Chemical Engineering Science 59 (2004) 3141–3157 www.elsevier.com/locate/ces Principal characteristics of turbulent gas-particulate ow in the vicinity of single tube and tube bundle structure Y.S. Morsi a ,J.Y.Tu b , G.H. Yeoh c ; * ,W.Yang a a Centre for Modelling and Process Simulation Research, Swinburne University of Technology, Hawthorn, Victoria, Australia b School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University, Victoria 3083, Australia c Australian Nuclear Science and Technology Organisation (ANSTO) PMB 1, Menai, NSW 2234, Australia Received 16 July 2002; received in revised form 4 June 2003; accepted 1 December 2003 Abstract In this paper the particle rebounding characteristics of a gas–particle ow over a cylindrical body and an in-line tube bundle arrangement is investigated. With the aid of both experimental and numerical approaches, the mean particulate ow patterns, comprising both incident and rebound particles resulting from the impact of particles on solid walls, are examined. In the experimental investigation, a two-dimensional laser-Doppler anemometry (LDA) technique is used in the immediate vicinity of the body surface to measure the instantaneous incident and rebound particle velocities. The Reynolds-averaging Navier–Stokes equations are solved for the continuum gas phase and the results are used in conjunction with a Lagrangian trajectory model to predict the particle-rebound characteristics. For the single tube model, the experimental observations, also conrmed through computations, reveal a particle rebound zone where the mean particulate ow pattern is signicantly modied due to the contribution of the rebound particles during the process of particle-wall impact interaction. This particle rebound zone is found to be a function of mainly the Stokes number (particle inertia), and to a lesser extent on the uid Reynolds number (gas ow condition) except for high gas ow velocities. For the in-line tube bundle model, particles being rebounded from the rst row of tubes at upstream migrated downstream and impinged the other tubes in an extremely complex and random disposition. Detailed measurements on the ow and turbulent characteristics within the subset containing two cylindrical tubes representing the ow over the rst and second row tubes in the tube bundle conguration revealed that the heavier particles possessed higher axial and transverse velocity uctuations than the gas and lighter particles. A means of quantifying the erosion rate using a semi-empirical relationship and CFD approach is presented. The erosion distributions were found to be signicantly dierent between the lighter and heavier particles. Analysis of the eect of the above-mentioned parameters on the rebounding particle ow characteristics and their interrelationship has provided a better understanding on the behaviour of particulate ow impinging on a solid wall body or series of solid bodies. The usefulness of employing the experimental and computational approaches to quantify the particle-wall impact interaction phenomena in this study provides the basis for additional investigations to be undertaken to better comprehend the particulate behaviour in tube bundle structure, for example staggered tube arrangement commonly found in many commercial heat exchangers. ? 2004 Elsevier Ltd. All rights reserved. Keywords: LDA technique; Particle-wall impact; Conned gas-particle ow; CFD; Lagrangian approach 1. Introduction The requirement for the continual optimisation of the de- sign, operation and maintenance of energy conversion sys- tems demands an understanding on the phenomena of tur- bulent particle-laden gas ows. The bombardment of solid particles on the wall surfaces of these industrial devices for ∗ Corresponding author. Tel.: +61-2-9717-3817; fax: +61-2-9717-9263. E-mail address: guan.yeoh@ansto.gov.au (G.H. Yeoh). considerable periods of time can cause signicant ero- sion to the extent that may result in catastrophic conse- quences because of the continual removal of materials from these walls. It is crucial that the disposition of the erosion/corrosion distribution is fundamentally understood because it can signicantly aect and degrade the perfor- mance and operations of typical applied systems such as industrial advanced coal-red combustors and commercial heat exchangers. With the aim to maintain and achieve peak operational eciency in these systems, it is important that a more in-depth investigation is performed to better 0009-2509/$-see front matter ? 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.ces.2003.12.032