Wyniki wyszukiwania - BazTech

1

Comparative analysis of heat release in a reciprocating engine powered by a regular fuel with pyrolysis oil addition

Chwist Mariusz

Combustion Engines

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2022

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R. 61, nr 3

104--112

EN

The article presents a comparative analysis of heat release rate in a spark-ignition engine powered by various fuels as follows: butanol, gasoline, a mixture of butanol with tire pyrolysis oil (TPO), and mixtures of butanol with oil from biomass pyrolysis (BPO). Selected combustion phases were analyzed. Additionally, ignition delay calculations were performed in the ANSYS Chemkin Pro program for the surrogates of the tested fuels. Popular surrogates quoted in numerous publications were used as substitute fuels. The paper presents an original surrogate of oil from tire pyrolysis.

2

Combustion stability of dual fuel engine powered by diesel-ethanol fuels

Nowak Łukasz, Tutak Wojciech

Combustion Engines

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2019

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R. 58, nr 3

155--161

EN

The paper presents result of combustion stability assessment of dual fuel engine. The authors analyzed results of co-combustion of diesel fuel with alcohol in terms of combustion stability. The comparative analysis of both the operational parameters of the engine and the IMEP, as the parameters determining the stability of the combustion process, were carried out. It was analyzed, among others values of the COVIMEP coefficient, the spread of the maximum pressure value, the angle of the position of maximum pressure and the probability density distribution of the IMEP. The experimental investigation was conducted on 1-cylinder air cooled compression ignition engine. The test engine operated with constant rpm equal to 1500 rpm and constant angle of start of diesel fuel injection. The engine was operated with ethanol up to 50% of its energy fraction. The influence of ethanol on ignition delay time spread and end of combustion process was evaluated. It turns out that the share of ethanol does not adversely affect the stability of ignition.

3

Quick-Acting Electric Blasting Caps

Nita M., Warchoł R.

Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa

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2018

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Vol. 9, Nr 2 (32)

111--120

EN

The paper presents the constructions of new, fast-acting electric initiating blasting caps of WN-1 and WN-1A types, developed at the Military Institute of Armament Technology in Zielonka (Poland). These blasting caps have been characterized in terms of the materials used for their production and the applied explosives. The investigation results of selected blasting caps and their most important characteristics are given. Among others, dependence between a response time of a blasting cap and a supply voltage was presented as well as influence of extreme temperatures on its reliability and response time was given. The investigations of the blasting caps for initiation of blasting explosives were performed and the results confirming their usefulness are presented.

PL

W artykule zaprezentowano konstrukcje nowych, szybkodziałających elektrycznych spłonek pobudzających typu WN-1 i WN-1A, opracowanych i wykonywanych w Wojskowym Instytucie Technicznym Uzbrojenia w Zielonce. Spłonki te scharakteryzowano pod względem użytych do ich wykonania materiałów konstrukcyjnych i wybuchowych. Zaprezentowano wyniki wybranych badań spłonek oraz ich najistotniejsze charakterystyki. Przedstawiono między innymi zależności czasu zadziałania spłonek od napięcia zasilania, jak również wpływ skrajnych temperatur na niezawodność i czas zadziałania. Wykonano i zaprezentowano wyniki badań potwierdzających przydatność spłonek do pobudzania ładunków kruszących materiałów wybuchowych.

4

Evaluation of the possibilities of adapting a constant volume combustion chamber for research on ignition of hypergolic propellants under low and high-pressure conditions

Krzesicki M., Boruc Ł., Kapusta Ł. J.

Combustion Engines

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2018

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R. 57, nr 2

9--13

EN

In this study, the adaptation possibilities of a constant volume combustion chamber (CVCC) for research on the ignition of hypergolic propellants are presented. The application of hypergolic bipropellants and crucial parameters regarding their ignition behaviour are discussed. The initial studies on ignition delay measurements presented here does not cover the whole range of conditions present in practical systems where hypergolic ignition occurs. In the study, a need for an evaluation of the influence of pressure on the ignition delay was indicated as the reason to conduct research on hypergolic ignition in low and high-pressure environments. Moreover, the study reviews the state-of-the-art experimental methods of investigating the ignition under atmospheric, low and high-pressure conditions, including those utilizing a constant volume combustion chamber. The drop test was pointed out as the most commonly used method; this makes it advantageous in terms of comparing the results with those obtained by other researchers. Therefore, the drop test was selected as a method to be used in a CVCC. The test rig developed here was designed based on a CVCC initially designed for diesel sprays’ visualization in high-pressure conditions. All the required modifications, especially the design of the oxidizer dosing unit, are presented in the study.

5

Effect of division of initial dose on combustion parameters of a dual fuel CI engine

Stelmasiak Z.

