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    Combustion, performance and emissions of a diesel power generator fueled with biodiesel-kerosene and biodiesel-kerosene-diesel blends
    (Elsevier, 2017-02-05) Bayındır, Hasan; Işık, Mehmet Zerrakki; Argunhan, Zeki; Yücel, Halit Lütfi; Aydın, Hüseyin
    High percentages of biodiesel blends or neat biodiesel cannot be used in diesel engines due to high density and viscosity, and poor atomization properties that lead to some engine operational problems. Biodiesel was produced from canola oil by transesterification process. Test fuels were prepared by blending 80% of the biodiesel with 20% of kerosene (B80&K20) and 80% of the biodiesel with 10% of kerosene and 10% diesel fuel (B80&K10&D10). Fuels were used in a 4 cylinders diesel engine that was loaded with a generator. Combustion, performance and emission characteristics of the blend fuels and D2 in the diesel engine for certain loads of 3.6, 7.2 and 10.8 kW output power and 1500 rpm constant engine speed were experimented and deeply analyzed. It was found that kerosene contained blends had quite similar combustion characteristics with those of D2. Mass fuel consumption and Bscf were slightly increased for blend fuels. HC emissions slightly increased while NOx emissions considerably reduced for blends. It was resulted that high percentages of biodiesel can be a potential substitute for diesel fuel provided that it is used as blending fuel with certain amounts of kerosene.
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    An experimental investigation of the effect of thermophysical properties on time lag and decrement factor for building elements
    (Gazi University, 2020-06-01) Oktay, Hasan; Yumrutaş, Recep; Argunhan, Zeki
    The time lag (TL) and decrement factor (DF) are essential for the heat storage capabilities of building elements, which strictly depend on the thermophysical properties of the elements. Many investigations are presented in literature arguing to find the influence of each thermophysical property on TL and DF by keeping the other properties constant. This study aims to investigate the effect of each property on TL and DF, utilizing relationships between the measurement values of the thermophysical properties of wall materials. Therefore, first, 132 new concrete wall samples were produced, and their thermophysical properties were tested. Secondly, TL and DF values for each building element are computed from the solution of the problem by Complex Finite Fourier Transform (CFFT) technique. Finally, a multivariate regression analysis has been performed, and the variations of each thermophysical property versus TL and DF are presented, and also the findings are compared with literature. The results show that each property alone (keeping the other properties constant) is not adequate to identify the thermal inertia and thermal performance of a wall element. Besides, 87.3 % decrease in thermal diffusivity corresponds to 6.03 h increase in the value of TL and 88.8 % decrease in value of DF; respectively, for W1 wall assembly.
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    The efficiency of Al2O3 water nanofluid on a flat plate solar collector
    (SETCOR publications, 2015) Budak Ziyadanoğulları, Neşe; Yıldız, Cengiz; Argunhan, Zeki; Tekalp, Selen; Yücel, Halit Lutfi
    Solar collectors are particular kind of heat exchangers that transform solar radiation energy into internal energy of the transport medium. One of the most effective methods is replacing the working fluid (water, ethylene glycol, engine oil…) by developing a new class of fluids with a higher thermal conductivity for thermal systems. In the present work the effect of Al2O3-water, as working fluid, on the efficiency of a flat plate solar collector is investigated experimentally. The mass flow rate of nanofluid is 150 Lit/h. The volume fraction of the nanoparticles is 0.2 %, 0.4 % and 0.8 % respectively. The results reveal the impact and importance of each of these parameters. Experimental results reveal that utilizing the nanofluid increases the collector efficiency in comparison to water as an absorbing medium
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    Experimental investigation of solar stills integrated with solar water heating collectors
    (Türk Isı Bilimi ve Tekniği Derneği, 2017-10-31) Argunhan, Zeki; El, Emin; Yıldız, Cengiz; Çakmak, Gülşah
    Solar still is a more practical way of obtaining clean water. In this study, we aimed to improve the efficiency of solar still systems and obtain distilled water at the same time. For this purpose, 5 different solar still systems were designed. Type 1; conventional solar still, Type 2; conventional solar still integrated with solar water heating collector and run via natural convection, Type 3; conventional solar still integrated with solar water heating collector and tubular heat exchanger and run via natural convection, Type 4; conventional solar still placed with plate heat exchanger and integrated with solar water heating collector and run via natural convection, Type 5; conventional solar still placed with plate heat exchanger and integrated with solar water heating collector and run via forced convection. In this study, the experiments were carried out on the parameters influencing the performance, the amount of distilled water obtained, and the efficiency of experiment settings designed in different types; and finally the results were presented. The amount of distilled water and efficiency of conventional solar still were 2389 ml and 51.47%, respectively. Maximum total amount of water and efficiency from natural convection systems were obtained from Type 4, and the values calculated were found as to be 5788 ml and 55.91%. Maximum amount of distilled water and the efficiency were obtained by utilizing forced convection system were found as to be 6068 ml and 58.99%, respectively.
