Online

Ligon, Samuel Braggins

Mechanical Engineering

2020

M.S.

One of the largest issues concerning industrial cube satellite manufacturing is the development of propulsion systems at extremely small scales. Bipropellant cube satellite propulsion systems face challenges associated with the mixing of two fluids which operate in low Reynolds number environments. Low Reynolds, or laminar, fluid flow is unique to cube satellite injection systems because of their unprecedented small scale. This work is intended to both test the validity of a proposed cube satellite injection system, and to test the accuracy of numerical method approaches to solving the problem of laminar flow mixing in such devices. The proposed injector is an unlike doublet impinging system operating in laminar conditions and incorporating swirl methods to encourage mixing. Several geometries are examined each with different angles of propellant injection to the combustion chamber. The numerical approaches are characterized by use of the VOF model. Numerical cases are compared directly to experimental cases via image comparison. The numerical methods are then used to conduct a parametric sweep examining fluid interface size of different combustion injection geometries. Qualitative results indicate reasonable similarity in a steady state numerical case, but differences in the transient case. This is likely the result of irregular hydrophilic behavior between polymer surfaces and liquid water present in the experimental case but not the numerical. The parametric sweep indicates that fluid mixing is maximized when fluid injection angles are between 0 and 20 degrees in a gravity influenced environment. Above 30 degrees, fluid contact is lost entirely.