Session: 37-11 Combustors Design Methods

Paper Number: 82420

82420 - Flow Design Using CFD for a Constant-Section Recursive Sequential Combustor 

MÖBIUS (MOmentum-Enhanced Blend of the reactants with recIrculated bUrnt gaseS, a new combustion concept called recursive sequential combustion described in [GT2021-59592]) deals with designing a recursive sequential combustor using CFD simulations and assessing the flow design on 3D-printed prototypes. This paper concentrates on the latest developments of the variant called constant section. Based on previous results the combustion chamber is torus-shaped with a double-spiral-like cross section. Two air inlets and one fuel (Methane) inlet feed the combustion chamber with the intent of creating a stable, lean and continuous flame, with flue gasses being partly fed back into the combustion process due to the present swirl. This recirculation increases combustion efficiency and decreases the amount of generated nitrogen oxides. To stabilise the flame a large swirl is necessary, which is achieved by the round combustion chamber and guiding vanes in the in- an outlet pipes leading towards the chamber. The air outlet is also designed to force this interaction between outgoing burnt gasses and fresh inlets. Current simulations and tests show a large swirl in the chamber, as well as sustaining a circulation in the toroidal direction, which is essential to the concept. Previous simulations with only one air inlet and without guiding vanes resulted in smaller swirls and the flame touching the chamber walls. Current simulations are carried out in 3D to ensure stable combustion behaviour and meet expectations in terms of functionality.

Presenting Author: Andrea Hofer CBOne

Presenting Author Biography: Combustion Bay One employee since September 2019. Tasks deal with computational fluid dynamics (CFD), simulation of flows in combustion chambers using OpenFOAM and analysing the results with MATLAB. Different solvers have been used for both steady state and transient cases.<br/><br/>Bachelor’s thesis consists of two parts. The first part deals with the problem of simulating ice accretion on aircraft wings, for which the software Ansys Fluent was used. Several parameters influencing ice growth have been identified, including temperature, ambient velocity and water droplet size. The second part covered simulating fluid flows in standard and specific geometries to confirm the accuracy of the boundary/inlet conditions and apply this knowledge to more complicated meshes.<br/><br/>Master&#39;s thesis focuses on the simulation of a small combustion chamber using OpenFOAM. The iterative process starts with a simple geometry on which a fluid flow CFD simulation is performed. Based on the results the geometry is refined and a new simulation started. Once the geometry is refined enough combustion simulations are started, which are more complex than fluid flow simulations. The refined geometry is a circular combustion chamber with in- and outlet pipes of variable width. Due to pipe positioning and entry angle there is a large swirl in the chamber, stabilizing the combustion process and protecting the walls.

Authors:

Andrea Hofer CBOne
Fabrice Giuliani CBOne
Nina Paulitsch CBOne