its pitch was reset before each test repetition. Known procedures for the determination of the open-water test uncertainty do not allow one to extract the manufacture impact directly, without building many models. This factor was addressed with the use of lifting surface calculations. Under certain additional assumptions, these calculations were performed for 100 generic versions of each propeller’s geometry, which were generated by random deviations from the theoretical data within the limits of allowed tolerances. The results of the conducted analyses made it possible to extract separate factors, which were connected to the test’s repeatability, measurement bias and geometry tolerance.
EN
The researched object is a helicopter main rotor with blades of variable geometric twist characteristics. Variable torsion refers to systems of actuators made of shape memory alloys. The presented numerical analyses allow for evaluating both the dynamics of the rotor in transient states, i.e. in the zone between the static phase and the full activation phase and the impact of the change on the pulsation of the amplitude of the necessary power generated by the rotor corresponding the flight state, and thus covering the demand by the disposable power generated by the engine. This study follows a methodology of numerical analyses based on Multi Body Dynamics and the Finite Element Method and uses fluid mechanics elements and algorithms to analyze lift generation, compiled in a single computational environment referring to the same period of time.
EN
Recently, there has been a significant development of ecological propulsion systems, which is in line with the general trend of environmentally friendly “green shipping”. The main aim is to build a safe, low-energy passenger ship with a highly efficient, emission-free propulsion system. This can be achieved in a variety of ways. The article presents the main problems encountered by designers and constructors already at the stage of designing the unit. The research conducted made it possible to create a design with an effective shape of the hull, with the prospect of an energy-efficient and safe propulsion system with good manoeuvrability. The scope of the research included towing tank tests, recalculation of the results in full-scale objects and a prediction of the energy demand of the propulsion system. The results obtained were compared to indicate power supply variants depending on the hull shape.
EN
The following paper presents wind tunnel investigation of aerodynamic characteristics of hovering propellers. This propulsion system may be applied on a lightweight Quad Plane VTOL (Vertical Take-Off and Landing) UAV (Unmanned Aerial Vehicle). A Quad Plane is a configuration consisting of a quadcopter design combined with a conventional twin-boom airplane. This kind of design should therefore incorporate the advantages of both types of vehicles in terms of agility and long endurance. However, those benefits may come with a cost of worse performance and higher energy consumption. The characteristics of a fixed-wing aircraft and propellers in axial inflow are well documented, less attention is put to non-axial flow cases. VTOL propellers of a hybrid UAV are subject to a multitude of conditions – various inflow speeds and angles, changing RPMs, interference between propellers and between nearby aerodynamic structures. The tested system presented in this article consists of four electric motors with two coaxial pairs of propellers mounted on one of the fuselage beams. Such a configuration is often chosen by designers of small and medium hybrid UAVs. There is a need for studies of clean, efficient ways of transporting, and this article can aid future designers of a new type of electric UAVs.
EN
Numerical studies on detonation wave propagation in rotating detonation engine and its propulsive performance with one- and multi-step chemistries of a hydrogen-based mixture are presented. The computational codes were developed based on the three-dimensional Euler equations coupled with source terms that incorporate high-temperature chemical reactions. The governing equations were discretized using Roe scheme-based finite volume method for spatial terms and second-order Runge-Kutta method for temporal terms. One-dimensional detonation simulations with one- and multi-step chemistries of a hydrogen-air mixture were performed to verify the computational codes and chemical mechanisms. In two-dimensional simulations, detonation waves rotating in a rectangular chamber were investigated to understand its flowfield characteristics, where the detailed flowfield structure observed in the experiments was successfully captured. Three-dimensional simulations of two-waved rotating detonation engine with an annular chamber were performed to evaluate its propulsive performance in the form of thrust and specific impulse. It was shown that rotating detonation engine produced constant thrust after the flowfield in the chamber was stabilized, which is a major difference from pulse detonation engine that generates repetitive and intermittent thrust.
