火焰预热塞汽化腔内柴油流动汽化特性研究

The combustion characteristics of intake manifold burner have a great influence on cold start characteristics of heavy-duty diesel engine, and the flow and vaporization characteristics of fuel in vaporizing chamber determine the ignition characteristics and flame stability of intake manifold burner. In this paper, a quartz intake manifold burner was designed to visually study the flow and vaporization process of diesel. At the same time, the flow and vaporization process of diesel with different flow rates in vaporization chamber were simulated based on volume of fluid (VOF) model and fluid-solid coupled model. The results show that the diffusion of diesel at the inlet is fan-shaped after pumping fuel into the burner, and diesel begins to vaporize at the edge of sector area. When diesel flows into the high-temperature region close to the heating rod, a large number of bubbles generate, namely the vaporization occurs. Compared with the case of low flow rate, the diesel with large flow rate diffuses faster and flows into the heating area earlier, while more heat is taken away and the interaction time with high-temperature wall is shortened, resulting in the weakening of vaporization capacity and the reduction of diesel vapor volume fraction in vaporization chamber and at the outlet in the steady state. Large flow rate of diesel also slows down or even declines the temperature rise of heating rods, which is not conducive to the vaporization of subsequent diesel. Therefore, it is necessary to reasonably control the diesel flow rate in intake manifold burner to ensure the vaporization, so as to ensure the stable development of flame and intake air preheating performance.