The purpose of this thesis is to simulate flame spread in zero gravity and identify different factors that can impact the flame spread rate. This was possible using the CFD code written in FORTRAN developed by Bhattacharjee. The fuel studied in this thesis is Poly (methyl methacrylate) (PMMA). A mathematical model that shows how spread rate is being calculated is explained. The importance of grids used in CFD was shown by choosing appropriate number of grids for a given domain and a rule for choosing the domain was established. Impact of boundary layer or flow development distance was deeply understood and a formula for flame tip velocity or equivalent velocity was developed. Computational spread rate was then non-dimensionalized by dividing it with spread rate obtained from de- Ris formulae and plotted against Damkohler number which was calculated based on opposed flow velocity and equivalent velocity. A large variation of opposed flow for different fuel thicknesses was plotted against spread rate to show how fuel-half thickness affects the spread rate and the impact of radiation was understood. A critical fuel-thickness up to which flame existed in a quiescent microgravity was computed using this flame code. The impact of oxygen level was also studied in detail for a given fuel thickness. Pressure was varied in the microgravity regime to see its impact on flame spread rate.