Simulated Syngas Ash Deposits on a Flat Plate Using Teflon and PVC Particles

Abstract

Solid and molten ash particles from coal derived syngas in the hot gas path can deposit on and erode turbine blade surfaces causing issues with performance that potentially could result in failure. Conducting experiments at the firing temperatures of actual turbine engines (∼ 1500 K) is difficult, so an experimental method of substituting the ash particles for particles with a lower melting temperature is presented. This allows particle deposition tests to be run at more reasonable laboratory conditions. To fully simulate ash deposition, dynamic similitude was used to design a lower-temperature experiment with using PVC and Teflon particles with an average size of 24 and 6 microns respectively. The carrier flow, air, varies over a temperature range of 350–475 K, and the deposition surface varies over a temperature range of 400–475 K. The data and geometry from other experiments were also scaled and compared directly to the results of the current study. The deposition surface was a polished flat plate angled 45° normal to the flow. Initial observations indicate trends with PVC and Teflon particles in the scaled experiment agree with that of coal ash. Observed trends were an increase in capture efficiency with fluid temperature and decrease in capture efficiency as the deposition surface temperature is lowered. Capture efficiencies are all in the range of 0.5–10%. Further tests will be conducted using this scaling method with PVC particles on leading edge geometry with film cooling.

A Compressor Fouling Review Based on an Historical Survey of ASME Turbo Expo Papers

“…[177]. Other contri-982 butions can be found in relation to the effects of the electrostatic 983 charge on particle deposition [178,179] and for evaluating the 984 effects of the temperature of the particle and target surface and the 985 turbulence intensity [180][181][182][183][184][185][186][187]. 986 Regarding experimental tests, particle deposition is investigated 987 in order to understand the turbine section contamination and the 988 interaction between cooling hole and particle deposition.…”

“…994 Other experimental contributions can be found in Refs. 995 [171,173,185,. 996 5.2 Experimental Analysis.…”