Müjdat Fırat

Effects of inclination angle on natural convection in an inclined open porous cavity with non‐isothermally heated wall

Purpose – The purpose of this numerical study is to investigate the effects of inclination angle and non‐isothermal wall boundary conditions in a partially open cavity filled with a porous medium.Design/methodology/approach – In this study, the governing dimensionless equations were written using Brinkman‐Forchheimer model. They are numerically solved by using finite volume method with SIMPLE solution algorithm by applying open boundary conditions in one side. The opposed side of the open cavity is under non‐isothermal boundary conditions.Findings – Results are presented by streamlines, isotherms, velocity and temperature profiles as well as the local and mean Nusselt numbers for different values of the governing parameters such as Grashof numbers, porosity, amplitude of sinusoidal function and inclination angle of the cavity. It is found that inclination angle is the most important parameter on the temperature and flow field.Originality/value – The originality of this study is the open sided enclosure fi...

Using Gasoline-like Fuel Obtained from Waste Automobile Tires in a Spark-ignited Engine

An experimental study on performance and exhaust emission of a spark-ignited engine fueled by gasoline-like fuel obtained from waste automobile tires using the prolysis process was performed in this study. Gasoline-like fuel has a higher octane number than unleaded gasoline; however, it has higher in viscosity in comparison to unleaded gasoline, which limited the use of gasoline-like fuel in neat form. Therefore, gasoline-like fuel was blended with unleaded gasoline from 0% to 100% with an increment of 10%, volumetrically. Obtained blends were then used in a spark-ignited engine. It was observed that the test engine was normally run up to blended fuel containing gasoline-like fuel of 60%. It is concluded that gasoline-like fuel can be partially substituted for the gasoline fuel up to 60% in blended form in terms of performance parameters and emissions without any engine modification.

Numerically investigation of MHD liquid lithium flow under cooling conditions in a circular channel

Bu çalışmada, lityum sıvısı dıştan manyetik alan indüksiyonuna maruz bırakılan üç boyutlu dairesel bir kanalda sayısal olarak incelenmiştir. Manyetik alan, kanala akış yönüne dik olarak uygulanmıştır. Re=2250 ve manyetik alan kuvveti sırasıyla 0T, 0.04T, 0.08T ve 0.12T olarak seçilmiştir. Bunun yanında, akışkan sıcaklığı 473.15 K iken cidar sıcaklığı 373.15 K’dir. Hesaplamalar ANSYS-Fluent ticari yazılımı ile gerçekleştirilmiştir. Manyetik alanın akışkan hızı, basınç ve sıcaklık üzerindeki etkileri grafiksel olarak sunulmuştur. Manyetik alan etkisinin akışkan hızını azaltırken, basıncı arttırdığı gözlemlenmiştir. Ayrıca, manyetik alan boru uzunluğu boyunca kanalın farklı bölgelerinde, sıcaklığı farklı şekilde etkilediği gözlemlenmiştir. In this study, the lithium fluid was numerically analyzed in a threedimensional circular channel exposed to external magnetic field induction. The magnetic field is applied perpendicular to the flow direction of the channel. Re=2250 and the magnetic field strength was selected as 0T, 0.04T, 0.08T and 0.12T, respectively. Besides, while the fluid temperature is 473.15 K, the wall temperature is 373.15 K. Calculations were performed with ANSYS-Fluent commercial software. The effect of the magnetic field on the fluid velocity, pressure and temperature has presented graphically. While the magnetic field seriously has reduced the fluid velocity, the pressure has observed to increase. Also, it has been observed that the magnetic field affects the temperature differently in different regions of the channel along the pipe length.

Numerical Investigation of Heat Transfer, Fluid Flow and Formation of Emissions in Diesel Engines

The present study has been performed on heat transfer, fluid flow and formation of emissions in a diesel engine by different engine parameters. The analysis aims at an investigation of flow field, heat transfer, combustion pressure and formation of emission by means of numerical simulation which is using as parameter; hole number of injector and crank angle. Numerical simulations are performed using the AVL-FIRE commercial software depending on the crank angle. This software is successfully used in internal combustion engine applications, and its validity has been accepted. In this paper, k-zeta-f is preferred as turbulence model and SIMPLE/PISO used as algorithms. Thus, results are presented with pressure traces, temperature curves and NOx and soot levels for engine operating conditions. In addition, the relationship between the spray behaviors and combustion characteristics including NOx emissions, soot emissions, combustion pressure and temperature were illustrated through this analysis.Copyright