Session: 03-01 Ammonia as Fuel and Hydrogen Carrier – Combustion, Storage, and Safety

Submission Number: 179360

Thermal Analysis of Gas Turbine Combustor Liner With Integrated Ammonia Cracker 

Ammonia as a fuel in commercial aviation is a promising pathway towards net-zero emissions. However, direct ammonia combustion is largely inefficient, creating the need for onboard cracking to generate hydrogen for improved combustion characteristics. One pathway for onboard cracking is to have the hardware live around the combustor liner where heat generated from the combustion process can be used to sustain the reaction. This study investigates heat transfer from an ammonia–hydrogen combustion flame to quantify convective and radiative heat loads on the combustor liner. A one-dimensional thermal energy balance model is developed that accounts for external and internal radiation, convective heat transfer, and conduction through the liner wall. For the 1D model, radiative heat exchange is modeled assuming a nonluminous gray-body and considers  as the main radiating species in the combustion products. This simplified analytical framework serves as a preliminary design tool for evaluating liner heat loads. The objective is to predict average uncooled liner temperatures and determine the maximum theoretical cracking achievable with the available heat flux. The model is extended to computational fluid dynamic (CFD) simulation using the discrete ordinate radiation model with weighted sum of grey gas (WSGG) model. The endothermic nature of the reaction is expected to have a measurable impact on liner wall temperatures, affecting film cooling and thermal barrier coating requirements. Combustor operating parameters are obtained from full engine cycle simulations using NPSS software. Preliminary results indicate that, at baseline cruise operating conditions, the available heat flux from combustion is insufficient to achieve high cracking efficiencies for the desired fuel flow rate. However, reducing the mass flow rate of ammonia demonstrates a measurable improvement in conversion efficiency.

Presenting Author: Mairah Ahmed University of Central Florida

Presenting Author Biography: I am a second-year PhD student of Mechanical Engineering at the University of Central Florida. As a graduate research assistant at the Center for Advanced Turbomachinery and Energy Research (CATER) lab, I work on developing process designs that enable decarbonisation in aviation. My current research involves exploring ammonia as an alternative fuel in aviation and investigating techniques to integrate ammonia into existing aircraft engines using simulation software for process optimization.

Authors:

Andrew Menendez University of Central Florida
Benjamin Turner University of Central Florida
Mairah Ahmed University of Central Florida
Shinjan Ghosh University of Central Florida
Nishant Brijlal University of Central Florida
Ghanshyam Mandal University of Central Florida
Saqib Shahzad University of Central Florida
Erik Fernandez University of Central Florida
Marcel Otto University of Central Florida
Jayanta Kapat University of Central Florida
Stefano Orsino ANSYS