Papers by Keyword: Combustion Characteristics

Abstract: This study was conducted using the existing ignition device to verify the effectiveness of LFG, a renewable energy source. The experimental method used a constant volume combustion chamber to check the flame propagation process and combustion pressure. The experiment was carried out by changing the fuel composition ratio of LFG in the range of LFG70 to LFG40. From the result, it was found that the methane combustion occurred smoothly in LFG70 during the flame propagation process, and that combustion progressed gradually over time. In the LFG60 and LFG50 regions, which are fuels with a high CO2 ratio, it was confirmed that the combustion slowed down and the brightness of the light decreased at the same time. In LFG40 with 40% of CH4, a misfire phenomenon in which combustion does not occur was discovered. For combustion pressure, the CH4 chemical composition of the LFG was lowered, which led to the combustion delay and the reduction of combustion pressure

Abstract: The ignition and combustion characteristics of the fibre-reinforced phenolic composite were studied experimentally employing cone calorimeter. Various parameters, including the ignition time, the mass loss and mass loss rate (MLR), the heat release rate (HRR) and the concentration of the carbon dioxide and carbon monoxide were measured and presented. Linear correlations of the transformed ignition time (1/t_ig)^0.55 and 1/t_ig, the first and second peak MLR, the average MLR and the peak HRR with the heat flux were demonstrated. Based upon the correlations and theoretical analyses, flammability properties including the critical heat flux (CHF) and the minimum heat flux, the ignition temperature, the heat of gasification and the heat of combustion were calculated. The specimen with the thickness of 3 mm was prone to be thermally thin material. The peak concentration of the carbon dioxide increased with the heat flux. However, the peak concentration of the carbon monoxide declined with an increase in the applied heat flux.

Abstract: This work reports a special bio-fuel derived from sludge. Heat value, density, dropping intensity and heating stability were examined, and the influences of various process parameters were established. It was found that the addition of an aiding agent could increase the caloric value and higher briquetting pressure contributed to the quality and stability of the bio-fuel. Furthermore, the combustion properties of the bio-fuel products under different temperature were investigated.

Abstract: The combustion characteristics of an HCCI engine fueled with n-butanol were investigated on a modified two-cylinder, four stoke diesel engine. The experiments were conducted on the HCCI engine with λ of 2.0, 2.5 and 3.0, and the intake air temperature and engine speed were kept at 140 °C and 1000rpm, respectively. Effects of λ on combustion characteristics including in-cylinder pressure rise rate, heat release rate, CA05 and combustion duration of HCCI combustion engine are discussed in details based on the recorded in-cylinder pressure. The results indicate that in-cylinder pressure and the rate of pressure rise both decrease with the increase of λ, the maximum heat release rate also decreases with the increase of λ but occurs at late crank angles. In addition, as λ increases, the combustion phasing retards and combustion duration becomes longer.

Abstract: In order to study the influence of intake temperature on the combustion characteristics of HCCI engine fueled with n-butanol, the 2nd cylinder of a water-cooled, naturally aspirated and double-cylinders diesel engine was converted into HCCI combustion mode. The cylinder pressure (P), rate of pressure rise (dp/dφ), heat release rate (dQ/dφ) and cycle-to-cycle variations (CCV) were compared and analyzed by bench tests under the conditions with different intake temperatures at engine speed of 1000r/min, excess air coefficient of 2.5. The experiment results show that the peak pressure (P_max), the peak rate of pressure rise and maximum heat release rate tend to rise and the peak arrives in advance with the increase of intake temperature. As the intake temperature rises, the coefficient of variation for P_max reduces and combustion stability increases.

Abstract: In order to study the combustion and explosion characteristics of-10 military diesel and-35 military diesel, using combustion performance testing device tested the combustion performance of diesel, and analyzed the combustion performance at different temperatures. Using explosion sphere vessel tested the explosion parameters of the diesel to evaluate the explosion performance. The results show that the combustion performance of-35 military diesel are better than-10 military diesel, the maximum explosion pressure and maximum temperature have a rising trend with the pressure spray increase. The maximum explosion pressure of-10 military diesel is larger than that of-35 military diesel at the same spray pressure and the maximum explosion temperature of-35 military diesel is higher than that of-10 military diesel. The results of the two kinds of diesel can be used to evaluate their characteristics and safety.

Abstract: The combustion characteristics of corn stalk and low volatile coal were carried out through the thermogravimetric experiments.The heating rates is 40°C/min.We used the Q50.It is found that the combustion processes of corn stalk and the low volatile coal combustion include moisture evaporation,volatile evolution and combustion,char combustion three stages.The main stage of corn stalk is volatile evolution and combustion and the main stage of low volatile coal is char combustion.Compare the TG and DTG curves of the corn stalk and the low volatile coal combustion we find the corn stalk is easy to be ignited and fires quickly at the atmosphere of pure oxygen.The corn stalk weightlessness mainly happens between 120~300°C,the biggest weight loss rate is 252%/min while the low volatile’s is 56%/min.The firing effect of corn stalk is better than the low volatile’s.

Abstract: Ignition temperature is an important parameter in fuel combustion characteristics research. In this paper, tradition ignition temperature determination methods and their application limitations were discussed by analyzing the DTA curve. All discussions were demonstrated in sweet sorghum fermentation residue particles combustion test. As commonly-used methods were totally established with no consideration of thermal analyzing, the calculating value error were obvious. Taking account detected time t_k (uV>0) and delay time() in DTG (derivative thermogravimetry)-DTA (differential thermal analyses) profile, DTG-DTA delay time method was established in this paper. The calculated values comparison has been performed between new method and TG-DTG dividing point method，the latter was recognized as the most accurate method. It was showed that new method has almost the same ignition temperature to that of TG-DTG dividing point method. While new method needs only half workloads of TG-DTG diving point method. The physical conception of new method is clear and corresponded ignition temperature is accurate. Therefore, new method is suitable for biomass ignition temperature determination.

Abstract: Combustion characteristics of single base propellant are tested with closed bomb. Combustion characteristic parameters are calculated through P-t curves. Gunpowder force f=974.30J·g^-1, covolume α=1.111cm³·g^-1. Laws of combustion rate are u=4.97×10^-3P^0.82 (charge density Δ₁=0.10g·cm^-3) and u=3.97×10^-3P^0.86(charge density Δ₂=0.16g·cm^-3).