Wyniki wyszukiwania - Biblioteka Nauki

1

Modeling of thermal cycle ci engine with multi-stage fuel injection

100%

Jamrozik A. , Tutak W. , Gnatowski A. , Gnatowska R. , Winczek J. , Sosnowski M.

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2017

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tom Vol. 11, no 3

179--186

EN

This work presents a complete thermal cycle modeling of a four-stroke diesel engine with a three-dimensional simulation program CFD - AVL Fire. The object of the simulation was the S320 Andoria engine. The purpose of the study was to determine the effect of fuel dose distribution on selected parameters of the combustion process. As a result of the modeling, time spatial pressure distributions, rate of pressure increase, heat release rate and NO and soot emission were obtained for 3 injection strategies: no division, one pilot dose and one main dose and two pilot doses and one main dose. It has been found that the use of pilot doses on the one hand reduces engine hardness and lowers NO emissions and on the other hand, increases soot emissions.

2

Thermal modelling of laser welding Part II: An assessment of thermal cycle - examples

100%

Ranatowski E.

Advances in Materials Science

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2003

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tom Vol. 3, nr 1(3)

41--50

EN

This part is a natural continuation of PART I. In this paper the non-linear analytic - numerically computed methods are presented. For a plate with optional thickness, the radiative heat transfer on both surfaces is taken into account. Temperature dependent materials properties are also considered and this makes these methods competitive with other non-linear ones. Finally, a few analytical examples with use of C-I-N heat source for thermal modelling of laser welding are demonstrated.

3

Criteria for the assessment of the engine efficiency of the multi-purpose aircraft missions

100%

Wygonik P.

Journal of KONES

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2014

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tom Vol. 21, No. 3

301--307

EN

The problem of design parameters selection of the turbine engine is the most important task at the preliminary design stage of the multi-purpose aircraft. A special feature of the multi-purpose aircraft mission is a sudden (even pulse) weight change, especially its decrease as a result of discharge of cargo bombing or rockets due to the ammunition consumption during air combat manoeuvring. In this article the attempt to use economic and mass criteria to assess the impact of the type of air missions on the choice of the design parameters of the engine was done. As the design, parameters there were selected the following measures: compression ratio, the turbine temperature and the bypass ratio. A mathematical model of the engine – aircraft – air task system was built (taking into account the flight conditions, the mission elements – the subsonic and supersonic flight, flight time, thermo-gas-dynamic and mass model of the engine). The model enables to conduct the simulation research of the complex flight missions and their assessment on the basis of the constructed criteria. The model includes a parametric description of physical processes in the turbofan engine, thereby allowing a direct assessment of the impact of the selection of engine parameters on the effectiveness of the mission. The paper presents the results of calculations according to the classical criteria (e.g. kilometre fuel consumption, specific fuel consumption of the engine). New criteria for evaluation were presented; they are the energy efficiency of complex mission of an aircraft and the relative total and specific fuel consumption. The values of circuit parameters that need to be taken as design constraints for the engine to allow the implementation of the aviation missions were determined. The results are shown in an illustrative way on the number of graphs.

4

Kryteria doboru parametrów silnika turbinowego do samolotu wielozadaniowego

100%

Wygonik P.

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tom R. 45, nr 4

19-33

PL

Na etapie wyboru zespołu napędowego do samolotu wielozadaniowego należy rozwiązać problem wzajemnych relacji między wymiarami samolotu i silnika. Wychodząc z równań ruchu samolotu i teorii podobieństwa wyznaczono kryteria i wskaźniki wiążące geometrycznie i energetycznie silnik oraz samolot. Przeprowadzono analizę wpływu warunków lotu samolotu i parametrów obiegu porównawczego silnika na wybrane wymiary geometryczne. W pracy wykazano, że zasadniczym stanem lotu determinującym relacje między parametrami geometrycznymi samolotu i silnika jest jego start lub przelot naddźwiękowy na dużej wysokości. Zwykle doboru parametrów obiegu cieplnego silnika turbinowego dokonuje się na podstawie charakterystyk wewnętrznych silnika - ciąg jednostkowy, jednostkowe zużycie paliwa. W oparciu o model silnika dwuprzepływowego z mieszalnikiem strumieni i dopalaczem oraz model samolotu (przyjęto uproszczone charakterystyki aerodynamiczne i masowe) określono wpływ parametrów obiegu na podstawowe wskaźniki samolotu jak doskonałość aerodynamiczna, zasięg umowny i zasięg teoretyczny.

