In this work, we study the heat transfer performance and particle dynamics of a high mass-loaded, compressible, particle-laden flow in a horizontally oriented pipe using an Eulerian–Eulerian (two-fluid) computational model. Previous experimental work by our group provides the basis for the study. Specifically, a 17 bar coflow of nitrogen gas and copper powder are modeled with inlet Reynolds numbers of 3 × 104, 4.5 × 104, and 6 × 104 and mass loadings of 0, 0.5, and 1.0. Eight binned particle sizes were modeled to represent the known powder properties. Significant settling of all particle groups is observed leading to asymmetric temperature distributions. Wall and core flow temperature distributions are observed to agree well with measurements. In high Reynolds number cases, the predictions of the multiphase computational model were satisfactorily aligned with the experimental results. Low Reynolds number model predictions were not as consistent with the experimental measurements.