The computational fluid dynamics modeling of solid particles hydrodynamic based on the Lagrangian framework for diluted solid-gas flow through 90° gas pipeline bend is carried out to discover the effect of particles size distribution on particles flow pattern and their erosive effect on the bend. Particles size distribution has been obtained experimentally by measuring the sizes of solid particles that are flowing through the gas pipelines of Aghajari gas booster station. Also the erosion rate at the outer wall of the bend is predicted. The pipeline bend under study has a pipe diameter of 56 inches and ratios of the bend radius of the curvature to the pipeline diameter of 1.5. For the validation of computational model, firstly, the computational modeling is performed for a published experimental solid-gas flow data. The computational results include radial gas velocity and radial particle velocity profiles on planes which are at different angles through the bend. The comparison between the predicted numerical results and similar experimental data proves that the predictions of the computational model are acceptable. Finally, the particles' size distributions on each plane through the bend and the erosion rate on the outer wall of the bend have been obtained. The maximum rate of erosion is found to be 3.2？nm/s, occurring between 40 and 65° of the bend. 1. Introduction In the oil and gas industry, black powder (BP) is the brief name that is used to describe the black materials found inside most of the gas pipelines worldwide. Black powder can be found in several forms, such as wet with a tar-like appearance or dry in the form of a very fine powder [1–5]. It is composed of different forms of iron sulfide (FeS), iron oxides (Fe3O4, FeOOH), and iron carbonate (FeCO3), mechanically mixed or chemically combined with any number of contaminants, such as salts, sand, liquid hydrocarbons, and metal debris [2]. Once BP exists and is moving with the flow, it can represent a serious threat to the integrity of the gas pipelines by eroding compressor components and pipeline control valves, plugging metering instrumentation and filters and reducing the accuracy of the in-line inspection. Also, BP could have major adverse effects on customers by contaminating the customers’ sales gas supply leading to interruptions of the customers’ operations and/or poor quality of products in which the sales gas is used as feedstock [3]. The required fluid velocity has been determined [6, 7] to entrain and carry away BP in liquid and gas pipelines, respectively. These two studies
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