Thermal Performance Investigation of Plain Finned-Tube Evaporators Used in Household Refrigerator

Öz

In this study, thermal performance of plain finned-tube evaporators in household refrigerators are investigated numerically and experimentally. The design parameters affecting on the cooling capacity are determined as air flowrate, evaporator temperature, tube alignment, number of tubes and number of fins. In the initial stage, the effects of those parameters on the cooling capacities are simulated by CoilDesigner software. The number of experiments that are necessary to obtain correlations is determined by Minitab software. The experiments are carried out in a no-frost household refrigerator in the off-mode. At the end of each experiment, air side heat transfer coefficients are calculated to generate a Nusselt (Nu) correlation as a function of the mentioned design parameters.  The generated correlation of the cooling capacity can predict 95% of the experimental results within a confidence range of 15%.  The correlation of the cooling capacity is converted to the Nusselt number correlation which is found to be consistent with available data in literature. The experiments reveal that the cooling capacity is dominantly affected by the evaporator temperature followed by air flow rate, tube alignment, number of tubes and the number of fins.

 

Anahtar Kelimeler

• Plain Finned Tube Evaporator,Cooling Capacity,Design of Experiments,Nusselt Number Correlation,Numerical Model

Evsel Bir Buzdolabında Kullanılan Düz Kanatlı Borulu Buharlaştırıcıların Isıl Performanslarının İncelenmesi

Öz

Bu çalışmada, düz kanatlı borulu buharlaştırıcıların ev tipi buzdolaplarındaki ısıl performansı sayısal ve deneysel olarak incelenmiştir. Soğutma kapasitesini etkileyen tasarım parametreleri, hava debisi, buharlaştırıcı sıcaklığı, boru düzeni, boru sayısı ve kanat sayısı olarak belirlenmiştir. İlk aşamada, bu parametrelerin soğutma kapasiteleri üzerindeki etkileri CoilDesigner yazılımı ile modellenmiştir. Isıl inceleme için gerekli olan deneylerin sayısı Minitab yazılımı tarafından simülasyon sonuçlarına göre belirlenmiştir. Deneyler ev tipi bir buzdolabında kapalı soğutma çevrimi olmaksızın yapılmıştır. Her deneyin sonunda hava tarafı ısı transfer katsayıları, söz konusu tasarım parametrelerinin bir fonksiyonu olarak ve Nusselt (Nu) korelasyonu oluşturmak için hesaplanır. Soğutma kapasitesi için oluşturulan korelasyon, deneysel sonuçların % 95'ini % 15'lik bir güven aralığında tahmin etmektedir ve literatürdeki mevcut verilerle tutarlı bulunmuştur. Deneyler, soğutma kapasitesinin baskın olarak buharlaştırıcı sıcaklığından ve ardından hava kütlesel debisinden, boru düzeninden ve kanat sayısından etkilendiğini ortaya koymuştur.

Anahtar Kelimeler

• Kanatlı Borulu Buharlaştıcı,, Soğutma Kapasitesi,Deney Tasarımı,Nusselt Sayısı Korelasyonu,Sayısal Model

Kaynakça

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