PL
Przedstawiono badania numeryczne propagacji fali detonacyjnej w wirującym silniku detonacyjnym oraz jego wydajności pędnej z jedno- i wielostopniową mieszanką chemiczną na bazie wodoru. Kody obliczeniowe opracowano w oparciu o trójwymiarowe równania Eulera w połączeniu z pojęciami źródłowymi, które obejmują wysokotemperaturowe reakcje chemiczne. Obowiązujące równania zostały zdyskredytowane przy użyciu metody skończonej objętości opartej na schemacie Roe'a dla terminów przestrzennych oraz metody Runge-Kutta drugiego rzędu dla terminów czasowych. W celu weryfikacji kodów obliczeniowych i mechanizmów chemicznych przeprowadzono jednowymiarowe symulacje detonacji z jedno- i wieloetapowymi chemikaliami mieszaniny wodoru i powietrza. W symulacjach dwuwymiarowych badano fale detonacyjne obracające się w komorze prostokątnej w celu zrozumienia jej charakterystyki pola przepływu, gdzie udało się uchwycić szczegółową strukturę pola przepływu zaobserwowaną w doświadczeniach. Przeprowadzono trójwymiarowe symulacje dwufalowego wirującego silnika detonacyjnego z komorą pierścieniową w celu oceny jego właściwości pędnych w postaci ciągu i impulsu właściwego. Wykazano, że wirujący silnik detonujący wytwarza stały ciąg po ustabilizowaniu się pola przepływu w komorze, co stanowi istotną różnicę w stosunku do silnika detonującego impulsowo, który wytwarza powtarzalny i przerywany ciąg.
EN
This article presents the design and implementation of the next stage of research conducted as part of the design and construction of an underwater inspection robot. Its purpose was to create a universal test stand for testing the parameters of underwater robots’ thrusters. Factors taken into account when constructing the station were, among others, the possibility of cavitation and its impact on the strength of the device's thruster system, as well as noise pollution of the underwater environment. The sensor system in which the dynamometer is equipped will automatically acquire a number of readings that will allow the design of propulsors to be tested taking into account many parameters. The collected data is sent and analysed using microcontrollers and dedicated, custom-written software. The proposed solution will accelerate and automate research work and allow quick modifications of the mathematical model for describing the underwater vehicle propulsion module.
EN
Cogeneration systems are mainly used in industrial power plants (combined heat and power plants), but based on the analysis carried out in this publication, that suitably adapted and selected devices will be able on board of ships. A number of arguments have been obtained for using the indicated gas engine in a vessel. The cogeneration system guarantees high overall efficiency, as shown in the example of the cogeneration unit under study, for which the value of general efficiency was above 80%. In addition, the use of natural gas as a fuel could ensure a significant reduction in the amount of toxic compounds emitted to the atmosphere, especially nitrogen oxides (2-3 times) and smog (dust with PM10) around 25 times than standard limits. The use of natural gas as a fuel guarantees similar dynamic parameters as with the use of standard fuels.
PL
W artykule przeanalizowano dynamiczne aspekty napędzania wózka inwalidzkiego wyposażonego w ręczny napęd. Skupiono się zarówno na dynamice całego układu antropotechnicznego jak i na dynamice ciała człowieka. Ponad to na podstawie uzyskanych konkluzji zaproponowano dwa alternatywne rozwiązania techniczne ręcznych napędów wózków inwalidzkich.
EN
The article analyzes the dynamic aspects of driving a wheelchair equipped with a manual drive. The focus was both on the dynamics of the entire anthropotechnical system as well as on the dynamics of the human body. Moreover, based on the obtained conclusions, two alternative technical solutions for manual wheelchair drives have been proposed.
EN
Progress in miniaturization of satellite components allows complex missions to be performed by small spacecraft. Growing interest in the small satellite sector has led to development of standards such as CubeSat, contributing to lower costs of satellite development and increasing their service competitiveness. Small satellites are seen now as a prospective replacement for conventional sized satellites in the future, providing also services for demanding users. New paradigms of multi-satellite missions such as fractionation and federalization also open up new prospects for applications of small platforms. To perform a comprehensive simulation and analysis of future nanosatellite missions, an adequate propulsion system model must be used. Such model should account for propulsion solutions which can be implemented on nanosatellites and used in multisatellite missions. In the paper, concepts of distributed satellite systems (constellations, formations, fractionated and federated) are described with a survey of past, on-going and planned multi-satellite nanosatellites missions. Currently developed propulsion systems are discussed and the models of propulsion systems embedded in the WUT satellite simulation model are presented.