EN

At the stage of a power unit selection for a multi-purpose aircraft the problem of mutual relations between the dimension of an aircraft and an engine should be solved. Starting from the motion equation of an aircraft and the theory of similarity the criteria and performance were determined which connect in a geometrical and power way the engine and the aircraft. The analysis of the influence of flight conditions and the parameters of an engine comparative cycle on the geometrical dimensions was conducted. In the paper it was shown that the fundamental flight stage which determines the relations between the geometrical parameters of the aircraft and the engine is the take-off or supersonic flight on the big altitude. Usually the parameters selection of the turbine engine thermal cycle is done on the basis of the internal characteristics of the engine, such as specific thrust and specific fuel usage. In case of the turbofan engine model with the mixer, afterburner, and the aircraft model (with simplified aerodynamic and mass characteristics) the influence of the cycle parameters on the performance and aerodynamic lift/drag ratio, the agreed range and the theoretical range was described.

5

Application of Strain Gauges in Measurements of Strain Distribution in Complex Objects

100%

Tutak P.

Journal of Applied Computer Science Methods

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2014

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tom Vol. 6 No. 2

135--145

EN

This article presents an application of strain gauges in measurements of strain which occurs in charge air cooler during the thermal cycle test. The work shows the main idea of measuring system based on strain gauges and important aspects that should be considered when performing measurement. In this article there has been also presented construction and principle operation of a strain gauge measurement system.

6

Steady state and transient analysis of solid oxide fuel cell within the framework of thermodynamic energy cycles

100%

Matysko R.

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2023

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tom Vol. 44, no 4

317--333

EN

The provided article comprehensively explores the modelling and analysis of solid oxide fuel cell (SOFC) systems within the context of thermodynamic energy cycles. The paper provides insight into various applications of these cells, with a specific emphasis on their role as the primary source of electrical energy in systems that work with biogas and heat recovery. The technological structure of these systems is delineated, with a focus on their principal components and the chemical reactions occurring within SOFCs. Moreover, the article incorporates a mathematical model of SOFCs and presents calculation results that illustrate the influence of air and fuel temperature on the cells’ efficiency. The research indicates that optimal SOFC efficiency is attained at higher temperatures of supplied air and fuel. The presentation of the results of calculations for the solid oxide fuel cell and its thermodynamic cycle, considering fuel supply and its thermodynamic parameters under both steady-state and transient conditions, is the main aim of the article.

7

Thermodynamics and mass selection criterions of low bypass turbine engine parameters for multi-purpose

100%

Wygonik P.

Journal of KONES

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2008

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tom Vol. 15, No. 2

543-551

EN

Parameters of the turbofan engine comparative cycle (turbine inlet temperature, compression of compressors), by-pass ratio, fan compressor, (or low pressure compressor) are the most important engine parameters which determine their characteristics and construction. In order to fulfill the task there is a necessity for searching the optimum parameters for the system. The most important equation that binds airplane and engine characteristics is mass balance equation. The sum of engine mass and fuel mass was called total engine-fuel mass. In the paper specific total engine mass index was introduced (gamma 2). This index is equal to total engine-fuel mass divided by thrust in design point. Impact of the choice of the design point on the total mass index of the engine and the fuel used up was presented for different airplane mission. The next problem is to find those thermodynamics parameters (compression ratio, turbine inlet total temperature, bypass ratio) which give minimum of total mass of engine and consumed fuel for different airplane missions. A very important parameter that plays the part in fuel consumption is airplane flight time. The most important conclusion is that the best thermodynamics parameters from minimum mass criterion are less than for minimum specific fuel consumption.

