Previous numerical simulations of Atlas rocket plumes showed poor agreement with experimental radiation data. It was proposed that the lack of agreement is partly due to inadequate grid resolution, disregarding turbulence effects and the absence of any modeling of soot which is present in the flow. In the present work two of these issues are addressed by using a higher order numerical scheme to overcome the computational grid size requirements and a two-equation turbulence model to address the effects of turbulence. A parametric study conducted on an axisymmetric plume for various initial values of turbulent kinetic energy, k∞, and turbulent dissipation rate, ϵ∞, indicates that there are upper and lower limits to the values of these parameters to sustain turbulence in the flow. In all above cases, an increase in temperature is seen in the shear layer and as a consequence a significantly higher number density of OH is observed. Higher OH number density is expected to result in increased radiance in the UV spectrum. A grid resolution study for a fixed k∞ and ϵ∞ case indicates that there is an increase in the turbulence level as the grid is refined. A laminar run with inflow energy level equivalent to one of the turbulent cases indicates an increase in temperature in the shear layer which is comparable to that in the turbulent case, and consequently higher OH number densities. Also increasing initial turbulent kinetic energy resulted in higher temperature even when turbulence was not sustained by the flow. Hence the flow energetics may play an important role in determining the flow physics and species concentrations. The results obtained from the axisymmetric parametric study are used to determine the parameters needed for the turbulence model in the 3D computations. A third order accurate MUSCL Steger-Warming scheme with the k-ϵ turbulence model is used compute the three-dimensional Atlas II flow solutions. This turbulent solution shows higher temperature and OH number density in the shear layer.
|Original language||English (US)|
|State||Published - Jan 1 1999|
|Event||35th Joint Propulsion Conference and Exhibit, 1999 - Los Angeles, United States|
Duration: Jun 20 1999 → Jun 24 1999
|Other||35th Joint Propulsion Conference and Exhibit, 1999|
|Period||6/20/99 → 6/24/99|