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    Wyświetlanie 1-9 z 9
    Tytuł:
    Research on the maritime logistics pricing model of risk-averse retailer-dominated dual-channel supply chain
    Autorzy:
    Fang, Q.
    Tong, Z.
    Ren, L.
    Liu, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/258648.pdf
    Data publikacji:
    2018
    Wydawca:
    Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
    Tematy:
    dual channel
    risk-averse
    retailer-dominated
    supply chain
    Opis:
    Price decision is studied in a risk-averse retailer-dominated dual-channel supply chain, which consisting of one manufacturers and one retailer with both off-line and on-line channels. Firstly, two mean-variance models in centralized and decentralized supply chain are established. Secondly, the optimal solutions under the two decision modes are compared and analyzed. The results shows that the price of dual-channel of retailer decreased with the increase of retailers’ risk- aversion coefficient and the standard deviation of the fluctuation of market demand, while the wholesale price changes is on the contrary; in addition, when the market demand is greater than a certain value, the prices of dual channel are correspondingly higher in decentralized supply chain than in centralized supply chain, and vice versa. In addition, when the retailer’s risk aversion is in a certain interval, the expected utility of the whole supply chain is greater in centralized supply chain than in decentralized decision, and vice versa. Finally, a numerical example is given to verify the above conclusions.
    Źródło:
    Polish Maritime Research; 2018, S 2; 107-116
    1233-2585
    Pojawia się w:
    Polish Maritime Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Investigations of the working process in a dual-fuel low-emission combustion chamber for an FPSO gas turbine engine
    Autorzy:
    Serbin, Serhiy
    Diasamidze, Badri
    Dzida, Marek
    Powiązania:
    https://bibliotekanauki.pl/articles/1585065.pdf
    Data publikacji:
    2020
    Wydawca:
    Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
    Tematy:
    gas turbine engine
    dual-fuel combustion
    combustion chamber
    liquid fuel
    Opis:
    This investigation is devoted to an analysis of the working process in a dual-fuel low-emission combustion chamber for a floating vessel’s gas turbine. The low-emission gas turbine combustion chamber with partial pre-mixing of fuel and air inside the outer and inner radial-axial swirlers was chosen as the object of research. When modelling processes in a dualflow low-emission gas turbine combustion chamber, a generalized method is used, based on the numerical solution of the system of conservation and transport equations for a multi-component chemically reactive turbulent system, taking into consideration nitrogen oxides formation. The Eddy-Dissipation-Concept model, which incorporates Arrhenius chemical kinetics in a turbulent flame, and the Discrete Phase Model describing the interfacial interaction are used in the investigation. The obtained results confirmed the possibility of organizing efficient combustion of distillate liquid fuel in a low-emission gas turbine combustion chamber operating on the principle of partial preliminary formation of a fuel-air mixture. Comparison of four methods of liquid fuel supply to the channels of radial-axial swirlers (centrifugal, axial, combined, and radial) revealed the advantages of the radial supply method, which are manifested in a decrease in the overall temperature field non-uniformity at the outlet and a decrease in nitrogen oxides emissions. The calculated concentrations of nitrogen oxides and carbon monoxide at the flame tube outlet for the radial method of fuel supply are 32 and 9.1 ppm, respectively. The results can be useful for further modification and improvement of the characteristics of dual-fuel gas turbine combustion chambers operating with both gaseous and liquid fuels.
    Źródło:
    Polish Maritime Research; 2020, 3; 89-99
    1233-2585
    Pojawia się w:
    Polish Maritime Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Application of alcohols to dual – fuel feeding the spark-ignition and self-ignition engines
    Autorzy:
    Stelmasiak, Z.