PL

Parametry obiegu porównawczego dwuprzeplywowego turbinowego silnika odrzutowego determinują jego charakterystyki i schemat konstrukcyjny. W pracy przedstawiono problem poszukiwania optymalnych wartości parametrów termogazodynamicznych obiegu porównawczego silnika turbinowego. Do tych parametrów zaliczono: spręż całkowity sprężarki, temperaturę przed turbiną, stopień podziału strumieni. Przedstawiono wpływ wybranych warunków lotu, sprężu sprężarki i temperatury przed turbiną na zmianę ciągu jednostkowego i jednostkowego zużycia paliwa. Jako kryterium optymalizacji wybrano sumaryczną masę silnika i paliwa, wymaganą do wykonania zadania lotniczego. Wykorzystano, zbudowany na potrzeby innych prac, model silnika, który jest funkcją parametrów termogazodynamicznych. Wyprowadzono zależności pozwalające na optymalizację jednostkowej masy sumarycznej (jako kryterium bezwymiarowego). Przeprowadzono szereg obliczeń, których wyniki przedstawiono na wykresach. Wykazano, że na podstawie wybranego kryterium optymalizacji, jakim jest sumaryczna masa silnika i paliwa, można wyznaczyć wartości sprężu sprężarki, dla których wskazane kryteria oceny masy osiągają swoje minimum.

8

Analiza możliwości modyfikacji struktury obiegu bloków węglowych pracujących na parametry ultranadkrytyczne

75%

Elsner W. , Kowalczyk Ł.

Modelowanie Inżynierskie

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2012

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tom T. 13, nr 44

57-64

PL

W artykule przedstawiono analizę wpływu modyfikacji obiegu cieplnego (wprowadzenie układ krzyżowego i turbiny pomocniczej) na parametry ultranadkrytyczne bloku węglowego (700/720 C) dla przypadku z pojedynczym i podwójnym przegrzewem międzystopniowym. Wprowadzenie tak wysokich parametrów pary powoduje konieczność zastosowania wysokostopowych materiałów na regenerację wysokoprężną oraz wzrost spiętrzenia temperatur i w konsekwencji duże straty egzergii. Problem ten można rozwiązać, wprowadzając do obiegu turbinę pomocniczą zasilaną z wylotu części HP. Jak wykazano, dołożenie do obiegu cieplnego schładzacza pary nie daje istotnych zysków, jeżeli chodzi o sprawność, jednak pozwala na zmniejszenie parametrów pary upustowej podawanej na związany z nim wymiennik oraz na zmniejszenie powierzchni wymiany ciepła.

EN

This paper presents an analysis of the impact of thermal cycle modification (introduction of desuperheater and auxiliary turbine) on the parameters of ultra-supercritical coal unit (700/720 C) for the case with single and double steam reheat system. Application of such high steam parameters result in the need for expensive high alloys and cause an increase of bleed steam temperature and so the exergy loss. This problem can be solved by the introduction of the auxiliary turbine (T-T) supplied from the outlet of the HP. As it was shown, application of desuperheater to the thermal cycle do not give significant gains in terms of efficiency. However, it allows for reduction of bleeding steam parameters directed to the associated heat exchanger and for reduction of its heat exchange surface.

9

Masowe kryteria doboru parametrów dwuprzepływowego silnika odrzutowego do samolotu wielozadaniowego, dla wybranych zadań lotniczych

75%

Wygonik P.

Silniki Spalinowe

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2007

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tom R. 46, nr SC1

302-312

EN

Two-spool, low bypass mixed turbofan engines with afterburner are used for the power of multi-purpose aircrafts. Parameters of the engine comparative cycle (turbine inlet temperature, compression of compressors), by-pass ratio, fan compressor, (or low pressure compressor) are the most important engine parameters which determine their characteristics and construction. En engine and an aircraft form the complex dependence system, which is additionally complicated by a flight task. In order to fulfill the task there is a necessity for searching the optimum parameters for the total system. The most important equation that binds airplane and engine characteristics is mass balance equation. Accepting the constant value of the masses of the aircraft, obtaining of the maximum masses of the charge is possible at minimization of the masses of the engine and the fuel. The presented model of the masses of the engine, and the fuel consumption model which are the functions of thermodynamic parameters were described in the article. The sum of engine mass and fuel mass was called total engine-fuel mass. In the paper specific total engine mass index was introduced ( γε ). This index is equal to total engine-fuel mass divided by thrust in design point. Impact of the choice of the design point (Mach velocity and altitude H) on the total mass index of the engine and the fuel used up was presented for different airplane mission. The next problem is to find those thermodynamics parameters (compression ratio, turbine inlet total temperature, bypass ratio) which give minimum of total mass of engine and consumed fuel for different airplane missions. A very important parameter that plays the part in fuel consumption is airplane flight time. For long-lasting mission minimum γε is occurs for compression ratio near his economic value (for specific fuel consumption). For short missions minimum of γε occurs for smaller compression ratio (near 20-30), but greater than for those giving maximum specific thrust. A little change in minimum value of gS gives a big difference in compression ratio. The most important conclusion is that the best thermodynamics parameters from minimum mass criterion are less than for minimum specific fuel consumption. Specific total engine-fuel mass is a very important figure of merit for parameters optimization at the first step of aircraft engines design.

