​The HPOC allows for the observation and optical analysis of gas and liquid flames operating in diffusion and premix modes. The combustion air is supplied by a 2.2MW Joy compressor capable of delivering up to 5kg/s of air at 16bara. This air is pre-heated by a non-vitiating heater capable of raising the air temperature to 900K. A convergent-divergent nozzle pf diameter of 45mm accelerates the flow to Mach 5. Liquid fuel is delivered via a pressurised accumulator which can supply different liquids including kerosene, and bio-derived oils. Oxygen enhancement is supplied either unmixed or pre-mixed with the air upstream of the inlet, where the fuel is then introduced to the oxidant mixture via a specific mass flow controller. Downstream of the combustor in the exhaust there is an R-Type thermocouple to give representative entry temperatures and upstream of this the gas analysis sample is taken. Combustor acoustics are measured using dynamic pressure transducers at multiple configurable locations. This setup was intended to demonstrate the velocity distributions in the flow-field and flame-front location, which allows for the determination of critical combustion parameters such as integral length scales and turbulence intensities.