Strain Response and Aerodynamic Damping of a Swirl Distortion Generator Using Computational Fluid Dynamics

Hayden, Andrew P.; Untăroiu, Alexandrina

doi:10.1115/1.4052139

Cited by 5 publications

References 5 publications

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Role of Secondary Ions on the i-v Characteristics of Oxyfuel Flame Subject to an Electric Field

Untăroiu

Rahman

Martin

2023

Journal of Fluids Engineering

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Recent use of ion currents as a sensing strategy in the mechanized oxyfuel cutting process motivated a series of studies which revealed that the steel work piece contributes secondary ions in addition to the primary ions classically identified in the oxyfuel flame. In this work, we present a computational model that has linked carbon related chemi-ions as a source of secondary ions in preheating stage of oxyfuel cutting process subject to electric bias voltages. The flames' response to the electric field at different positive and negative polarity manifested a better understanding of the physical behavior of current- voltage (i-v) relationship. While copper surface exhibits stable and repeatable i-v characteristics, sporadically enhanced current was observed in positive saturation regime for steel surface, and this is believed be due to the presence of secondary chemi-ions. To this extent, a source term of gaseous carbon has been assigned to mimic the 'work surface' reactions. The hypothesis is that since carbon is an important element, it will be diffusing out of the steel surface and evaporating into the flame.

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Role of Secondary Ions on the i-v Characteristics of Oxyfuel Flame Subject to an Electric Field

Untăroiu

Rahman

Martin

2023

Journal of Fluids Engineering

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Simulating the Effect of Electric Bias Voltages on the Electrical Characteristics of Oxyfuel Preheat Flame Using Reduced Combustion Mechanism

Rahman

Warrier

Untăroiu

et al. 2023

Journal of Fluids Engineering

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A three-dimensional (3D) computational model is presented in this paper that illustrates the detailed electrical characteristics, and the current-voltage (i-v) relationship throughout the preheating process of premixed methane-oxygen oxyfuel cutting flame subject to electric bias voltages. As such, the equations describing combustion, electrochemical transport for charged species, and potential are solved through a commercially available finite-volume Computational Fluid Dynamics (CFD) code. The reactions of the methane-oxygen (CH4 -O2) flame were combined with a reduced mechanism, and additional ionization reactions that generate three chemi-ions, H3O+, HCO+, and e-, to describe the chemistry of ions in flames. The electrical characteristics such as ion migrations and ion distributions are investigated for a range of electric potential, V ∈ [-5V, +5V]. Since the physical flame is comprised of twelve Bunsen-like conical flame, inclusion of the third dimension imparts the resolution of fluid mechanics and the interaction among the individual cones. It was concluded that charged ‘sheaths’ are formed at both torch and workpiece surfaces, subsequently forming three distinct regimes in the i-v relationship. The i-v characteristics obtained out of the current study have been compared to the previous experimental and two-dimensional (2D) computational model for premixed flame. In this way, the overall model generates a better understanding of the physical behavior of the oxyfuel cutting flames, along with a more validated i-v characteristics. Such understanding might provide critical information towards achieving an autonomous oxyfuel cutting process.

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High Throughflow StreamVane Swirl Distortion Generators: Design and Analysis

Hayden,

Gillespie,

Hefner

et al. 2023

Journal of Engineering for Gas Turbines and Power

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In recent years, the StreamVane technology has developed into a mature and streamlined process that can reproduce swirl distortion for ground-test evaluation of fan and compressor performance and durability. A StreamVane device consists of complex turning vanes that accurately output a distorted secondary velocity field at a defined distance downstream. To further advance the applications and conditions in which these devices operate, a research effort was developed and completed to investigate methods to increase critical Mach numbers. The effort was split into three separate stages: 1) Perform high fidelity computational fluid dynamics (CFD) to identify peak Mach number locations within twin and quad swirl vane pack designs; 2) Conduct thorough literature reviews on relevant high throughflow techniques; 3) Design and implement selected techniques to evaluate improvements using the same high-fidelity CFD methods. It was predicted that employing blade lean within high-speed vane junctions increased critical Mach numbers by 6.6%, while blade sweep resulted in a 3.5% increase. The results and conclusions from this effort are presented throughout this paper with a primary focus on comparing Mach numbers and swirl profiles between vane packs with and without high throughflow designs.

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Strain Response and Aerodynamic Damping of a Swirl Distortion Generator Using Computational Fluid Dynamics

Cited by 5 publications

References 5 publications

Role of Secondary Ions on the i-v Characteristics of Oxyfuel Flame Subject to an Electric Field

Role of Secondary Ions on the i-v Characteristics of Oxyfuel Flame Subject to an Electric Field

Simulating the Effect of Electric Bias Voltages on the Electrical Characteristics of Oxyfuel Preheat Flame Using Reduced Combustion Mechanism

High Throughflow StreamVane Swirl Distortion Generators: Design and Analysis

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