Development of Liquid Fuel Combustion by Relaxation of Phase Change in Liquid-Vapor

在作为家用能源装置的燃油汽化锅炉中，汽化燃烧器的缺点是需要消耗大量电能对燃料汽化器进行预热，以便瞬间准备热水供应。降低燃料气化器的电能消耗是提高成本优势的必然要求。在以前的工作中，有报道称，在稳定燃烧状态下，煤油的汽化加热可以缓解，这是因为煤油的汽化持续加强了火焰和高温炉的辐射热回流，并具有较高的孔隙率。另一方面，在点火和启动状态下，电能消耗大的问题尚未解决。为了满足上述技术要求，我们提出了超声雾化燃烧器煤油点火装置。但超声雾化燃烧器的基本燃烧特性存在…开发了一种新的液体燃料燃烧过程，即利用高频超声振荡器雾化液体燃料，通过与空气的瞬时混合来实现液体燃料的快速相变。本文研制了超音速雾化预混燃烧器，并对其点火特性进行了研究。在考虑燃烧空气供给的情况下，对该超声燃烧器的稳定燃烧范围和NOx排放进行了考察。研究结果表明：1)超声雾化法制备的煤油液滴具有数个微米级的直径和锐利的粒度分布。因此，超声雾化方法对煤油的瞬时着火是有效的。2)超声雾化燃烧器的稳定燃烧区域取决于一次风量和二次风量的平衡。3)与常规模型相比，在适当的送风量较少的情况下，由于高温区在火焰中的扩散，可以极大地减少NOx的排放。

In oil vaporizing boiler as an energy device for home use, the vaporizing combustor has a demerit that much consumption of electric energy is required for pre-heating of fuel vaporizer in order to prepare the hot water supply instantaneously. It is required for improvement of the cost advantage that the consumption of the electric energy is reduced on fuel vaporizer. In the previous work, it was reported that a kerosene vaporizing heating could be mitigated during the stable combustion state because the kerosene vaporization was sustained to enhance the heat reflux of radiation of the flame and high temperature furnace with higher porous ceramic plate burner. On the other hand, the problem in large consumption of the electric energy has not been solved yet at the ignition and start up state. To meet the techniques of requirement above, we proposed the kerosene ignition device with ultrasonic atomizing burner. But fundamental combustion characteristics of ultrasonic atomizing burner had … More been little researched.To develop the new liquid fuel combustion process, which is a quick phase change in liquid fuel atomized with high frequency ultrasonic oscillator, through an instantaneous mixing with air. In this work, we manufactured ultrasonic atomizing premixed burner and the ignition characteristics was investigated. As other characteristics of this ultrasonic combustor, the stable combustion range and NOx emission were examined with considering the combustion air supply. We have clarified research results as shown below.1) Kerosene droplets had several micron diameter and sharp size distribution caused by ultrasonic atomizing method. Accordingly, ultrasonic atomizing method is effective for instantaneous ignition of kerosene.2) The stable combustion region of ultrasonic atomizing burner was decision by the balance between primary and secondary air flow rate.3) Compared with conventional models, NOx emission could be extremely reduced because of diffusion of the high temperature zone in the flame with appropriate air supply Less