    Powiązania:
    https://bibliotekanauki.pl/articles/258762.pdf
    Data publikacji:
    2014
    Wydawca:
    Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
    Tematy:
    dual-fuel engine
    alcohol
    share of methanol
    overall efficiency
    toxicity
    Opis:
    This paper concerns analysis of possible use of alcohols for the feeding of self - ignition and spark-ignition engines operating in a dual- fuel mode , i.e. simultaneously combusting alcohol and diesel oil or alcohol and petrol . Issues associated with the requirements for application of bio-fuels were presented with taking into account National Index Targets , bio-ethanol production methods and dynamics of its production worldwide and in Poland. The considerations are illustrated by results of the tests on spark- ignition and self- ignition engines fed with two fuels : petrol and methanol or diesel oil and methanol, respectively. The tests were carried out on a 1100 MPI Fiat four- cylinder engine with multi-point injection and a prototype collector fitted with additional injectors in each cylinder. The other tested engine was a SW 680 six- cylinder direct- injection diesel engine. Influence of a methanol addition on basic operational parameters of the engines and exhaust gas toxicity were analyzed. The tests showed a favourable influence of methanol on combustion process of traditional fuels and on some operational parameters of engines. An addition of methanol resulted in a distinct rise of total efficiency of both types of engines at maintained output parameters ( maximum power and torque ). In the same time a radical drop in content of hydrocarbons and nitrogen oxides in exhaust gas was observed at high shares of methanol in feeding dose of ZI ( petrol) engine, and 2-3 fold lower smokiness in case of ZS ( diesel) engine. Among unfavourable phenomena, a rather insignificant rise of CO and NOx content for ZI engine, and THC and NOx – for ZS engine, should be numbered. It requires to carry out further research on optimum control parameters of the engines. Conclusions drawn from this work may be used for implementation of bio-fuels to feeding the combustion engines.
    Źródło:
    Polish Maritime Research; 2014, 3; 86-94
    1233-2585
    Pojawia się w:
    Polish Maritime Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    An optimization study on an eco-friendly engine cycle named as Dual-Miller cycle (DMC) for marine vehicles
    Autorzy:
    Gonca, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/259357.pdf
    Data publikacji:
    2017
    Wydawca:
    Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
    Tematy:
    Dual-Miller cycle engine
    engine performance
    power density
    finite-time thermodynamics
    Opis:
    The diesel engine is an indispensable part of technology and it is commonly used in land and marine vehicles. However, diesel engines release NOx emissions due to high combustion temperatures. They have harmful effects on the environment such as sources of photo-chemical fog and climate changes. Therefore, they must be reduced and limited. The Miller cycle application is a NOx control method and it is popular in the recent years to abate NOx produced from the internal combustion engines (ICEs). A performance investigation of a Dual-Miller cycle (DMC) engine in terms of power (PO), power density (PD) and effective efficiency (EE) has been performed using a new finite-time thermodynamics modeling (FTTM) in this study. The effects of engine design and operating parameters on the engine performance (EPER) have been examined. Additionally, the energy losses have been determined resulting from incomplete combustion (IC), friction (FR), heat transfer (HT) and exhaust output (EO). The results presented could be an essential tool for DMC marine engine designers.
    Źródło:
    Polish Maritime Research; 2017, 3; 86-98
    1233-2585
    Pojawia się w:
    Polish Maritime Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Particulate matter emission from dual fuel diesel engine fuelled with natural gas
    Autorzy:
    Stelmasiak, Z.
    Larisch, J.
    Pielecha, J.
    Pietras, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/260157.pdf
    Data publikacji:
    2017
    Wydawca:
    Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
    Tematy:
    dual fuel engine
    natural gas
    particulate matter
    emission
    opacity
    Diesel engine
    Opis:
    The paper presents the results of examination of particulate matter emission from the Diesel engine FPT 1.3 MJT simultaneously fuelled with diesel oil and natural gas CNG. The basic premise for engine adaptation was the addition of a small amount of CNG to reduce exhaust gas opacity and particulate matter emission. At this assumption, diesel oil remained the basic fuel, with contribution amounting to 0,70-0,85 of total energy delivered to the engine. The dual fuel engine was examined using an original controller installed in the Diesel engine FPT 1.3 MJT which controlled the diesel fuel dose. The dose of the injected natural gas was controlled by changing the opening time of gas injectors at constant pressure in the gas collector. The examined issues included the exhaust gas opacity, and the total number and fractional distribution of the emitted particles. The measurements were performed at twenty selected measuring points corresponding to the New European Driving Cycle (NEDC) test. The performed tests have demonstrated a positive effect of gas addition on exhaust gas opacity and particulate matter emission. Depending on test conditions, the exhaust gas opacity was reduced by 10÷92%, and the total number of particles by 30÷40%. The performed tests have revealed that a small addition of gas can reduce the load of the DPF filter, extend its lifetime, and increase engine reliability. Longer time intervals between successive DPF filter regenerations improve ecological properties of the engine.
