IN-24-001 - The Role of Heat Transfer in Smoke Control of Long Atria

This research evaluates the impact of neglecting boundary heat transfer on the development of a smoke layer in long atria, predicted using computational fluid dynamics (CFD) fire modeling. A parametric study was conducted which evaluated the effects of varying fire size, atrium height, atrium width, and thermal transfer rates of walls and ceilings on the results. Boundary heat transfer was found to impact the development of the smoke layer. The root cause of the differences in results, with and without heat transfer, was the increase in turbulent mixing of the ceiling jet with the ambient air below. This resulted in deceleration of the ceiling jet as well as thickening and cooling of the smoke layer. On a distance-synchronized basis, the difference between models with and without heat transfer was found to follow a power-law relationship with atrium length. This observation was used to develop an equation relating the atrium dimensions, material boundaries, and fire size to the impact of neglecting boundary heat transfer on the development of the smoke layer. The atrium length, height, and width were found to be the primary drivers of this difference, in decreasing levels of significance.