Laboratory investigations of a low-swirl injector with H2 and CH4 at gas turbine conditions

Abstract

Laboratory experiments were conducted at gas turbine and atmospheric conditions (0.101 < P 0 < 0.810 MPa, 298 < T 0 < 580K, 18 < U 0 < 60 m/s) to characterize the overall behaviors and emissions of the turbulent premixed flames produced by a low-swirl injector (LSI) for gas turbines. The objective was to investigate the effects of hydrogen on the combustion processes for the adaptation to gas turbines in an IGCC power plant. The experiments at high pressures and temperatures showed that the LSI can operate with 100% H 2 at up to φ = 0.5 and has a slightly higher flashback tolerance than an idealized high-swirl design. With increasing H 2 fuel concentration, the lifted LSI flame begins to shift closer to the exit and eventually attaches to the nozzle rim and assumes a different shape at 100% H 2 . The STP experiments show the same phenomena. The analysis of velocity data from PIV shows that the stabilization mechanism of the LSI remains unchanged up to 60% H 2 . The change in the flame position with increasing H 2 concentration is attributed to the increase in the turbulent flame speed. The NO x emissions show a log linear dependency on the adiabatic flame temperature and the concentrations are similar to those obtained previously in a LSI prototype developed for natural gas. These results show that the LSI exhibits the same overall behaviors at STP and at gas turbine conditions. Such insight will be useful for scaling the LSI to operate at IGCC conditions.

A high turndown, ultra low emission low swirl burner for natural gas, on-demand water heaters

“…A large recirculation (indicated by negative values of u z /U o ) is also formed. The trends of these profiles are consistent with those measured previously on larger LSBs (Cheng, 2009). Because swirler SW4 has a higher swirler number than other LSB developed for commercial use (attained by have a larger blockage of the center plate), the flame position is close to the burner exit.…”

“…At higher heat outputs (greater than 38 kBTU/hr), the velocity profiles are more consistent, as the turbulent divergent flow is fully developed and assumes similarity features reported by Cheng et al (2009). A large recirculation (indicated by negative values of u z /U o ) is also formed.…”

Lewis number effects in distributed flames

“…Burning under lean conditions reduces the exhaust gas temperatures, and consequently, thermal NOx emissions. Low-swirl burner technology, introduced by [1] as a tool for studying the fundamental properties of lean premixed turbulent flames has proven to be an effective stabilization mechanism for a wide range of fuels, see [2] and [3]. However, high-swirl injectors, often used in gas turbines, can generate much higher levels of turbulence.…”

Conceptual Studies of a Fuel-Flexible Low-Swirl Combustion System for the Gas Turbine in Clean Coal Power Plants

“…In addition, laboratory tests have shown that the fundamental operating principle of the LSI provides not only fuel flexibility but also smooth transitions between various fuels. Laboratory results obtained at simulated gas turbine conditions using simulated coal-based syngases [3] and natural gas and hydrogen blended fuels [4] show that the LSI does not require any hardware change to operate with these different fuels.…”