Effect on Heat Transfer of Periodic Oscillations of a Vertical Flat Plate

Year 2020, , 1317 - 1326, 01.12.2020

Selma Akçay , Ünal Akdağ

https://doi.org/10.2339/politeknik.648373

Abstract

In this study, effects on heat transfer of periodic oscillation of a vertical flat plate are experimentally and numerically investigated. The experimental setup includes a transparent enclosure hosting a moving experimental model, flywheel-motor assembly generating the oscillating movement of the model, power supply, data logger and personal computer. The experimental model comprises two copper plates with attached thermocouples and Kapton heaters placed between the plates. In the study, heat flux applied to surface of the plates (q″), the Womersley number (Wo) and dimensionless oscillation amplitude (Ao) are varied and the effect of these parameters on the heat transfer is analysed. Furthermore, the study is numerically solved using a control-volume based CFD solver based on experimental data. The numerical results are compared with the experimental results. Instantaneous velocity and temperature profiles of the plate are obtained to explain the heat transfer mechanism. The numerical and experimental results are shown heat transfer is significantly affected by oscillation parameters and the heat transfer increases with the increase in both oscillation amplitude and frequency.

Keywords

Oscillation frequency, oscillation amplitude, moving the vertical plate, heat transfer

Düşey Düz bir Levhanın Periyodik Salınımlarının Isı Transferine Etkisi

Abstract

Bu çalışmada, düşey düz bir levhanın periyodik
salınımlarının ısı transferi üzerindeki etkisi deneysel ve sayısal olarak
incelenmiştir. Deney sistemi, içinde deneysel modelin hareket ettiği şeffaf  bir muhafazayı,  modelin salınım hareketini üreten volan-motor sistemini,
güç kaynağını, veri toplama sistemini ve bilgisayarı içerir. Deneysel model,
üzerine termoelemanlar yerleştirilmiş iki bakır levha ve levhalar arasına
yerleştirilmiş Kapton ısıtıcılardan oluşur. Çalışmada, levhanın yüzeyine
uygulanan ısı akısı (q″), Womersley sayısı (Wo) ve boyutsuz salınım genliği
(Ao) değiştirilmiş ve bu parametrelerin ısı transferi üzerindeki etkisi analiz
edilmiştir. Ayrıca, çalışma deneysel verilere dayalı kontrol hacim tabanlı bir
HAD çözücüsü kullanılarak sayısal olarak çözülmüştür. Sayısal sonuçlar,
deneysel sonuçlarla karşılaştırılmıştır. Salınım genliği ve frekansının ısı
transferine etkisini göstermek için levha yüzeyinde anlık hız ve sıcaklık görüntüleri
elde edilmiştir. Sayısal ve deneysel sonuçlar, ısı transferinin salınım parametrelerinden
önemli derecede etkilendiğini ve salınım genliği ve frekansının artması ile arttığını
göstermiştir. 

Keywords

salınım genliği, salınım frekansı, hareketli düşey levha, ısı transferi

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