Simulations of Multiphase Particle Deposition on Endwall Film-Cooling Holes in Transverse Trenches

Abstract

Integrated gasification combined cycle (IGCC) power plants allow for increased efficiency and reduced emissions as compared to pulverized coal plants. A concern with IGCCs is that impurities in the fuel from the gasification of coal can deposit on turbine components reducing the performance of sophisticated film-cooling geometries. Studies have shown that recessing a row of film-cooling holes in a transverse trench can improve cooling performance; however, the question remains as to whether or not these improvements exist in severe environments such as when particle deposition occurs. Dynamic simulations of deposition were completed using wax injection in a large-scale vane cascade with endwall film cooling. Endwall cooling effectiveness was quantified in two specific endwall locations using trenches with depths of 0.4D, 0.8D, and 1.2D, where D is the diameter of a film-cooling hole. The effects of trench depth, momentum flux ratio, and particle phase on adiabatic effectiveness were quantified using infrared thermography. Results showed that the 0.8D trench outperformed other geometries with and without deposition on the surface. Deposition of particles reduced the cooling effectiveness by as much as 15% at I = 0.23 with the trenched holes as compared to 30% for holes that were not placed in a transverse trench.

Combined Influence of Surface Deposition and Hole-Blockage on Film-Cooling Performances

“…As discussed by Barigozzi et al [22] and Chen et al [23], the upstream deposition or ramp can uplift mainstream from the wall, and cause an area of low pressure behind the deposition or ramp, which can provide a separation cavity, which leads to coolant flow residing in the cavity. Therefore, the 6 Copyright © 2016 by ASME deposition model D1.5 can improve film cooling effect. These experimental phenomena obtained from the simplified model are in accord with previous researches carried out in real environment [5].…”

“…Their results indicated that the cooling effectiveness is highest in the case that deposition only in the upstream of film hole and the other deposition models deteriorate film cooling performance. Using the accelerated deposition facility, Lawson et al [6] found that the film hole in a transverse trench can defense the deposition caused by impurities in the fuel, and the trench with 0.8 diameter depth can outperform others. The phenomenon was also found by Albert et al [7]in a turbine vane experiment.…”

A review of multiphase flow and deposition effects in film-cooled gas turbines

“…Two particle filters were located at the outlet of the flow channel. A clearer explanation of the experimental facility was shown in [45,46]. The wax was injected by using a wax particle generator to simulate the deposition process.…”

The Effect of Blowing Ratio on Film Cooling Effectiveness Using Cylindrical and Row Trenched Cooling Holes with Alignment Angle of 90 Degrees

“…They reported that maximum cooling effectiveness can be obtained when the trench depth was = 0.8 ( is the trench depth and is the diameter of the cooling hole). However, Lawson and Thole [10] found different results, suggesting that this trench depth gives negative effect on the cooling performance downstream the cooling hole. Later, Lu et al [11] and Maikell et al [12] found that the trench depth of = 0.75 gave the optimum efficiency and it was validated by CFD studies.…”