582 / 2019-01-19 11:03:35

Study on the morphological development of fuel droplets impacting on metal surfaces with different wettability

Fuel Droplets; Wettability; Dynamic Contact Angle; Rebound Factor; Spreading Factor

全体主题 > 燃料利用与化学循环技术

The morphological developing process of droplets of three different fuels, after impacting onto metal surfaces with different wettabilities and different temperatures, is experimentally studied in this paper. The results show that at an atmosphere temperature, with an increased surface wettability, the dynamic contact angle and rebound factor of the fuel droplets against the surface decrease gradually, while the spreading factor increases. In addition, as the surface wettability increases, the spreading speed of the fuel droplets along the wall increases, but the rebound speed decreases. Four different heat exchange statuses between the fuel droplets and the surface will appear in turn with an increased surface temperature, including natural convection, nuclear boiling, transition boiling and stable film boiling. Additionally, at the beginning stage after hitting the wall, the instantaneous spreading factor of the droplets increases first and then decreases with the increase of surface temperature; but the rebound factor is found increasing linearly with the surface temperature. This paper also compared the effects of surface lipophilicity and oleophobicity on morphology development of different fuel droplets after impacting onto metal surface. The test result provides a theoretical guidance for surface design of combustion chamber of future internal combustion engine under different thermal conditions.