A Numerical Study of Liquid Fuel Wick Flames in Artificial Partial Gravity in a Centrifuge Facility

Numerical simulations are performed to support a combustion and fire safety experiment campaign in partial (Lunar and Martian) gravity in a centrifuge designed for use in conjunction with the NASA Glenn Research Center's Zero Gravity Research Facility 5.2 second drop tower. The centrifuge is a circular dome chamber ~ 0.3 m3 with 81.3 cm diameter. The artificial gravitational field is controlled by the rotation rate of the chamber. This is complicated by gravitational gradients as a function of radius and Coriolis force as a function of flow velocity. The model is constructed with Ansys FLUENT utilizing a rotating non-inertial reference frame and simulates the entire chamber volume containing a heptane candle with a wick length of 10 mm x 3.18 mm diameter located at 32 cm from the centrifuge center. The candle is oriented in the radial direction (flame towards center). Simulation results locally near the candle are compared to a series of experiment images where the flame tip bends in the Coriolis force direction. The complex flow recirculation in the chamber under the influence of artificial gravity and Coriolis forces is discussed to help interpret the results and improve future test configurations.