    Źródło:
    Polish Maritime Research; 2017, 2; 96-104
    1233-2585
    Pojawia się w:
    Polish Maritime Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Design and experiment of low-pressure gas supply system for dual fuel engine
    Autorzy:
    Gu, Xiaoyong
    Jiang, Guohe
    Guo, Zhenghua
    Ding, Shangzhi
    Powiązania:
    https://bibliotekanauki.pl/articles/260121.pdf
    Data publikacji:
    2020
    Wydawca:
    Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
    Tematy:
    gas supply system
    dual fuel engine
    spiral-wound heat exchanger
    buffer tank
    Opis:
    A low-pressure gas supply system for dual fuel engines was designed to transport liquid natural gas from a storage tank to a dual fuel engine and gasify it during transportation. The heat exchange area and pressure drop in the spiral- wound heat exchanger, the volume of the buffer tank and the pressure drop in the pipeline of the gas supply system were calculated by programming using Python. Experiments were carried out during the proces of starting and running the dual fuel engine using this gas supply system. Experimental data show that the gas supply system can supply gas stably during the process and ensure the stable operation of the dual fuel engine. The effects of the parameters of natural gas and ethylene glycol solution on the heat exchange area of the spiralwound heat exchanger and the volume of the buffer tank in the gas supply system were studied. The results show that the heat exchange area calculated according to pure methane can adapt to the case of non-pure methane. The temperature difference between natural gas and ethylene glycol solution should be increased in order to reduce the heat exchange area. The heat exchange area selected according to the high pressure of natural gas can adapt to the low pressure of natural gas. The volume of the buffer tank should be selected according to the situation of the minimum methane content to adapt to the situation of high methane content. The main influencing factor in selecting the volume of the buffer tank is the natural gas flow. The results can provide guidance for the design of the gas supply system for dual fuel engines.
    Źródło:
    Polish Maritime Research; 2020, 2; 76-84
    1233-2585
    Pojawia się w:
    Polish Maritime Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Investigations of the emission characteristics of a dual-fuel gas turbine combustion chamber operating simultaneously on liquid and gaseous fuels
    Autorzy:
    Serbin, Serhiy
    Diasamidze, Badri
    Gorbov, Viktor
    Kowalski, Jerzy
    Powiązania:
    https://bibliotekanauki.pl/articles/1573591.pdf
    Data publikacji:
    2021
    Wydawca:
    Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
    Tematy:
    gas turbine engine
    dual-fuel combustion
    combustion chamber
    liquid and gaseous fuels
    Opis:
    This study is dedicated to investigations of the working process in a dual-fuel low-emission combustion chamber for a floating vessel’s gas turbine. As the object of the research, a low-emission gas turbine combustion chamber with partial premixing of fuel and air inside the outer and inner radial-axial swirls was chosen. The method of the research is based on the numerical solution of the system of differential equations which represent the physical process of mass and energy conservation and transformations and species transport for a multi-component chemically reactive turbulent system, considering nitrogen oxides formation and a discrete ordinates model of radiation. The chemistry kinetics is presented by the 6-step mechanism of combustion. Seven fuel supply operating modes, varying from 100% gaseous fuel to 100% liquid fuel, have been analysed. This analysis has revealed the possibility of the application of computational fluid dynamics for problems of dual-fuel combustion chambers for the design of a floating vessel’s gas turbine. Moreover, the study has shown the possibility of working in different transitional gaseous and liquid fuel supply modes, as they satisfy modern ecological requirements. The dependencies of the averaged temperature, NO, and CO concentrations along the length of the low-emission gas turbine combustion chamber for different cases of fuel supply are presented. Depending on the different operating modes, the calculated emission of nitrogen oxides NO and carbon monoxide CO at the outlet cross-section of a flame tube are different, but, they lie in the ranges of 31‒50 and 23‒24 mg/nm3 on the peak of 100% liquid fuel supply mode. At operating modes where a gaseous fuel supply prevails, nitrogen oxide NO and carbon monoxide CO emissions lie in the ranges of 1.2‒4.0 and 0.04‒18 mg/nm3 respectively.
