Alt Duvarı Dalgalı Kapalı Kare Geometride Yüzey Işınımı ile Doğal Taşınımın Sayısal İncelenmesi

Alt duvarı dalgalı ve tüm duvarlarında aynı yüzey ışınım yayma oranına sahip kapalı kare geometridebirleşik doğal taşınım ve yüzey ışınımı sayısal olarak incelenmiştir. Geometride alt duvar ısıtılmış, üstduvar soğutulmuş, dikey duvarlar ise yalıtılmıştır. Sıcak ve soğuk duvarlar izotermal ve sabit sıcaklıktatutulmuştur. Doğal taşınım için tanımlanan momentum ve enerji denklemi 10 4 ≤Ra≤10 6 ve 0≤ε≤1alınarak SIMPLE algoritması ile sonlu hacimler kullanılarak Fluent paket programında çözülmüştür.Katılımcı olmayan ortam için yüzeyler arası ışınımla ısı transferi denklemi Discrete Ordinate Metod(DOM) kullanılarak çözülmüştür. Soğuk duvar üzerinden hesaplanan ortalama Nusselt sayısı vegeometride meydana gelen akış değişimleri değişen Rayleigh sayısı, yüzey ışınım yayma oranı, alt duvardalga sayısı ve dalga genliği için analiz edilmiştir. Dalgalı duvarın dalga sayısı ve genliğinin değişimi aynışartlardaki düz duvara göre bazı durumlarda ortalama toplam Nusselt sayısında maksimum %8.82değerinde bir iyileştirme sağlamıştır.

Numerical Investigation of Natural Convection and Surface Radiation in an Air Filled Square Enclosure with a Wavy Bottom Wall

The coupled natural convection and surface radiation of a square gray enclosure having undulated bottom wall and same wall emissivity was numerically investigated. The bottom wall of the enclosure was heated up while the upper wall was cooled down and the side walls were adiabatic. Hot and cold walls were isothermal and kept at a constant temperature. The momentum equations described in natural convection, and the energy equation has been solved Fluent Software by the finite volume method in SIMPLE algorithm taking 10 4 ≤Ra≤10 6 and 0≤ε≤1 into account. The radiative heat equation between surfaces for non-participating medium was solved using the Discrete Ordinate Method (DOM). The mean Nusselt numbers computed over the cold surface and of the flow variations over the enclosure were analyzed for different number of undulations and amplitudes, varying Rayleigh number, and changed wall emissivity. The fluctuation of the wave number and amplitude of the wave wall have provided an improvement of 8.82% maximum in the mean total Nusselt number in some cases compared to the same flat wall.

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