In Shortly about Energy and Energy Sources

Energy is an effective force, a life activity, a determination. Energy in physics is the ability of a body or system to do some work; a quantity that characterizes the motion, rest, or position of a body, liquid, particle, or system of particles, and a quantity to describe field particles transmitted by natural forces and particle interactions. Energy appears in nature, technology and industry in various forms that are transformed into each other according to the principle of energy conservation: it cannot be spend or created, but only change its form. An energy source is any substance which serves as a raw material in the process of obtaining energy.

How Particle–Particle and Liquid–Particle Interactions Govern the Fate of Evaporating Liquid Marbles

Liquid marbles refer to droplets that are covered with a layer of non-wetting particles. They are observed in nature and have practical significance. These squishy objects bounce, coalesce, break, inflate,...

CFD Evaluation of Bend Angle Effects on Sand Particle Erosion in Multiphase Flows

In many industrial applications, gas-liquid-particle three-phase flows are observed. Predicting erosion damage in this type of flow is a challenging issue, and so many factors, such as the liquid film behavior have significant effects on the erosion rate. In the present study, the Eulerian-Lagrangian approach was implemented to study the process of sand particle erosion in elbows with different bend angles. For this purpose, gas and liquid phases under annular flow conditions were introduced at the pipe inlet, and the volume of fluid (VOF) method was employed to solve the governing equations. For evaluating the erosion rate, the Det Norske Veritas (DNV) model was applied. The predicted erosion results for the bend angles of 30°, 60° and 90° at different orientations were compared with those of the two-phase gas-particle flows. The simulation results indicated that for gas-liquid-particle flow, the behavior of film thickness in the bend plays a major role on the particle impact velocity and the corresponding erosion rates. By comparing the impact characteristics for gas and liquid superficial velocities of 40 and 0.4 m/s, respectively, in the 90° elbow, it was found that the impact velocities for gas-particle and gas-liquid-particle flows at the erosion hotspot are 38 and 14 m/s, respectively. In addition, among the studied geometries, the 30° elbow is the most erosion-resistant bend angle configuration among those studied for both two- and three-phase flows.

Modelling the Dynamics of Wetting of an Absolutely Rigid Tank Using the Particles Method

This work examines a model consisting of two systems of particles, those of liquid and of a tank wall. The tank is not deformed, and its particles are stationary. The liquid particles move in a plane under the action of forces. Each liquid particle interacts with each tank wall particle. The system of liquid particles “wets” the surface of the tank if it is close enough to the system of tank wall particles. The norm of proximity of the two systems is called the degree of wetting. A dynamic process of the liquid particle transfer from the initial to the final state is studied in this work. In the initial state, the system of liquid particles is arbitrarily positioned relative to the particles of the tank wall. In the final state, liquid particles transfer to the nearest neighbourhood of the tank wall particle system and “wet” it. The problem is considered in a two-dimensional formulation. The particle is a material point with a set power characteristic, and a liquid particle is associated with a drop. The analysis of the transfer process is a droplet dynamics problem. The equations of dynamics of the liquid particles are integrated using Runge-Kutta method. The solution converges quickly with regard to particle numbers.

Optimized Tree-Type Cylindrical-Shaped Nanoporous Filtering Membranes with 3 or 5 Branch Pores in Each Pore Tree

Background: It is necessary to investigate the performances of the optimized tree-type cylindrical-shaped nanoporous filtering membranes with 3 or 5 branch pores in each pore tree. Objective: To explore the design method for and the performances of the liquid-particle and liquidliquid separations of the optimized tree-type cylindrical-shaped nanoporous filtering membranes with 3 or 5 branch pores in each pore tree. Methods: The analysis was made for the flow resistance of the studied membrane based on the nanoscale flow equation. The optimum ratios of the radius of the trunk pore to the radius of the branch pore were typically calculated for yielding the lowest flow resistance of this membrane. The capability of the liquid-liquid separation of this membrane was investigated by exploring the flow resistances of this membrane for different liquids. Results: The optimum ratios of the radius of the trunk pore to the radius of the branch pore were typically calculated for the maximum fluxes of these membranes for different passing liquid-pore wall interactions. They can be used for the design of the studied membranes for liquid-particle or liquid-liquid separations. The flow resistances of the studied membranes in the optimum condition for different liquids were also calculated, and the capability of the liquid-liquid separation of the membranes is evidenced. Conclusion: The obtained results can be used for the design of the studied membranes for achieving their optimum operating condition, by taking the ratio of the radius of the trunk pore to the radius of the branch pore as optimum. The studied membranes also have good capabilities of liquid-liquid separations if the mixed liquids have greatly different interactions with the pore wall and the radius of the branch pore is below 3nm or less.