    Źródło:
    Polish Maritime Research; 2021, 2; 85-95
    1233-2585
    Pojawia się w:
    Polish Maritime Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Design of the dual constellation GPS/GALILEO mobile device for improving navigation of the visually impaired in an urban area
    Autorzy:
    Drypczewski, K.
    Moszyński, M.
    Demkowicz, J.
    Bikonis, K.
    Stepnowski, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/258979.pdf
    Data publikacji:
    2015
    Wydawca:
    Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
    Tematy:
    dual constellation receiver
    GPS
    Galileo
    voice maps
    navigation for the blind
    visually impaired
    personal navigation device
    PND
    Opis:
    The article discusses damages of essential tribological associations in crankshaft and piston systems of large power two-stroke engines used as main engines, which take place during transport tasks performed by those ships. Difficulties are named which make preventing those damages impossible, despite the fact that the technical state of engines of this type is identified with the aid of complex diagnostic systems making use of advanced computer technology. It is demonstrated that one of causes of the damages is the lack of research activities oriented on recognising random properties of the loads leading to those damages. A proposal is made for the loads acting at a given time t on tribological associations in crankshaft and piston systems of internal combustion engines used as main engines to be considered as random variables Qt. At the same time the loads examined within a given time interval tr ≤ t ≤ tz would be considered stochastic processes {Q(t): t ≥ 0}. Essential properties of the loads of the abovementioned tribological associations are named and explained by formulating hypotheses which need empirical verification. Interval estimation is proposed for estimating the expected value E(Qt) of the load Qt acting at time t. A relation is indicated between the mechanical load and the thermal load acting on tribological associations in the ship main engine crankshaft and piston system. A suggestion is formulated that a stochastic form of the relation between these types of load is to be searched for, rather than statistic relation, and a proposal is made to measure the intensity (strength) of the stochastic relation using the Czuprow’s convergence coefficient.
    Źródło:
    Polish Maritime Research; 2015, 4; 15-20
    1233-2585
    Pojawia się w:
    Polish Maritime Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Investigation of the efficiency of a dual-fuel gas turbine combustion chamber with a plasma‒chemical element
    Autorzy:
    Serbin, Serhiy
    Diasamidze, Badri
    Dzida, Marek
    Chen, Daifen
    Powiązania:
    https://bibliotekanauki.pl/articles/32921246.pdf
    Data publikacji:
    2023
    Wydawca:
    Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
    Tematy:
    gas turbine engine
    power plant
    dual-fuel combustion
    combustion chamber
    liquid fuel
    gaseous fuel
    plasma-assisted combustion
    Opis:
    The study is devoted to the possibility of increasing the efficiency of the working process in dual-fuel combustion chambers of gas turbine engines for FPSO vessels. For the first time, it is proposed to use the advantages of plasma‒chemical intensification of the combustion of hydrocarbon fuels in the dual-fuel combustion chambers, which can simultaneously operate on gaseous and liquid fuels. A design scheme of a combustion chamber with a plasma‒chemical element is proposed. A continuous type mathematical model of a combustion chamber with a plasma‒chemical element has been developed, which is based on the solution of a system of differential equations describing the processes of chemical reactions in a turbulent system, taking into consideration the initiating effect of the products of plasma‒chemical reactions on the processes of flame propagation. A modified six-stage kinetic scheme of hydrocarbon oxidation was used to simultaneously predict the combustion characteristics of the gaseous and liquid fuels, taking into account the decrease in the activation energy of carbon monoxide oxidation reactions when the products of the plasma‒chemical element are added. The results reveal that the addition of plasma‒chemical products significantly reduces CO emissions in the outlet section of the flame tube (from 25‒28 ppm to 3.9‒4.6 ppm), while the emission of nitrogen oxides remains practically unchanged for the studied combustion chamber. Further research directions are proposed to enhance the working process efficiency of a dual-fuel combustion chamber for gas turbine engines as part of the power plant of FSPO vessels.
    Źródło:
    Polish Maritime Research; 2023, 2; 68-75
    1233-2585
    Pojawia się w:
    Polish Maritime Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-9 z 9

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