10

Wpływ temperatury austenizowania na mikrostrukturę i twardość stali typu Hardox 450

75%

Dziurka R. , Łętkowska B. , Zbyrad-Kołodziej W.

Przegląd Spawalnictwa

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2018

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tom R. 90, nr 5

136--141

PL

W pracy przedstawiono symulację wpływu temperatury na zakres przemian fazowych w strefie wpływu ciepła w obszarze temperatur przegrzania. Wybrano pięć różnych temperatur austenityzowania, tj.: 900, 1000, 1100, 1200 oraz 1300 ̊C. Symulacje nagrzewania i chłodzenia wykonano na wysokorozdzielczym dylatometrze L78 R.I.T.A. Po austenityzowaniu, próbki chłodzono z dwoma wybranymi szybkościami 5 i 1 ̊C/s do temperatury pokojowej. Na próbkach po ochłodzeniu wykonano analizę mikrostruktury i twardości. W oparciu o przedstawione wyniki określono wpływ temperatury na hartowność w zakresie badanych szybkości chłodzenia i w konsekwencji zmian w mikrostrukturze oraz jednorodności uzyskanych map twardości.

EN

The paper presents the simulation of the temperature effect on phase transformation in the heat-affected zone in the area of superheat temperatures. Five different temperatures were selected, i.e. 900, 1000, 1100, 1200 and 1300 ̊C. Heating and cooling simulations were carried out on the L78 R.I.T.A high-resolution dilatometer. After austenitizing, the samples were cooled with two selected rates 5 and 1 ̊C/s. On the samples after cooling, microstructure analysis and hardness distribution analysis were performed. Based on the results, the influence of temperature on the increase of hardenability in the range of the tested cooling rates was determined and as a consequence changes in the microstructure and homogeneity of the obtained hardness maps.

11

Analiza sprawności obiegu cieplnego ultra-nadkrytycznego bloku kondensacyjnego dla szeregowej konfiguracji skraplaczy

75%

Wróblewski W. , Łukowicz H. , Rulik S.

Archiwum Energetyki

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2013

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tom T. 43, nr 1/2

117--127

PL

Przedmiotem niniejszej analizy jest dobór parametrów oraz konfiguracji układu chłodzenia dla bloku ultra-nadkrytycznego o mocy 900 MW. Analizę pracy skraplacza oparto o amerykańską normę Heat Exchange Institute. Przedstawione badania obejmują porównanie dwóch wariantów układu chłodzenia, które dotyczą konfiguracji równoległej oraz szeregowej pracy skraplacza. Układ równoległy jest powszechnie stosowany, a rozdzielenie strumienia wody chłodzącej na poszczególne skraplacze bądź sekcje skraplacza daje w nich jednakowe warunki kondensacji. W przypadku konfiguracji szeregowej całkowity strumień wody chłodzącej przepływa szeregowo przez skraplacz pierwszy, a następnie trafia do skraplacza drugiego. Takie rozwiązanie w stosunku do układu równoległego powoduje wzrost sprawności obiegu wynikający z obniżenia całkowitego ciśnienia w skraplaczu. Konfiguracja szeregowa powoduje, że obniżeniu ciśnienia w pierwszej sekcji skraplacza towarzyszy nieznaczny wzrost ciśnienia w drugiej sekcji skraplacza. Stąd też pole powierzchni wymiany ciepła drugiej sekcji skraplacza jest często zwiększone w celu poprawy warunków kondensacji. Niniejsza praca stanowi uzupełnienie oraz rozszerzenie przedstawionych w literaturze analiz. Dotyczy to w szczególności dokładnego uwzględnienia wpływu straty wylotowej turbiny niskoprężnej na wartość uzyskiwanych przyrostów sprawności obiegu cieplnego w przypadku konfiguracji szeregowej pracy skraplacza.

