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Title: Challenges and possibilities in cooling electronics equipment
Authors: Karayiannis, TG
Pike Wilson, EA
Chen, L
Mahmoud, M
Tian, Y
Keywords: Microchannel;Flow Boiling
Issue Date: 2014
Publisher: Brunel University London
Citation: 4th Micro and Nano Flows Conference, University College London, UK, 7-10 September 2014, Editors CS König, TG Karayiannis and S. Balabani
Series/Report no.: ID 170
Abstract: Flow boiling patterns of R245fa in a 1.1 mm diameter copper tube were used to evaluate flow pattern maps in small to micro tubes. The flow boiling experiments were conducted over an experimental range of mass flux 100-400 kg/m2s, heat flux 3-25 kW/m2, inlet pressure of 1.85 and 2.45 bar and inlet subcooling of 5 K. The test section was heated directly using DC current. The effect of hysteresis was also investigated by increasing and decreasing the heat flux. A borosilicate glass observation section at the test section outlet was used for flow visualization. Hysteresis was evident across the whole experimental range, with obvious changes in the flow patterns between increasing and decreasing heat flux. The four main flow patterns were bubbly, slug, churn and annular flow. Confined flow was also evident. For increasing heat flux, only annular flow was evident but all the flow patterns were evident with decreasing heat flux. Therefore, the evaluation of flow pattern maps carried out in the present study was based on the decreasing heat flux data, as this covered the full range of flow patterns.
Description: This paper was presented at the 4th Micro and Nano Flows Conference (MNF2014), which was held at University College, London, UK. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute, ASME Press, LCN London Centre for Nanotechnology, UCL University College London, UCL Engineering, the International NanoScience Community,
ISBN: 978-1-908549-16-7
Appears in Collections:Brunel Institute for Bioengineering (BIB)
The Brunel Collection

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