Combustion Engines

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2013

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R. 52, nr 3

12--24

EN

Worsening of economic and environmental parameters of a dual fuel engine at partial engine loads results from protracted combustion of leaned gas-air mixture. This leads to reduction of overall efficiency and growth of CO and THC emissions. Such problems are difficult to solve in traction engines due to their frequent operation at partial loads and rapid changes of engine load and rotational speed. Negative effects of leaning of gaseous mixture can be partially diminished through division of initial dose and activation of combustion of gaseous mixture through delayed injection of additional portion of liquid fuel. In the paper are presented test results of experimental SB3.1 engine run on CNG with divided dose of the Diesel oil. There were analyzed overall efficiency and selected parameters of combustion process. Division of the dose influenced advantageously on parameters of the engine. The overall efficiency increased, while maximal pressure pmax, heat release rate (dQ/dα)max, and pressure growth rate (dp/dα)max decreased. The engine with divided dose operated more smoothly with less noise.

PL

Pogorszenie parametrów ekonomiczno-ekologicznych silnika dwupaliwowego przy częściowych obciążeniach wynika z przewlekłego spalania zubożonej mieszaniny gaz-powietrze . Prowadzi to do zmniejszenia sprawności ogólnej silnika i wzrostu emisji CO i THC. Problemy te są trudne do rozwiązania w silnikach trakcyjnych z uwagi na częstą pracę przy częściowych obciążeniach oraz szybkie zmiany w czasie obciążenia i prędkości obrotowej. Negatywne skutki zubożenia mieszaniny gazowej można częściowo zmniejszyć przez podział dawki inicjującej i aktywizację spalania mieszaniny gazowej poprzez opóźniony wtrysk dodatkowej porcji paliwa ciekłego. W pracy przedstawiono wyniki badań silnika badawczego SB3.1 zasilanego CNG i dzieloną dawką oleju napędowego. Analizie poddano sprawność ogólną i wybrane parametry spalania. Podział dawki korzystnie wpłynął na parametry silnika. Sprawność silnika wzrosła, natomiast zmniejszeniu uległy ciśnienie maksymalne pmax, szybkość wydzielania ciepła (dQ/dα)max, szybkość przyrostu ciśnienia (dp/dα)max. Silnik z dzieloną dawką pracował bardziej równomiernie i wykazywał mniejszą hałaśliwość.

6

An analysis of EGR impact on combustion process in the SI test engine

Tutak W.

Silniki Spalinowe

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2012

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R. 51, nr 1

11-16

EN

The results of modeling of thermal cycle of spark ignition internal combustion engine with exhaust gas recirculation are presented. Results of the impact of EGR on the ignition delay and the combustion duration are presented. The optimization of thermal cycle was carried out in terms of ignition advance angle in order to obtain the possible highest value of efficiency and the least NO emission. The results indicated a significant impact of EGR on the ignition delay and combustion duration.

PL

W pracy przedstawiono wyniki modelowania obiegu cieplnego tłokowego silnika spalinowego z recyrkulacją spalin. Przedstawiono wyniki wpływu EGR na zwłokę zapłonu oraz na długość spalania. Przeprowadzono optymalizację obiegu silnika pod względem kąta wyprzedzenia zapłonu w celu osiągnięcia największej wartości sprawności obiegu przy niskiej emisji NO. Wyniki wykazały znaczny wpływ EGR na opóźnienie zapłonu i na długość spalania.

7

Influence of exhaust gas recirculation on the ignition delay in supercharged compression ignition test engine

Tutak W.

ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes

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2012

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Vol. 1, No 2

57-62

EN

The results of analysis of thermal cycle of the test engine are presented in the paper. The study focused on determining the ignition delay in compression ignition engine. The correlations available in literature, Hardenberg and Hase, Wolfer and Watson and Assanis were used to determine ignition delay. With the increase of the EGR the ignition delay has increased. It turned out that very often it is necessary to determine own ignition delay correlation.

8

On the modeling of pilot dose ignition delay in a dual-fuel, self ignition engine

Piętak A., Mikulski M.

Silniki Spalinowe

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2011

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R. 50, nr 3

EN

The goal of the present work, was to determine possible applications of discussed formulas in predicting ignition delay for dual-fuel engines. In order to achieve this goal in-cylinder pressure traces have been recorded for a one cylinder, dual-fuel engine, for different power outputs and different ratios of liquid and gas fuels. Using those results moments of autoignition have been determined for the tested conditions. The measurement data has been compared with calculation results of three different delay models. It has been shown that the equation proposed by Assanis is able to describe ignition delay very well, for pilot dose quantity more than 20% overall fuel energy.

