In recent years, the global energy transition has highlighted the need for sustainable fuel alternatives, with hydrogen emerging as a key player in reducing carbon emissions. As a carbon-free fuel, hydrogen offers significant potential to decarbonize important sectors such as transportation and industry when blended with traditional fuels. This study investigates the combustion of a natural gas-hydrogen mixture in a vertical continuous-flow combustion chamber using computational fluid dynamics (CFD) in ANSYS Fluent. The experimental setup involved a co-firing and reburn chamber fueled with natural gas. The chamber, with a heating power of 25 kW, features a side exhaust duct, seven side ports for six temperature measurements along its length and the insertion of a gas analyzer. Axial and radial temperature profiles for three air-fuel mixtures were recorded, along with concentrations of CO, CO2, NOx, and O2 as products. A computational model of non-premixed natural gas and air combustion was developed in Fluent under the same experimental conditions for validation. To date, the model has been simulated with natural gas only, showing good agreement with the experimental data. The maximum temperature reached was 1700 °C, and both axial and radial temperature profiles closely match the experimental results. The wall temperature contour revealed the swirling behavior of the mixture, and the total sensible heat transfer rate was 18 kW aligning with the chamber’s heating power of 25 kW, further validating the accuracy of the computational model. This study is ongoing, and hydrogen is set to be introduced into the mixture at concentrations of 15%, 30%, and 45% to analyze its effects on combustion products and temperature distribution within the chamber.