Mühendislik Fakültesi, Makine Mühendisliği Bölümü, Bildiri & Sunum Koleksiyonu

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https://hdl.handle.net/11492/877

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Evaluation of heat release and combustion analysis in spark ignition Wankel and reciprocating engine
(Elsevier, 2019) Cihan, Omer; Dogan, Huseyin Emre; Kutlar, Osman Akın; Javadzadehkalkhoran, Majid
In this study, a single-rotor multi side port Wankel research engine and a single cylinder spark ignition (SI) engine having three different type combustion chamber geometry (MR, Cylindrical bowl, Flat) were used. Engine experiments were performed at 2000 rpm, 3 bar and 5 bar bmep (brake mean effective pressure) and stoichiometric conditions. Combustion analysis was performed for Wankel and a reciprocating SI engine with three types combustion chamber geometries, which are not included in the literature. In the Wankel engine, the maximum pressure value was lower than the reciprocating SI engines and the maximum pressure obtained far away from the TDC. The reason of this is lower burning velocity and combustion progress toward the expansion stroke. Wankel engine's lower burning velocity also reduced the maximum temperature values. The normalized cumulative heat release rate was about 15% higher than the reciprocating SI engine with different combustion chambers. In Wankel engine, NO emissions are 15-45% lower due to the lower combustion temperatures. On the contrary, THC emissions were up to two times higher due to the combustion chamber geometry and absence of squish effect. The MR type combustion chamber has the highest combustion speed and pressure value due to the intense flow and mixture conditions. In the Wankel engine, combustion process is shifted toward the expansion phase, thus resulting to the lower thermal efficiency. In order to improve this process, additional precaution, such as different mixture formation and flow intensification methods in the combustion chamber are required.
Experimental study on cylindrical grinding with helical grooves wheels
(Kaunas Univ Technology Press, 2016) Köklü, Uğur; Kına, Muammer; Morkavuk, Sezer
The effects of flat and helical grooved wheels on vibration, surface roughness, residual stress and surface topography have been experimentally investigated. The biggest vibration data has been measured on the helical grooved grinding wheels with 15. The best surface quality has been acquired from helical grooved wheels with 45. Flat grinding wheel has produced much more residual stress than helical grooved wheels.
An approach of joint probability assessment for multi-attribute mechanical design optimization
(Kaunas Univ Technology Press, 2016) Mayda, Murat
In this work, a novel practical approach of joint probability assessment to be used for probabilistic optimization of the obtained design data from finite element analysis or experimental studies is proposed. The applicability and efficiency of the proposed approach are demonstrated by conducting a case study, which is the design of a leaf spring for automobiles. At the result of the example design process, performances of design optimizations conducted with different distributions (normal, uniform, Weibull and lognormal) are compared, and it is observed that it allows us to practically and accurately focus on the most feasible design space, and to explicitly see the most probable optimum design points that can be directly used for the multi-attribute design problem. Besides, the opportunity to select the type of distribution for a better optimization performance is another important contribution of this work.
Wind power plants for low rated wind speed regions: feasibility analysis and simulation of a system
(EDP Sciences, 2016) Kaya, Mehmet Numan; Köse, Faruk; Filipowicz, M; Dudek, M; Olkuski, T; Styszko, K
The use of wind power has become an important and growing part of the electrical energy supply in many countries all over the world. Wind turbines are the main components of wind power stations and every single development on these turbines affects the market. Latest developments in wind turbine technologies caused to decrease in costs, thus, besides high-wind-speed regions, low-wind-speed regions are taken into account as a feasible option to generate electricity. The present work investigates the feasibility of a wind power station located in a low rated wind speed region of Turkey providing a general approach for selection of the suitable wind turbine. Economic analysis was performed by calculating the key financial figures such as net present value (NPV), basic payback period (BPP) and the internal rate of return (IRR) for five various options and hourly mean, monthly and seasonal power productions are simulated for the most feasible option using the wind speed measurements in the region. Results show that it is possible to obtain a reasonable capacity factor in low rated wind speed regions with wind turbines that have larger rotors. Although the average wind speed is low in the examined region, a wind power station is still found to be feasible. According to the simulation results, maximum power is produced during the evening hours on a daily basis and during the summer months on a seasonal basis, ensuring power flow usually when maximum power consumption levels are reached. All the data used in this study are based on long-term measurements.
Rule-based Mamdani-type fuzzy modelling of thermal performance of fintube evaporator under frost conditions
(EDP Sciences, 2016) Özen, Dilek Nur; Altınışık, Kemal; Dinçer, Kevser; Ateş, Ali; Sertkaya, Ahmet Ali; Tolu, Muhammed Emin; Filipowicz, M; Dudek, M; Olkuski, T; Styszko, K
Frost formation brings about insulating effects over the surface of a heat exchanger and thereby deteriorating total heat transfer of the heat exchanger. In this study, a fin-tube evaporator is modeled by making use of Rule-based Mamdani-Type Fuzzy (RBMTF) logic where total heat transfer, air inlet temperature of 2 degrees C to 7 degrees C and four different fluid speed groups (ual=1; 1.44; 1.88 m s-1, ua2=2.32; 2.76 m s-1, ua3=3.2; 3.64 m s-1, ua4=4.08; 4.52; 4.96 m s-1) for the evaporator were taken into consideration. In the developed RBMTF system, outlet parameter UA was determined using inlet parameters Ta and ua. The RBMTF was trained and tested by using MATLAB (R) fuzzy logic toolbox. R-2 (%) for the training data and test data were found to be 99.91%. With this study, it has been shown that RBMTF model can be reliably used in determination of a total heat transfer of a fm-tube evaporator.
Complementarity of wind power and pumped hydro energy storage systems – a case study: meeting the electrical energy demand of rural irrigation pumps of Cumra, Alibeyhuyugu
(Yayıncı Yok, 2012) Köse, Faruk; Kaya, Mehmet Numan
