Thermal Viability in an Advanced Injector Concept

The challenge

The injector geometry meant significant heat transfer from the combustion gases into the injector body. The engineering question was whether temperatures could be controlled across the full range of load conditions expected in service, and what secondary fuel flow rates would be required for cooling.
As a concept that sat outside of the conventional injector design philosophy, a rigorous engineering approach was required to understand the thermal behaviour and how it would vary across operating conditions.

PTL’s role

PTL built a 1D engine model with a detailed combustion object and calibrated it against combustion CFD to derive representative heat-transfer parameters and thermal boundary conditions. These boundary conditions then fed a steady-state FEA model of the injector, allowing heat flow through the components to be characterised and the cooling requirements to be defined with confidence rather than estimated from conventional design assumptions.

Why it mattered

The iterative approach, from engine model to CFD calibration, to component FEA was necessary to ensure that physically representative behaviour was captured. This is critical when analysing designs that fall outside of the range where standard assumptions and guidelines can be depended upon.

The outcome was a clear set of cooling flow requirements, providing defensible engineering data to a question that directly determined whether the injector concept was viable with regards to thermal performance. By resolving that uncertainty analytically, the programme risk was reduced before committing to a definitive design and hardware.