Analysis of common reactions of a developed diesel-biodiesel combined chemical scheme

FEDERICO KRAUCH; RODNEY ROMAN; DARIO ALVISO; JUAN CARLOS ROLON

Vitória, ES

Congreso; 16 th Brazilian Congress of Thermal Sciences and Engineering; 2016

ABCM

Diesel is a complex real fuel, which is derived from conventional petroleum sources, and is composed of hundreds of compounds. Although the composition of petroleum-based diesel fuel is highly variable, there are some trends: The carbon numbers of the components range from approximately C10-C22 . An average carbon number is14 or 15. These characteristics indicate the difficulty of using diesel for experimental studies associated with numerical simulations. In order to avoid these difficulties, simplified synthetic fuels, called "surrogate fuels", with shorter chain lengths and known physical chemical properties are chosen to carry combustion studies. On the other hand, biodiesel is a complex mixture of methyl esters with different chain lengths and degrees of unsaturation and can be used in pure form or may be blended with diesel without major modifications in diesel engines. However, changing the fuel in diesel engines induces changes in combustion behavior, which can impact pollutants emission. This paper presents numerical studies of diesel-biodiesel blends combustion in a 1D freely propagating gaseous premixed flame. We have developed and validated a new chemical scheme by carefully combining two chemical schemes: one for diesel and one for biodiesel. This guarantees reproducing the principal features of both fuels combustion characteristics. The new combined scheme, consists of 235 species and 1113 elementary reactions. The new combined model was validated comparing laminar flame velocities of pure diesel and pure biodiesel using the combined model and the original models.