Investigation of a reacting jet injected into vitiated crossflow using CARS, high repetition rate OH-PLIF, and high repetition rate PIV

Mario Roa, Purdue University

Abstract

The proposed PhD thesis research program will be carried out in a staged combustion test rig developed with funding from Siemens Power Generation Inc. and the United States Department of Energy. This research program will study the reacting flow field created by an injector that is axially distributed along the combustor with use the laser diagnostics methods: Coherent Anti-Stokes Raman Spectroscopy (CARS), high repetition rate OH Planar Laser Induced Florescence (OHPLIF), and high repetition rate Particle Image Velocimetry (PIV), to determine why certain conditions result in low NOx emissions. This data will be used to validated the development of more precise computer models. These laser diagnostic techniques will be applied to the reacting jet produced using an extended, premixed 10 mm injector using both natural gas (NG) and hydrogen (H2) as fuels. The objective of this thesis research is to use advance laser diagnostics to gain insight into the reacting flow field resulting form transverse injection into a vitiated cross flow. The advance laser diagnostics will also provide insight into pollution formation mechanisms and will be used for validating CFD models of the transverse jet injection. The following measurements will be performed: (1) dual pump nitrogen/hydrogen (H2/ N2) CARS at the midplane of the extended 10 mm nozzle, (2) high repetition rate OH-PLIF and emission sampling for the same extended nozzle using NG and H2 as secondary fuel, (3) and combing both high repetition OH-PLIF and high repetition rate PIV for extended 10 mm nozzle for both NG and H2 secondary fuel. The PIV measurements will be combined with OH-PLIF in a simultaneous manner, with the OH fluorescence centered between the two PIV laser pulses. The dual pump H2/N2 CARS system will be used to measure both temperature of the reacting jet and the species concentration ratio of H2/ N2. The high repetition rate OH-PLIF, conducted with a 5 kHz, dual cavity Nd:YAG laser that optically pumps a dye laser tuned to the Q1(7) OH florescence transition. It will be used to visualize the flame front of the reacting jet. The high repetition rate PIV will be performed with a dual cavity laser at 10 kHz. High repetition rate PIV will be used to characterize the velocity and vortical structures produced in the reacting flow field. This research project will aid in the understanding of NOx creation in an staged gas turbine combustor and provide crucial data that will be used to develop precise computer models that will be used in designing the next power generation gas turbines. As power generation turbines increase in usage in future due to the abundance of NG as a fuel source or H 2 gas produced via green energy policies, it will be vital to make these new generation turbines more efficient and further reduce pollutant emission levels.

Degree

Ph.D.

Advisors

Lucht, Purdue University.

Subject Area

Aerospace engineering|Mechanical engineering

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