EN

The aim of this paper is the selection of parameters and configuration of the cooling system of 900 MW ultra-supercritical power unit. The performed analysis of the condenser was based on the Heat Exchange Institute standard. The presented studies include comparison of two variants of cooling water system. Both, the parallel and serial configuration of the condenser was investigated. Parallel cooling water system is widely used, and the separation of the cooling water stream into individual sections of the condenser or condensers give equal conditions of condensation. In the case of a serial configuration, the total flow of cooling water flows through the first condenser and then it goes to the second condenser. This causes the decrease of pressure in the first and increase of pressure in the second condenser. Hence, the heat exchange surface area of the second condenser is often increased to improve the conditions of condensation. This paper extends the analyzes presented in the literature. It particularly concerns the investigation of influence of the exhaust loss for obtained efficiency gains in case of the serial configuration of condenser.

12

Numeryczny model obliczeniowy obiegu turbiny klasy 300 MW

75%

Grzymkowska A. , Głuch J. , Gardzilewicz A.

Mechanik

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2015

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tom R. 88, nr 7CD

253--260

PL

Niniejszy artykuł stanowi opis modelu obiegu cieplnego turbiny o mocy 360 MW, utworzonego w preprocesorze numerycznego programu obliczeniowego o nazwie DIAGAR. Zadaniem opisywanego modelu jest odtwarzanie zjawisk fizycznych zachodzących w poszczególnych urządzeniach składowych obiegu, zarówno podczas poprawnej (sprawnej) pracy bloku energetycznego, jak i w przypadku pojawienia się niesprawności. Utworzony model posłuży w przyszłości jako narzędzie cieplno-przepływowej diagnostyki analizowanego bloku energetycznego, pracującego w jednej z polskich elektrowni.

EN

In this article the model of the 360 MW turbine thermal cycle has been described. The model has been created with the preprocessor of the numerical computational program called DIAGAR. The described model is supposed to recreate the physical phenomena which occur in the particular cycle components, not only during the correct (efficient) work of the power unit, but also when a malfunction occurs. The created model will be used in the future as the heat-flow diagnostic tool for the analysed power unit, which works in one of the polish power plants.

13

Problems of welding in shipbuilding - an analytic-numerical assessment of the thermal cycle in HAZ with three dimensional heat source models in agreement with modelling rules Part II An analytical assessment of thermal cycle by used C-I-N and D-E heat sources models

75%

Ranatowski E.

Polish Maritime Research

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2010

|

tom nr 2

60--66

EN

This part is continuation of PART I. The basis of this analytic solution are the Fourier - Kirchhoff partial differential equation with appropriated boundary conditions. For a plate with optional thickness, the radiative heat transfer on both surfaces is taken into account. It is assumed that moving C-I-N or D-E heat sources during a very short period of time, generate an impulse of energy inducing an instantaneous thermal field in the plate area and the analytic solution is received by used Fourier transformation. These fields are being continuously summed up to obtain resultant thermal field ... . Finally, the temperature fields generated by C-I-N and D-E heat sources in both stationary and moving co-ordinates systems are established.

14

The influence of the constraint effect on the mechanical properties and weldability of the mismatched weld joints. Part I

75%

Ranatowski E.

Polish Maritime Research

|

2012

|

tom nr 1

44-51

EN

The process of welding has dynamic character and is related with the local change of the internal energy E of welded system and can be defined by general dependence between intensive .j and extensive .j parameters. The knowledge of the run of thermo-dynamical process under welding indicates on the possibility of active modelling of weldability and the control of welding process: .j = .E/..j. Hence, these process can be enhanced by mathematical modelling and numerical analysis of weldability models of, i.e. welding processes of material behaviour in welding and the strength of welded structures. The main attention is focused on the assessment of susceptibility of materials under defined welding conditions using fracture mechanics parameters. The analysis is based on the normalised parameters such as: ./.c, KIth/KIC, as a measure of the susceptibility of materials in welding process. The deformation process and fracture parameters calibrations are influenced by constraint; hence the importance of determining the deformation behaviour and fracture parameters as a function of constraint. Furthermore, there established analytically the condition of welding process in mismatched weld joints for strength equal to base metal. Finally, same analytical examples which present new capabilities of weldability estimates and mechanical properties of mismatched weld joints are presented.

