Session: 04-26: Novel Combustors II

Paper Number: 102889

102889 - Recursive Sequential Combustion Using Multiple Discrete Sectors 

Recursive Sequential Combustion (RSC, introduced in paper GT2021-59592) is a new concept that maximises the interaction between burnt gases and fresh reactants. The novelty compared to other concepts of flue gas recirculation in gas turbines is that this interaction is solely generated by a new inlet/outlet arrangement and well-designed flow dynamics, which avoids complex extraction, reconditioning and re-injection of flue gases. The main feature is the burner arrangement which places the flames one after the other in a closed loop, maintaining a trapped circulation of constantly renewed hot gases flowing along the chamber's annulus. The aim is to achieve robust lean combustion supported by the high temperature of the flue gases, combined with the re-burning effect of sequential combustion. The expected benefit of this technology is a steady lean operation with NOx and soot performance much higher than in conventional GT combustors. As the flow dynamics are ensured by high injection velocities and rapid mixing in a hot, oxygen-depleted environment, this concept designed to keep the flame aerodynamically stabilised and positioned at a safe distance from the walls could also be considered for lean premixed hydrogen combustion.

This concept is in an early TRL phase, so the technical challenges to be addressed are the advanced flow design (fresh mixture supply and hot gas discharge are along the sides of the ring, while the hot gas circulation is maintained along the toroidal direction), process start-up, operational envelope, flow stability and the higher level of thermal stress on the walls of the combustion chamber.

This paper focuses on the flow design using a multiple discrete sector approach. A discrete sector has an inlet and an outlet accompanying the recursive hot gas flow, which is supplemented by fresh mixture injection, a flow mixer/conditioner, a flame tube and a flue gas separator. The N sectors are then arranged in a closed loop. Side feeds and outlets, as well as periodic boundaries along the annulus, allow circulation to occur. The name "discrete" refers to the fact that the four functionalities of a single sector are separated (fresh mixture injection, mixer/flow conditioner, flame tube and flow divider) and that the flow transformations occur one after the other. By comparison, an alternative arrangement called constant section RSC was presented in GT2022-82420, where the four functions coincide in each normal section of the toroidal combustor. 

An advanced discrete-sector concept designed for demonstration purposes is presented. The flow design is studied by CFD and supported by basic experiments. It is shown that the burnt gas circulation and interaction are effective, demonstrating the plausibility of the concept.

Presenting Author: Fabrice Giuliani Combustion Bay One E. U.

Presenting Author Biography: Born in 1974 in France.

Studies of Mechanical Engineering at the ESSTIN of Nancy, France. Engineering diploma in 1997 in fluid mechanics and energetics.

Diploma Course at the von Karman Institute near Brussels, Belgium, 1998.

Doctorate (with Honors) at the ISAE-SUPAERO national aeronautics engineering school in Toulouse, 2002.

Research engineer at the VKI near Brussels, the ONERA Toulouse, and the DLR Cologne, Germany from 1998 to 2004.

Teaching fluid dynamics, GT technology and combustion at the ENAC (Ecole Nationale d'Aviation Civile), ENSICA (École nationale supérieure d'ingénieurs de constructions aéronautiques), SUPAERO, and TU Graz and FH Joanneum since 2004.

Founder and CEO of Combustion Bay One e.U. since 2012. CBOne is an engineering office for advanced combustion management. It offers services of expertise, design, and manufacturing of hot core parts with extreme thermal and mechanical strains for laboratory as well as industrial applications. In parallel, it performs its research and development, with more than 30 scientific publications and 4 patents since the company exists.

Authors:

Fabrice Giuliani Combustion Bay One E. U.
Andrea Hofer Combustion Bay One e.U.
Nina Paulitsch Combustion Bay One e.U.
Bugra Akin Combustion Bay One e.U.