An analytical and experimental investigation of the velocities of particles entrained by the gas flow in nozzles

Abstract

Among the parameters which determine the erosion damage sustained by the walls of a nozzle, in which a mixture of gas and particles is flowing is the speed attained by the particle before collision with the wall surface. This work is concerned with the determination of the particle velocity, and a number of relationships are given from which the variation in particle velocity can be obtained for a variety of gas conditions. The changes of state and velocity of the gas, occasioned by the interchange of heat and work between the gas and the particles are dependent on the ratio of the mass flow rate of particles to the mass flow rate of gas. It is shown that if this ratio is small the particle velocity may be obtained without serious error by assuming that the gas conditions are not affected by the presence of particles. Figures for the limiting value of this ratio for certain flows are given. The effects of particle size, density and initial relative velocity are investigated analytically and experimentally.

Designing a Scaled Erosion Test With Computational Fluid Dynamics Methods

“…The difference between actual diameters and equivalent wear diameter should be taken into account when discussing erosion rates based on a mean particle diameter. Neilson and Gilchrist, 1968 showed that the erosion mainly depends on the wall material, the particle velocity, and the angle of attack. In this model, it is assumed that erosion is mainly controlled by particle impingement against the pipe wall.…”

“…Further, it is assumed that there are no particle-particle interactions within the slurry flow field. Neilson and Gilchrist, 1968 showed that the erosion coefficient, ξ erosion , mainly depends on the incident particle speed, v in , particle size, d p , and the incident angle, β in , which is the angle between a plane tangent to the surface at the impact and the direction of motion of the incident particle. The form of the empirical relation used for the present erosion model is, Designing a scaled erosion test with CFD methods Page 6 of 10 WSRC-MS-2001-00500…”

A Microcomputer Model for Cutting Transport in Air Drilling

“…Others (7,8) have assumed that aerodynamic drag is responsible for particle motion but that there is no effect of the particle motion on the gas flow. Others (7,8) have assumed that aerodynamic drag is responsible for particle motion but that there is no effect of the particle motion on the gas flow.…”

Errors in the numerical integration of a linearized equation for particle flows

“…Examples include dust ingestion in turbomachinery [ 1,2], solid propellant motion in rocket nozzles [3], raindrop impingement on aircraft surfaces [4], and pulverized coal combustion [5]. In each of these examples and in many others, the particles governing differential equations (namely Newton's second law) are integrated in time over small steps.…”