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    Konsantrik boru tip ısı değiştiricilerinde türbülatörlerin kanat delik geometrisinin ısı transferine ve basınç düşüşüne etkisi
    (Fırat Üniversitesi, 2011) Işık, Mehmet Zerrakki; Argunhan, Zeki; Yıldız, Cengiz
    The effect of wing hole geometry of the vortex generator on heat transfer and pressure drop in concentric tube type heat exchangers has been investigated in this study.For experiments, two type of hole geometrywereselected.One has four rectengular hole with 2x7mm in dimension andthe other four circular hole with 5mm in diameter andapplied for 55-65-75-90 degree blade angles. Turbulator diameter is 60 mm and includes 6 blades. Air was used as hot stream, whereas water as cold stream. Experimental results were scrutinized.Heat transfer and pressure drop werefound high with usage of circular holes geometry.
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    Experimental investigation of the effects of diesel-like fuel obtained from waste lubrication oil on engine performance and exhaust emission
    (Journals & Books, 2010-10) Argunhan, Zeki; Yumrutaş, Recep; Arpa, Orhan
    In this study, effects of diesel-like fuel (DLF) on engine performance and exhaust emission are investigated experimentally. The DLF is produced from waste engine lubrication oil purified from dust, heavy carbon soot, metal particles, gum-type materials and other impurities. A fuel production system mainly consisting of a waste oil storage tank, filters, a reactor, oil pump, a product storage tank, thermostats and control panel is designed and manufactured. The DLF is produced by using the system and applying pyrolitic distillation method. Characteristics, performance and exhaust emissions tests of the produced DLF are carried out at the end of the production. The characteristic tests such as density, viscosity, flash point, heating value, sulfur content and distillation of the DLF sample are performed utilizing test equipments presented in motor laboratory of Mechanical Engineering Department, University of Gaziantep, Turkey. Performance and exhaust emission tests for the DLF are performed using diesel test engine. It is observed from the test results that about 60 cc out of each 100 cc of the waste oil are converted into the DLF. Characteristics and distillation temperatures of the DLF are close to those values of a typical diesel fuel sample. It is observed that the produced DLF can be used in diesel engines without any problem in terms of engine performance. The DLF increases torque, brake mean effective pressure, brake thermal efficiency and decreases brake specific fuel consumption of the engine for full power of operation.
  • Küçük Resim
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    Dairesel kesitli bir borunun girişine yerleştirilen delikli sabit kanatçıklı dönme üreticinin ısı geçişi ve basınç düşüşüne etkileri
    (Pamukkale Üniversitesi, 2006-02-01) Argunhan, Zeki; Yıldız, Cengiz
    Bu çalışmada iç içe borulu ısı değiştirgecinde farklı delik sayılı dönme üreticilerin ısı transferine ve basınç düşüşüne etkisi deneysel olarak araştırılmıştır. Bu amaçla değiştirgecin 60 mm çapındaki iç borunun girişine 55º kanat açısına sahip ve kanatlarında birer, ikişer, üçer ve dörder adet dairesel delikler bulunan dönme üreticiler yerleştirilerek deneyler yapılmıştır. Bunlar iç borunun girişine rahat takılıp sökülebilecek şekilde dizayn edilmişlerdir. İç borunun içinden sıcak akışkan olarak hava, iç borunun dışından ise soğuk akışkan olarak su geçmektedir.
