In many arid regions, particle ingestion can occur within propulsive gas turbines. The ingested particles can severely impact performance and may damage many primary gas path components through erosion or deposition. Characterizing crystalline deposits on metallic substrates can allow for the prediction of deposition to improve component resilience and develop health monitoring algorithms. This work investigates the effect of temperature and angle on sand deposits and attempts to quantitatively characterize the deposition of Arizona Test Dust (ATD) onto Hastelloy X.
The first study presented in this thesis describes a preliminary investigation of sand deposition at temperatures and velocities similar to those found in the turbine section of propulsive gas turbine engines and presents an equation for predicting deposition as a function of gas path temperature and impact angle. The sand and air mixture maintained a constant flow velocity of approximately 70 m/s, impact angle was varied from 30° to 90°, and the gas path temperature was varied from 1000 °C to 1100 °C. The number of deposits was found to linearly increase with temperature for all coupon angles tested. The model was able to explain approximately 67% of the deposition that occurs, with the remaining percentage due to other factors such as injection rates and surface temperature.
The second study describes an improved investigation of sand deposition and presents an equation for predicting deposition as a function of surface temperature and impact angle. This study characterizes deposition using percent coverage in addition to deposits per square millimeter. Deposition is a quadratic function of both near surface coupon temperature and coupon angle. The model using deposits per mm2 was able to explain 96.3% of the deposition that occurred and the model using percent coverage was able to explain 98.9% of the deposition that occurred. / Master of Science / In desert regions, sand particles can be sucked into helicopter and airplane jet engines which can severely impact performance and may damage many engine components through erosion or hot deposits. By measuring the sticking properties of sand on materials used in jet engines, equations to predict sticking can be created and combined with previous erosion research to develop computational simulations of sand behavior in jet engines.
This work investigates the effect of temperature and angle on sand deposits and numerically characterizes the deposition of sand particles onto jet engine materials. The first study presented in this thesis describes an initial investigation of sand deposition at temperatures and speeds similar to those found in the turbine section of jet engines and presents an equation for predicting deposition as a function of flow temperature and impact angle. The model was able to explain approximately 67% of the deposition that occurs, with the remaining percentage due to other factors such as injection rates and test coupon surface temperature. The second study describes an improved investigation of sand deposition and presents an equation for predicting deposition as a function of metal surface temperature and impact angle. The model is able to explain 98.9% of the deposition that occurred.
The improved sand sticking model will allow designers to improve engine resilience and develop health monitoring algorithms. Improved resilience and health monitoring will increase airplane safety as well as reducing maintenance and operating costs when flying in sandy or arid regions.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/83233 |
| Date | 22 November 2016 |
| Creators | Hutchinson, John Patrick |
| Contributors | Mechanical Engineering, Ng, Wing Fai, Ekkad, Srinath, Lowe, K. Todd |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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