A Study Of Fuel Temperature Effects On The Cavitation Within A Single-hole Diesel Nozzle

According to relevant researches, cavitation phenomenon which happens in the diesel nozzle had been proved to post significant effects on the diesel spray. A better quality of the spray will lead to a better combustion process, which meet the needs of achieving better energy conservation as well as less emission.After a very brief historical survey about cavitation studies, the author found that the effects of fuel temperature variations on the cavitation within a diesel nozzle have seldom been discussed in spite of such numerous researches already made in this field. Therefore, this article aims at figure out such effects, which will be in favor of gaining better understandings of cavitation itself.Considering the extremely small geometry of a real diesel nozzle, direct experiment may not be a proper method for this article. Thus, the author turns to a numerical study, which has been proved to be an effective way in cavitation researches. According to the numerical results, the effects of fuel temperature were discussed separately in aspects of the cavitation inception, the developing cavitation and the supercavitaion. Furthermore, the effects on the spray were studied, and the nature that how fuel temperature affects the cavitation phenomenon was discussed as well. Meanwhile, the article also focused on the influence of nozzle geometry and pressure conditions on the cavitation, and discussed again the temperature effects under such situations.The principle conclusions of this article are as follow. The effects of fuel temperature on the cavitation within a diesel nozzle are significant, which will lead to an earlier appearance of cavitation as well as a higher degree of cavitation development. Once the supercavitation reached, the effects are no longer obvious. Moreover, the variations of parameters such as Re, We, and outlet velocity against fuel temperature also shows a significant relationship between fuel temperature and the spray. It turns out that higher fuel temperature will improve the quality of the spray. Moreover, the effects of fuel temperature on the cavitation phenomenon was achieved by influenced the fuel properties. Specifically, the effect of fuel temperature on the cavitation inception is considered to be an integrated influence derived of variations of Pv, μ and p. Once cavitation happens, the major factor contributing to effects of fuel temperature is thought to be the variation of μ. Meanwhile, the effect of variations of σ on the cavitation can be ignored. On the other hand, both the geometry and pressure conditions of the nozzle have great influences on the cavitation.