15

The influence of the constraint effect on the mechanical properties and weldability of the mismatched weld joints. Part II

75%

Ranatowski E.

Polish Maritime Research

|

2012

|

tom nr 2

39-42

EN

Currently the welding as a technological process is concerned with special processes, the results of which cannot be checked in a complete degree by subsequent control, test of production what finally causes uncertainty of work of welded constructions. The process of welding is related to the local change of the internal energy of welded system and that leads to the local change of state of material expressing by change of microstructure and mechanical properties. This phenomena decide on the assessment of susceptibility of materials under defined welding condition and estimate of the weldability. It is compound relation and the mechanical behaviour of welded joints is sensitive to the close coupling between modules: heat transfer, microstructure evolution an mechanical fields. Welding process in physical meaning it is jointed with three laws govern mass and heat flow the laws of conservation of: mass, momentum and energy. The knowledge of the run of thermo-dynamical process under welding indicates on the possibility of active modelling and control of welding process with use intensive and extensive parameters. As the weld metal cools in the temperature range 2300 to 1800°K, the dissolved oxygen and deoxidising elements in liquid steel react to form complex oxide inclusions of 0.1 to 1 žm size range. In the temperature range 1800 to 1600°K, solidification of liquid to . ferrite starts und envelops these oxide inclusions. After . ferrite transforms to austenite in the temperature range 1100 to 500°K, the austenite transforms to different ferrite morphologies such as ferrite: allotriomorphic, Widmanstättena, and acicular. The macro-mechanical heterogeneity of welded structures is one of their primary features. The heterogeneous nature of the weld joints is characterised by macroscopic dissimilarity in mechanical properties. Numerical weldability analysis is a new powerful research and development tool which is useful for metallurgistics technologist and design engineers. Saying strictly the numerical analysis of weldability comprises thermodynamic, thermomechanical and microstructural modelling of the welding process. The result of this analysis is material susceptibility (SU). The fracture resistance of welded joints is mainly characterised by normalised parameters: SU1 = KIth / KIC for cold cracking or in the exploitation condition by SU2 = ./.C or J/JC, SU1 . SU2. From above-mentioned equations result that does not exist one global parameter which defines the step of susceptibility SU of base materials has been also executed with use of SINTAP program.

16

Optymalizacja obiegu cieplnego siłowni skojarzonej

75%

Panowski M. , Klajny R.

Prace Naukowe Politechniki Warszawskiej. Mechanika

|

2003

|

tom z. 202

139--148

PL

W opracy zaprezentowano metodykę modelowania i optymalizacji złożonych układów cieplnych z wykorzystaniem modeli danych i narzędzi symulacyjnych. do generowania danych stanowiących źródło dla algorytmów formułowania modeli danych zastosowano symulacyjne oprogramowanie narzędziowe IPSEpro firmy SimTech [4]. Zastosowane metody optymalizacji wywodzą się z grup programowania liniowego i kwadratowego, odpowiednio dla modeli liniowych i kwadratowych, a za główne kryterium optymalizacji przyjęto całkowitą sprawność egzergetyczną analizowanego układu cieplnego. W pracy zaprezentowano rezultaty optymalizacji parametrów procesowych bloku BCF-100 pracującego w Elektrociepłowni Katowice SA.

EN

The article presents the novel method for modelling and optimization of combined thermal systems with use of data models of simulation software. Software tool IPSEpro from SimTech was used to generate a set of data that is the source for algorithms of formulation of data models. Optimisation methods used in the software are derived from groups of linera and quadratic programming and as the main optimisation criteria the total exergetic efficiency of analysed thermal system was chosen. The article presents results of optimisation of thermodynamic parameters of BCF-100 power plant working at Elektrociepłownia Katowice S.A.

17

Wpływ wielokrotnych cykli cieplnych na ciągliwość symulowanej SWC stali o dużej wytrzymałości

75%

Mroczka K. , Tasak E.

