An experimental study on head loss characteristics of pipe bends for flow of coal–water slurry at high solid concentration

Abstract

Bending of pipes is a major problem facing the engineers during the construction of a long pipeline for transporting coal–water slurry. However, the use of 90° bends in slurry transportation is restricted because it causes high head loss, and so very high pumping power is required to overcome this resistance. In this context, the present study is carried out to reduce the head loss for the flow of coal–water suspension across 90° pipe bends by varying bend geometry. Rheological experiments were performed to study flow characteristics of coal–water suspension with/without the additive. Coal–water slurry exhibits Newtonian behavior at a solid concentration of 30 wt% and pseudoplastic flow nature at concentration above 30%. Head loss experiments were carried out on a pilot plant test loop for a solid concentration of 30.27–61.56% with flow velocity ranging from 2 to 5 m/s. The r/ D ratio for the pipe bend varied within the range of 1.5–2.5. The present study reveals that the head loss across pipe bends increased as solid concentration and flow velocity was increased. The optimum r/ D ratio value for a minimum head loss was found to be 2.0. Also, significant decreases in apparent viscosity and head loss were perceived with the addition of a small amount of sulfonic acid. Power required to pump coal–water slurry was decreased by 15.93% with the use of an additive. A correlation for the head loss in terms of solid concentration, flow velocity, and r/ D ratio was also developed.

Solid Concentration Estimation by Kalman Filter

“…Solid concentration (SC) estimation plays an important role in the detection of pipeline multiphase flow [ 1 , 2 ], essentially in dredging engineering [ 3 ]. The high precision of SC is necessarily required to effectively control industrial processes, while a small error of estimated SC can cause huge economic cost and efficiency repercussions.…”

CFD Modeling of Multi-Sized Particulate Slurry Flow through Pipe Bend

“…The particle size is one of the dominating parameters affecting the pressure drop and particle flow characteristics (Mukhtar et al 1995) across the bend. Many investigators (Mukhtar et al 1995;Mishra et al 1998a;Kaushal and Tomita, 2002;Verma et al 2006;Singh et al 2019) experimentally determined the pressure drop and flow characteristics of the solids inside the bend. Numerical approach has also been used to understand the complexity of flow over a wide range of parameters which are difficult to obtain through the experiments.…”