International Journal of Mathematical, Engineering and Management Sciences Vol. 5, No. 2, 248-259, 2020 https://doi.org/10.33889/IJMEMS.2020.5.2.020 248 CFD Modelling of Multi-Particulate Flow through Concentric Annulus Satish Kumar Dewangan Mechanical Engineering Department, National Institute of Technology, Raipur, 492010, Chhatisgarh, India. Vivek Deshmukh Mechanical Engineering Department, National Institute of Technology, Raipur, 492010, Chhatisgarh, India. Corresponding author: vdeshmukh.phd2018.me@nitrr.ac.in (Received December 26, 2018; Accepted August 31, 2019) Abstract In this investigation, flow of multiparticulate lodaded liquid through concentric annulus has been considered with the consideration of rotating inner wall. The present work guides the research studies for petroleum industries in the field of wellbore drilling. The hole-cleaning issue is of utmost importance for the wellbore drilling applications. In oil-well drilling, the horizontal drilling is given more priority. The behaviour of hole cleaning is analyzed through various parameters like axial inlet flow velocity of particulate flow, inner cylinder rotational speed and inlet solid cuttings particle concentration. The effect of these aforementioned parameters on the distribution of solid-phase concentration is studied. Flow is taken as steady, incompressible and multi-particulate slurry flow with primary medium (which carries the solid phase) being water and silica sand with 6 different sizes as the six different phases. The present flow simulation has been done by taking the Eulerian approach. The shape of Silica sand is considered as spherical. ANSYS FLUENT has been used for modelling and solution. Graphs for comparison are obtained using Microsoft Excel. Keywords- Multi-particulate flow, Concentric annulus, Drilling fluids, Slurry flow, Bed formation. 1. Introduction In various industrial processes, fluids are transported through closed conduits. It is prior to design the pipe system for the transportation of a specified quantity of fluid between specified locations with minimum pressure loss considering the initial cost of the piping system. Transportation of particle laden slurries (through the pipeline) is a commonly seen feature for many variety of industrial scenerio such as food processing industries, pharmaceuticals manufacturing industries, chemicals preparation & process industries and mining industries etc. Globally the scientists and researchers are striving for developing precise models of the velocity profile and solid phase distribution in a slurry pipeline. Escudier et al. (2002) studied both the concentric annulus and an eccentric annulus (with 80% eccentricity ratio) with and without center body (inner wall) rotation for the shear thinning fluid flow. Nouri and Whitelaw (1997) had considered axial, radial and tangential velocity components of Newtonian and Non-Newtonian fluid. They concluded that when uniform axial-flow across the annulus occurs the rotation of inner wall had similar behaviour both for Non-Newtonian and Newtonian fluids. Kim and Hwang (2003) have simulated a vortex flow inside the annulus. Cruz and Pinho (2004) researched the concentric annulus with helical flow of fluids considering inner cylinder rotation. Kelessidis and Bandelis (2004) put forward the concept of coiled tube drilling which is efficient in the transportation of drill cuttings however it is still in its early stages. Han et al. (2008, 2009) presented the study of a vertical wellbore system in which the slurry is