Pressure drop across micro-pin heat sinks under unstable boiling conditions

Koşar, Ali and Özdemir, Mehmed Rafet and Keskinöz, Mehmet (2010) Pressure drop across micro-pin heat sinks under unstable boiling conditions. International Journal of Thermal Sciences, 49 (7). pp. 1253-1263. ISSN 1290-0729

This is the latest version of this item.

Full text not available from this repository.

Official URL: http://dx.doi.org/10.1016/j.ijthermalsci.2009.12.018


Flow boiling was investigated under unstable boiling conditions in three different micro-pin fin heat sinks using water and R-123 as working fluids. Once boiling was initiated severe temperature fluctuations were recorded for all the tested (three) micro-pin fin heat sinks. Flow images and fast-Fourier transform (FFT) of pressure signals during flow boiling were used to explain experimental results. The boiling instability mechanisms behind unstable boiling were discussed for both water and R-123. Accordingly, no significant pressure fluctuations with respect to time averaged pressure drop were evident for the tested micro-pin fin heat sinks before and after flow boiling instability initiates. However, a step change in the pressure signals were recorded with the inception of unstable boiling, and a sharp increase in the magnitude peaks of the FFT profiles was observed in the device operated with R-123, while there was no significant change in the FFT profiles in the devices operated with water. According to complementary flow visualization studies, the oscillation frequency of the periodic flow patterns for the device operated with R-123 was higher (fnot, vert, similar80 Hz) than that of the devices operated with water (fnot, vert, similar20 Hz).

Item Type:Article
Uncontrolled Keywords:Micro pin fins; Microchannels; Unstable boiling; Boiling instabilities
Subjects:T Technology > TJ Mechanical engineering and machinery
ID Code:13931
Deposited By:Mehmet Keskinöz
Deposited On:12 May 2010 10:18
Last Modified:24 Jul 2019 16:51

Available Versions of this Item

Repository Staff Only: item control page