PL

Celem niniejszej pracy jest sprawdzenie możliwości zastosowania dyskutowanych formuł do opisu opóźnienia zapłonu w silniku dwupaliwowym. W tym celu wykonano pomiary przebiegów ciśnienia w jednocylindrowym silniku dwupaliwowym, dla różnych obciążeń i różnych proporcji poszczególnych paliw. Na ich podstawie wyznaczono momenty wystąpienia zapłonu w silniku. Dane pomiarowe porównano z wynikami obliczeń dla poszczególnych modeli opóźnienia zapłonu. Wykazano, że równanie zaproponowane przez Assanisa bardzo dobrze opisuje opóźnienie samozapłonu w systemie dual-fuel, przy założeniu, że dawka oleju napędowego jest nie mniejsza niż 20% całkowitej energii dostarczanej z paliwem.

9

The effect of injection pressure and strategy in a Jaguar V6 diesel engine

Abdullah N. R., Mamat R., Rounce P., Wyszynski M. L., Tsolakis A., Xu H. M., Tian G.

Journal of KONES

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2009

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Vol. 16, No. 2

9-22

EN

In recent years, the improvement of engine performance and emissions has become an extremely important concern. This study focuses on the injection strategy based on the injection pressure (IP) and duration between pilot injection and the main injection (dMI) using a multi cylinder common rail multiple injections diesel engine. The study was designed to produce improvements in fuel mixing via the injection strategy, to reduce the main ignition delay. This would contribute to a minimum amount of fuel burnt in the premixed combustion phase, leading to a reduction in emissions. Recent evidence shows that premixed combustion is significant in the controlling of emissions of nitrogen oxides (NOx) and soot. Six different IPs combined with a short and long dMI were compared in the attempt to improve engine performance and emissions. The engine performance was measured in terms of brake specific fuel consumption, ignition delay, heat release and peak in-cylinder pressure and emissions, specifically nitrogen oxides (NOx), total unburned hydrocarbons (THC), carbon monoxide (CO) and smoke emissions for each engine test condition. The evidence from this study shows that the effect of IP is more dominant than dMI in terms of peak cylinder pressure, heat release, brake specific fuel consumption and emissions. However, the dMI shows a strong effect at a higher engine speed.

10

Mathematical modelling of catalytic ignition of methane - air mixture.

Abatorab A., Teodorczyk A.

Prace Naukowe Instytutu Chemii i Technologii Nafty i Węgla Politechniki Wrocławskiej. Konferencje

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1999

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Vol. 9, nr 56

297-304

EN

Catalytic combustion is a promising approach for controlling pollutant emissions. The catalyst surface may influence gas phase chemistry by adsorbing or desorbing reactive intermediates and permits low temperature combustion below the traditional lean limit. We have constructed a numerical model of catalytic combustion in a constant volume chamber and open flow geometry with detailed gas phase and surface chemistry. The model was used to study the ignition process of methane-air mixture with platinum catalyst because methane is the major constituent of natural gas and reactions of the methyl radical are among the rate limiting steps the gas phase combustion of larger hydrocarbons. The numerical model was solved using a combination of four computer codes: CHEMKIN II for gas phase chemical kinetics, SURFACE CHEMKIN for heterogeneous chemical kinetiks, MULTICOMPONENT TRANSPORT for avaluation of mixture molecular transport properties and TWOPNT for solution of the conservation differential equtions. The surface chemistry mechanism has been compiled primarily from the published reactions. The thermodynamic data of surface species are derived from the heats of adsorption, where entropies were obtained by estimating surface vibrational frequencies and applying standard statistical mechanisms formulas. The results of computations indicate that the evolution of all parameters during the ignition process depends on the temperature of catalyst and fraction of the available surface sites. The ignition dealy is highly sensitive to the catalyst temperature.

PL

Spalanie katalityczne umożliwia usuwanie lub zmniejszenie stężenia tlenków azotu, tlenku węgla oraz węglowodorów ze spalin, jeżeli jest zapewniona dostatecznie duża powierzchnia i odpowiedni czas kontaktu reagentów w temperaturze nieco wyższej od temperatury zapłonu. Spalanie katalityczne zachodzi wówczas, gdy strumień paliwa gazowego w mieszaninie z powietrzem przepływa przez warstwę odpowiedniego katalizatora. Zadaniem katalizatora jest obniżenie energii aktywacji wymaganej dla przebiegu danej reakcji, w wyniku czego ten sam stopień konwersji osiąga się w niższej temperaturze, z większą szybkością, w krótszym czasie przebywania (~ms). W rezultacie maleje zapotrzebowanie na dodatkowe paliwo i jednocześnie zmniejsza się nadmiar stosowanego powietrza oraz możliwość tworzenia Nox podczas spalania.