CCS and Power Systems

Crosscutting Research - University Training and Research


Multiphase Flow Research-Uncertainty Quantification Tools for Multiphase Gas-Solid Flow Simulations using MFIX


Project No: FE0006946


Project Description

Uncertainty quantification (UQ) in complex multiphase computational fluid dynamics (CFD) codes is needed to determine the effect of uncertainty in input parameters, boundary conditions, and theoretical sub-models on the numerical results provided by these codes. One of the most often applied and successful methods to quantify uncertainty from a probabilistic point of view, is the polynomial chaos (PC) method.

Polynomial chaos methods (PC) have been developed both by reformulating a set of equations in order to obtain a system of coupled equations to evaluate the strength of the PC modes (the so-called intrusive approach), and by using deterministic or random sampling of the original deterministic model to evaluate the PC modes from the outputs of an existing numerical implementation of the model (the non-intrusive approach). The application of intrusive UQ to multiphase codes such as MFIX (Multiphase Flow with Interphase eXchanges) for gas-solids flows is prohibitive due to the complexity of the underlying model equations and the time-dependent nature of the output.

This project will develop a PC non-intrusive approach to implement UQ in MFIX. This methodology will generate a set of samples from the output results of the original model. For each sample, a PC expansion as a function of the uncertain parameter is determined, and the expectation for the Galerkin projection is determined by considering all the samples under consideration.


Project Details