Application of trioxygen difluoride in liquid- rocket-propellant technology.

Abstract

The use of trioxygen difluoride (O3F 2 ), a metastable compound of oxygen and fluorine, has been proposed as an additive to render liquid oxygen (LO 2 ) hypergolic with a wide range of fuels. The prime aim of the work reported was to determine the environmental limits of reliable hypergolic ignition of LO 2 : OsF 2 with liquid and gaseous hydrogen (LH2 and GH2). The results indicate that hypergolicity of OzFz is associated with its thermal decomposition, which contributes to the formation of reactive radicals. A significant dependence of ignition delay on the time-averaged weight ratio of oxidant to fuel (O/F) was found for all injector types. It is believed that the experimental results provide the engineering background necessary for any future consideration of scale-up to larger rocket engines. This study has shown that rather critical requirements must be met if satisfactory ignition is to be achieved; hence, OsF 2 is not a simple panacea for eliminating ignition or combustion problems in rocket systems that use LO 2 . Included is a review of the advantages and disadvantages of using LO 2 : O^Fz from the standpoint of the project engineer. NomenclatureF = total integrated flow of fuel up to ignition time, Ib g -gravity, ft/sec 2 / = ion-probe channel L* = chamber volume/nozzle-throat area, in. 0 = total integrated flow of oxidizer up to ignition time, Ib O/F = oxidizer-fuel mass flow rate ratio O/F = mass ratio of the total integrated oxidizer-fuel flow to the combustor up to the time of ignition P = pressure, psi S = area, ft 2 t = time, sec T = absolute temperature, °K V = velocity, fps Z = height, ft p = density, lb/ft 3 Subscripts C = combustor hardware IH, IO = hydrogen injector and oxygen injector, respectively

Theoretical Characterization of the F2O3 Molecule by Coupled-Cluster Methods

“…At least one patent for trioxygen difluoride in liquid oxygen has been granted, 10 and its uses as a rocket propellant have been considered. 11 Although molecular F 2 O 3 has not been detected experimentally, current high-level theoretical methods should be able to provide predictive-quality data on this species that can aid future laboratory identification, which is the goal of this paper. The only chemically sensible structure for a molecule with formula F 2 O 3 is the FOOOF chain isomer.…”

“…Although mixtures with F and O in a 2:3 ratio can be prepared, they apparently do not contain F 2 O 3 molecules. At least one patent for trioxygen difluoride in liquid oxygen has been granted, and its uses as a rocket propellant have been considered …”