Analysis of early-stage frost formation in natural convection over a horizontal cylinder

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

“…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.…”

“…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.…”

“…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.…”

“…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.…”

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

“…Recently, Tahavvor and Yaghoubi (2009) developed a numerical model to simulate the early-stage of frost formation in natural convection and a correlation is proposed for predicting transition time with respect to all the relevant parameters.…”