基于PLIF技术的天然气喷射流场摩尔浓度特性  

Concentration Characteristics in the Flow Field of a Natural Gas Injection Based on PLIF

作　　者：任晓光 王兰红[2] 董全[1] 宋恩哲[1] 姚崇[1] Ren Xiaoguang;Wang Lanhong;Dong Quan;Song Enzhe;Yao Chong(College of Power and Energy Engineering,Harbin Engineering University,Harbin 150001,China;Weifang Vocational College,Weifang 261000,China)

机构地区：[1]哈尔滨工程大学动力与能源工程学院,黑龙江哈尔滨150001 [2]潍坊职业学院,山东潍坊261000

出　　处：《内燃机学报》2020年第5期417-425,共9页Transactions of Csice

基　　金：国家自然科学基金资助项目(KY10300180095).

摘　　要：利用平面激光诱导荧光技术(PLIF),对天然气喷射射流摩尔浓度场展开研究,分析了气源压力与气流温度对流场摩尔浓度特性的影响,之后对激波现象在摩尔浓度场上的特性进行分析.结果表明:射流初期阶段持续0.8 ms左右,射流主体阶段的摩尔浓度分为核心区、摩尔浓度速降区与低摩尔浓度扩散区,其中核心长度先波动后趋于稳定,气温为22℃时升高喷气压力会使其稳定均值由10.52 mm降至6.55 mm,而加温会使其发生持续波动.平均摩尔浓度先降低后趋于稳定,气温为22℃时升高喷气压力会提升平均摩尔浓度的初始值与下降率,其最终的稳定值由0.009 mol/L升至0.026 mol/L;而升高气流温度作用与之相反,气压为0.7 MPa时摩尔浓度稳定值由0.021 mol/L降至0.006 mol/L.头部摩尔浓度规律与平均摩尔浓度类似.激波结构数量与总长均是先升高后趋于稳定,其稳定值与喷气压力正相关,升高气流温度会使其数值持续波动;表现在摩尔浓度场上的马赫盘高度与其理论值基本吻合.Planar laser induced fluorescence(PLIF)measurement was used to visualize the development of a natural gas injection,the effects of the jet pressure and the air temperature on the concentration characteristics is analyzed.The shock phenomenon was also explained from the perspective of concentration.The results show that the initial stage of the jet lasts about 0.8 ms.In the main stage of the jet,the concentration is divided into three parts:the core zone,the concentration drop zone and the low-concentration zone.The length of the core zone fluctuates first and then tends to be stable.The increase of jet pressure makes the stable mean value to drop from 10.52 mm to 6.55 mm at the air temperature of 22℃,and the heating makes the jet more fluctuating.Increasing the jet pressure raises the initial value and its decreasing rate of the average jet concentration at 22℃,and its steady concentration value increases from 0.009 mol/L to 0.026 mol/L.Also,the effect of increasing the gas flow temperature on the concentration has an opposite trend,and the concentration stable value drops from 0.021 mol/L to 0.006 mol/L at the jet pressure of 0.7MPa.The concentration variation in the head area of the jet is similar to the average concentration variation.Furthermore,the number and total length of the shock wave structure increases first and then tends to be stable.The steady value is positively correlated with the jet pressure,while the elevated air temperature causes its value to fluctuate continuously.The Mach disc height in the concentration field is basically consistent with the theoretical value.

关 键 词：天然气发动机 天然气喷射 摩尔浓度场 激波 

分 类 号：TK431[动力工程及工程热物理—动力机械及工程]