  The primary target of this paper is to present novel compounds in view of
their possible use as oxidizers in propulsion applications using molecular
modeling calculations and supersonic flow simulations. Carbon-based
heterocyclic compounds tend to have strained molecular structures leading to
high heats of formation and energetic behavior. In the present work, molecular
modeling calculations for molecules of 37 such potential propellant oxidizers
are presented. Density functional theory (B3LYP) was employed for the geometry
optimization of the proposed molecular structures using the 6-311++G(d,p) basis
set. Heats of formation of the compounds were calculated using the molecular
modeling results. Appropriate propellant compositions were considered with the
proposed compounds as oxidizer components and Ideal specific impulse
(Ivac,ideal*) was calculated for each composition assuming isentropic flow,
computed using the NASA CEA software package. To predict the actual delivered
specific impulse (Ivac,act*), supersonic nozzle flow simulations of equilibrium
product gases of each propellant composition have been carried out using
OpenFOAM. The standard k-epsilon turbulence model for compressible flows
including rapid distortion theory (RDT) based compression term, has been
employed. As the problem is inherently transient in nature, local time stepping
(LTS) methodology has been further implemented to reach a steady-state
solution. These simulations accounted for divergence losses, turbulence losses
and boundary layer losses and gave a more realistic estimation of the specific
impulse. It was observed that the Ivac,act* for all propellant compositions lie
between 88% to 91% of the corresponding ideal value. The newly proposed
oxidizers showed considerable improvement in propulsion performance as compared
to ammonium perchlorate.
