Yazar "Aktas, Abdurrazzak" seçeneğine göre listele

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    EFFECTS OF LPG PERCENTAGE TO PERFORMANCE AND EXHAUST EMISSIONS IN A DUAL FUEL ENGINE
    (Gazi Univ, Fac Engineering Architecture, 2010) Aktas, Abdurrazzak; Dogan, Oguzhan
    In this study, an experimental investigation was presented to determine the effects of various ratios of Liquefied Petroleum Gas (LPG), containing 30% propane and 70% butane, on the performance and exhaust emission in a dual fuel engine with direct injection. The tests were performed at maximum torque speed of 2600 rpm with a various loads of maximum torque (20%, 40%, 60%, 80% and 100%) by using pure diesel fuel or dual fuel containing 20%, 40%, 60%, 80% and 90% of LPG. The test results showed that the smoke and Nitrogen oxide (NOx) emissions decrease, while carbon monoxide (CO) and hydrocarbon (HC) emissions increase at all mixtures of LPG and diesel fuel. Brake specific fuel consumption (bsfc) decreases by 3.5-15% with 40% LPG while the load increases. Exhaust gas temperatures at the mixture fuel were lower than that of diesel fuel in general. It was concluded that LPG can be used with diesel fuel as a mixture up to 40-60% of LPG, provided that CO and HC emissions can be lowered.
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    Effects of Soybean Oil Methyl Ester on Diesel Engine Performance and Exhaust Emissions
    (Gazi Univ, 2008) Sekmen, Yakup; Aktas, Abdurrazzak
    Biodiesel is an alternative fuel for diesel engine that can be produced by chemically reacting a vegetable oils, waste cooking oils, and animal fats with an alcohol to form alkyl esters. It is an oxygenated, sulfur-free, non-toxic, biodegradable, and renewable fuel with a higher cetan number and lubricity and can be used as pure or blends without any significant modification in diesel engines. In this study, the effects of using soybean oil methyl ester as a fuel in a direct injected diesel engine on the performance and exhaust emissions were investigated experimentally. Experimental study was performed using diesel fuel no. 2 and soybean oil methyl ester at full load and engine speeds ranging from 1200 to 2400 rpm. The results showed that the biodiesel produced lower effective power and higher specific fuel consumption than diesel fuel due to lower heating value of soybean oil methyl ester. In addition, CO, HC, NOx and smoke emissions from biodiesel were lower than that of diesel fuel no.2.
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    Effects of using blends of melon kernel oil methyl ester and Diesel fuel on the engine performance and emissions
    (Sila Science, 2012) Aktas, Abdurrazzak
    Many types of vegetable oils and their methyl esters were tested in diesel engines as an alternative fuel. Melon has a high potential of production. Wasted Melon kernel, generally has a high oil ratio and similar properties with other biodiesel sources and can be used for biodiesel production. In this study, the oil was produced from melon kernel and then converted to the biodiesel. The effects of pure melon kernel oil methyl ester (MKOME) and its 2% and 20% blends with Diesel fuel no.2. on performance and emissions was investigated in a single cylinder, direct injection diesel engine at full load and various engine speeds. Melon kernel oil methyl ester blended with diesel by 2% produced slightly higher torque, power and nitrogen oxides emission along with lower carbon monoxide, hydrocarbon and smoke density. Torque, power, carbon monoxide and hydrocarbon emissions were decreased as the ratio of melon kernel oil methyl ester is increased. The lowest Hydrocarbon emission was measured for 20% melon kernel oil methyl ester-diesel fuel blend.
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    AN EXPERIMENTAL INVESTIGATION OF THE EFFECT OF REFRIGERANT CHARGE LEVEL ON AN AUTOMOTIVE AIR CONDITIONING SYSTEM
    (Turkish Soc Thermal Sciences Technology, 2011) Atik, Kemal; Aktas, Abdurrazzak
    During the last 25 years automotive air conditioning (AAC) systems have significant development introduced by the industry and research institutes in the world to minimize the global warming threat to the environment. This paper reports the results of a study on the performance of an AAC system with measuring the compressor driving speed and the refrigerant leakage. For this purpose an experimental set up is designed and constructed to investigate the system performance. Although, the manufacturer's recommended amount for the tests with R-134a as refrigerant was 750 g, the experiments were also carried out by selecting different amount of the same refrigerant charges to analyse the coefficient of performance (COP), the cooling capacity and the compressor power change with respect to the rotating speed of the compressor. The evaluation of experimental data revealed that the best cooling capacity was achieved at 500 g refrigerant charge. Although, while the charge level decreased 40% below or increased 20% above the 500g of the charge amount, cooling capacity loss increased up to 25% when optimum value of 500 g of the cooling refrigerant was utilized. The test results proved in each case that increasing the compressor driving speed cause almost a linear change in the corresponding power level. The test results also shown that COP of the cooling system was decreased effectively when the revolution speed increased for any specified charge amount of the refrigerant.
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    Performance parameters estimation of MAC by using artificial neural network
    (Pergamon-Elsevier Science Ltd, 2010) Atik, Kemal; Aktas, Abdurrazzak; Deniz, Emrah
    In this study, a modeling of a mobile air conditioner system in different amounts of refrigerant and in different compressor revolution speeds was carried out via artificial neural network (ANN). The three-layered ANN that is utilized in order to be able to model this system has 2 cells in its input layer and 3 cells in its output layer. The least problem-yielding ANN structure was analyzed by examining the number of cells in hidden layer from 6 to 19. The best result was obtained in the ANN with 10 hidden cells. A 0.945 was obtained in estimating coefficient of correlation cooling capacity, 0.985 was found in the power consumed in compressor, and 0.994 was established in COP estimation. The obtained correlation coefficients showed that ANNs can be used with a high precision in guessing the performance parameters of mobile air conditioner (MAC) systems. (C) 2010 Elsevier Ltd. All rights reserved.