Biuletyn Instytutu Spawalnictwa w Gliwicach

|

2003

|

tom R. 47, nr 5

65--69

PL

Przedstawiono wybrane wyniki badań właściwości stali o wysokiej wytrzymałości poddanych różnym symulowanym, pojedynczym i złożonym, cyklom cieplnym. Stwierdzono, że wzrost czasu chłodzenia w zakresie t8/5 powoduje równoczesny spadek udarności i twardości. Te niekorzystne zmiany związane są z tworzeniem się wysp M-A oraz procesami utwardzania wydzieleniowego ferrytycznej osnowy.

EN

It has been presented some selected test results for high strenght steels subjected to different simulated thermal cycles, simple and complex ones. It was found that the increase in cooling time in the range of t8/5 resulted in the simultaneous decrease in toughnees and hardness. These negative changes are connected with formation of martensite-austenitic island and processes of precipitation hardening of ferritic matrix.

18

Sprzężony model obiegu cieplnego i układu wody chłodzącej dla siłowni na parametry nadkrytyczne

75%

Wróblewski W. , Dykas S. , Rulik S.

Rynek Energii

|

2008

|

tom nr 6

54-60

PL

W artykule przeprowadzono analizę warunków pracy obiegu cieplnego bloku nadkrytycznego. Uwzględniono w niej sprzężenie obiegu cieplnego z obiegiem wody chłodzącej. Przedstawiono model obiegu cieplnego oraz algorytm jego rozwiązania, model skraplacza oraz model chłodni kominowej mokrej o ciągu naturalnym. Analizowano również pracę układu cieplnego i układu wody chłodzącej w zmiennych warunkach. Do analizy zastosowano obieg referencyjny siłowni na nadkrytyczne parametry pary o mocy 600MW. Dla tego bloku założono parametry zamkniętego układu chłodzenia, przyjęto wymiary skraplacza oraz gabaryty chłodni kominowej. Analizowano różne warianty pracy bloku, uwzględniające różne parametry powietrza atmosferycznego. Rozważono również możliwość regulacji obiegu wody chłodzącej w celu określenia optymalnych, ze względu na sprawność cieplną siłowni, warunków pracy pomp. Przedstawiono wyniki obliczeń dla założonych charakterystyk poszczególnych elementów układu i sformułowano wnioski.

EN

In this paper the thermal cycle model of supercritical power plant conjugated with the cooling system working at different operating conditions was presented. The calculations for reference unit of 600 MW output with close cooling system were made. The basic parameters and construction type of cooling tower and condenser were assumed. The algorithm for cooling system consists of the cooling tower model and condenser model and enables calculations for different working regimes. The iteration process to calculate the parameters of thermal cycle and cooling water cycle was described. The influence of atmospheric temperature changes typical for the one-year period on the power plant performance indicators and cooling water control possibilities were discussed. The chosen results were presented and the investigations were summed up.

19

Application of numerical modeling to optimize the thermal cycle of the internal combustion engine

75%

Jamrozik A. , Tutak W.

Prace Naukowe Instytutu Matematyki i Informatyki Politechniki Częstochowskiej

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2012

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tom Vol. 11, nr 2

43-52

EN

The paper presents the results of numerical modeling of the complete thermal cycle of the Andoria 1hc102 test engine. Modeling was carried out in the AVL Fire program. Modeling was used in order to determine the optimal ignition angle of the test IC internal combustion (IC) engine. Model tests were carried out for the spark ignition (SI) engine to operate with excess air ratio equal to λ = 1.2. As a criterion for estimating the quality of engine operation cycle, a value of maximum indicated pressure and indicated efficiency were taken. An additional criterion taken was the so-called knock combustion that limits engine performance. Courses of heat release rate and total heat release as a result were obtained. Modeling results show that the test engine powered by a lean mixture of λ = 1.2, should work with the ignition advance angle equal to 12 deg before top dead centre (BTDC). At this ignition advance angle in the engine knock occurred and the engine reached the indicated pressure and the indicated efficiency and were equal to respectively 0.82 MPa and 34.6%.

20

Numerical analysis of the impact of EGR on the knock limit in SI test engine

75%

Tutak W.

Teka Komisji Motoryzacji i Energetyki Rolnictwa

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2011

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tom 11