Experimental study of the hydraulic characteristics of a coal log train in a pipe

Abstract

The pressure distribution around two coal logs in tandem (a coal log train) flowing in a horizontal pipe (inner diameter of 50 mm) is experimentally studied. Experiments are conducted at three water velocities (0.92, 1.10, and 1.50 m/s; corresponding Reynolds numbers 45 771, 54 726, and 74 627, respectively). The hydraulic characteristics of the coal log train are analyzed, and the results are used to calculate the lift and drag forces together with the lift and drag coefficients. The pressure at the faces and surfaces of the coal log train increases at rising water velocity, enhancing the lift and drag forces. The forces acting on the first coal log are the largest, and forces on other coal logs decrease stepwise. The hydraulic characteristics of the first coal log are more complex than that of other coal logs. The lift and drag coefficients decrease with increasing water velocity. Both the lift and drag forces on individual coal logs are smaller than those on a single coal log in a pipe, when the coal logs follow one another. These results show the great difference in hydraulic characteristics between a coal log train and a single coal log in a pipe.

Experimental study of the wheeled capsule motion inside hydraulic pipeline

“…In addition, equation (3) shows that the friction f acting on the wheeled capsule decreased. The larger the diameter of the wheeled capsule d was, the greater the lateral area of the wheeled capsule was; therefore, according to equation (4), the greater the pressure gradient force acting on the wheeled capsule was. The larger the diameter of the wheeled capsule d and the greater its length L were, the larger the lateral area of the wheeled capsule was.…”

“…In this technique, coal powder was first compacted into coal logs, followed by transporting the coal logs by pipe over great distances. 4,5 Liu et al and others experimentally investigated hydrodynamics, the design of transportation pipelines, coal log manufacturing, wear of coal logs, and the effect of polymer additives. [6][7][8][9] However, in coal log pipeline hydraulic transportation, coal powder needs to be molded or extruded into waterresistant and wear-resistant cylindrical coal log before being transported and coal log needs to be processed into coal powder after being transported, thus increasing the transportation cost.…”

Study of the energy consumption of the piped vehicle hydraulic transportation

“…Substituting equations (7), (9), and (15) into equation (6), the additional energy consumption of flow around the piped vehicle Dh w can be expressed as…”

“…6,7 The molding product pipeline hydraulic transportation was proposed by H Liu 8 at the University of Missouri-Columbia, resulting in a US patent. Following that, researchers have investigated the hydrodynamics, 9,10 design of transportation pipelines, 11,12 molding product manufacturing, 13 pressure characteristics of the molding product, 14,15 motion characteristics of the molding product, 16,17 wear of coal logs, 18 and the drag reduction of the molding product transported. 19 However, in the molding product pipeline hydraulic transportation, the bulk material needs to be molded or extruded into a water-and wearresistant cylindrical molding product before being transported and the molding product needs to be processed into bulk material after being transported, thus increasing the transportation cost.…”

Mathematical Model of the Piped Vehicle Motion in Piped Hydraulic Transportation of Tube‐Contained Raw Material

“…The molding product pipeline hydraulic transportation [20] was proposed by Henry Liu and Marrero at the Capsule pipeline Research Center of the University of Missouri Columbia and obtained a U.S. patent. In this technique, bulk material was firstly compacted into the cylindrical molding product, and then the molding product was transported by pipe over great distances [21,22]. Liu et al conducted many experimental studies, investigating hydrodynamics [23], molding product manufacturing [24], the effect of polymer additives [25], economics of molding product hydraulic pipeline transportation, and so on [26].…”