A preliminary heat transfer analysis of pulse detonation engines

Detonation engines offer higher theoretical thermal efficiencies as compared to their deflagration-based counterparts. Simultaneous pressure gain during heat addition through the detonation wave provides the superiority to the Zeldovich-von Neumann-Dring (ZND) cycle which is used to define the thermodynamic process of detonation engines. Combustion temperatures can rise as high as 3000 K across the detonation wave. The continuous exposure to such elevated temperature may risk the integrity of the structural components of the engines. Consequently, heat management of the detonation engines highlights an important parameter on the construction of a demonstrator. In order to be able to design an appropriate cooling system, both for pulse detonation and rotating detonation engines (PDE & RDE), an accurate estimation of the heat load stands as an essential prerequisite. Hence, a preliminary numerical study of the heat transfer on a pulse detonation engine model was conducted to quantify the heat load. Conservation equations for deflagration-to-detonation transition (DDT) in detonation engines were solved through open source fluid dynamics solver OpenFOAM equipped with ddtFoam module. Reactive flow field of premixed mixtures (Hydrogen-air) was modeled with a URANS second-order approximate Riemann solver equipped with Weller combustion model, and Arrhenius equations of O'Connaire reaction scheme for Hydrogen-air detonation. Multiple boundary conditions were tested to achieve the most appropriate model. Natural convection over the lateral combustor peripheries found to be the most realistic boundary condition for the problem. In order to observe cooling process better, PDE tubes in different length were also simulated. Finally, the transient heat transfer phenomenon across the pulse detonation tube is documented for various conditions investigated.