A mixed Euler-Euler/Euler-Lagrange approach to erosion prediction

Providing quantitative assessment of erosion in the various parts of a piping system is of considerable importance in the oil&gas industry. Field and lab erosion testing are extremely onerous and, for this reason, this task is typically achieved by means of algebraic erosion correlations in conjunction with CFD two-phase models based on the Euler–Lagrange approach for flow computation. However, the high computational burden makes this approach onerous even for relatively simple benchmark cases, and it cannot be actually applied in many practical applications. In this paper, we present an innovative approach to erosion prediction, which relies on the combined use of Euler–Euler and Euler–Lagrange CFD two-phase models. The strength of the proposed approach, compared to the standard practice, resides in its numerical efficiency, arising from the fact that the Lagrangian description of the solid phase is restricted to certain subdomains bounded by the surfaces most vulnerable to erosion. The outcomes of two application cases, namely an abrasive jet impingement test and a simplified model of a needle and seat choke valve, demonstrate that the new approach allows considerable reduction of the computational burden for particle tracking and wear estimation. This will open the way for addressing more complex flows of considerable interest in practical applications, which are actually precluded at present.