Identifier

etd-04172009-120423

Degree

Master of Science in Mechanical Engineering (MSME)

Department

Mechanical Engineering

Document Type

Thesis

Abstract

Pressure and heat transfer data has been generated in a high-pressure, high-temperature vane cascade. This cascade differs from many others seen in typical low-pressure facilities using room temperature air. Primarily, a natural gas-fired combustor generates realistic turbulence profiles in the high-temperature exhaust gases that pass through the vane cascade. The fixed-vane cascade test sections have film cooling holes machined into the surfaces in arrangements that closely model configurations seen in real-life first-row nozzle guide vanes (NGV). Theoretical coolant jet-to-crossflow blowing ratios (M) range from 0.5 to 3.0. Coolant jet-to-crossflow theoretical density ratios (DR) used for typical tests vary between 1.0 and 2.5. A strong relationship has been observed between blowing ratio and density ratio. Mostly due to increased mass associated with the addition of combustion gases, pressure data for heated crossflows shows slight decreases in crossflow-to-surface pressure ratios (PR) when compared to non-heated data. Heat transfer data consists of normalized metal temperatures (NMT) and heat transfer coefficients (HTC). All sets of NMT and HTC data at different crossflow-to-coolant temperature ratios (TR) show general increases with rising blowing ratio. Temperature ratios can be altered with the combustor’s integrated fuel control system. NMT data typically indicates better coolant performance for lower temperature ratios. Averaged overall endwall NMT values go through regions dependent on blowing ratio where varying the temperature ratio gives best performance. Higher blowing ratios cause lower NMT generally due to reduced coolant coverage along the vane suction surface (SS). HTC data reflects similar trends as the NMT data. At low blowing ratios, high HTC values near the passage throat on the endwall signify defined flow acceleration toward the throat. Higher HTCs evolve on the endwall in the region upstream of the throat with increases in coolant associated with higher blowing ratios. Vane HTC data shows best performance near the leading edge of the midspan plane where many film cooling holes have been located.

Date

2009

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Sumanta Acharya

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