Examination of a collision-limiter direct simulation Monte Carlo method for micropropulsion applications

A wide range of flow regimes occur in micronozzles, from the transitional to the continuum regime, which prevents the use of a single computational method such as direct simulation Monte Carlo or computational fluid dynamics and Navier-Stokes. A collision-limiter approach is proposed that extends the applicability of direct simulation Monte Carlo to the continuum regime and can be used to solve a wide range of microelectromechanical system flows when it is coupled with the baseline direct simulation Monte Carlo. A comparison of the results obtained with this computational technique with new experimental data and Navier-Stokes results suggests consistency between experimental and computational methods for three-dimensional microelectromechanical system micronozzles with stagnation pressures on the order of 5 atm. However, the level of agreement was found to vary with the nozzle geometry, suggesting that additional research is needed for both computations and experiments in this flow regime.