Bir Soğuk Hava Deposunda Ortam Koşullarının Sayısal Modellenmesi ve Deneysel Geçerliliğinin Belirlenmesi

Bu araştırmanın amacı; deneysel bir soğuk depo için sıcaklık ve bağıl nem dağılımını sayısal ve deneysel yöntemleri birlikte kullanarak incelemektir. Granny Smith elma ile dolu bir soğuk depoda hava hızı ve sıcaklığın dağılımını değerlendirmek için kararsız üç boyutlu hesaplamalı akışkanlar dinamiği modeli geliştirilmiştir. Depolama sıcaklığı ve bağıl nem 2 o C ve % 90 olarak belirlenmiştir. Bağıl nem ve sıcaklık soğuk hava deposu içinde üç farklı düzlemde 36 farklı noktada ölçülmüştür. Sayısal gereksinimler için üç boyutlu matematiksel model oluşturulmuştur. Sayısal modelin geçerliliği aynı koşullarda uygulamadan elde edilen deneysel verilerle test edilmiştir. Modelin bağıl hatası sıcaklık için % 13 ve hava hızı için % 1.43 olarak hesaplanmıştır. Sıcaklık ve bağıl nem için modellemeden elde edilen sayısal sonuçlar oldukça iyidir. Model ile ölçümler arasındaki en yüksek farklılıklar yüzeyler üzerinde ısı değişimlerinin en güçlü olduğu soğuk odanın sınırlarına yakın saptanmıştır. Soğuk deponun ortasında model ve ölçümler arasında küçük hatalar olmasına rağmen hem sıcaklık hem de bağıl nem için daha homojen bir dağılım elde edilmiştir.

Anahtar Kelimeler:

Hesaplamalı akışkanlar dinamiği (HAD), Soğuk depo, Sıcaklık, Bağıl nem, Elma

Numerical Modelling and Experimental Validation of a Cold Store Ambient Factors

The objective of this study was to analyse air temperature and relative humidity distribution in an experimental cold store fully loaded with apples by using both experimental and numerical (CFD) methods. An unsteady three-dimensional computational fluid dynamics model was developed to assess the distribution of temperature and relative humidity in a cold store fully loaded with Granny Smith apples. The storage temperature and relative humidity were maintained at 2 °C and 90%, respectively. The relative humidity and temperature were measured at 36 different points inside the cold store in three different planes. A three-dimensional mathematical model was built for the numerical needs. The numerical model was validated against experimental data from the same facility. Relative error of the model was calculated 13% for temperature and 1.43% for relative humidity. Numerical results obtained from the simulations agreed quite well with experimental data for temperature and relative humidity. Maximum differences were observed near the borders of the cold store which can be attributed to the stronger thermal gradients taking place on these surfaces. A more homogeneous distribution was achieved in the middle of the cold store both for air temperature and relative humidity leading to even smaller errors between measurements and simulations.

Keywords:

Computational fluid dynamics (CFD), Cold store, Temperature, Relative humidity, Apple,

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