Phase Transitions, Nucleation and Mixing Modeling through Trans-Critical Conditions

ABSTRACT: The goal of the Phase I effort is to develop a detailed and comprehensive plan that identifies specific, tangible improvements to improve the fidelity of modeling trans-critical combustors. Both hydrogen/oxygen as well as hydrocarbon (RP-1, RP-2) / oxygen systems will be considered. The focus will be on developing improved modules for equations of state for trans-critical mixtures, as well as a more general framework for flowfields that can transition from sub-to-supercritical or vice versa. These upgrades will be developed in a modular fashion to permit incorporation within in-house CFD tools used at AFRL after testing and validation in a follow-on Phase II effort. BENEFIT: This Phase I effort and the subsequent Phase II effort will further enhance our capabilities for modeling both liquid rocket as well as gas turbine engines for DoD and NASA. Within the Air Force, this effort would support the development of the Hydrocarbon Boost technology Demonstrator (HBTD). This product also impacts technology efforts for future civilian gas turbine engines that are being developed under the N+3 generation engine program by NASA; these engine designs are driven by higher efficiency and lower emission requirements. The high-fidelity models developed under this effort will support both these programs. The commercial market for our product will primarily be for diesel engines which operate at high pressures that are generally supercritical. This is a very large and diverse market and includes marine engines, railroad engines, trucks and automobiles, as well as heavy industrial engines. With rising energy costs, a primary concern for these companies is the design of newer more efficient injector systems that provide improved mixing and combustion. The ability to provide accurate performance predictions at transcritical condition would enable the product from this effort to play a design support role.