| Summary: | 碩士 === 國立成功大學 === 機械工程學系 === 87 === A stagnation-point spray burner with a water cooling plate is developed to carry out experimental simulations on combustion chamber deposit in diesel engine. The properties of the flow field are measured at the same time with a Phase Doppler Particle Analyzer. In the way, we can study the action of diesel droplets in different downstream heat loss. Besides, the mechanism of deposit formation and the types of deposits are investigated, and then the components of deposits are processed the analysis of HC ratio.
When the net supplying rate of diesel is on the increase, sauter mean diameter of diesel droplets, initial number density and axial velocity of diesel droplets after flame will increase. With the increasing of the gas flow at the nozzle exit, sauter mean diameter and axial velocity will increase. The amount of deposit is relatively on the increase. The formation of deposit is related to the wall temperature. In other words, increasing the wall temperature leads to a decrease in deposit formation. The impingement of the droplets has a great influence on deposit formation of diesel. There are three different types of black deposits on the water cooling plate. The deposit in zone 1 is sticky and oily. The deposit in zone 2 is strongly structured. The deposit in zone 3 is like soot. As far as the HC ratio in concerned, the zone 1 is the largest and the zone 3 is smallest.
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