Ignition and combustion stability of controllable solid propellants with injection of liquid monopropellant decomposition products

1968 ◽  
Author(s):  
N. COHEN ◽  
R. ROBERTS
Keyword(s):  
Combustion Stability ◽  
Solid Propellants ◽  
Decomposition Products ◽  
Ignition And Combustion

Modeling of Ignition and Combustion of Boron-Containing Solid Propellants

2021 ◽  
Vol 57 (3) ◽  
pp. 308-313
Author(s):  
V. A. Arkhipov ◽  
S. A. Basalaev ◽  
V. T. Kuznetsov ◽  
V. A. Poryazov ◽  
A. V. Fedorychev
Keyword(s):  
Solid Propellants ◽  
Ignition And Combustion

Enhancement of Propane Flame Stability by Dielectric Barrier Discharges

2005 ◽  
Vol 8 (2) ◽  
Author(s):  
Yongho Kim ◽  
Sy M. Stange ◽  
Louis A. Rosocha ◽  
Vincent W. Ferreri
Keyword(s):  
Barrier Discharge ◽  
Air Flow ◽  
Combustion Efficiency ◽  
Combustion Stability ◽  
Dielectric Barrier Discharges ◽  
Lean Burn ◽  
Decomposition Products ◽  
Dielectric Barrier ◽  
Novel Applications ◽  
Barrier Discharges

AbstractNon-thermal plasmas have recently found novel applications in improving fuel combustion. Typical electron temperatures in such plasmas are of order a few electron volts. Such electrons are sufficient to break down fuel molecules and to produce free radicals which may significantly affect combustion efficiency. In this work, we use a dielectric barrier discharge (DBD) to activate propane (C3H8) fuel before it is mixed with air and ignited. The use of activated propane enables us to operate combustion in very lean-burn conditions; for 0.2 lpm propane, air flow was 38 lpm, compared with an air flow of 26 lpm in the absence of a plasma. A residual gas analyzer (RGA) measures the decomposition products of the propane discharge, indicating that atomic and molecular hydrogen are produced in the plasma and that their concentrations depend on the DBD energy density. Based on the observations discussed in this work, we have shown that by activating propane, the DBD increases combustion stability.

Numerical and Experimental Analysis of Ignition and Combustion Stability in EGR Dilute GDI Operation

2014 ◽  
Author(s):  
Riccardo Scarcelli ◽  
Nicholas S. Matthias ◽  
Thomas Wallner
Keyword(s):  
Flame Propagation ◽  
Numerical Results ◽  
Operating Conditions ◽  
Combustion Stability ◽  
Ignition Process ◽  
Ignition System ◽  
Cyclic Variability ◽  
Beneficial Effects ◽  
Engine Testing ◽  
Ignition And Combustion

This paper discusses the characteristics of EGR dilute GDI engines in terms of combustion stability. A combined approach consisting of RANS numerical simulations integrated with experimental engine testing is used to analyze the effect of the ignition source on flame propagation under dilute operating conditions. A programmable spark-based ignition system is compared to a production spark system in terms of cyclic variability and ultimately indicated efficiency. 3D-CFD simulations are carried out for multiple cycles with the goal of establishing correlations between the characteristics of the ignition system and flame propagation as well as cycle-to-cycle variations. Numerical results are compared to engine data in terms of in-cylinder pressure traces. The results show that an improved control over the energy released to the fluid surrounding the spark domain during the ignition process has beneficial effects on combustion stability. This allows extending the dilution tolerance for fuel/air mixtures. Although affected by cyclic variability, numerical results show good qualitative agreement with experimental data. The result is a simple but promising approach for relatively quick assessment of stability improvements from advanced and alternative ignition strategies.

IGNITION AND COMBUSTION OF SOLID PROPELLANTS

1962 ◽  
Author(s):  
Rex C. Mitchell ◽  
John A. Keller ◽  
Alva D. Baer ◽  
Norman W. Ryan
Keyword(s):  
Solid Propellants ◽  
Ignition And Combustion

Potential Usage of Energetic Nano-sized Powders for Combustion and Rocket Propulsion

2003 ◽  
Vol 800 ◽  
Author(s):  
Kenneth K. Kuo ◽  
Grant A. Risha ◽  
Brian J. Evans ◽  
Eric Boyer
Keyword(s):  
Burning Rate ◽  
Energy Release ◽  
Solid Propellant ◽  
Nano Particles ◽  
Solid Fuels ◽  
Solid Propellants ◽  
Regression Rate ◽  
Combustion Behavior ◽  
Boron Particles ◽  
Ignition And Combustion

