RAPTOR is a massively parallel flow solver for the simulation of turbulent combustion. In preparation for the upcoming Summit system at the Oak Ridge Leadership Computing Facility, a performance portable and GPU-ready version of RAPTOR has been developed. A combination of programming models have been used to convert the distributed memory parallel code to a hybrid parallel code with multiple levels of parallelism. Major performance-critical kernels have been reimplemented in C++ using the Kokkos programming model. The main flow solver has been accelerated using OpenMP compiler directives. We'll present the performance characteristics of RAPTOR on the IBM Minsky system for a high-pressure, supercritical reacting flow problem with applications in the aerospace and energy industry.