Title page for ETD etd-09082009-124832


Type of Document Master's Thesis
Author Villarreal, Daniel Christopher
URN etd-09082009-124832
Title Digital Fuel Control for a Lean Premixed Hydrogen-Fueled Gas Turbine Engine
Degree Master of Science
Department Mechanical Engineering
Advisory Committee
Advisor Name Title
Walter O''Brien Committee Chair
Johnson, Martin E Committee Member
Uri Vandsburger Committee Member
Keywords
  • Flashback
  • System Identification
  • Hydrogen
  • Lean Premixed Combustion
  • Gas Turbine Control
Date of Defense 2009-08-28
Availability unrestricted
Abstract
Hydrogen-powered engines have been gaining increasing interest due to the global concerns of the effects of hydrocarbon combustion on climate change. Gas turbines are suitable for operation on hydrogen fuel. This thesis reports the results of investigations of the special requirements of the fuel controller for a hydrogen gas turbine. In this investigation, a digital fuel controller for a hydrogen-fueled modified Pratt and Whitney PT6A-20 turboprop engine was successfully designed and implemented. Included in the design are safety measures to protect the operating personnel and the engine. A redundant fuel control is part of the final design to provide a second method of managing the engine should there be a malfunction in any part of the primary controller.

Parallel to this study, an investigation of the existing hydrogen combustor design was performed to analyze the upper stability limits that were restricting the operability of the engine. The upstream propagation of the flame into the premixer, more commonly known as a flashback, routinely occurred at 150 shaft horsepower during engine testing. The procedures for protecting the engine from a flashback were automated within the fuel controller, significantly reducing the response time from the previous (manual) method. Additionally, protection measures were added to ensure the inter-turbine temperature of the engine did not exceed published limits. Automatic engine starting and shutdown procedures were also added to the control logic, minimizing the effort needed by the operator. The tested performance of the engine with each of the control functions demonstrated the capability of the controller.

Methods to generate an engine-specific fuel control map were also studied. The control map would not only takes into account the operability limits of the engine, but also the stability limits of the premixing devices. Such a map is integral in the complete design of the engine fuel controller.

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