Relation of chemical and physical processes in two-phase detonations

Lu, Pai-Lien; Slagg, Norman; Fishburn, B.

doi:10.1016/b978-0-08-025442-5.50049-4

Cited by 5 publications

(3 citation statements)

References 12 publications

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“…al. [11] in the 1960s and 1970s, with related work by Lu [12]. These experiments detonated poly and nearly monodisperse sprays of heavy hydrocarbon droplets in oxygen.…”

Section: Introductionmentioning

confidence: 66%

RETRACTED: Droplet Breakup and Evaporation in Liquid-Fueled Detonations

Young,

Duke-Walker,

McFarland

2024

Preprint

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In liquid-fueled detonations droplets are subjected to a myriad of complex codependent physical phenomena occurring on overlapping temporal and spatial scales. Developing an understanding of droplet dynamics in such an environment with high pressures, temperatures, reactions, and unsteady accelerations is imperative to developing detonation-driven propulsion systems. These condition are also relevant to other challenging engineering problems such as hydrometeor interactions with hypersonic flight vehicles. This article describes a new multiphase detonation tube facility capable of creating and imaging liquid-fueled detonations and presents initial experiments highlighting the role of droplet breakup in the detonation. Experimental initial conditions, including the droplet size distribution, are characterized and reported. Droplets interactions with the detonation wave are observed with laser optical imaging and analyzed to measure breakup cloud morphology and droplet survival time. Data from the experiments is compared to existing breakup and evaporation models for shock-droplet interactions. The results provide a means for validating more complex droplet models for detonations and hypersonic regimes.

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“…al. [11] in the 1960s and 1970s, with related work by Lu [12]. These experiments detonated poly and nearly monodisperse sprays of heavy hydrocarbon droplets in oxygen.…”

Section: Introductionmentioning

confidence: 66%

RETRACTED: Droplet Breakup and Evaporation in Liquid-Fueled Detonations

Young,

Duke-Walker,

McFarland

2024

Preprint

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“…Fan et al conducted research on liquid fuel PDEs using liquid fuel and gas oxidizers, studying the performance based on the geometric shape of the PDE [13]. In addition, Lu et al indicated the importance of breakup for sustaining fuel detonability and proposed the addition of additives as a potential solution [14]. Therefore, an appropriate flow rate is essential in maintaining stable combustion over a short duration.…”

Section: Liquid Fuel/oxidizer For Detonationmentioning

confidence: 99%

Investigation of Spray Characteristics for Detonability: A Study on Liquid Fuel Injector and Nozzle Design

Choi,

Oh,

Park

2024

Aerospace

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Detonation engines are gaining prominence as next-generation propulsion systems that can significantly enhance the efficiency of existing engines. This study focuses on developing an injector utilizing liquid fuel and a gas oxidizer for application in detonation engines. In order to better understand the spray characteristics suitable for the pulse detonation engine (PDE) system, an injector was fabricated by varying the Venturi nozzle exit diameter ratio and the geometric features of the fuel injection hole. Analysis of high-speed camera images revealed that the Venturi nozzle exit diameter ratio plays a crucial role in determining the characteristics of air-assist or air-blast atomization. Under the conditions of an exit diameter ratio of Re/Ri = 1.0, the formation of a liquid film at the exit was observed, and it was identified that the film’s length is influenced by the geometric characteristics of the fuel injection hole. The effect of the fuel injection hole and Venturi nozzle exit diameter ratio on SMD was analyzed by using droplet diameter measurement. The derived empirical correlation indicates that the atomization mechanism varies depending on the Venturi nozzle exit diameter ratio, and it also affects the distribution of SMD. The characteristics of the proposed injector, its influence on SMD, and its velocity, provide essential groundwork and data for the design of detonation engines employing liquid fuel.

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“…Combustion performance of a liquid hydrocarbon fueled pulse detonation engine is hindered by the presence of fuel droplets and long ignition times 5,6 . The presence of droplets indicates that locally fuel rich and fuel lean regions exist, and that the overall mixture lacks the required homogeneity for ideal combustion performance.…”

Section: Introductionmentioning

confidence: 99%

The Use of a Flash Vaporization System with Liquid Hydrocarbon Fuels in a Pulse Detonation Engine

Tucker¹,

King²,

Bradley

et al. 2004

42nd AIAA Aerospace Sciences Meeting and Exhibit

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In recent research, 1,2 liquid fuel droplets were found to hinder the detonation process in a pulse detonation engine (PDE). In the current work, multi-phase effects are eliminated with a flash vaporization system that vaporizes the liquid fuels prior to mixing with air. Hydrocarbon and air mixtures have been transitioned from deflagration to detonations previously, 1 but exhibited long ignition and deflagration to detonation transition (DDT) times. Here, two liquid hydrocarbon fuels, with different octane numbers (ON), are detonated with air in a PDE to determine the effect of octane number on the ignition time and the DDT time. The premixed, combustible mixture fills the PDE tubes via an automotive valve and cam system described in detail elsewhere.3 N-heptane (ON-0) and isooctane (ON-100) are evaluated individually to determine the effects of automotive octane number on pulse detonation engine combustion performance. The ON has been considered previously 4 as an acceptable criterion in determining the detonability for PDEs, and it is derived based on the tendency to "knock" or detonate relative to isooctane in an automotive engine application. _____________________________ * Correspondence can be addressed to: kelly.tucker@wpafb.af.mil. The views expressed in this paper are those of the authors and do not reflect the official policy or position of the United States Air Force, the Department of Defense or the US Government. †This paper is declared a work of the U.S. Government and is not subject to copyright protection in the United States.The goal of this research is to show that a flash vaporized liquid hydrocarbon fuel system can provide the fuel and air homogeneity required to achieve detonations. The octane number is studied to determine its influence on the ignition and DDT time for hydrocarbon fuels.The flash vaporization system provided an outstanding method for achieving the desired mixing and vaporization, and the systems operating points matched well with the liquid vapor equilibrium model results. The ignition times showed little dependence on fuel injection temperatures or octane number and no droplet effects were noted. The DDT trends were octane number dependent and the isooctane was difficult to detonate with wave speeds below the stable Chapman-Jouget (CJ) wave speeds. The heptane readily detonated and produced wave speeds at or above CJ.

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Relation of chemical and physical processes in two-phase detonations

Cited by 5 publications

References 12 publications

RETRACTED: Droplet Breakup and Evaporation in Liquid-Fueled Detonations

RETRACTED: Droplet Breakup and Evaporation in Liquid-Fueled Detonations

Investigation of Spray Characteristics for Detonability: A Study on Liquid Fuel Injector and Nozzle Design

The Use of a Flash Vaporization System with Liquid Hydrocarbon Fuels in a Pulse Detonation Engine

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