Mechanical Engineering / Makina Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/4129

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Publisher: search.filters.publisher.Begell HouseSubject: search.filters.subject.Porous media

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  • Article
    Interfacial Convective Heat Transfer for Randomly Generated Porous Media
    (Begell House, 2018) Uçar, Eren; Mobedi, Moghtada; Ahmadi, Azita
    Heat and fluid flow in 20 random porous media is investigated by using the Monte Carlo (MC) procedure. Each porous medium consists of long square rods distributed randomly in flow direction. The continuity, momentum, and energy equations are solved for a row of porous media representing the entire domain of a random porous medium. The microstructure properties of each random porous medium which are the mean and standard deviations of the Voronoi areas, the nearest neighbor distance and orientation are obtained. The rods in the domain are classified into three groups as blocker, active, and passive rods according to their effects on the penetration of heat in porous media. 'The interfacial convective heat transfer coefficients for each rod and entire porous medium are calculated and plotted for different Reynolds numbers. A characteristic length based on the microstructure properties of the generated porous media is defined, and three correlations relating to the upper limit, lower limit, and mean of the overall interfacial convective heat transfer coefficient are proposed.
  • Article
    Citation - WoS: 6
    Citation - Scopus: 6
    A Study on Numerical Determination of Permeability and Inetia Coefficient of Aluminum Foam Using X-Ray Microtomography Techniques: Focus on Inspection Methods for Reliability (permeability and Inertia Coefficient by Tomography)
    (Begell House, 2019) Mobedi, Moghtada; Nakayama, Akira; Özkol, Ünver; Çelik, Hasan
    The volume-averaged (i.e., macroscopic) transport properties such as permeability and inertia coefficient of two aluminum foams with 10 and 20 pores per inch (PPI) pore density are found using microtomography images. It is shown that a comparison between the numerical values and the experimental results may not be sufficient to prove the correctness of the obtained results. Hence, in addition to traditional validation methods such as grid independency and comparison with reported results in literature, further inspections such as (a) checking the development of flow, (b) inspection of Darcy and non-Darcy regions, (c) conservation of flow rate through the porous media, (d) sufficiency of number of voxels in the narrow throats, and (e) observation of transverse velocity gradients in pores for high and low Reynolds numbers can be performed to further validate the achieved results. These techniques have been discussed and explained in detail for the performed study. Moreover, the obtained permeability and inertia coefficient values are compared with 19 reported theoretical, numerical, and experimental studies. The maximum deviation between the present results and the reported studies for 10 PPI is below 25%, while for 20 PPI it is below 28%.