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Title: An experimental investigation on friction characteristics of air flow in microtube with structured surface roughness
Authors: Lin, TY
Chen, CW
Yang, CY
Kandlikar, SG
3rd Micro and Nano Flows Conference (MNF2011)
Keywords: Roughness effects;Flow characteristics;Heat transfer coefficient;Micro-tubes;Nickel;CO2;Air
Issue Date: 2011
Publisher: Brunel University
Citation: 3rd Micro and Nano Flows Conference, Thessaloniki, Greece, 22-24 August 2011
Abstract: Experiments were conducted in this research to investigate roughness effect to flow characteristics and heat transfer coefficient of air and CO2 flow in circular micro-tubes. The internal surface of tested tube included smooth, structure helical fin surfaces and random roughness surfaces. Smooth tube is a commercial S. S. 304 tube with internal diameter of 962 μm and average roughness Ra=0.8 μm, while rough circular tubes were lab made Nickel tube with diameters ranging from 926 μm to 977 μm and roughness elements from 5.3 μm to 44.6 μm in height. The experimental results indicated that f and Nu in smooth tube was predicted very well by conventional correlations both for air and CO2. In rough tubes the friction factor was significant higher than the prediction of conventional correlations both in laminar and turbulent flow. Heat transfer enhancement in laminar flow is slightly, nevertheless, in turbulent flow the heat transfer enhancement was significant and the enhancement increases with the increasing of Re. The random rough tubes revealed a higher heat transfer enhancement than the structured helical fin tubes.
Description: This paper was presented at the 3rd Micro and Nano Flows Conference (MNF2011), which was held at the Makedonia Palace Hotel, Thessaloniki in Greece. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, Aristotle University of Thessaloniki, University of Thessaly, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute.
ISBN: 978-1-902316-98-7
Appears in Collections:Brunel Institute for Bioengineering (BIB)
The Brunel Collection

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