PL
Postępująca miniaturyzacja podzespołów satelitarnych pozwala na realizację skomplikowanych misji przez małe satelity. Wzrost zainteresowania małymi satelitami przyczynił się do powstania standardów takich jak CubeSat, umożliwiając zmniejszenie kosztów budowy oraz wzrost konkurencyjności usług oferowanych przez małe satelity. Istnieje przekonanie, że w najbliższym czasie małe satelity zastąpią satelity duże oferując usługi także wymagającym użytkownikom. Nowe architektury misji wielosatelitarnych jak federacyjne systemy satelitarne czy frakcjonowanie satelitów wskazują nowe możliwości wykorzystania małych satelitów. Aby umożliwić zaawansowaną symulację i analizę nowych misji realizowanych przez nanosatelity konieczne jest wykorzystanie odpowiedniego modelu zespołu napędowego. Taki model powinien obejmować rozwiązania, które mogą zostać użyte na nanosatelitach do realizacji misji wielosatelitarnych. W artykule opisano architektury misji (konstelacje, formacje, federacje i frakcjonowanie), a także przedstawiono przegląd zakończonych, trwających i planowanych misji wielosatelitarnych wykorzystujących nanosatelity. Omówione są obecnie wykorzystywane systemy napędowe oraz zaprezentowany jest model systemu napędowego wykorzystanego w modelu symulacyjnym satelity opracowanym przez zespół autorów.
EN
The subject of this paper is an analysis of the process of applying kinetic energy to a projectile made from a non-magnetic, electrically conductive material and placed inside of an inductance coil live with alternating current. A digital model of an acceleration system was built, comprising a high-current coil and a cylindrical projectile located inside of the coil. Analytical formulas of the three-dimensional distribution of the axial and radial components of the magnetic field generated by the coil were applied [1]. The mathematical model described herein included the projectile and coil three-dimensional system (with the dimensions and distribution of the coil turns), the parameters of the power supply system and their variations, caused by the energy input to the projectile (and including the variation of: coupling coefficient, pulsation, coefficient of attenuation, inductance, and resistance), and the balance of momentum of the projectile and coil system. A system of equations which depicted the projectile and coil system (the law of electromagnetic induction, the Biot-Savart law, electric-to-kinetic energy transfer, and the balance of momentum of the projectile and coil system) was solved with numerical methods. The conclusions relevant to the design and technology of an ICG (Inductance Coil Gun), derived from the foregoing numerical analysis, were experimentally verified. Initial calculations were completed to optimise the acceleration process. The acceleration efficiency in a cascade of 10 coils was calculated.
PL
Przedmiotem pracy jest analiza procesu nadawania energii kinetycznej pociskowi wykonanemu z niemagnetycznego materiału przewodzącego, umieszczonemu wewnątrz cewki, przez którą płynie prąd zmienny. Zbudowano model cyfrowy układu akceleracyjnego złożonego z wysokoprądowej cewki oraz umieszczonego wewnątrz niej metalicznego pocisku w kształcie walca. Wykorzystano analityczne wzory na przestrzenny rozkład składowej osiowej i radialnej pola magnetycznego wytwarzanego przez cewkę [5]. Model matematyczny uwzględnia układ przestrzenny cewka-pocisk (wymiary oraz rozkład zwojów cewki), parametry układu zasilającego z uwzględnieniem ich zmienności w czasie spowodowanej przekazem energii do pocisku, w tym zmienność współczynnika sprzężenia, pulsacji, współczynnika tłumienia, indukcyjności i oporności, a także bilans pędu układu cewka-pocisk. Układ równań opisujący układ (prawo indukcji elektromagnetycznej, prawo Biota-Savarta, przemiana energii elektrycznej w kinetyczną, bilans pędu układu cewka-pocisk) rozwiązano metodami numerycznymi. Dokonano eksperymentalnej weryfikacji płynących z analizy wniosków istotnych z punktu widzenia konstrukcji i technologii urządzenia miotającego typu Inductance Coil Gun (ICG). Wykonano wstępne obliczenia mające na celu optymalizację procesu akceleracji. Przeprowadzono także obliczenia wydajności akceleracji w kaskadzie złożonej z 10 cewek.
PL
W pracy zaproponowano kryteria oceny cech jednostek napędowych, które mogą mieć zastosowanie na śródlądowych jednostkach pływających. Przedstawiono schematy zależności doboru jednostki napędowej od stosowanego paliwa jak i od akwenu. Schematy te, mogą służyć jako algorytmy działań ułatwiających racjonalny dobór jednostki napędowej w ramach optymalizacji rozwiązań stosowanych w żegludze śródlądowej.
EN
The paper proposes criteria for the evaluation of characteristics of propulsion units can be used on inland waterway vessels. Diagrams of dependence of the selection of the drive unit on the fuel used and on the body of water are presented. These diagrams may serve as algorithms of actions facilitating rational selection of the propulsion unit within the framework of optimisation of solutions applied in inland navigation.
