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Design and Development of a Novel Injector (Micro-Mixer) with Porous Injection Technology (PIT) for Land-Based Gas Turbine Combustors

Ibrahim, Mahmoud I, Ph.D.
http://orcid.org/0000-0003-3205-2473
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1522419312986562

Abstract Details

2018, PhD, University of Cincinnati, Engineering and Applied Science: Aerospace Engineering.
The goal of this work is to design and develop an injector with a novel porous injection technology (PIT) for dry low NOx combustor (DLN). One of the key factors that is essential for lowering NOx levels is the efficient mixing of fuel-air in both spatial and temporal domains. The porous injection technology has the potential to reduce the spatial and temporal gradients to a minimum. This novel injector design utilized different concepts such as lean premixing, micro-mixing and straight flow with bluff bodies’ stabilization mechanism. The micro-mixer is a multi-injector block with nine injectors arranged in an equally spaced rectangular 3 by 3 array. Each injector in the multi-injector block has a porous tube through which fuel is injected. The porous tube is made of stainless steel with 30 µm porosity. Each porous tube is surrounded by eight smaller tubes through which compressed air is passed. The centerbody is mounted above the porous tube. The fuel and air mix in the annular space between the injector wall and the porous tube. The reacting and non-reacting flows of the micro-mixer under atmospheric conditions and a pressure drop of 4% were investigated as part of the injector development process. To evaluate the fuel-air mixing quality, two measurement techniques were used. The CO2 mixing technique - developed in-house, was used to quantify the spatial variations in the fuel mass fraction. Planar Laser Induced Fluorescence (PLIF) was used to obtain both spatial and temporal fuel mass fractions. The CO2 mixing measurements were used to validate the PLIF data for quantification. The RMS fluctuations in spatial and temporal domains were quantified from PLIF data. The length of the upper block was optimized and decided based on the mixing quality. Furthermore, Particle Image Velocimetry (PIV) measurements were conducted to study the injector’s aerodynamics under the same operating conditions. The PIV measurements showed a Central Toroidal Recirculation Zone (CTRZ) downstream of the individual tube and an outer weak recirculation zone (ORZ) was also observed between the jets. Preliminary combustion tests using natural gas (NG) and syngas’s were carried out to visualize the flame shape and heat release distribution. The flame shape followed the velocity contours. The results showed a stable flame for all fuels without combustion instabilities. The emission performance for the micromixer was investigated at atmospheric pressure with a preheated temperature of air from 500 to 650 K, equivalence ratio between 0.45 and 0.8, at a pressure drop across the injector of 4%. The PIT micro-mixer design showed low NOx levels of 4 ppm for NG and around 0.5 ppm for syngas at ~1866 K. A probability density function (PDF) was created using the mixture fraction and velocity experimental results at the exit of the injector block. Chemkin analysis was carried out to estimate the emissions based on the experimentally obtained PDFs and measured heat losses. The Chemkin analysis for NG fuel agreed with the experimental result and showed low NOx values at the same testing conditions.
San-Mou Jeng, Ph.D. (Committee Chair)
Jun Cai, Ph.D. (Committee Member)
Jongguen Lee, Ph.D. (Committee Member)
Bassam Mohammad Abdelnabi, Ph.D. (Committee Member)
172 p.
Aerospace Materials
Combustion; Land-Based Gas Turbine Combustors; Micro-mixer; Porous Injection Technology; Nox Emissions; Natural Gas and Syngas Fuels

Recommended Citations

Citations

  • Ibrahim, M. I. (2018). Design and Development of a Novel Injector (Micro-Mixer) with Porous Injection Technology (PIT) for Land-Based Gas Turbine Combustors [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1522419312986562

    APA Style (7th edition)

  • Ibrahim, Mahmoud. Design and Development of a Novel Injector (Micro-Mixer) with Porous Injection Technology (PIT) for Land-Based Gas Turbine Combustors. 2018. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1522419312986562.

    MLA Style (8th edition)

  • Ibrahim, Mahmoud. "Design and Development of a Novel Injector (Micro-Mixer) with Porous Injection Technology (PIT) for Land-Based Gas Turbine Combustors." Doctoral dissertation, University of Cincinnati, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1522419312986562

    Chicago Manual of Style (17th edition)

ucin1522419312986562
1,159
© 2018, some rights reserved.Creative Commons License Design and Development of a Novel Injector (Micro-Mixer) with Porous Injection Technology (PIT) for Land-Based Gas Turbine Combustors by Mahmoud I Ibrahim Ph.D. is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by University of Cincinnati and OhioLINK.