Numerical simulation of the internal ballistics of a hybrid rocket motor

Cheng, Gary; Farmer, R. C.; Jones, H. Stephen; McFarlane, J.

doi:10.2514/6.1994-554

Cited by 55 publications

(36 citation statements)

References 5 publications

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“…Helical flows also introduce a centrifugal component into the flowfield. This centrifugal flow component suppresses the well-known "wall blowing" effect [30] where heat transfer from the flame to the wall is reduced by the radial flow emanating from the regressing fuel grain. The centrifugal flow induced by the helical fuel port thins the wall boundary layer, bringing the flame zone closer to the wall surface and increasing the flame diffusion efficiency.…”

Section: Regression Rate Enhancement Using Helical Fuel Port Structuresmentioning

confidence: 99%

Three-Dimensional Printing of “Green” Fuels for Low-Cost Small Spacecraft Propulsion Systems

Whitmore

2018

Journal of Spacecraft and Rockets

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This paper details the advantages of employing modern additive manufacturing methods to fabricate hybrid rocket fuels for intrinsically safe and green small spacecraft propulsion systems. Using additive manufacturing overcomes multiple issues frequently associated with hybrid propulsion, including poor volumetric efficiency, system ignitability, and low fuel regression rates. When certain three-dimensionally printed thermoplastics are subjected to a high-voltage low-wattage charge, electrostatic arcing along the surface pyrolizes a small amount of material that, with the introduction of an oxidizer, "seeds" combustion and produces immediate and reliable ignition. Thermoplastic fuel grains can be printed with port shapes that enhance burn properties and increase volumetric efficiencies. Embedded helical fuel ports significantly increase regression rates. The presented test results from several prototype systems using gaseous oxygen and printed acrylonitrile butadiene styrene demonstrate the various advantages of additive manufacturing, including low-power ignition, regression rate enhancement, and system scalability. The test results from both ambient and vacuum tests of a 25 N flight-weight small spacecraft thruster are presented. Multiple burn tests allowed statistical characterization of ignition timing and burn-to-burn thrust, as well as total impulse consistency. The test results demonstrating specific impulse values exceeding 295 s are presented. When fully developed, this propulsion technology has the potential for "drop-in" replacement of many hydrazine-based propulsion applications. = propellant mass flow rate, kg∕s N = number of fuel grain helical loops n = fuel regression rate fit exponential factor O∕F = oxidizer-to-fuel ratio P = helical pitch distance, cm P R = helical pitch ratio P 0 = combustion chamber pressure, kPa p exit = nozzle exit pressure, kPa R g = gas constant for combustion products, J∕kg ⋅ K r = instantaneous longitudinal mean of the fuel port radius, cm r 0 = initial fuel port radius, cm _ r = instantaneous longitudinal mean of the fuel port regression rate, cm S = internal fuel port run length, cm T 0 = combustor flame temperature, K t = time, s γ = ratio of specific heats ΔM fuel = consumed fuel mass, g η = combustion efficiency μ = sample mean ρ fuel = fuel material density, g∕cm 3 σ = sample standard deviation τ rise = motor ignition time, ms

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Section: Regression Rate Enhancement Using Helical Fuel Port Structuresmentioning

confidence: 99%

Three-Dimensional Printing of “Green” Fuels for Low-Cost Small Spacecraft Propulsion Systems

Whitmore

2018

Journal of Spacecraft and Rockets

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“…Westbrook and Dryer [23], presented global singlestep and two-step mechanisms which are commonly in use for several numbers of hydrocarbons. According to a two-step mechanism applied by Venkateswaran [9] and Cheng [7] for simulation of internal ballistics of hybrid rocket motors, at first C 4 H 6 produces H 2 O and CO being oxidized and afterwards in the second step, reaction of CO and excess Oxygen forms CO 2 . In quasi-global mechanisms, at first step and after reacting with gaseous Oxygen, hydrocarbon converts to H 2 and CO.…”

Section: Chemical Kinetics Modelsmentioning

confidence: 99%

“…With making develop in concepts of the boundary layer related to combustion mechanism of hybrid combustion by Marxman, other researchers such as Altman [3], Smoot [4], Muzzy [5] and Chiaverini [6], developed modified relations based on experiments to determine the regression rate of solid fuel. As well, a few various numerical studies were carried out for modeling the combustive flow in hybrid rocket motors so far [7][8][9][10][11]. However, there is no research worthy of being mentioned in the field of modeling the combustive gaseous flow on the solid fuel in atmospheric conditions, and in most of the studies only boundary layer of combustive flow has been analyzed.…”

Section: Introductionmentioning

confidence: 98%

An investigation on the effect of chemical kinetics in the modeling of combustive gaseous oxidizer flow on a solid fuel surface

Ahangar

Yaghmaei

Ebrahimi

2011

Proceedings of 5th International Conference on Recent Advances in Space Technologies - RAST2011

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In this study, the combustion process of gaseous Oxygen on the surface of HTPB (Hydroxyl-Terminated Polybutadiene) solid fuel has been investigated. To simulate the chemically reactive flow, Navier-Stokes equations and species transport equations were solved using LU-SW implicit scheme. Modeling this kind of combustion process demands a deep understanding of the pyrolysis phenomenon on the solid fuel surface. Experimental studies conducted in this field show that the main gaseous product of the pyrolysis process is C 4 H 6 . An experimental equation which is dependent to the temperature of the fuel surface is used to determine the gas production rate during pyrolysis process. The temperature of the fuel surface can be obtained by applying energy equation in gas-solid interface. The combustion process of gaseous Oxygen and C 4 H 6 has been described by two quasi-global chemical kinetics models. According to the obtained results, the main characteristic parameters of combustive flow such as the flame temperature and mass fraction of chemical species are strongly affiliated to the applied chemical kinetics model. Finally, the results of modeling based on two different models of chemical kinetics are presented and solid fuel surface regression rate is compared with other numerical results.

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“…The design of hybrid rocket engines consequently requires a detailed knowledge of these closely interlinked physical phenomena. 2D and 3D CFD models, based on energy and mass balance at the interface and the treatment of the surface pyrolysis by an Arrhenius law, exist for classical polymeric fuels [2,19,17,4]. However, in the preliminary design process of hybrid rocket engines, when various geometrical configurations and performances are studied, a simpler approach can be useful to reduce the computational cost.…”

Section: Introductionmentioning

confidence: 98%