Description:
OBJECTIVE: Develop and demonstrate novel, electrostatic methods for improved fine sand/dust particle separation in turbine engines. DESCRIPTION: Sand/Dust particles have significant detrimental effects on turbine engine performance and durability causing impact on mission effectiveness and sustainment costs. Fine sand particles melt in the combustor and solidify (turn to glass) on turbine vanes, blades, and other hot section components thereby disturbing flow characteristics and reducing efficiency. Glass releases during engine cycles/transients and can damage downstream components. These fine particles also can get into the turbine cooling flow and plug up cooling passages in turbine blades and vanes causing premature oxidation. The above effects reduce turbine performance, increase turbine temperatures, and shorten the life of hot section components resulting in more frequent engine overhauls. Fine particles (1-80 micron size) are much more difficult to separate from the main flow stream because they tend to more easily follow the flow and are not easily filtered by inertial effects. The goal of this program is to improve separation of these fine particles via novel electrostatic methods (i.e., attraction/deflection of particles into the scavenge flow or conglomeration of the particles into larger masses which can more easily be filtered/scavenged) to enable more effective aerodynamic separation techniques. The goal metric is to improve fine particle (1-80 micron size) separation efficiency from current level of about 70% in current inertial separators to greater than 90%. The electrostatic system design effort should include calculations/modeling and/or subcomponent tests to determine the most effective methods along with the required electrostatic charges and particle velocity limits to effectively conglomerate/deflect the sand/dust particles for subsequent aerodynamic filtration. A key technical challenge will be the ability to effectively achieve electrostatic conglomeration/deflection of fine sand particles in a turbine engine realistic airflow environment. Another key technical goal to be addressed will be the ability to integrate the proposed electrostatic separation method into the engine with no increase in pressure drop and no more than a 15% increase in filtration system weight and volume relative to the proposed baseline engine filtration system. The size and weight of the proposed system will be dependent on the intended engine application. Proposed electrostatic filtration concepts can be applied to various parts of the engine wherever most effective. System development and validation efforts should include component testing to demonstrate the electrostatic system effectiveness as a function of inlet particle size distributions, where inlet to exit particle sizes will be evaluated. Small businesses are encouraged to work with major engine manufacturers to ensure effective application of proposed technologies into future gas turbine engine configurations. PHASE I: Key components of proposed electrostatic filtration methods should be developed and validated to substantiate the feasibility to achieve improved fine particle separation in turbine engines. Fine particles (1-80 micron size) are much more difficult to separate from the main flow stream because they tend to more easily follow the flow and are not easily filtered by inertial effects. The goal metric is to improve fine particle (1-80 micron size) separation efficiency from current level of about 70% in current inertial separators to greater than 90%. PHASE II: Fully develop, fabricate, and demonstrate the electrostatic filtration system in a ground test environment to validate improved fine particle (0-80 microns) separation efficiency from current level of 70% to greater than 90% in turbine engines, while not debiting the coarse sand separation capability. The current efficiency levels are typically 90%-97% for coarse sands (80-1000 microns). PHASE III: Phase III options should include endurance testing and integration of the enhanced electrostatic filtration system into a turbine engine system to demonstrate the performance of the system with engine sand ingestion ground testing. The resulting technology will enable significantly enhanced durability of hot section components of future advanced turbine engines operating in sand and dust environments. Both the military and commercial aircraft applications are likely to encounter such an environment and thereby will derive benefit from this technology. This improvement in electrostatic technology should improve fuel consumption and power density. It may reduce overall maintenance costs.
