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

Abstract

The demand for cleaner, more efficient energy has driven the motivation for improving the performance standards for gas turbines. Increasing the combustion temperature is one way to get the best possible performance from a gas turbine. One problem associated with increased combustion temperatures is that particles ingested in the fuel and air become more prone to deposition with an increase in turbine inlet temperature. Deposition on aero-engine turbine components caused by sand particle ingestion can impair turbine cooling methods and lead to reduced component life. It is necessary to understand the extent to which particle deposition affects turbine cooling in the leading edge region of the nozzle guide vane where intricate showerhead cooling geometries are utilized. For the current study, wax was used to dynamically simulate multiphase particle deposition on a large scale showerhead cooling geometry. The effects of deposition development, coolant blowing ratio, and particle temperature were tested. Infrared thermography was used to quantify the effects of deposition on cooling effectiveness. Although deposition decreased with an increase in coolant blowing ratio, results showed that reductions in cooling effectiveness caused by deposition increased with an increase in blowing ratio. Results also showed that effectiveness reduction increased with an increase in particle temperature. Reductions in cooling effectiveness reached as high as 36% at M = 1.0.

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 results indicated that the deposition caused a greater reduction in cooling performance for the case with combined film and impingement cooling compared to the case with only film cooling. By using 100 g, 200 g, and 300 g of wax injection, Lawson et al [46] performed experimental research of the deposition effect on the leading-edge film cooling. They found that the largest reduction in effectiveness was observed after just 200 g of wax injection, and there was 2% difference between results from 200 g and 300 g of injection.…”

Variations of cooling performance on turbine vanes due to incipient particle deposition

“…12 and Lawson et al. 13 simulated deposition on leading-edge geometries with showerhead cooling at a room temperature. It was concluded that increasing coolant blowing ratios decreased deposits but reduction of cooling effectiveness due to deposition increased with the blowing ratios.…”

“…In this work, comparisons of cooling performance before and after deposits are made in detail on a turbine vane. To emphasize the effects of deposits, the past studies 12–16 were conducted in a condition in which the turbine hardware had been exposed to particle concentration environment for a long period, resulting in much thick deposits on the turbine airfoils. For the current study, specially, the deposition effects on film cooling are investigated at an early stage of particle deposition processes, which allows to enrich the knowledge of the dynamic effects of the deposits during their build-ups over the entire service lifetime of an engine.…”

“…More importantly, the experimental work conducted in the TuRFR focused on deposition patterns only, without considering the resulting deposition effects on film cooling performance, in turn. By using wax as the particle matters, Albert et al 12 and Lawson et al 13 simulated deposition on leading-edge geometries with showerhead cooling at a room temperature. It was concluded that increasing coolant blowing ratios decreased deposits but reduction of cooling effectiveness due to deposition increased with the blowing ratios.…”