摘 要：基于生物乙醇燃料的贫燃预混、预蒸发燃烧技术（Lean Premixed Pervaporation，LPP），采用数值模拟方法，研究了预混室内生物乙醇雾化蒸发流场，分析了预热空气温度为500、600和1 000 K以及旋流数为0.47、0.8和1.41时的生物乙醇蒸发和气体混合特性的规律。研究表明：在LPP预混室旋流流场中，中心回流区宽度随预混室距离的增加先增大后减小，并且会受喷雾射流的影响拉伸变长，中心回流区随旋流强度的增大更贴近喷雾出口，角回流区的长度随旋流强度增大而缩短直至消失，旋流强度对液雾整体蒸发速率影响不大，但会影响液雾分布；进气温度增加会增大进气速度，提高液滴蒸发速率，缩短液雾炬长度；液滴蒸发过程存在一定程度上的压力振荡，会对LPP不稳定燃烧过程产生一定影响。

Abstract:Based on the lean premixed and prevaporization (LPP) combustion technology for a bioethanol,a numerical simulation method was adopted to study the atomization and vaporization flow field of a bioethanol inside the premixed chamber and analyze the law governing the vaporization and mixing characteristics of the bioethanol with gases when the preheated air temperature is 500,600 and 1 000 K as well as the swirling number is 0.47,0.8 and 1.41 respectively.It has been found that in the swirling flow field inside the LPP premixed chamber,the width of the central flow return zone will first increase and then decrease with an increase of the distance of the premixed chamber from the central flow return zone and become widened as influenced by the atomization and jet flow.The central flow return zone will be more close to the atomization outlet with an increase of the swirling intensity.The length of the flow return zone will become shortened until zero with an increase of the swirling intensity.Furthermore,the swirling intensity will have not a big influence on the overall vaporization speed of the liquid fog,however,will have an influence on the distribution of the liquid fog.To increase the gas inlet temperature will increase the gas inlet speed,enhance the vaporization speed of the liquid drops and shorten the length of the liquid fog torch.There will exist a pressure oscillation in the vaporization process of the liquid drops to a certain extent and such an oscillation will produce a certain influence on the LPP unsteady combustion process.

TK16