Energy has been one of the most important components for human beings to have a comfortable life. Much has been discussed about energy production methods since energy is such a remarkable topic. Renewable energy sources have become more popular in recent years because of the limited amount of fossil fuels. However, the dependency of renewable energy sources on the weather and climate, pointed people to search energy storage methods to supply firm power. Especially storing wind energy is one of the most popular topics for researchers. Pumped-hydro, compressed air and battery energy storage systems are the bulk energy storage systems to store wind energy. Pumped-hydro energy storage (PHES) systems are a step ahead among other bulk energy storage methods because they are more efficient and they have higher storage capacities. In this study, we have designed and analyzed a wind-pumped hydro hybrid energy supply system to meet the electrical energy demand of water pumps used for rural irrigation in Cumra, Alibeyhüyüğü and sell the excess energy to the government or local consumers. ALWIN program is used for annual energy generation prediction.
The Importance of Renewable Energy Sources for Sustainable Development in Turkey
(Yayıncı Yok, 2012) Köse, Faruk; Kaya, Mehmet Numan; Berber, Adnan
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Experimental Investigation of the Use of Solar Collectors for Space Heating: A case study for Karaman, Turkey
(Yayıncı Yok, 2015-06) Kaya, Mehmet Numan; Akpınar, Hasan Abdurrahim; Köse, Faruk
Space heating is necessary for humankind to have a comfortable life and it is mostly performed using fossil fuels causing to serious environmental impacts. In this study, a solar heating system is designed and installed to a seperate house located at the Karamanoglu Mehmetbey University in Karaman, Turkey. Main components of the solar heating system is solar collectors and hot water storage tank which are connected each other through pipes. In addition, a natural gas-fired combi boiler is installed for meeting the heating demand in the periods when solar collectors can not cover the heating need. Reduction in CO2 emissions afforded by the use of this facility compared to conventional system were calculated. Additionally, an economic analysis was performed where basic payback period, NPV and IRR calculated.
Investigation of Effects of LED Color on Power Performance of a Solar Powered LED Lighting System for Selcuk University
(Yayıncı Yok, 2014-06) Köse, Faruk; Berber, Adnan; Kaya, Mehmet Numan; Sözer, Halit Çetin; Dinçer, Kevser
Generally, 20% of the electric power is used for lighting and rate of consumption of the total electric power within the lighting category keeps increasing every year. Solar powered lighting systems are among the areas where solar panels are used most. In this study a solar powered light emitting diode (LED) lighting system was designed. While the best power performance was 91.67 Watt occurring at red color LED, the poorest performance recorded was 515.625 Watt taking place at the blue LED. It was also found that the color of the LED used affects the power performance of the solar panel.
Use of Pumped Hydro Energy Storage to Compliment Renewable Energy: A case study for Cumra, Turkey
(Yayıncı Yok, 2014-06) Kaya, Mehmet Numan; Köse, Faruk
Energy has become one of the main requirements of human beings today. Different energy supply methods have been developed until today but the limitation of fossil fuels pointed researches to work on renewable energy systems since renewable energy sources are unlimited, clean and sustainable. The dependency of renewable energy sources on the weather and climate was another problem for researchers because of the requirement of firm power. Energy storage systems have been seen as a solution to prevent power fluctuations and supply firm power from energy production systems. The situation is same for Turkey, investments on renewable energy sources increases day by day and this causes Turkey to require energy storage systems to balance the energy in the network. In this paper, bulk energy storage methods, especially pumped hydro energy storage, are examined. A case study is performed to meet the electrical energy demand of irrigation pumps which have huge electrical energy consumption in total and used for irrigation in Alibeyhuyugu, Cumra, Turkey. Simulation and also economic analysis results have been presented
Solar trackers and feasibility analysis of usage of solar trackers in electricity production in Konya, Turkey
(Yayıncı Yok, 2012) Kaya, Mehmet Numan; Tolu, Muhammed Emin
World energy needs increases every day and it becomes more difficult to meet the energy demand of the growing population without harming the environment. Therefore, renewable energy is the main area of study for concerned researchers and scientists. Electricity production by using solar energy is one of the best alternatives to fossil fuels that lose its importance, due to rising costs and damage to the environment. The number of studies to advance the efficiency of solar systems increases day by day. Especially in electricity supply, usage of high efficiency solar energy systems can meet the expectations. At this stage, solar trackers that provide us efficient utilization of solar energy, gains importance. In this paper, working principles, usage advantages and economical contributions of solar trackers are discussed. Fixed systems, one axis systems and two axis systems are compared in terms of efficiencies and economic advantages. During this study, Photovoltaic Geographical Information System (PVGIS) is used for comparison between systems. It is obtained that solar power generation systems with solar trackers are more feasible than fixed systems.
Comparison of Energy Demand Coverage with a CHCP Plant and a Convetional System: A Case Study for a Hospital in Konya, Turkey
(Yayıncı Yok, 2015-06) Tolu, Muhammed Emin; Kaya, Mehmet Numan
Combined heating, cooling and power (CHCP) plants are one of the most efficient options for meeting the entire energy demand of humankind. Today, they are used very widely arround the world and the use of these has an increasing trend. High efficiency of CHCP plants help to reduce CO2 emmision and this make them environment friendly compared to other energy supply methods from fossil fuels. In this study, a comparasion of energy demand coverage of a commercial hospital located in Konya, Turkey with a CHCP plant and a conventional system which is installed now, is performed. The electrical load and heat load for both space heating and hot water were obtained by using real consumption data of the hospital for previous years. Economic analysis was performed, the feasibilty and enviromental impact of both systems are compared.

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