Approaches to Low Fuel Regression Rate in Hybrid Rocket Engines

Pastrone, Dario Giuseppe

doi:10.1155/2012/649753

Cited by 92 publications

(37 citation statements)

References 56 publications

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“…However, classical solid fuel hybrids have a diffusion-limited combustion process that takes places at the turbulent boundary layer and hence, their regression rate is still limited. Consequently, the improvement of their performance has been historically faced through three different approaches 3 : mitigation methods such as multiport grains, use of solid fuel additives and advanced oxidizer injector designs. Although multiport grains increase the fuel surface area for a given rocket size, they have many drawbacks (e.g.…”

Section: Introductionmentioning

confidence: 99%

Development and Three-dimensional Numerical Simulation of a Double-tube Hybrid Rocket Motor

Lorente¹,

Yu²,

Zeng³

et al. 2014

50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

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This paper presents a new concept of Hybrid Rocket Motor (HRM) called Double-tube.In this configuration, the gaseous oxidizer is injected using a head end injector and an inner tube with injector holes distributed along the motor longitudinal axis. The inner tube is located inside the combustion chamber, is coaxial to the motor case and goes from the motor head end to the aft end of the fuel grain. In order to test the potential advantages of this design, a series of three-dimensional numerical simulations have been carried out with gaseous oxygen (GOX) as oxidizer and hydroxyl terminated polybutadiene (HTPB) as solid fuel. The simulation model considers realizable k-ε turbulence model combined with eddydissipation combustion model. Furthermore, the solid fuel pyrolysis is computed through customized user-defined functions. This numerical model has been validated for previous conventional HRM designs by comparing the computational results against experimental data. The results obtained for the Double-tube have shown that the regression rate can be increased over 50% with respect to classical hybrid rockets. Indeed, the characteristic velocity, combustion efficiency and species mixing are improved by injecting the oxidizer where it is most needed thanks to an appropriate distribution of the inner tube injector holes. Finally, the Double-tube design allows for a higher control of the oxidizer-to-fuel ratio along the grain because the inner tube provides a customized distribution of oxidizer. NomenclatureA = Arrhenius preexponential constant, mm/s a = preexponential factor of the regression rate law c* = characteristic exhaust velocity, m/s D = port diameter, mm d = diameter of the injector holes, mm E a = activation energy, J/mol e = energy, J/kg G ox = oxidizer mass flux, kg/m 2 s H = enthalpy, J/kg k = kinetic energy of turbulent fluctuations L = grain length, mm ṁ ox = total oxygen mass flow rate, kg/s N = total number of chemical species n = exponent of the oxidizer mass flux O/F = oxidizer-to-fuel ratio p c = chamber pressure, atm or Pa p t = effective pressure, Pa R 2 = coefficient of determination R u = universal gas constant, J/kg-K 1 Master's Degree candidate, School of Astronautics, Beihang University, arnau.pons.lorente@gmail.com, and AIAA Student Member. 2 r = regression rate, mm/s T = temperature, K t = time, s u = velocity, m/s Y m = mass fraction of the mth species α = inner tube injection angle ε = turbulence dissipation rate η = c* efficiency, ratio between the simulated and the theoretical characteristic velocity λ = ratio of inner tube oxidizer mass flow rate to total oxidizer mass flow rate λ' = thermal conductivity, W/m-K μ = viscosity, kg/s-m ρ = density, kg/m 3 Subscripts f = fuel g = gas HE = head end IT = inner tube n = normal direction ref = reference s = fuel surface

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Section: Introductionmentioning

confidence: 99%

Development and Three-dimensional Numerical Simulation of a Double-tube Hybrid Rocket Motor

Lorente¹,

Yu²,

Zeng³

et al. 2014

50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

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“…The key operating principle is to alter the classical flow field in the combustion chamber in order to improve the heat transfer to the solid fuel grain surface and thus the regression rate. The most promising approaches are [18,60]: The solutions presented are mostly still investigated at a laboratory scale and need further researches, to better understand the scaling effects. This thesis is focussed on the last presented method, and especially on the swirl injection in sideburning grains, used to obtain a substantial increase of the combustion efficiency and of the regression rate.…”

Section: Chaptermentioning

confidence: 99%

Scaling of Hybrid Rocket Motors with Swirling Oxidizer Injection

Paccagnella¹,

Karabeyoğlu²,

Barato³

et al. 2015

51st AIAA/SAE/ASEE Joint Propulsion Conference

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“…In previous studies the authors analyzed the effect of the presence of uncertainties in the design parameters, such as in the regression rate, on rocket performance and mission goals [6,7]. Results showed that even small uncertainty in the determination of the regression rate may jeopardize vehicle performance and threaten seriously the mission.…”

Section: Introductionmentioning

confidence: 99%

Viability of an Electrically Driven Pump-Fed Hybrid Rocket for Small Launcher Upper Stages

2019

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An electrically driven pump-fed cycle for a hybrid rocket engine is proposed and compared to a simpler gas-pressurized feed system. A liquid-oxygen/paraffin-based fuel hybrid rocket engine which powers the third stage of a Vega-like launcher is considered. Third-stage ignition conditions are assigned, and engine design and payload mass are defined by a proper set of parameters. Uncertainties in the classical regression rate correlation coefficients are taken into account and robust design optimization is carried out with an approach based on an epsilon-constrained evolutionary algorithm. A mission-specific objective function, which takes into account both the payload mass and the ability of the rocket to reach the required final orbit despite uncertainties, is determined by an indirect trajectory optimization approach. The target orbit is a 700 km altitude polar orbit. Results show that electrically driven pump-fed cycle is a viable option for the replacement of the conventional gas-pressurized feed system. Robustness in the design is granted and a remarkable payload gain is achieved, using both present and advanced technologies for electrical systems.

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Approaches to Low Fuel Regression Rate in Hybrid Rocket Engines

Cited by 92 publications

References 56 publications

Development and Three-dimensional Numerical Simulation of a Double-tube Hybrid Rocket Motor

Development and Three-dimensional Numerical Simulation of a Double-tube Hybrid Rocket Motor

Scaling of Hybrid Rocket Motors with Swirling Oxidizer Injection

Viability of an Electrically Driven Pump-Fed Hybrid Rocket for Small Launcher Upper Stages

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