| Summary: | 碩士 === 國立成功大學 === 航空太空工程學系 === 88 === The objective of the present study is to investigate combustion characteristics of emulsive heavy-oil with added water and furthermore to develop a mono-size heavy-oil droplet generation technique. In order to analyze combustion characteristics with emulsive heavy-oil quantitatively, we also develop one method to control droplet motion. On the initial stage, observe the special characteristic “micro-explosion” in depth. On the middle stage, the uniform heavy-oil droplet had been produced successfully. In order to increase the distance between droplets, then recommended the concept with charging droplet to develop a method to separate neighbor droplets, we also develop a heavy-oil spray system and try to reduce particle size as far as possible to expect reduce particle pollutants after burned in the boiler, finally.
The results show the emulsive oil droplet which has more water would explode obviously. When the environment temperature is higher, micro-explosion will occur earlier. When the emulsive oil has less water inside, it will also occur earlier. Secondly, the mono-size droplet generator system which a perturbation is imposed on the exiting liquid stream using a piezoelectric ceramic can produce a mono-size heavy oil droplet when the perturbation is optimum. Comparing with water, heavy oil is sticky enough to lead the frequency working band narrowly. Higher working temperature would help the large and small droplet collision and higher viscosity would help working frequency which can generate mono-size droplet reduce. In brief, the result conform the trend of Weber theory that extends Rayleigh theory. About droplet separation technique, we found that use electric charge reaction that let droplet surface charging would make jet breakup mode complex, and the working frequency which can generate mono-size would be wide. Results show that the droplet separation method can separate the liquid stream into two streams regularly and droplet density is reduced. Finally, the results about heavy oil atomization show that emulsive oil with too much water may cause SMD number distribution widely. Added applicable water not only can make SMD volume distribution uniformly but also let the SMD identically. We also find that increase oil temperature would reduce the SMD of emulsive oil with different water.
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