Numerical study on the effects of experimental parameters on evaporation characteristic of a droplet

摘要

The simulation is used to research the effect of experimental parameters on evaporation characteristics of n-butanol-dodecane blends. These experimental parameters include droplet diameter, wire diameter, junction diameter, ambient temperature and n-butanol concentration. The equilibrium temperature (T-equ) slowly increases with time for the case with a thermocouple and it is nearly unchanged without a thermocouple. The change of droplet diameter at location 1# (D-1#, location 1# is the beginning of droplet motion) has little impact on T-equ for the case without a thermocouple. With increasing D-1#, the average evaporation rate (K-ave) increases with a thermocouple and it is nearly constant without a thermocouple. Both K-ave and T-equ firstly increase and then decrease with increasing wire diameter (D-wir) or junction diameter (D-jun). From 600 to 800 K, K-ave is the maximum when D-wir is 0.10 mm. The maximum is at Djun of 0.3 mm for 800 K and it is at 0.4 mm for 600 and 700 K. The change of D-wir or D-jun has little effects on T-2#, which is the droplet temperature at the location of 2# (location 2# is the end of droplet motion). Both T-2# and K-ave decrease with increasing n-butanol concentration. An obvious transition can be found for K-ave when the mass fraction of n-butanol ranges from 12.5% to 25%. The normalized evaporation rate is reasonably predicted using a polynomial model.