Abstract

Straight vegetable oils have a huge potential to minimize the dependence of the automobile and energy sectors on conventional fossil fuels. In the present study, the impact of a single drop of Jatropha straight vegetable oil on a stainless steel surface is investigated for various surface temperatures. The effects of the impact velocity and the surface temperature on both spreading and receding of the drops are examined. Experiments are conducted at nine surface temperatures and four impact velocities. The impact morphology reveals that the minimum surface temperature required for the initiation of the bubble nucleation is independent of the Weber number or the drops’ initial kinetic energy. The Leidenfrost point is not observed even at the highest temperature tested for the entire Weber number range. The average receding velocity is not found to depend on Weber number at a given surface temperature in the film evaporation and the film boiling regime. It increases initially with surface temperature up to 280 °C and remains constant for further higher surface temperatures. Although the receding distance increases monotonously with the surface temperature, the average receding velocity does not increase beyond 280 °C.

摘要

纯植物油具有巨大的潜力，可以最大限度地减少汽车和能源部门对传统化石燃料的依赖。在本研究中，研究了一滴麻风树纯植物油对不锈钢表面的各种表面温度的影响。检查了冲击速度和表面温度对液滴扩散和后退的影响。实验在九个表面温度和四个冲击速度下进行。冲击形态表明，引发气泡成核所需的最低表面温度与韦伯数或液滴的初始动能无关。即使在整个韦伯数范围内测试的最高温度下也没有观察到莱顿弗罗斯特点。在膜蒸发和膜沸腾状态中，在给定表面温度下，平均后退速度不取决于韦伯数。它最初随着表面温度高达 280°C 而增加，并在表面温度进一步升高时保持不变。尽管后退距离随地表温度单调增加，但平均后退速度不会增加超过 280 °C。