scholarly journals Experimental and Computational Study of n-Heptane Autoignition in a Direct-Injection Constant-Volume Combustion Chamber

2014 ◽  
Vol 136 (9) ◽  
Author(s):  
James C. Allen ◽  
William J. Pitz ◽  
Brian T. Fisher
Keyword(s):  
Combustion Chamber ◽  
Computational Study ◽  
Direct Injection ◽  
Negative Temperature ◽  
Constant Volume ◽  
Chamber Pressure ◽  
Combustion Model ◽  
Significant Finding ◽  
Constant Volume Combustion ◽  
Constant Volume Combustion Chamber

The purpose of this study was to characterize experimental n-heptane combustion behavior in a direct-injection constant-volume combustion chamber (DI-CVCC), using chamber pressure to infer ignition delay and heat-release rate. Measurements generally displayed expected trends and indicated entirely premixed combustion with no mixing-controlled phase. A significant finding was the observation of negative temperature coefficient (NTC) behavior. Comparing results with CHEMKIN-PRO simulations, it was found that a homogeneous combustion model was reasonably accurate for ignition delays longer than 5 ms. The combination of NTC behavior and homogeneous fuel-air mixtures suggests that this DI-CVCC can be useful for validation of chemical-kinetic mechanisms.

scholarly journals Numerical Study on Direct Injection of Hydrogen-Methane Blends into a Constant Volume Combustion Chamber

2019 ◽  
Author(s):  
Mohammadrasool Morovatiyan ◽  
Martia Shahsavan ◽  
John Hunter Mack
Keyword(s):  
Natural Gas ◽  
Combustion Chamber ◽  
Volume Fraction ◽  
Numerical Study ◽  
Computational Study ◽  
Constant Volume ◽  
Chamber Pressure ◽  
Compression Ignition ◽  
Constant Volume Combustion ◽  
Constant Volume Combustion Chamber

Natural gas is not commonly used in compression ignition cycles due to difficulty in achieving autoignition conditions. The addition of hydrogen to natural gas can help overcome this issue considering hydrogen’s flammability range and ability to autoignite. In this computational study, the turbulent injection of hydrogen-methane mixtures with varied composition of the gaseous fuels into a constant volume combustion chamber has been modeled. All conditions including injection pressure, initial chamber temperature, and initial chamber pressure are kept constant; the jet properties and combustion characteristics were then investigated. The results indicate that adding hydrogen to methane drastically shortens the ignition delay, enables the system to run at a lower initial temperature, and provides appropriate conditions for the compression ignition of the gaseous fuel. Increasing the volume fraction of hydrogen in the mixture strongly affects the spray tip penetration length and cone angle, while altering the mixing rate of the injected fuel with air. The mixtures with higher hydrogen volume fractions penetrate more during the early stages of injection. However, the higher momentum of the mixtures with more methane compensates for this effect when the jet disperses significantly in the chamber.

The flame behaviour of liquefied petroleum gas spray impinging on a flat plate in a constant volume combustion chamber

2005 ◽  
Vol 219 (5) ◽  
pp. 655-663 ◽  
Author(s):  
Kweonha Park
Keyword(s):  
Combustion Chamber ◽  
Ambient Pressure ◽  
Constant Volume ◽  
Chamber Pressure ◽  
Cylinder Wall ◽  
Liquefied Petroleum Gas ◽  
Wide Range ◽  
Constant Volume Combustion ◽  
Constant Volume Combustion Chamber ◽  
Ignition Site

Liquefied petroleum gas (LPG) sprays and diffusion flames are investigated in a constant volume combustion chamber having an impingement plate. The spray and flame images are visualized and compared with diesel and gasoline images over a wide range of ambient pressure. The high-speed digital camera is used to take the flame images. The injection pressure is generated by a Haskel air-driven pump, and the initial chamber pressure is adjusted by the amount of pumping air. The LPG spray and flame photographs are compared with those of gasoline and diesel fuel at the same conditions, and then the spray and flame development behaviour is analysed. The spray photographs show that the dispersion characteristics of LPG spray are sensitive to the ambient pressure. In a low initial chamber pressure LPG fuel in the liquid phase evaporates quickly and does not reach down easily to the impinging plate having a hot coil for ignition. That makes the temperature and equivalence ratio low near the ignition coil, thus making ignition diffcult. On the other hand, in a high initial chamber pressure the spray leaving the nozzle gathers around the ignition site after impinging on the plate, which makes an intense flame near the plate. If applied to small-sized direct injection engines that are not able to avoid spray impinging on a cylinder wall, LPG will have faster and cleaner combustion than diesel or gasoline fuels. However, the chamber geometry should be carefully designed to enable a sufficient amount of vaporized fuel to get to the ignition site

scholarly journals Development of a Constant Volume Combustion Chamber for Material Synthesis

2018 ◽  
Author(s):  
Mohammadrasool Morovatiyan ◽  
Martia Shahsavan ◽  
John Hunter Mack
Keyword(s):  
Combustion Chamber ◽  
Adaptive Mesh Refinement ◽  
Experimental Testing ◽  
Adaptive Mesh ◽  
Constant Volume ◽  
Operating Conditions ◽  
Materials Synthesis ◽  
Material Synthesis ◽  
Constant Volume Combustion ◽  
Constant Volume Combustion Chamber

A constant volume combustion chamber (CVCC) was constructed to enable material synthesis procedures that are sensitive to temperature, pressure, and ambient species concentrations. Material synthesis processes require specific operating conditions in order to carry out the desired chemical reactions and property transformations, including the creation of paper-templated metals and nanoparticles. The 1.13 liter combustion chamber includes a test stand for conducting the material synthesis experiments. A premixed fuel-air mixture is ignited at a desired equivalence ratio in order to produce the required synthesis conditions. In comparison to furnaces and ovens, this approach provides greater flexibility for materials synthesis procedures. Computational modeling using adaptive mesh refinement, alongside preliminary experimental testing results, confirms that the CVCC can provide the appropriate conditions to synthesize paper-templated metals. The approach demonstrates that the CVCC can be a viable alternative to a furnace for use in materials synthesis applications.

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