EN
The subject of this paper is an analysis of the process of applying kinetic energy to a projectile made of non-magnetic electrically conductive material and located inside an induction coil live with alternating current. An experimental verification was carried out of the analytical conclusions that were pertinent to the design and technology of an inductance coil gun, which is a ranged weapon type.
PL
Przedmiotem pracy jest analiza procesu nadawania energii kinetycznej pociskowi wykonanemu z niemagnetycznego materiału przewodzącego, umieszczonemu wewnątrz cewki, przez którą płynie prąd zmienny. Dokonano eksperymentalnej weryfikacji płynących z analizy wniosków istotnych z punktu widzenia konstrukcji i technologii urządzenia miotającego typu Inductance Coil Gun (ICG).
EN
The hazards and risks associated with the handling, transportation and storage of hypergolic propellants based on highly concentrated hydrogen peroxide as an oxidiser, are discussed in the paper. The main focus has been placed on the assessment of possible hazards and preventative methods for the protection of technical staff and hardware associated with 98% hydrogen peroxide and the fast developing new “green” hypergolic propellants. The basic risks connected with the use of incompatible materials, human error and propellant properties have been described. The dangerous incidents and catastrophic accidents hitherto known with hypergolic propellants are related mainly to the toxic compounds based on hydrazine derivatives and dinitrogen tetroxide. The conclusions and remarks from available literature have been discussed and transferred into a form of handling procedures for “green” hypergols. As a result, the data, comparison with existing literature and the authors’ experience presented in this paper, try to illustrate what steps need to be taken during various research operations in a laboratory environment, when working with hypergolic rocket propellants. There are many ways of preventing unwanted events with the implementation of some being necessary to avoid or mitigate possible technical problems, incidents or even accidents. Some of the most important factors in risk minimization, when working with 98% hydrogen peroxide and hypergolic fuels, are presented.
PL
W artykule omówione zostały zagrożenia oraz ryzyka związane ze stosowaniem, transportem oraz przechowywaniem hipergolicznych materiałów pędnych, bazujących na wysoko stężonym nadtlenku wodoru, jako utleniacz rakietowy. W tym celu określone zostały potencjalne zagrożenia i metody ich zapobieganiu w odniesieniu do ochrony fizycznej personelu technicznego oraz aparatury, która może mieć bezpośredni kontakt z 98% nadtlenkiem wodoru oraz paliwami hipergolicznymi klasy „green”, tj. „ekologicznymi” i niskotoksycznymi. Przedstawiono podstawowe ryzyka wynikające ze stosowania materiałów konstrukcyjnych, niekompatybilnych z wybranymi cieczami, ludzkich błędów oraz właściwości wybranych paliw i 98% nadtlenku wodoru. Znane są groźne zdarzenia oraz katastroficzne w skutkach wypadki związane z wykorzystaniem samozapłonowych, toksycznych rakietowych materiałów pędnych bazujących na hydrazynie i jej pochodnych, w kontakcie z czterotlenkiem diazotu. Zdobyte doświadczenia oraz uwagi zawarte w dostępnej literaturze, a związane z toksycznymi, hipergolicznymi materiałami pędnymi, zostały przedstawione i zasugerowane jako procedury do zastosowania przy stosowaniu nowych, „ekologicznych” związków samozapłonowych. Na tej podstawie dokonano próby opisania środków zapobiegawczych przeciw potencjalnym zagrożeniom, występującym w praktyce badań laboratoryjnych z tego typu związkami. Opisane zostały również scenariusze zdarzeń i związane z nimi zagrożenia, a także wskazano procedury i metody, które je minimalizują lub całkowicie eliminują.
EN
Gas turbines are used as marine prime movers but the market is dominated by the diesel engines (of course turbocharged but they are still diesels). The share of gas turbines is on a level of 4-5% in the worldwide shipping. It was presented the chosen parameters of Rolls-Royce gas turbine MT30 with nominal power 36 MW or 40 MW prepared for marine utilization. It is a good example of development of marine gas turbines with the trial to eliminate the effect of ambient temperature especially on turbine load. It was discussed the significance presented data for possibility of utilization on vessels. It was indicated the advantages and disadvantages of gas turbine sharing. It was mentioned the installation problems: pressure drop in inlet and outlet ducts on the accessible turbine power and specific fuel consumption. It was discussed what important parameters ought to be known for safe turbine operation and maintenance. There is a little information lack. The gas turbine ought not to be treat as a black box. In the end, some final remarks are presented.
