Author
Rohan Gejji
Bio: Rohan Gejji is an academic researcher from Purdue University. The author has contributed to research in topics: Combustor & Detonation. The author has an hindex of 11, co-authored 52 publications receiving 330 citations.
Topics: Combustor, Detonation, Combustion, Combustion chamber, Materials science
Papers
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TL;DR: In this article, a natural gas-fueled rotating detonation engine was operated at flow conditions typical of gas turbine engines, and high-speed broadband chemiluminescence images, particle image velocimetry (PIV), and particle images were used.
Abstract: A natural-gas-fueled rotating detonation engine was operated at flow conditions typical of gas turbine engines. High-speed broadband chemiluminescence images, particle image velocimetry (PIV), and ...
42 citations
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TL;DR: In this paper, the authors studied the self-sustained, periodic generation of detonation waves from low amplitude deflagrative fronts and steepened as they traveled through the combustion channel.
41 citations
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TL;DR: This paper adopts tools from dynamical systems and complex systems theory to understand the dynamical transitions from a state of stable operation to thermoacoustic instability in a self-excited model multielement liquid rocket combustor based on an oxidizer rich staged combustion cycle.
Abstract: Liquid rockets are prone to large amplitude oscillations, commonly referred to as thermoacoustic instability. This phenomenon causes unavoidable developmental setbacks and poses a stern challenge to accomplish the mission objectives. Thermoacoustic instability arises due to the nonlinear interaction between the acoustic and the reactive flow subsystems in the combustion chamber. In this paper, we adopt tools from dynamical systems and complex systems theory to understand the dynamical transitions from a state of stable operation to thermoacoustic instability in a self-excited model multielement liquid rocket combustor based on an oxidizer rich staged combustion cycle. We observe that this transition to thermoacoustic instability occurs through a sequence of bursts of large amplitude periodic oscillations. Furthermore, we show that the acoustic pressure oscillations in the combustor pertain to different dynamical states. In contrast to a simple limit cycle oscillation, we show that the system dynamics switches between period-3 and period-4 oscillations during the state of thermoacoustic instability. We show several measures based on recurrence quantification analysis and multifractal theory, which can diagnose the dynamical transitions occurring in the system. We find that these measures are more robust than the existing measures in distinguishing the dynamical state of a rocket engine. Furthermore, these measures can be used to validate models and computational fluid dynamics simulations, aiming to characterize the performance and stability of rockets.
29 citations
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TL;DR: A combustor was developed to operate with natural gas and air as the primary propellants at elevated chamber pressures and air preheat temperatures representative of land-based power generation gas.
Abstract: A combustor was developed to operate with natural gas and air as the primary propellants at elevated chamber pressures and air preheat temperatures representative of land-based power generation gas...
29 citations
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08 Jan 201827 citations
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01 Dec 1988
TL;DR: In this paper, the basic processes in Atomization are discussed, and the drop size distributions of sprays are discussed.Preface 1.General Considerations 2.Basic Processes of Atomization 3.Drop Size Distributions of Sprays 4.Atomizers 5.Flow in Atomizers 6.AtOMizer Performance 7.External Spray Charcteristics 8.Drop Evaporation 9.Drop Sizing Methods Index
Abstract: Preface 1.General Considerations 2.Basic Processes in Atomization 3.Drop Size Distributions of Sprays 4.Atomizers 5.Flow in Atomizers 6.Atomizer Performance 7.External Spray Charcteristics 8.Drop Evaporation 9.Drop Sizing Methods Index
1,214 citations
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TL;DR: An overview of the research done worldwide to address some of the challenges and questions pertaining to the physics of rotating detonation combustors operation is provided in this paper, where notable parallels are drawn to the phenomena of low and high frequency instabilities in solid and liquid rockets that have been recognized as the most severe hindrance to their operation.
204 citations
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TL;DR: The present work is to outline the current status, technical challenges and development progress of the active control approaches (in open- or closed-loop configurations) and a brief description of feedback control, adaptive control, model-based control and sliding mode control are provided.
142 citations
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TL;DR: In this paper, the effect of different fuel candidates on the operability of gas turbines by comparing a conventional petroleum-based fuel with two other alternative fuel candidates is evaluated, and large-eddy simulations are performed to examine the performance of these fuels on the stable condition close to blowout in a referee gas turbine combustor.
126 citations
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112 citations