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文件名称：Regulated transient pool boiling of water during quenching
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更新时间：2021-09-28 13:39:41
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The effects of surface wettability, from superhydrophilic to superhydrophobic, on transient pool boiling
of water under atmospheric pressure were experimentally examined by means of the quenching method
with hot stainless steel spheres. The wettability changes, with a contact angle ranging from nearly 0to
more than 160, were realized by nanostructured coating on the spheres. The quenching cooling rate was
shown to slow down with increasing the contact angle as the vapor film was stabilized and retained by
surface hydrophobicity even at very low wall superheats. Remarkable boiling heat transfer enhancement,
with critical heat flux (CHF) increase up to nearly 70%, was achieved for the superhydrophilic case as
compared to the original hydrophilic baseline case. As observed by high-speed imaging on the dynamic
quenching processes, violent rewetting that stems from superhydrophilicity facilitated early collapse of
the vapor film, thus leading to the great increase in film boiling heat transfer and CHF. The observations
suggested an active means of regulation of transient pool boiling by employing the nanostructured
surfaces with modified wettability to the extremes, toward either enhanced boiling heat transfer orretention of stable film boiling phase