Translated Abstract
With the rapid growth of economy, the energy scenario of the world is undergoing a series of change. However, in the foreseeable future, fossil oil remains the world＇s most important energy. With the development of drilling technology, the supply of oil is enough, and the current technical recoverable oil resources is much higher than the total demand in 2015-2050 even after. By 2035 China will account for 26% of the total energy consumption of the world, accounting for 35% of the energy net incresae of the world, and half of the oil demand growth are from China market. At the same time, the global car number will be double in the next 20 years, and the car market of China and India will present the rapid growth tendency. According to statistics, gasoline vehicles of China accounted for 84.7% in the motor vehicle.
In order to design a more efficient engine, the fundamental combustion characteristics and reaction mechanism of National V gasoline must be studied. In this paper, laminar combustion characteristics of different octane numbers of National V gasoline under different initial conditions was studied and a new Multicomponents surrogate models was constructed for different octane numbers of National V gasoline.
In this paper, we use a constant volume bomb combined with high-speed schlieren system to get the schlieren pictures of 92#, 95#, 98# National V gasoline at different initial temperatures Tu(373K, 413K, 453K), and different initial pressures Pu(0.1MPa, 0.3MPa, 0.5MPa) and different equivalent ratios (0.7~1.4). By using the combustion pressure data to analyze the explosion characteristics of the gasolines. A new five-components surrogate models was constructed for different octane numbers of National V gasoline according to the measured components of gasoline. The results are shown below:
For given initial conditions, Markstein length gradually declines with the increase of initial pressure, indicating that the instability of flame front surface increases with the increase of initial pressure. The effect of the initial temperature on Markstein length is not obvious. When the initial temperature is increased from 373K to 413K, Markstein length decreases obviously and the instability of the flame increases. While the initial temperature is from 413K to 453K, Markstein length shows less difference. With the increase of equivalent ratio, Markstein length becomes smaller and flame instability increases. The relationship of Markstain length and octane number of gasolines are shown: 98#＞ 95#＞ 92#, indicating that the stability of 98# gasoline is the best, while the stability of 92# gasoline is the worst.
At given initial condition, laminar burning velocity of gasoline increases with the increase of initial temperature, and decreases with the increase of initial pressure. With the increase of equivalent ratio, laminar burning velocity firstly decreases and then rises. The maximum value of laminar burning velocity appeares at the equivalent ratio of 1.1. The ranking rate of the laminar burning velocity for different octane number of gasoline is: 98#＞ 92#＞ 95#.
The explosion pressure, maximum rate of pressure rise, the flame development and combustion duration are obtained from combustion pressure data for different gasolines at different initial conditions. At the equivalent ratio of 1.1, the combustion pressure is the largest, and combustion duration reaches fastest. Mixtures become rich or lean can lead to the decrease of combustion pressure, reduction of burning velocity and long combustion duration.
In this paper, multicomponents surrogate model based on the actual RON, MON and H/C of 92#, 95#, 98# gasoline are constructed, consisting of n-heptane, iso-octane, toluene, and DIB. The simulations with new surrogate models in this study are compared with the experimental laminar burning velocity at different initial conditions. A good predictions on the laminar burning velocity of this four-components surrogate model are achieved.
Translated Keyword
[Explosion charcteristics, Gasoline, Laminar burning velocity, Markstein length, Surrogate model]
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