The influence of swirl and fuel composition of boron-containing fuels on combustion in a solid fuel ramjet combustion chamber

1989 ◽  
Author(s):  
R. PEIN ◽  
F. VINNEMEIER
Keyword(s):  
Combustion Chamber ◽  
Solid Fuel ◽  
Fuel Composition

scholarly journals Challenges of Ablatively Cooled Hybrid Rockets for Satellites or Upper Stages

Aerospace ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 190
Author(s):  
Francesco Barato
Keyword(s):  
Combustion Chamber ◽  
Solid Fuel ◽  
Diameter Ratio ◽  
Propulsion System ◽  
Burning Time ◽  
Regression Rate ◽  
Hybrid Propulsion ◽  
Deep Impact ◽  
Time Ratio ◽  
Hybrid Rockets

Ablative-cooled hybrid rockets could potentially combine a similar versatility of a liquid propulsion system with a much simplified architecture. These characteristics make this kind of propulsion attractive, among others, for applications such as satellites and upper stages. In this paper, the use of hybrid rockets for those situations is reviewed. It is shown that, for a competitive implementation, several challenges need to be addressed, which are not the general ones often discussed in the hybrid literature. In particular, the optimal thrust to burning time ratio, which is often relatively low in liquid engines, has a deep impact on the grain geometry, that, in turn, must comply some constrains. The regression rate sometime needs to be tailored in order to avoid unreasonable grain shapes, with the consequence that the dimensional trends start to follow some sort of counter-intuitive behavior. The length to diameter ratio of the hybrid combustion chamber imposes some packaging issues in order to compact the whole propulsion system. Finally, the heat soak-back during long off phases between multiple burns could compromise the integrity of the case and of the solid fuel. Therefore, if the advantages of hybrid propulsion are to be exploited, the aspects mentioned in this paper shall be carefully considered and properly faced.

An Accurate Performance Prediction of Solid Fuel Ramjets Using Coupled Intake-Combustor-Nozzle Simulation

2020 ◽  
Vol 36 (6) ◽  
pp. 933-941
Author(s):  
A. M. Tahsini
Keyword(s):  
Combustion Chamber ◽  
Solid Fuel ◽  
Solid Phase ◽  
Three Dimensional ◽  
Flow Fields ◽  
Reacting Flow ◽  
Computational Domain ◽  
Regression Rate ◽  
Fuel Flow ◽  
Accurate Performance

ABSTRACTThe performance of the solid fuel ramjet is accurately predicted using full part simulation of this propulsion system, where the flow fields of the intake, combustion chamber, and the nozzle are numerically studied all together. The conjugate heat transfer is considered between the solid phase and the gas phase to directly compute the regression rate of the fuel. The finite volume solver of the compressible turbulent reacting flow is utilized to study the axisymmetric three dimensional flow fields, and two blocks are used to discretize the computational domain. It is shown that the combustion chamber's pressure is changed due to the fuel flow rate's increment which must be taken into account in predictions. The results demonstrate that omitting the pressure dependence of the regression rate and also the effect of the combustor's inlet profile on the regression rate, which specially exists when simulating the combustion chamber individually, under-predicts the solid fuel burning rate when the regression rate augmentation technique is applied to improve the performance of the solid fuel ramjets. It is also illustrated that using the inlet swirl to increase the regression rate of the solid fuel augments considerably the thrust level of the considered SFRJ, while the predictions without considering all parts of the ramjet is not accurate.

The effect of fuel composition and additive packages on deposit properties and homogeneous charge compression ignition combustion

2019 ◽  
Vol 21 (9) ◽  
pp. 1631-1646
Author(s):  
Joshua Lacey ◽  
Karthik Kameshwaran ◽  
Zoran Filipi ◽  
Peter Fuentes-Afflick ◽  
William Cannella
Keyword(s):  
Combustion Chamber ◽  
Homogeneous Charge Compression Ignition ◽  
Fuel Composition ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Single Cylinder ◽  
Compression Ignition Combustion ◽  
Deposit Layer ◽  
Combustion Chamber Deposit ◽  
Homogeneous Charge

