Physical Aspects of Deposition From Coal-Water Fuels Under Gas Turbine Conditions

Abstract

Deposition, erosion, and corrosion (DEC) experiments were conducted using three coal-water fuels (CWF) in a staged subscale turbine combustor operated at conditions of a recuperated turbine. This rich-quench-lean (RQL) combustor appears promising for reducing NOx levels to acceptable levels for future turbines operating with CWF. Specimens were exposed in two test sections to the combustion products from the RQL combustor. The gas and most surface temperatures in the first and second test sections represented temperatures in the first stators and rotors, respectively, of a recuperated turbine. The test results indicate deposition is affected substantially by gas temperature, surface temperature, and unburned carbon due to incomplete combustion. The high rates of deposition observed at first stator conditions showed the need for additional tests to identify CWF coals with lower deposition tendencies and to explore deposition control measures such as hot gas cleanup.

Simulations of Multiphase Particle Deposition on a Showerhead With Staggered Film-Cooling Holes

“…Deposition in turbomachinery from ingestion of foreign particles, such as sand, into the engine intake is highly dependent on factors such as combustion temperature and particle melting temperature. Experiments conducted by Wenglarz and Fox [5], Richards et al [6], and Wenglarz and Wright [7] explored the effects of gas and surface temperatures on deposition in turbomachinery. Wenglarz and Fox [5] found that an increase in gas temperature resulted in an increase in the number of molten particles that deposit upon impaction of a turbine surface.…”

“…Experiments conducted by Wenglarz and Fox [5], Richards et al [6], and Wenglarz and Wright [7] explored the effects of gas and surface temperatures on deposition in turbomachinery. Wenglarz and Fox [5] found that an increase in gas temperature resulted in an increase in the number of molten particles that deposit upon impaction of a turbine surface. Richards et al [6] found that deposition rates on a surface could be decreased by increasing cooling near the surface.…”

A dynamic model for the Lagrangian stochastic dispersion coefficient

“…the velocity 'seen' by the inertial particle v f @p 21,23,24 , or the incremental change of the unresolved fluid velocity seen by the particle 20 . One of the main problems arising from such LS-LES models is the evaluation of the eddy interaction time-scale seen by the particle and the dispersion coefficient C * o required to evaluate the turbulent diffusion coefficient of equation (3). The aforementioned parameters exhibit a dependence on the Stokes number and the grid spacing and an effort has been made to fit empirical curves for the eddy interaction time-scale such as in the work of Jin et al 36 .…”

“…Firstly, the model describes non-inertial particles in a RANS framework. The model compensates for the temporal fluctuations of the continuous phase velocity using a stochastic Lagrangian forcing quantified by the diffusion coefficient in equation (3). In the context of LES the stochastic contribution is required to simulate the unresolved turbulent scales, i.e.…”

“…Particles understood in such manner can interact with each other and with the surroundings. Both types of interactions can become of central importance in numerous applications ranging from largescale chemical reactors and pulverized coal burners 1 , to the small-scale nanoparticle and soot formation and agglomeration in Internal Combustion Engines 2 and Gas Turbines 3,4 .…”