Development of Low-Emission Combustors for Power-Generating GTUs

The main results of VTI’s investigations into low-emission combustors for gas-turbine units (GTU) are presented. In recent years, the combustion of a premixed fuel-air mixture (FAM) in a swirling flow in a limited space has been under development for this purpose to attain more complete combustion, stable fluctuation-free operation of a combustor in a wide range of parameters, and compliance with environmental protection requirements. To solve the problems encountered in this field, a procedure has been developed for assessing the effect of temperature in the combustion zone, flow velocity, combustor pressure, and other factors on the combustion stability. A review is presented of a comprehensive approach employed by VTI’s specialists to study the processes in combustors using numerical and experimental methods enabling them to cut down the cost and time of activities on development of low-emission combustors. For example, a relationship is presented between the numerically estimated quality of the produced fuel-air mixture and the experimental nitrogen oxide concentrations. A design parameter relating the process conditions in a flame tube with the vibration combustion amplitude is proposed. The experiments demonstrated a good correlation of the proposed parameter with measured pressure fluctuation amplitude. Of real interest are the presented examples of changes in the velocity and temperature fields with an increase in the working pressure, which should be considered in designing and bench testing the combustor. The low-emission combustors (LEC) developed for large- and medium-power GTUs are presented. The potential for scaling the combustors for other GTUs is examined.