Keresés

Keresési eredmények

• Numerical Model Analysis of Natural Gas Combustion Burners

  67-71

  Ibraheem Amjd

  Szodrai Ferenc

  Megtekintések száma:

  159

  Traditional power plants still the dominating power source for all the major industries and powerdemanding facilities, the most crucial facility for the whole plant operations is the industrial boiler which generatessteam, heating energy or electrical power. Boilers generate energy by combustion. The improvement of combustion efficiency could greatly influence the energy consumption and will make the boiler more efficient and cleaner (less emissions), that’s why it is important to understand the combustion and thermal flow behaviours inside the boiler. Beside experimental testing, computational work nowadays becoming more and more important due to lower cost and acceptable accuracy with minimum error. With numerical calculations method, the computational model created by a Computational Fluid Dynamics (CFD) software could reduce a lot of trial and error on experimental work. In this paper utilizing the ANSYS FLUENT 19.1 software to make crate the combustion model. The ratio of air to fuel mixture, the equivalency factor, mass flow rate of the mixture, velocity, mass fractions of the mixture components (fuel and air) and their temperatures will serve as the input parameter while the exhaust gase component mass fraction, temperature, mass flow and velocity will be monitored.

• Optimizing the combustion processes of a small scale solid fuel-fired boiler

  358-369

  Mentes Dóra

  Sajti Zoltán

  Koós Tamás László

  Póliska Csaba

  Megtekintések száma:

  144

  Over the last decade, the public has been paying increasing attention to reducing greenhouse gas and acid rain emissions and reducing particulate matter, which is extremely harmful to health and the environment. To improve air quality, the European Commission has achieved a range of measures to reduce air pollutant emissions in the transport, heat and electricity, industrial and agricultural sectors. In Hungary, the amount of gas and solid air pollutants from solid fuel combustion used by the public during the heating season represents a significant percentage of the total amount present in the atmosphere. In 2016, taking into the total emission, the 29% of CO2 emissions; 85% of CO emissions; 75% of the particulate matter emissions and 21% of the NOx emissions were derived from households. It follows that the improvement of air quality can also be achieved by controlling the emissions of solid fuel combustion plants. During our research we aimed to optimize the operation of a newly purchased TOTYA S18 boiler and a pilot pellet boiler. Operating the boilers in the correct mode minimizes air pollutant emissions, and the greater part of the heat generated is actually turns to heating the home, as with poor settings, a lot of heat leaves through the chimney. The data obtained during the tests can also be used to determine whether the boilers comply with the emission values set out in Commission Regulation (EU) 2015/1185.

• The Impact of Electrical Vehicles on Sustainability: Jordan as a Case Study

  393-403

  Malak M. Shatnawi

  Megtekintések száma:

  217

  The Global concern is moving toward making a revolution in favor of exploitation of renewable energy in order to improve environment conditions, limit emissions and minimizes consumption of non-renewable resources within the planet. In this context, it is necessary to focus on the transport sector as it contributes of at least 30% of the total primary energy consumption. Therefore, a set of rules must be developed to maintain economic, environmental and social sustainability to address the problems so as not to increase their severity and these cannot be done unless there are joint measures and regulations from governments, companies, manufacturers and users. Unfortunately, the Jordanian transport system mostly depend on the individual transport which supported by cars, and that because of the weak role played by the public transport sector, especially at the capital, Amman. Buying hybrid cars (internal combustion engine + electric motor) and Electrical Vehicles (EV), in the past few years in Jordan is increasing, which is compatible with the global trend to use Electrical Vehicles (EV) instead of Internal Combustion Engine vehicles (ICE) powered by fossil fuels, this issue will have a direct and indirect impact on gas stations companies, also it will have direct impact on labor sector and the current car industry since electric charging stations as well as EV manufacturing is not labor intensive. The main purpose of the study is to show how much it is necessary now to start theoretical assumptions through studying the expected annual increase in passenger cars and its impact on sustainability and predicting the future fuel consumption and emissions and compare them with the base situation.

• Combustors with Low Emission Levels for Aero Gas Turbine Engines

  503-514

  Guellouh Noureddine

  Szamosi Zoltán

  Siménfalvi Zoltán

  Megtekintések száma:

  411

  The aircrafts are responsible for emitting several types of pollutants, especially the pollutants in the form of NOX, CO2, CO, UHC, SOX and Particulate Matter PM (smoke/soot). The impact of aviation emissions on the global is well known, where these emissions modify the chemical and microphysical properties of the atmosphere resulting in changes of earth’s climate system, which can ultimate in critical changes in our planet fragile ecosystem, also the pollutants produced by aircraft engines cause many health problems. This is why the International Civil Aviation Organisation (ICAO) is seriously seeking to control the emission levels by issuing new standards during the successive meetings of the Committee on Aviation Environmental Protection CAEP (CAEP/01 in 1986, CAEP/2, CAEP/4, CAEP/6, CAEP/8, etc). The new regulations include more stringent standards aimed to reduce emission levels, this led to increased interest in low emission technologies. In this paper, a comprehensive review of low emissions combustion technologies for modern aero gas turbines is represented. The current low emission technologies include the high Technologies Readiness Level (TRL) including RQL, TAPS, DAC and LDI. Also, there are advanced technologies at lower TRL including LPP, ASC and VGC.

