The burning process of a fuel droplet adjacent to an oxidizer droplet under an oxidizing convective flow is studied numerically by a quasi-steady body-fitted computation. Hypergolic propellants such as monomethyl hydrazine and nitrogen tetr9xide served as the fuel oxidizer sources, respectively. The computation took into account the variable properties of bipropellant species and products, with a single-step global finite-rate chemical reaction being assumed for the gas-phase combustion. The results obtained from the present numerical analysis show that multiple flame-configurations and vaporization-rates characteristic of temperature-sensitive, high-activation-energy Arrhenius kinetics, occurring under certain flow conditions for n-octane droplet burning in air flow (Jiang et al. 1993), are not exhibited by the present hypergolic propellants, which are characterized by a low-activation-energy of reaction. The oxidizer droplet adjacent to the fuel droplet substantially influences both flame configuration and the vaporization-rates of the fuel droplet by providing extra oxidizer vapor as well as changing the surrounding thermal-flow structures. At low Reynolds numbers (20), the fuel droplet vaporization rate is increased due to either a leading, or a trailing oxidizer droplet. Under these conditions, the fuel droplet vaporization rate is further increased by either a larger oxidizer droplet or smaller droplet center distance; results similar to those for biopropellant droplet burning in a stagnant environment. At high Reynolds numbers (20), the fuel droplet vaporization rate is not as significantly influenced by the accompanying oxidizer droplet as that at low Reynolds numbers. An excessively large leading oxidizer droplet, at Reynolds numbers higher than 60, results in a substantially lower fuel droplet vaporization rate than that exhibited by single droplet burning.
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)
- Fuel Technology
- Energy Engineering and Power Technology
- Physics and Astronomy(all)