Analysis of Self-Excited Combustion Instabilities Using Two- and Three-Dimensional Simulations

摘要

Three-dimensional simulations of combustion instability can provide extremely valuable insight into the problem physics, but they represent an enormous investment in time and, thus, may preclude parametric studies that are practical with two-dimensional simulations. Three numerical simulations of an unstable laboratory rocket combustor were performed to assess the effect of grid resolution and dimensionality on the ability to predict and model combustion instability. Computations show that two-dimensional axisymmetric simulations using both coarse and fine grids are able to capture the amplitude of the first longitudinal mode within an order of magnitude of what was measured in the experiment. Whereas the three-dimensional calculation based on the coarse grid resolution shows excellent agreement with the experimental level of instability two-dimensional simulations are valuable in parametric evaluations in developing diagnostic methods and in increasing the efficiency of expensive three-dimensional simulations.