Experimental and numerical studies of pressure effects on syngas combustor liner temperature

Abstract

Pressure effects on the liner temperature of a syngas model combustor are studied by experimental and numerical methods, with an attempt to analyze the influence mechanism. The model combustor, fueled with 10 MJ/Nm3 coal-derived syngas, is installed in a pressurized test-rig. Several diffusion flames with thermal powers up to 180 kw at pressures within 0.1–0.35 MPa are studied using a variety of measurement techniques. The liner temperature varies monotonically along the flow direction, and the maximum temperature appears around the dilution holes. Moreover, the liner temperature increases in the dilution zone but decreases in the primary zone with the increase of operating pressure, when the combustor exit temperature is maintained at 1073 K. Then, the combustion behaviors of the model combustor within pressure range of 0.1–2.0 MPa are simulated using CFD method, and the computed liner temperatures of testing cases agree well with the experimental data. The liner temperature varies approximately from −20 K to 150 K depending on locations when the pressure rises from 0.1 MPa to 2.0 MPa. It shows notable variation with operating pressure under low pressure conditions. However, as the operating pressure continues to increase, its impact on the liner temperature and the maximum temperature turns out to be very small. In order to explain the influence mechanism of operating pressure on the linear temperature, its effects on the flame structure, the liner heat flux, the convection and radiation are analyzed under different pressures. This study could be valuable for predicting and analyzing temperature distribution of the liner of gas turbine combustor.