Papers by Keyword: Flow Fluid

Abstract: In the paper, a velocity and fluid flow status of the melting process in twin-screw extruder were analyzed. To explore the optimum producing parameters of expanding food, several models of the flow field and velocity of twin-screw extruder were created with fake plastic Newton fluid. Then the velocity distribution rules in the cavity space were simulated. With the valuable verification of experiments, the results showed that, the velocity distribution near the inner wall is uniform, and increases at the delivery of the extruder. The velocity rises in the teeth root than in the top of the screws. At the mesh field, the velocity was changed frequently. The experiment of popped extrusion verified the simulation conclusion.

Abstract: This paper presents a mathematical model to predict the behaviour of the God particle, the Higgs boson, which adds mass to elementary particles appearing and disappearing in the time of Planck. The phenomenon of turbulence in the Planck scale in the modelling of space-time is the base on which is sustained this work. We measured the flow of fluid through the boundary that contains the studied mass (composed of virtual particles with characteristics similar to the Higgs boson) in full bubbling in a gravitational field with enormous surface gravity by calculating the divergence, the rotational and circulation of the fluid. The results show evidence of mass transfer of the particles consistent with the Theory of Special Relativity. The gravitational field (with mass like field source) acts as a conservative field, since its circulation along any closed curve is zero. By Stokes theorem, the flow is irrotational and therefore without vortices. In two arbitrary points of the gravitational field is found that the mechanical energy (sum of kinetic and potential energy) of the particles is constant, satisfying the theorem of conservation of energy in this inertial system isolated from conservative forces. Green's theorem defines sources and sinks of particles around a singularity in the mass center. For heat flow, the sources represent the heat production and the sinks represent its consumption. The irrotational gravitational field where is hosted the God particle has electrostatic and gravitational potential energy.

Abstract: With calculation results comparison of different throttle nozzle diameter value, This article analyses the flow field with throttle nozzle diameter variety of 1.0mm, 2.0mm, 2.4mm, 2.6mm, 2.8mm, 4.0mm, while the other parameters take same value (such as the inlet pressure is 20mpa, the outlet pressure is 10MPa, the temperature is 333k, and the well depth is about 2000m). the results present the influence upon downhole choke flow field including pressure, velocity, temperature distribution. The pressure field composed by minimum on the axis shows the pressure dropping change at the throttle nozzle outlet. Velocity field gives the maximum value of velocity and Mach number, which determines the flow field is subsonic or supersonic flow. With hydrate formation conditions, temperature field formed by minimum on the axis gives the existing judgment of hydrate formation under a certain condition. With the throttle nozzle diameter increasing, the outlet flow maximum velocity increases, and the differential pressure before and after nozzle becomes larger, which means the pressure drop effect is better. The downhole choke design of throttle nozzle needs to consider the combination effects of pressure drop and temperature drop. These parameters provide reference for downhole choke structure design and operating performance improvement.

Abstract: Natural gas downhole choke process inlet is high temperature and high pressure. Usually it can achieves 10~30MPa, while it will be higher in high pressure drilling well. It is installing thousands of meters underground. It is difficult carrying on field test during working process. These special situations make the choke outlet flow being complex, which includes expansion wave, compression wave, and energy transformation. The physical experiment is difficult. To be more accurately analyzing the compressible viscous turbulent motion of downhole choke internal flow field, this article uses RNG − model for three dimensional numerical simulation. It analyzes the result of flow field streamlines, velocity, Mach number, pressure, and temperature distribution. It analyzes the influence on hydrate formation of choke working process. Numerical calculation can provide useful reference for the prevention of natural gas hydrate formation and optimization design of downhole choke.