ABSTRACTNano-sized energetic metals and boron particles (with dimensions less than 100 nanometers) possess desirable combustion characteristics such as high heats of combustion and fast energy release rates. Because of their capability to enhance performance, various metals have been introduced in solid propellant formulations, gel propellants, and solid fuels. There are many advantages of incorporating nano-sized materials into fuels and propellants, such as: 1) shortened ignition delay; 2) shortened burn times, resulting in more complete combustion in volume-limited propulsion systems; 3) enhanced heat-transfer rates from higher specific surface area; 4) greater flexibility in designing new energetic fuel/propellants with desirable physical properties; 5) nano-particles can act as a gelling agent to replace inert or low-energy gellants; 6) nano-sized particles can also be dispersed into high-temperature zone for direct oxidation reaction and rapid energy release, and 7) enhanced propulsive performance with increased density impulse. In view of these advantages, numerous techniques have been developed for synthesizing nano-particles of different sizes and shapes. To reduce any possible hazards associated with the handling of nano-sized particles as well as unwanted particle oxidation, various passivation procedures have been developed. Some of these coating materials could enhance the ignition and combustion behavior, others could increase the compatibility of the particles with the surrounding material. Many researchers have been actively engaged in the characterization of the ignition and combustion behavior of nano-sized particles as well as the assessment of performance enhancement of propellants and fuels containing energetic nano-particles. For example, solid fuels could contain a significant percentage of nano-sized particles to increase the mass-burning rate in hybrid rocket motors, the regression rate of solid propellants can be increased by several times when nano-sized particles are incorporated into the formulation. Specifically, hybrid motor data showed that the addition of 13% energetic aluminum powders can increase the linear regression rate of solid HTPB-based fuel by 123% in comparison to the non-aluminized HTPB fuel at a moderate gaseous oxidizer mass flow rate. Strand burner studies of two identical solid propellant formulations (one with 18% regular aluminum powder and the other with 9% aluminum replaced by Alex® powder) showed that nano-sized particles can increase the linear burning rate of solid propellants by 100%. In addition to solid fuels and propellants, spray combustion of bipropellants has been conducted using gel propellants impregnated with nano-sized boron particles as the fuel in a rocket engine. High combustion efficiencies were obtained from burning nano-sized boron particles contained in a non-toxic liquid-fuel spray. Materials characterization such as chemical analyses to determine the active aluminum content, density measurements, and imaging using an electron microscope have been performed on both neat nano-sized particles and mixtures containing the energetic materials. In general, using energetic nano-sized particles as a new design parameter, propulsion performance of future propellants and fuels can be greatly enhanced.

Parametric Study of Ignition and Combustion Characteristics From a Gasoline Compression Ignition Engine Using Two Different Reactivity Fuels

2016 ◽  
Author(s):  
Khanh Cung ◽  
Toby Rockstroh ◽  
Stephen Ciatti ◽  
William Cannella ◽  
S. Scott Goldsborough
Keyword(s):  
High Speed ◽  
Injection Pressure ◽  
Operating Conditions ◽  
Combustion Stability ◽  
Injection Timing ◽  
Strong Impact ◽  
Boost Pressure ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Ignition And Combustion

Unlike homogeneous charge compression ignition (HCCI) that has the complexity in controlling the start of combustion event, partially premixed combustion (PPC) provides the flexibility of defining the ignition timing and combustion phasing with respect to the time of injection. In PPC, the stratification of the charge can be influenced by a variety of methods such as number of injections (single or multiple injections), injection pressure, injection timing (early to near TDC injection), intake boost pressure, or combination of several factors. The current study investigates the effect of these factors when testing two gasoline-like fuels of different reactivity (defined by Research Octane Number or RON) in a 1.9-L inline 4-cylinder diesel engine. From the collection of engine data, a full factorial analysis was created in order to identify the factors that most influence the outcomes such as the location of ignition, combustion phasing, combustion stability, and emissions. Furthermore, the interaction effect of combinations of two factors or more was discussed with the implication of fuel reactivity under current operating conditions. The analysis was done at both low (1000 RPM) and high speed (2000 RPM). It was found that the boost pressure and air/fuel ratio have strong impact on ignition and combustion phasing. Finally, injection-timing sweeps were conducted whereby the ignition (CA10) of the two fuels with significantly different reactivity were matched by controlling the boost pressure while maintaining a constant lambda (air/fuel equivalence ratio).

Heterogeneous reactions in ignition and combustion of solid propellants

AIAA Journal ◽  
1964 ◽  
Vol 2 (1) ◽  
pp. 179-180 ◽  
Author(s):  
RALPH ANDERSON ◽  
ROBERT S. BROWN ◽  
LARRY J. SHANNON
Keyword(s):  
Heterogeneous Reactions ◽  
Solid Propellants ◽  
Ignition And Combustion

Numerical Study on Layout of Refractory Belt and Fouling Deposition in Tangentially Fired Boiler

2016 ◽  
Author(s):  
Qiongliang Zha ◽  
Kai Chen ◽  
Jianwen Zhang ◽  
Jiangtao Li ◽  
Chang’an Wang ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Numerical Investigation ◽  
Numerical Study ◽  
High Surface ◽  
Three Dimensional ◽  
Furnace Wall ◽  
Combustion Stability ◽  
Particle Capture ◽  
Dimensional Simulation ◽  
Ignition And Combustion

The refractory belt installed in primary combustion zone provides simplest and most effective solution to suppress ignition delay and enhance combustion stability for low volatile anthracite and lean coal. The fouling deposition generally formed on radiative refractory lined wall of the boiler due to a high surface temperature. The growth of deposition thickness is mainly dependent on the parcile impact on the surface of water wall. A particle capture submodel was used to determine whether a particle was captured to form deposition or not when it reached the furnace wall, and the particle capture criterion was based on the particle’s viscosity and the temperature of the furnace wall. A reduced fouling deposition model was implemented in a three dimensional simulation of a tangentially fired boiler. The numerical investigation was conducted to assess the performance of different layouts of refractory belt. Furnace temperature, surface temperature of refractory belt, and deposition distributions on the furnace wall should be taken into account when layouts of refractory belt are optimized. Based on this, three layouts of refractory belt were proposed for tangentially fired boilers. A numerical investigation was conducted to assess the performance of different layouts of refractory belt and the results showed that the temperature in furnace was increased, and the ignition and combustion processes were stabilized when refractory belts were installed. The reasonable arrangement of refractory belt could reduce the possibility of fouling deposition in furnace.

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