A Plug Flow Reactor for studying fuel autoignition chemistry at pressures of up to 50 bar

In this thesis, a High Pressure Flow Reactor (HPFR) is designed to study the combustion chemistry of conventional and alternative fuels over a wide range of conditions. The facility can operate at pressures of up to 50 bar and temperatures of up to 1000 K. At these conditions, the reactor was designed such that it meets the most recent Australian Standards (AS) and University of Melbourne safety requirements. The design methodology is divided in four step:
1. reaction rate calculations to set the design constraints
2. sizing, structural dimensioning and CAD modelling of the pressure vessel
3. characterisation and development of the static in-line coaxial mixer
4. accuracy and efficiency numerical estimation of the mixer within the reactor
The chemical kinetics calculations were conducted using Chemkin software. At the heart of the PFR is a 1 m quartz tube with an internal diameter of 25 mm. The entire length of the tube is considered as the test section and is maintained isothermal to within 5 K using four insulated ceramic fibre heaters. The mixing section consist in a series of parallel injectors used to supply the fuel and the oxidiser to the flow reactor. For a better understanding of the reactions in the HPFR, a model was developed using Comsol Multiphysics , which couples the injection process and the mixing reaction mechanism using a three-dimensional turbulent jet in a coaxial flow model. The injector configuration in the PFR was chosen to minimise the time to mix the injected fuel with the hot cross-flow of air.