CFD assessment of the pollutant environment from RD-170 propulsion system testing

Computational Fluid Dynamics (CFD) technology has been used to assess the exhaust plume pollutant environment of the RD-170 engine hot-fring on the F1 Test Stand at Marshall Space Flight Center. Researchers know that rocket engine hot-firing has the potential for forming thermal nitric oxides (Nod. as well as producing carbon monoxide (CO) when hydrocarbon fuels are used. Because of the complicated physics involved, however, little attempt has been made to predict the pollutant emissions from ground-based engine testing. except for simplified methods which can grossly underpredict and/or overpredict the pollutant formations in a test environment. The objective of this work, therefore, has been to develop a technology using CFD to describe the underlying pollutant emission physics from ground-based rocket engine testings. This resultant technology is based on a three-dimensional (3D). viscous flow, pressure-based CFD formulation. where wet CO and thermal NO finite-rate chemisuy mechanisms are solved with a Penalty Function method. A nominal hot-fring of a RD-170 engine on the F1 stand has been computed. Pertinent test stand flow physics have been captured. The predicted total emission rates compared reasonably well with those of the existing hydrocartmn engine hot-fuing test data. Nomenclature = turbulencemodeling constant, = 1.15 = turbulence modeling constant, = 1.9 =turbulence modeling constant, = 0.25 =activation energy =convection and diffusion fluxes = turbulent kinetic energy prcduction = enthalpy = Jaoobian of coordinate transformation = turbulent kinetic &agy =molecular weight =total number of species = static pressure =heat sou~ce =represents 1, u, v, w, h, k E and ai