Study Of Oxygen Enriched Combustor For Micro Gas Turbine

Micro gas turbine (MGT) is the core unit of distributed energy system, which is being widely used recently with the increase and diversification of energy demand. This paper carries out a research on a rated load30kW MGT combustor, which used oxygen enriched combustion technology to burn coal bed methane. Basic structure and geometric dimension of combustor were designed through the analysis and calculation. Numerical model built by CFD software and combustion experiment system were used to study the performance of designed combustor.Simulation result shows:combustor combustion efficiency and pressure loss meet the requirement of design, exit uneven coefficient is little higher than design objective. With the initial oxygen concentration increasing, the peak temperature in the combustor rose gradually and the combustion area was more concentrated, flue exit temperature decreased initially then increased, besides, the unevenness index of combustor outlet temperature decreased. With the increase of the initial oxygen concentration, the combustor outlet CH4mean concentration correspondingly decreased, however, CH4was completely burned under every combustion condition. Meanwhile, outlet CO2mean concentration was also correspondingly decreased and was above70%under every combustion condition, which facilitating the recovery of CO2. The average temperature of the flame tube radial section under different loads was basically the same. As the load increased, the average temperature of the combustor also increased, the combustor can maintain a stable combustion within the30%-150%load range. Combustion efficiency increased initially then decreased with the load increasing and reached maximum value under the120%load condition, which was slightly higher than the rated condition.Comparing modeling experimental results to simulation data, error was within an acceptable range, which indicating that numerical simulation model, meshing, boundary conditions sets were basically right. On the other hand, experimental results further validated that the performance of design MGT combustor was in line with the design requirements.