Experimental and numerical study of frost formation by natural convection over a cold horizontal circular cylinder

Tahavvor, Ali Reza; Yaghoubi, M.

doi:10.1016/j.ijrefrig.2010.06.004

Cited by 20 publications

(13 citation statements)

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“…This figure shows that for the top of the fins, initially the frost growth slope increases with time and then the slope gradually decreases. This observation basically confirms the experimental results reported by Tahavvor and Yaghoubi [6,7]. For low humidity, the frost thickness on the bottom of the fin is smaller compared with a bare tube.…”

Section: Frost Growthsupporting

confidence: 91%

“…These illustrations show that the effect of different relative air humidity is considerable. More humid air produces more frost as previously observed by Tahavvor and Yaghoubi [6,7] and de Silva et al [9]. But, for higher air temperatures and higher air humidities (higher super cooling degrees), the effect of humidity on the frost growth decreases and may disappear, as shown in Fig.…”

Section: Frost Growthsupporting

confidence: 72%

“…The control room and equipment are the same as described by Tahavvor and Yaghoubi [6,7]. For evaluating radiation heat transfer between the test surface and walls, the room surface temperature is measured at two positions as shown in Fig.…”

Section: Methodsmentioning

confidence: 99%

“…Figure 2(c) shows the test section with the surrounding probes measuring air temperature and humidity. The details of controlling room temperature and humidity as well as supplying constant tube surface temperature using data recording units ADAM 4518 and 4520MOXA ioLogic are presented in Tahavvor and Yaghoubi [7]. According to this data, command signals are transferred to the air heating (or cooling) unit and the humidifier.…”

Section: Methodsmentioning

confidence: 99%

“…Other investigations of force convection illustrate that for a lower surface temperature of the fin-tube, frost thickness is greater on the base and it decreases to the fin tip based on the work of Sekhar et al [2], Kim et al [3], Tso et al [4], and Yan et al [5]. For natural convection Tahavvor and Yaghoubi [6,7] provided new correlations for transition time on a circular cylinder. They showed that the frost is thicker on the top than on the bottom of cylinders, and when the difference between ambient air and cold surface temperature increases, transition time decreases.…”

Section: Heat Transfer-asian Research 41 (1) 2012mentioning

confidence: 99%

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Experimental study of natural frost formation over a horizontal tube with annular compact fins under natural convection

Mahdavi

Yaghoubi

2011

Heat Trans. Asian Res.

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This paper presents experimental measurements of natural convection heat transfer and frost deposition over a horizontal fin-tube. Measurements are made for a fin-tube of diameter 25.4 mm, fin thickness 0.4 mm, fin center diameter 56 mm, and fin spacing 2 mm. For measurements the ambient air temperature and relative humidity are changed from 18 to 25°C and from 35% to 55%, respectively. The tube surface temperature is changed from -5 to -9 °C, and super cooling degrees of 7.5 to 24.5 °C.Results include a visualization of frost deposition growth, frost accumulation rate, and heat transfer rate with respect to time for each experiment. The results show that cold air starts from the upper point and moves downward and frost deposition starts on the fin tips, and grows with time both radially and angularly. Frost growth thickness changes significantly from top to bottom, where the boundary layers of both thermal and concentration increase at the bottom of the fin-tube section without considerable separation. Frost growth only takes place on the fin's tip and it blocks the heat and mass transfer from the fin surfaces and the tube base which reduces convection and frost growth considerably.

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Section: Frost Growthsupporting

confidence: 91%