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    An investigation of the influence of thermophysical properties of multilayer walls and roofs on the dynamic thermal characteristics
    (Mugla Sitki Kocman University, 2016-06-09) Oktay, Hasan; Argunhan, Zeki; Yumrutaş, Recep; Işık, Mehmet Zerrakki; Budak Ziyadanoğulları, Neşe
    The growing concern about energy consumption of heating and cooling of buildings has led to a demand for improved thermal performances of building materials. To achieve this goal, in this study, an investigation is performed to analyze the influence of thermophysical properties and thickness of various multilayer building walls or roofs in a building on the dynamic thermal characteristics, such as the decrement factor (DF), time lag (TL) and heat gain. In order to find the thermal performance characteristics of building structures, such as briquette, brick, blockbims and autoclaved aerated concrete (AAC), which are commonly used in Turkey, an analytical solution method was developed in a computer program in MATLAB and results are compared to determine suitable wall or roof material. Calculation method for the heat flow is based on solution of transient heat transfer problem for the multilayer structures. The program is executed to calculate hourly heat gain values for these samples over a period of 24 h during design day for Gaziantep, Turkey. It was found that thermophysical properties of roofs or walls have a very profound effect on the time lag (TL), decrement factor (DF) and also heat gain.
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    Investigation of the thermal and acoustic performance of perlite- based building materials
    (European Journal of Technique (EJT), 2016-12) Oktay, Hasan; Argunhan, Zeki; Doğmuş, Recep
    Perlite is a siliceous volcanic glass that provides heat and sound insulation, whose volume can expand substantially under the effect of heat. Perlite ore is one of the most important mineral resources for Turkey where holds a large portion reserves in the world. Evaluation of perlite in building industry, which has advantages in terms of heat and sound insulation, will make an important contribution to the national economy. In this context, experimental investigations are performed for obtaining new concrete types with relatively high strength, low density and good thermal and acoustic properties for energy efficient buildings. For this purpose, 6 sets and different types of concrete samples were prepared with a constant watercement ratio, and normal aggregates replaced by expanded perlite aggregates at different volume fractions such as 10%, 20%, 30%, 40%, 50% and 60% of the total aggregate volume. Mechanical and thermal tests were all conducted and the hot disk method was used to establish thermal property values of concrete samples. The results of the experimental studies show that the compressive strength and density decreases, while highly increases the heat and sound insulation features with increasing in perlite content. As a result, it was found out that the reductions in thermal conductivity [Wm–1K–1] and ultrasonic pulse velocity [km/s] of the produced samples reached to 75% and 35%, respectively.
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    Comparison of heat gain values obtained for building structures with real and constant properties
    (Bitlis Eren Üniversitesi, 2019-12-24) Oktay, Hasan; Yumrutaş, Recep; Argunhan, Zeki
    The magnitude of energy consumption due to the heating and cooling of buildings has led to the demand for increasing the thermal performance of building structures. Many investigations are presented in literature arguing to find the effect of each thermophysical property on the thermal characteristics of building components, while the properties have been assumed as independent of each other. In this context, this paper focuses on the effect of each property on heat gain value utilizing relationships between the measurement values of the thermophysical properties of building structures. In the previous study, 102 new wall samples were produced, their thermophysical properties were tested and expressions among these properties are obtained. In this study, the heat gain values through the structures are computed using the solution of the transient heat transfer problem by using both the obtained expressions between the thermophysical properties and assumptions proposed from the literature. Results obtained for varying and constant thermophysical properties have been compared with those values presented in the literature. The results show that the assumptions are not realistic in a significant number of cases. Moreover, if one of the thermophysical properties of a material is known, heat gain values can be calculated easily for the selected wall or roof types.