• Review of Modern Vehicle Powertrains and Their Modelling and Simulation in MATLAB/Simulink

  232-250

  Szántó Attila

  Szíki Gusztáv Áron

  Megtekintések száma:

  1096

  Thanks to technological advances and environmental standards, as well as changing usage patterns, road vehicles are constantly developing. Electric and hybrid vehicles are playing an increasingly important role in today’s road transport. The most significant changes are probably in the powertrain of vehicles. The efficiency of internal combustion engines increases while their emissions continue to decline. In addition, high performance electric motors, batteries and even fuel cells play an increasingly important role in hybrid and electric vehicles. In this publication, we review the drive systems of current modern vehicles and the types and characteristics of their major components. We also review the available models and computer programs for their simulation, focusing mainly on MATLAB/Simulink applications. Based on this, we can develop our own models and simulation programs which will help us to perform different driving dynamics simulations and to compare the performance, dynamic and energetic characteristics of these powertrains and their components to each other.

• Introduction to Design and Analysis of Torsional Vibration Dampers in Vehicle Industry

  310-324

  Venczel Márk

  Veress Árpád

  Megtekintések száma:

  343

  The crankshaft of today’s internal combustion engines with high performance output are exposed to harmful torsional oscillations originated from the unbalanced gas and inertial forces. To avoid the fatigue damage of engine components, caused by the undesired vibrations, torsional vibration dampers can be applied. Viscodampers are one type of the torsional vibration dampers, which operational fluid is silicone oil. For cost-effective R&D activities and production, finite element and finite volume numerical discretization methods based calculation techniques must be involved into the engineering work supported by the modern computer technology. The aim of this paper is to provide an insight into the multidisciplinary design and development process of visco-dampers in vehicle industry applications. Four different examples as structural, fatigue, CFD analyses and structural optimization have been introduced in the present work. It turned out from the static structural and fatigue analyses, that the investigated damper has safety factor over the limit for both static structural and fatigue analyses, so it is suitable for the given load conditions. In the structural optimization process 34.36% mass reduction has been achieved. According to the coupled fluid dynamic and heat transfer simulations a rather stagnating air zone evolved between the engine and the damper during the operation, which can cause efficiency reduction of cooling fins mounted onto the housing. In light of the numerical results, the suitable damper position has been determined for the highest heat transfer.

• Vitorlás kishajóra ható ellenállás erő visgálata hajtáslánc csere okozta merülésváltozás esetén numerikus áramlástani szimulációk használatával

  30-35

  Ficzere Péter

  Lévai Emese

  Megtekintések száma:

  229

  Kedvtelési célú vízijárművek esetén a környezetvédelmi okokból egyre szigorodó szabályok miatt a motoros hajtások megoldásaiba való beavatkozás napjainkban gyakori munkafolyamat. Belsőégésű motorról elektromos motorra való átváltáskor a merülésváltozás hajónként eltérő, azonban közösen elmondható minden esetben, hogy a tömeg változásával a merülés is változik. Emiatt a hajóra ható ellenállási erő nagysága is változik. Jelen cikkben egy konkrét példán keresztül vizsgáljuk, milyen hozadékai vannak a tömegnövekedés okozta merülésváltozásnak különféle haladási sebességeknél.

• A modern járművekben alkalmazott hajtásrendszerek áttekintése

  728-732

  Szántó Attila

  Mankovits Tamás

  Szíki Gusztáv Áron

  Megtekintések száma:

  198

  Jelen közleményben áttekintjük a modern elektromos és hibrid rendszerű járműhajtásokat. Továbbá áttekintjük az azokban alkalmazott villanymotorok, akkumulátorok és üzemanyagcellák típusait, valamint a felépítésükkel és jellemző tulajdonságaikkal foglalkozó szakirodalmat. Továbbá, mivel a hibrid járművek fontos része a belsőégésű motor, áttekintjük azok hatékonyságának növelésére, valamint emissziójuk csökkentésére alkalmazott eljárásokat.

• Zöld növényi biomassza hasznosításának nemzetközi és hazai kilátásai

  85-105

  Antal Gabriella

  Megtekintések száma:

  160

  Napjainkban az emberiség energiafelhasználása még a fosszilis energiáktól függ, de a megújuló energiaforrások szerepe egyre inkább erősödik elsősorban a fosszilis energiaforrások kimerülése, a környezetvédelmi problémák felértékelődése és a klímapolitikai indokok miatt. A biomassza a világ negyedik legfontosabb energiaforrása, amely globális szinten közel 73%-ot képvisel a megújuló energiaellátásban. A biomassza felhasználás növekedésének évi üteme azonban meglehetősen elmarad a modern megújuló energiaforrásokhoz képest. A világon található biomassza igen sokrétű, különböző módon előkészíthetőek és feldolgozhatóak. Jelenleg a „zöld kémia” iparágon belül (a kőolaj-alapú, vegyipari szintetikus alapanyagok kiváltása növényi, biomassza eredetű anyagokkal) az eltüzelés, a pirolizálás, a biogáz-, a bioetanol- és a biodízel és a különböző kémiai alapvegyületek előállításának van jelentősége. Jelen kutatások célja az egyes megújuló energiaforrások és a biomassza felhasználásának globális és hazai helyzetének bemutatása, a Debreceni Egyetemen folyó kutatási programokban évek óta vizsgált potenciális évelő, lágyszárú biomassza növény, az olasznád (Arundo donax L.) hasznosítási lehetőségeinek ismertetése.