Experimental and numerical investigation of low sulfur heavy fuel oil spray characteristics under high temperature and pressure conditions

摘要

The spray characteristics of low sulfur heavy fuel oil (HFO) are firstly investigated by the experimental and numerical methods, and some new findings are obtained. First, the experiments have been conducted to evaluate the influence of low-sulfurization on the spray characteristics for HFOs under varied conditions, while little effect is found on the spray macroscopic features. The tip penetration of HFO spray behaves like a non-evaporating spray, but it is like an evaporation spray in terms of the cone angle under high temperature and pressure conditions. The large increment in ambient temperature is found to show little effect on its tip penetration but lead to a visible reduction in cone angle. This is because the spray tip penetration and cone angle are separately predominated by non-volatile and volatile components. The evaporation and pyrolysis penetration lengths are proposed for low sulfur HFO sprays as criteria for discriminating the dominant periods by volatile and nonvolatile components. Then, a multicomponent evaporation model combined with real-gas vapor-liquid equilibrium has been implemented into OpenFOAM code. The numerical simulations have been carried out and extensively validated against the experimental data. The simulated HFO spray exhibits a distinct liquid penetration length, which agrees with the proposed evaporation penetration length in experiment. This is contributed to confirming the occurrence of pyrolysis and polymerization in low sulfur HFO spray. Finally, the vapor distribution and stratification in the low sulfur HFO spray are presented, and the heavy-end multi-ring aromatics exhibit low evaporation rate and large effects on the mixture generations.