Homogeneous charge compression ignition combustion is highly dependent on in-cylinder thermal conditions that are favorable to auto-ignition, and the presence of deposits can dramatically impact the in-cylinder environment. Because fuels available at the pump can differ considerably in composition, and fuel composition and the included additive package directly affect how deposits accumulate in a homogeneous charge compression ignition engine, strategies intended to bring homogeneous charge compression ignition to market must account for this fuel and additive variability. In order to investigate this impact, two oxygenated refinery stream test fuels with two different additives were run in a single cylinder homogeneous charge compression ignition engine. The two fuels had varying chemical composition; one represents a “dirty” fuel with high aromatic content that was intended to simulate a worst-case scenario for deposit growth, while the other represents a California Reformulated Gasoline Blendstock for Oxygenate Blending fuel, which is the primary constituent of pump gasoline at fueling stations across the state of California. The additive packages are typical of technologies that are commercially available to treat engine deposits. Both fuels were run in an experimental, single-cylinder homogeneous charge compression ignition engine in a passive conditioning study, during which the engine was run at steady state over a period of time in order to track changes in the homogeneous charge compression ignition combustion event as deposits accumulated in-cylinder. Both the composition and the additive influenced the structure of the combustion chamber deposit layer, but more importantly, both the rate at which the layer developed and the equilibrium thickness it achieved. The overall thickness of the combustion chamber deposit layer was found to have a significant impact on homogeneous charge compression ignition combustion phasing.

Numerical Computation of Specific Impulse and Internal Flow Parameters in Solid Fuel Rocket Motors with Two-Phase Сombustion Products

2021 ◽  
pp. 98-107
Author(s):  
T.S. Sultanov ◽  
G.A. Glebov
Keyword(s):  
Combustion Chamber ◽  
Condensed Phase ◽  
Solid Fuel ◽  
Solid Propellant ◽  
Rocket Engine ◽  
Specific Impulse ◽  
Two Phase ◽  
Solid Propellant Rocket ◽  
Solid Propellant Rocket Engine ◽  
Propellant Rocket

Eulerian --- Lagrangian method was used in the Fluent computational fluid dynamics system to calculate motion of the two-phase combustion products in the solid fuel rocket motor combustion chamber and nozzle. Condensed phase is assumed to consist of spherical particles with the same diameter, which dimensions are not changing along the motion trajectory. Flows with particle diameters of 3, 5, 7, 9, and 11 μm were investigated. Four versions of the engine combustion chamber configuration were examined: with slotted and smooth cylindrical charge channels, each with external and submerged nozzles. Gas flow and particle trajectories were calculated starting from the solid fuel surface and to the nozzle exit. Volumetric fields of particle concentrations, condensed phase velocities and temperatures, as well as turbulence degree in the solid propellant rocket engine flow duct were obtained. Values of particles velocity and temperature lag from the gas phase along the nozzle length were received. Influence of the charge channel shape, degree of the nozzle submersion and of the condensate particles size on the solid propellant rocket engine specific impulse were determined, and losses were estimated in comparison with the case of ideal flow

Gasification of solid fuel pellets in a pressurized combustion chamber

2002 ◽  
Vol 2002.42 (0) ◽  
pp. 86-87
Author(s):  
Atsushi FUJII ◽  
Shinichiro KURITA ◽  
Harunori NAGATA ◽  
Tsuyoshi TOTANI ◽  
Isao KUDO
Keyword(s):  
Combustion Chamber ◽  
Solid Fuel ◽  
Fuel Pellets ◽  
Pressurized Combustion

scholarly journals Influence of dispersion aluminum powder on the burning rate of mixed solid fuel

2018 ◽  
Vol 194 ◽  
pp. 01065 ◽  
Author(s):  
Nikolay Zolotorev ◽  
Yana Dubkova ◽  
Aleksey Konovalenko
Keyword(s):  
Experimental Study ◽  
Combustion Chamber ◽  
Burning Rate ◽  
Metal Powder ◽  
Aluminum Powder ◽  
Solid Fuel ◽  
Constant Volume ◽  
Constant Volume Combustion ◽  
Constant Volume Combustion Chamber ◽  
Metal Fuel

In work results of experimental study of influence dispersion of metal powder on burning rate in mixed solid fuel are provided. As metal fuel used additive of aluminum of different type depending on dispersion of powder. The prepared samples of mixed solid fuel were tested in constant volume combustion chamber. The received results of burning rate show that at reduction of dispersion of aluminum powder the burning rate of mixed solid fuel increases.

Investigation on flow dynamics and temperatures of solid fuel particles in a gas-assisted oxy-fuel combustion chamber

Fuel ◽  
2021 ◽  
Vol 286 ◽  
pp. 119424
Author(s):  
Henrik Schneider ◽  
Sarah Valentiner ◽  
Nikita Vorobiev ◽  
Benjamin Böhm ◽  
Martin Schiemann ◽  
...  
Keyword(s):  
Combustion Chamber ◽  
Solid Fuel ◽  
Fuel Combustion ◽  
Flow Dynamics ◽  
Fuel Particles
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