The Brunel Collection is a newly created collection which contains both physical items and items on BURA. http://bura.brunel.ac.uk/handle/2438/5910 2013-05-23T04:27:34Z 2013-05-23T04:27:34Z Shiferaw, D Mahmoud, M Karayiannis, TG Kenning, DBR 2nd Micro and Nano Flows Conference (MNF2009) http://bura.brunel.ac.uk/handle/2438/6952 2012-10-12T09:31:28Z 2009-01-01T00:00:00Z

Title: One-dimensional mechanistic model for flow boiling pressure drop in small- to micro- passages Authors: Shiferaw, D; Mahmoud, M; Karayiannis, TG; Kenning, DBR; 2nd Micro and Nano Flows Conference (MNF2009) Abstract: Accurate predictions of two-phase pressure drop in small to micro diameter passages are necessary for the design of compact and ultra-compact heat exchangers which find wide application in process and refrigeration industries and in cooling of electronics. A semi-mechanistic model of boiling two-phase pressure drop in the confined bubble regime is formulated, following the three-zone approach of Thome et al. (2004) for heat transfer. The total pressure drop is calculated by time-averaging the respective pressure drop values of single-phase liquid, elongated bubble with a thin liquid film and single-phase vapour. The model results were compared with experimental data collected for a wide range of diameter tubes (4.26, 2.88, 2.02, 1.1 and 0.52 mm) for R134a at 6 – 12 bar. Description: This paper was presented at the 2nd Micro and Nano Flows Conference (MNF2009), which was held at Brunel University, West London, UK. The conference was organised by Brunel University and supported by the Institution of Mechanical Engineers, IPEM, the Italian Union of Thermofluid dynamics, the Process Intensification Network, HEXAG - the Heat Exchange Action Group and the Institute of Mathematics and its Applications.

2009-01-01T00:00:00Z Gedupudi, S Kenning, DBR Karayiannis, TG 2nd Micro and Nano Flows Conference (MNF2009) http://bura.brunel.ac.uk/handle/2438/6951 2012-10-12T09:27:08Z 2009-01-01T00:00:00Z

Title: 1-D modelling of pressure fluctuations due to confined bubble growth during flow boiling in a microchannel Authors: Gedupudi, S; Kenning, DBR; Karayiannis, TG; 2nd Micro and Nano Flows Conference (MNF2009) Abstract: A simple 1-D model is presented to study the effects of the wall heat flux, location of the nucleation site, channel dimensions and fluid properties on the pressure fluctuations caused by confined bubble growth in rectangular microchannels, for zero upstream compressibility. A simple isothermal compressibility model is then used to study the effects of the initial volume of non-condensable gas trapped in the upstream plenum, initial inlet velocity and nucleation site location on local pressure fluctuations and transient flow reversal. Both acceleration pressure drop and viscous pressure drop are considered. Description: This paper was presented at the 2nd Micro and Nano Flows Conference (MNF2009), which was held at Brunel University, West London, UK. The conference was organised by Brunel University and supported by the Institution of Mechanical Engineers, IPEM, the Italian Union of Thermofluid dynamics, the Process Intensification Network, HEXAG - the Heat Exchange Action Group and the Institute of Mathematics and its Applications.

2009-01-01T00:00:00Z Pontrelli, G König, CS Collins, MW Long, Q Succi, S 2nd Micro and Nano Flows Conference (MNF2009) http://bura.brunel.ac.uk/handle/2438/6950 2012-10-12T09:22:31Z 2009-01-01T00:00:00Z

Title: Modelling wall shear stress in small arteries using LBM and FVM Authors: Pontrelli, G; König, CS; Collins, MW; Long, Q; Succi, S; 2nd Micro and Nano Flows Conference (MNF2009) Abstract: In this study a finite-volume discretisation of a Lattice Boltzmann equation over unstructured grids is presented. The new scheme is based on the idea of placing the unknown fields at the nodes of the mesh and evolve them based on the fluxes crossing the surfaces of the corresponding control volumes. The method, named unstructured Lattice Boltzmann equation (ULBE) is compared with the classical finite volume method (FVM) and is applied here to the problem of blood flow over the endothelium in small arteries. The study shows a significant variation and a high sensitivity of wall shear stress to the endothelium corrugation degree. Description: This paper was presented at the 2nd Micro and Nano Flows Conference (MNF2009), which was held at Brunel University, West London, UK. The conference was organised by Brunel University and supported by the Institution of Mechanical Engineers, IPEM, the Italian Union of Thermofluid dynamics, the Process Intensification Network, HEXAG - the Heat Exchange Action Group and the Institute of Mathematics and its Applications.

2009-01-01T00:00:00Z Falcucci, G Ubertini, S Chiappini, D Succi, S 2nd Micro and Nano Flows Conference (MNF2009) http://bura.brunel.ac.uk/handle/2438/6949 2012-10-12T08:52:14Z 2009-01-01T00:00:00Z

Title: Modern Lattice Boltzmann methods for multiphase micro-flows Authors: Falcucci, G; Ubertini, S; Chiappini, D; Succi, S; 2nd Micro and Nano Flows Conference (MNF2009) Abstract: During the last decade, the Lattice Boltzmann (LB) method has captured an increasing attention as an efficient tool for the numerical simulation of complex fluids, particularly multi-phase and multi-component flows. In this paper, we revisit the basic features of two modern variants of lattice Boltzmann models for non-ideal fluids, which offer promising perspectives for the numerical simulation of complex micro- flows. Description: This paper was presented at the 2nd Micro and Nano Flows Conference (MNF2009), which was held at Brunel University, West London, UK. The conference was organised by Brunel University and supported by the Institution of Mechanical Engineers, IPEM, the Italian Union of Thermofluid dynamics, the Process Intensification Network, HEXAG - the Heat Exchange Action Group and the Institute of Mathematics and its Applications.

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