A comprehensive review of solid particle erosion modeling for oil and gas wells and pipelines applications

Fundamental aspects of modeling turbulent particle dispersion in dilute flows

In order to predict gas and droplet velocities, droplet temperature, and fractional solidification with flight distance during spray forming, the Newtonian heat transfer formulation has been coupled with the classical heterogeneous nucleation and the specific solidification process. It has been demonstrated that the thermal profile of the droplet in flight is significantly affected by process parameters such as droplet size, initial gas velocity, undercooling, and superheat. With increasing droplet size or initial gas velocity, the onset and completion of solidification are shifted to greater flight distances and the solidification process also extends over a wider range of flight distances. It has been found that the corresponding solid fractions formed during recalesced, segregated, and eutectic solidifications are linearly related to the degree of undercooling and that those solid fractions are insensitive to droplet size, initial gas velocity and superheat.

Solidification progress and heat transfer analysis of gas-atomized alloy droplets during spray forming

Turbulent dispersion of particles using eddy interaction models

Analytical description of particle/droplet-laden turbulent flows

A lagrangian model for solid particles in turbulent flows

Numerical study of the solid particle motion in grid-generated turbulent flows

This article introduces (1) the basic idea of a computer code on the basis of a Lagrangian model and (2) a method of computing particle concentration by the model. This computer program permits us to calculate the spatial distributions of particle velocity and concentration as well as the capture efficiency of the ventilation system in the two-dimensional confined turbulent flows. As a validation of the computer code, the experiment of Ruck and Makiola (1988), where the turbulent air flow passes a single-sided backward-facing step, is simulated. Then, we simulate a bounded turbulent field with a strong recirculation region to demonstrate the capability of the present program. The simulation is conducted for particles with diameters of 1, 60, and 100 μm and the predicted particle velocity and concentration distributions are given. The concentration of the 1-μm particles is also compared with that computed by the prediction program EOL (Fontaine et al., 1991).

Particle Motion in Two-Dimensional Confined Turbulent Flows

Applying the time series analysis idea to the spatial and temporal fluid-velocity correlation functions, a Lagrangian model for particle motion in anisotropic turbulent flows has been established. As applications, particle motion is numerically investigated in two shear turbulent flows: one flow is homogeneous and the other is not. In the present study, the Saffman lift force due to flow gradient is accounted for. Quantities such as the variations of particle dispersion tensor, the cross-correlation coefficient, and the principal angle of the particle dispersion tensor with time are calculated for 60 and 140-μm particles. As a reference, the corresponding quantities are also calculated for fluid dispersion. Comparisons for the cross-correlation coefficient and the principal angle of the fluid dispersion tensor are made with the available direct numerical simulation results. A good agreement is observed. For particle motion in the homogeneous flow, where the stochastic process of particle motion can be als...

Particle Dispersion in Shear Turbulent Flows

To deal with corner separation in high-load axial compressors, this paper proposes a new end wall contouring method aimed at controlling the end wall secondary flow in more than one local area, generating a geometry with fewer control variables that is applicable for multiple working conditions. The new method defines more than one surface unit function, with different effects on end wall secondary flow. Then, the geometry of these surface unit functions will be superposed to generate the end wall contouring, to combine their flow control effects. After applying the new method to a bi-objective optimization design process, with 15 design variables aimed at minimizing the loss of cascade at 0° and 4° incidence, the optimal design reduces the total pressure loss of the high-load cascade by 5% under the former incidence and by 3% under the latter. The most effective design rule is constructing an end wall surface with the rising suction side and sinking pressure side in the blade channel, while locally raising the SS corner with a gentle upstream slope. According to the analysis, the design variables of the new method show an intuitive influence on the variation of end wall geometry and the movement of secondary flow. The corner separation has been effectively suppressed, with fewer control variables than before. It, thus, indicates the advantage of the newly developed end wall contouring method compared with previous studies.

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Q. Q. Lu

Papers

A lagrangian model for solid particles in turbulent flows

Numerical study of the solid particle motion in grid-generated turbulent flows

Particle Motion in Two-Dimensional Confined Turbulent Flows

Particle Dispersion in Shear Turbulent Flows

Numerical Investigation into a New Method of Non-Axisymmetric End Wall Contouring for Axial Compressors