EN
Utilization of gas turbines on vessels is a reality. It was presented the examples of utilization on ships of United States Navy and the Rolls-Royce suggestion for sharing on merchant shipping. It was mentioned the advantages of gas turbine MT30 with nominal power 36 MW or 40 MW prepared for marine utilization. It was stated the characteristics of specific fuel consumption, the shaft power rating, the MT30 operating envelope with propeller characteristics as a power receiver. It was given propositions of vessel types for MT30 utilization. It was discussed the remarks on maintenance requirements and needed systems for upkeep the turbine in good technical state for the possibility of full nominal power independent on ambient temperature. It was discussed the requirements of emissions from exhaust gasses to the atmosphere in comparison gas turbines to diesel engines as a one of important problems for utilization engines as prime movers on vessels in merchant shipping. In the end, some final remarks with Rolls-Royce statements are presented.
PL
W artykule omówiono pneumatyczno-hydrauliczną jednostkę napędową oraz problemy związane ze sterowaniem tego typu jednostką. Opisano praktyczny sposób wykorzystania mikrokontrolera ARM w układach prototypowych systemu sterowania. Przeanalizowano dostępną dokumentację oraz literaturę pod względem zagadnień związanych ze sterowaniem zaworami oraz obsługi wybranych sensorów.
EN
This article discusses the pneumatic-hydraulic propulsion drive and problems with control of this type of drive. Described practical way of using the ARM microcontroller in the prototype systems of the control system pneumatic-hydraulic drive. Analyzed available documentation and literature in terms of valve control and sensor handling.
PL
W artykule omówiony został problem napędu głównego śródlądowych jednostek pływających w aspekcie bezpieczeństwa żeglugi i ekologii. Przedstawiono przykładowe rozwiązanie techniczne spełniające wymagania bezpieczeństwa żeglugi i przepisów ochrony środowiska.
EN
Paper discussed the problem of main propulsion inland waterway vessels in terms of shipping safety and ecology. This is an example of a technical solution that meets shipping safety and environmental regulations.
EN
Efficiency is crucial for an airplane to reduce both costs of operations and emissions of pollutants. There are several airplane concepts that potentially allow for increasing the efficiency. A few of them were not investigated thoroughly enough yet. The inverted joined wing configuration, where the upper wing is positioned in the front of the lower one is an example of such a concept. Therefore, a project consisting of an aerodynamic analysis and optimisation, development of the software for multidisciplinary optimisation, development of an electric propulsion system, development of an experimental scaled demonstrator, wind tunnel testing and flight-testing was undertaken by consortium led by the Institute of Aviation, including also Warsaw University of Technology, Air Force Institute of Technology and small company MSP. Results of this project led to the conclusion that inverted joined wing configuration allows to build an airplane with the best performance in the world, but its advantage against conventional airplanes is marginal. One reason for this is large trimming drag of the configuration with relatively high position of the thrust vector. Therefore, other configurations of the propulsion were also considered to see if airplane performance could be further improved. This effort is described in the present paper.
EN
The paper presents the main activities of the Institute of Aviation (IoA) in the field of chemical rocket propulsion. The relatively "fresh" research and development team performed many useful works within the last 5 years, starting from the strategy and ideas. Nowadays, the Space Technology Department of IoA acts as a member of international consortia realizing space projects, as well as itself working on its own assignments financed by the European Space Agency (ESA) and IoA funds. The important development aspect of rocket propulsion developed at IoA is the use of "green" propellants. These are chemicals, which are relatively safe for the environment and personnel, being a very promising alternative for storable toxic substances, e.g. hydrazine and derivatives, nitrogen tetroxide. R&D activities of STD are based on the use of Rocket Grade Hydrogen Peroxide (RGHP), also known as High Test Peroxide (HTP). This high-performance mono-propellant and oxidizer is regarded by European entities as one of the most promising candidates to replace hydrazine and its derivatives in the future. Due to numerous advantages, hydrogen peroxide is better suited for systems with human interaction that most of other propellant combinations. The paper contains selected results of research on green rocket propulsion performed at IoA, in which 98% hydrogen peroxide was used as oxidizer and monopropellant. Three types of rocket engines: monopropellant, liquid bipropellant and hybrid have been investigated and are still being developed.
EN
Bio-mimetic underwater robotics is an emerging area of research, which has the potential to substitute the conventional energy inefficient mode of underwater propulsion using thrusters. In this paper, the mathematical modelling of the undulating fin is done and the effect of various parameters of the mechanism design on the available workspace is studied. The mathematical beauty is revealed, for the curves representing the mechanical constraint and the family of undulating waves. The feasibility of a wave to be generated by the mechanism was analyzed.
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