Gas-Surface Interaction Measurements in the 30kW ICP Torch Facility
Start Date
2-3-2011 8:50 AM
Description
A series have tests have been conducted in the 30 kW ICP Torch Facility at the University of Vermont with the goal of obtaining a measurement of the graphite nitridation rate. This reaction is important for carbon-based heat shields in many planetary entry applications. Graphite also represents a simplified ablator, as the material is relatively homogeneous and the surface will recess without pyrolyzing. The measurements were made using laser-induced fluorescence (LIF) of the nitrogen atoms in the near-wall region along the stagnation streamline. These spatially resolved measurements provided values of the local translational temperature and relative atom number density. Additional measurements are ongoing to convert the relative measurements to absolute values. The gradient in atom concentration provides a qualitative indication of the reaction efficiency at the surface, while the absolute values allow a quantitative estimation of the reaction efficiency. Results from these tests are presented and discussed and additional activities supporting an investigation of pyrolysis are summarized.
Gas-Surface Interaction Measurements in the 30kW ICP Torch Facility
A series have tests have been conducted in the 30 kW ICP Torch Facility at the University of Vermont with the goal of obtaining a measurement of the graphite nitridation rate. This reaction is important for carbon-based heat shields in many planetary entry applications. Graphite also represents a simplified ablator, as the material is relatively homogeneous and the surface will recess without pyrolyzing. The measurements were made using laser-induced fluorescence (LIF) of the nitrogen atoms in the near-wall region along the stagnation streamline. These spatially resolved measurements provided values of the local translational temperature and relative atom number density. Additional measurements are ongoing to convert the relative measurements to absolute values. The gradient in atom concentration provides a qualitative indication of the reaction efficiency at the surface, while the absolute values allow a quantitative estimation of the reaction efficiency. Results from these tests are presented and discussed and additional activities supporting an investigation of pyrolysis are summarized.