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Öğe A new design for panel radiators using cfd(Yıldız Teknik Üniversitesi, 2016) Ekmekçi, İsmail; Aydar, EmirAn experimental study was conducted in accordance with EN442 in the standard test room in order to determine boundary conditions for computational study and verify numerical results. Tests were carried out in three different operating conditions. Turbulent natural convection coupled with thermal radiation in the test room and water flow inside the tested radiator were simulated by means of CFD together in order to compare with the experimental data obtained for this cavity at a Grashof number equal to 1.09x109. In carrying out numerical investigations, a three-dimensional, low-turbulence, two-parameter k–? model known as the low-Reynolds-number k–? turbulence model was used. Non-uniform temperature distribution on the front surface of tested panel radiator was observed. The difference between experimental and computational heat transfer rate are 1.70% in case of the excess temperatures of 50 °C. Quite good results are obtained for the excess temperature of 50 °C. The study shows that computational methods can be applicable in the design of new heater types. The aim of the study is the distribution of the fluid flow at each vertical duct inside panel homogeneously. High temperature gradients occur inside panel where fluid flows because of distinct values of mass flow rates at vertical ducts. It is found that the rate of heat transfer is increased by approximately 8% and weight is decreased by 17.22% using novel panel radiator compared to the rates obtained by tested panel radiator.Öğe Novel fin design for the panel type radiators using CFD(Springer International Publishing, 2014) Aydar, Emir; Ekmekçi, İsmail; Şen, YaşarThere are many panel radiator manufacturers in Turkey. Their panel radiator designs are very similar, and radiators that have been manufactured by various producers have very similar thermal efficiency values and specific heating per unit weight of the radiator. In this study, CFD analysis of existing panel radiators was made with a commercial CFD software of STAR-CCM+ with top-bottom-opposite-end connection method in three-dimensional space. Panel-convector-convector- panel, Type-22-600×500 steel panel radiator, was used in this numerical study. In the content of this analysis, new configurations at fin design were performed to increase the rate of heat transfer of the panel radiator. Four fin designs were drawn and examined. Since triangular profile fin design contains less material and has higher heat flux, it is more efficient than the other profiles, and therefore it is more suitable for applications requiring minimum weight. © Springer International Publishing Switzerland 2014.Öğe Panel tip radyatörlerin cfd yöntemiyle termal verim analizi(İKSES, 2014) Ekmekçi, İsmail; Aydar, Emir; Ermiş, Kemal; Şen, YaşarGünümüzde ısıtma sistemlerinde kullanılan panel radyatörlerin değişik modelleri bulunmaktadır. Değişik imalatçılar tarafından üretilen panel radyatör tasarımları genelde birbirlerine çok benzerdir ve yaklaşık birbirine benzer termal verime ve özgül ısıya sahiptirler. Bu çalışmada, mevcut panel radyatörün CFD (STAR-CCM+ kodu) analizleri, termal verim için üç boyutlu olarak değişik bağlantı yöntemleri ile yapılmıştır. Sayısal termal verim değerleri elde edilmiş ve bilinen katalog değerleri ile karşılaştırılmıştır. Bu sayısal çalışmada, radyatör modeli olarak Tip-22-600x500 panel-kanat-kanat-panel kullanılmıştır. Ayrıca bu çalışmada, hava tarafındaki ısı taşınım katsayısı değişiminin ısıl güç üzerindeki etkileri de incelenmiştir. Optimum hava tarafındaki ısı taşınım katsayısı belirlendikten sonra, sayısal çalışmalar bu değere göre yapılmıştır. Üstten girişi ve çapraz tarafta alttan çıkışı olan bağlantı için, kütle debisi dağılımının ilk iki ve son üç dikey kanalda olması gereken akıştan daha fazla olduğu belirlenmiştir. Giriş sınırına yakın ortadaki dikey kanallarda, kütle debisi dağılımının yaklaşık sıfıra eşit olduğu görülmektedir. Üstten girişi ve aynı tarafta alttan çıkışı olan bağlantı için, kütle debisi dağılımı ilk dört dikey kanalda olması gereken akıştan daha fazla olduğu belirlenmiştir. Geri kalan dikey kanallarda, kütle debisi dağılımının yaklaşık sıfıra eşit olduğu görülmektedir. Her iki bağlantı tipi için elde edilen sayısal sonuçlar ve ticari katalog değerlerinin birbirine çok yakın olduğu görülmüştür.Öğe Thermal efficiency estimation of the panel type radiators with CFD analysis(2012) Aydar, Emir; Ekmekçi, İsmailThere are many panel radiator manufacturers in Turkey. Their panel radiator designs are very similar and radiators that have been manufactured by various producers have very similar thermal efficiency values and specific heating per unit weight of the radiator. In this study, CFD analysis of existing panel radiators were made with a commercial CFD code of STAR-CCM+ with variable connection methods in three-dimensional space. Numerical thermal efficiency values were obtained and were compared with given catalogue values. Panel-convector-convectorpanel, Type-22-600×500 steel panel radiator was used in this numerical study. In the content of this analysis, the effect of variation at air-side convective heat transfer coefficient on the thermal output was also investigated. After optimum air-side convective heat transfer coefficient had been determined, numerical analyses of the panel radiator were done based on this value. For top-bottom-opposite-end connection, mass flow rate distribution is greater than exact flow at first two and last three vertical ducts. In the middle of the vertical ducts towards inlet boundary, mass flow rate distribution corresponds to about zero. For top-bottom-same-end connection, mass flow rate distribution is greater than exact flow at first four vertical ducts. In the last part of the vertical ducts, mass flow rate distribution corresponds to about zero. Numerical results and commercial catalog values are very close each other for TBOE and TBSE connections, and thus two basic connection methods can be used for this panel radiator. © 2012 TIBTD Printed in Turkey.Öğe THERMAL EFFICIENCY ESTIMATION OF THE PANEL TYPE RADIATORS WITH CFD ANALYSIS(Turkish Soc Thermal Sciences Technology, 2012) Aydar, Emir; Ekmekci, IsmailThere are many panel radiator manufacturers in Turkey. Their panel radiator designs are very similar and radiators that have been manufactured by various producers have very similar thermal efficiency values and specific heating per unit weight of the radiator. In this study, CFD analysis of existing panel radiators were made with a commercial CFD code of STAR-CCM+ with variable connection methods in three-dimensional space. Numerical thermal efficiency values were obtained and were compared with given catalogue values. Panel-convector-convector-panel, Type-22-600x500 steel panel radiator was used in this numerical study. In the content of this analysis, the effect of variation at air-side convective heat transfer coefficient on the thermal output was also investigated. After optimum air-side convective heat transfer coefficient had been determined, numerical analyses of the panel radiator were done based on this value. For top-bottom-opposite-end connection, mass flow rate distribution is greater than exact flow at first two and last three vertical ducts. In the middle of the vertical ducts towards inlet boundary, mass flow rate distribution corresponds to about zero. For top-bottom-same-end connection, mass flow rate distribution is greater than exact flow at first four vertical ducts. In the last part of the vertical ducts, mass flow rate distribution corresponds to about zero. Numerical results and commercial catalog values are very close each other for TBOE and TBSE connections, and thus two basic connection methods can be used for this panel radiator.