Faz Değiştiren Malzemelerle Termal Enerji Depolayan Bir Isı Değiştiricisinin Sayısal Analizi

Year 2018, , 403 - 409, 01.06.2018

Meltem Koşan , Mustafa Aktaş

https://doi.org/10.2339/politeknik.389594

Cited By: 4

Abstract

Bu çalışmada, termal enerji
depolama (TED) sistemlerinde kullanılan bir iç içe borulu ısı değiştiricisinde
faz  değiştiren malzemenin (FDM) erime
sürecindeki ısıl davranışı, kanatçıklı ve kanatçıksız modeller ile sayısal
analizi yapılarak incelenmiştir. Sayısal analizler, Hesaplamalı Akışkanlar
Dinamiği (HAD) yaklaşımını kullanan ANSYS Fluent ticari programı ile iki
boyutlu ve zamana bağlı olarak gerçekleştirilmiştir. Öncelikle literatürde
mevcut deneysel bir çalışma referans alınarak sayısal analiz kanatçıksız model
için doğrulanmıştır. Bu modelde ısı transfer akışkanı (ITA)’nın sıcaklıkları 50
^oC, 60 ^oC ve 70 ^oC alınarak ITA sıcaklığının
FDM erime süresine etkisi değerlendirilmiştir. Daha sonra bu modele 6, 9, 12 ve
15 adet kanatçıklar eklenip, kanatçık sayısının da FDM’nin erime süresine
etkisi araştırılmıştır. Yapılan sayısal çalışmada elde edilen sonuçlar, ITA
sıcaklığı ve kanat sayısı arttıkça FDM’nin erime süresinin azaldığını, böylece
FDM’nin daha hızlı bir şekilde ITA’dan ısıyı depoladığını göstermektedir. Kanat
etkenlikleri sırasıyla 2,66, 3,49, 4,32 ve 5,15 olan 6, 9, 12 ve 15 kanatçıklı
modellerin kanatçıksız modele göre erime süresini %72,5, %76,7, %78,4 ve %80
azalttığı belirlenmiştir.  

Keywords

Termal enerji depolama, faz değiştiren malzemeler, erime süresi

Numerical Analysis of a Heat Exchanger That Stores Thermal Energy with Phase Change Materials

Abstract

In this study, the thermal behavior of the phase
change material (PCM) during melting process inside a shell-and-tube heat
exchanger used in thermal energy storage (TES) systems has been investigated by
numerical analysis with fin and without fin models. Two dimensional transient
numerical analyzes have been carried out with the ANSYS Fluent commercial
program using the computational fluid dynamics (HAD) approach. The study has
been first validated for the without fin model with reference to an
experimental study available in the literature. In this model, the effect of
temperature of heat transfer fluid (HTF) 
on PCM melting time has evaluated by taking HTF’s temperatures 50 ^oC,
60 ^oC and 70 ^oC. Then, 6, 9, 12 and 15 fins have been
added to this model and the effect of the number of fins on the PCM melting
time has been investigated. The results obtained in the numerical study show
that as the HTF temperature and number of fins increase, the melting time of
PCM decreases, so that PCM stores more rapidly the heat from HTF. It has been
determined that the fin models with 6, 9, 12 and 15 which are 2,66, 3,49, 4,32
and 5,15 of fin effectiveness reduce the melting time by 72,5%, 76,7%, 78,4%
and 80% respectively, according to without fin model.

Keywords

Thermal energy storage, phase change materials, melting time

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