Numerical Simulation Study on the Effect of Bend Angle on the Flow Characteristics of Natural Gas Hydrate Particles

Abstract

Bend pipe is a commonly used part of long-distance pipelines. It is very important to study the flow law of hydrate particles in the bend pipe to optimize pipeline design. In addition, the efficiency and safety of pipeline gas transmission will be improved. The flow of hydrate particles in the bend pipe is the research object of this paper, and the short twist tape is used as the spiral device, and numerical simulation methods are used to study the effects of the bend angle and the twist rate on the velocity distribution, turbulence intensity distribution, wall shear, particle movement and pressure drop distribution of the spiral flow carrying hydrate particles. The results show that as the twist rate of the twist tape is smaller, and the spiral flow is stronger, the fluid can generate a larger tangential velocity when flowing through the bend. The maximum speed at the section closest to the entrance is 28% higher than at the section furthest. Maximum tangential speed increased by 2 times. When the angle of the bend is larger, and velocity is more conducive to maintaining the spiral flow pattern of the particles, it is also more conducive to maintain. However, the twist rate is smaller, and the resistance is greater, then the pressure drop is greater, and the resistance coefficient of the bend pipe section is greater. With the increase of torsion, the pressure drop decreased by 52%. When the angle of the bend pipe section becomes smaller, it increases the collision frequency between the pipe wall and the natural gas. Unit pressure drop loss increased by 13%. When the angle is smaller, the change in the direction of the velocity of the particles will be more violent, and the pressure drop is larger, and the drag coefficient is larger. In the same section, the maximum turbulence intensity is about twice the minimum.