学术论文

      单液氮液滴在气流中的蒸发运动特性研究

      Evaporation and Movement Characteristics of Single Liquid Nitrogen Droplet in High-Speed Gas Flow

      摘要:
      为了研究低温风洞中液氮喷雾降温蒸发特性,从而从微观上把握整个喷雾过程,以经典蒸发模型为基础,建立了适用于高速气流下的单液滴蒸发模型,计算了高速气流下单个液氮液滴的蒸发过程,得到其蒸发过程中液滴直径、速度、蒸发速率等参数的变化规律,并比较了环境温度、环境压力、气流速度等不同因素对各参数的影响.结果表明:环境温度对液滴蒸发速率影响较大,在100~300 K环境温度下,每升高100 K,2 m的距离内液滴相对蒸发量大约增加18%,而对液滴运动速度则基本没有影响;气流速度越大,对流换热越强,液滴等时间蒸发速率越大,但由于蒸发距离一定,高速气流情况下的实际蒸发量减少,在上述条件下,10~30 m/s的速度范围内,相对蒸发量在5%~6%;大粒径液滴具有大的绝对蒸发量,而小粒径液滴的相对蒸发量则较大;随着环境压力的增大,蒸发速率会随之增加.
      Abstract:
      An evaporation model of single moving liquid nitrogen droplet in high-speed gas flow is developed based on the classical evaporation model to reveal the evaporation of whole liquid nitrogen spray.The droplet evaporation rate,diameter and velocity are obtained in the evaporation process by adjusting ambient temperature,ambient pressure and gas flow velocity.The results show that for those parameters,the ambient temperature has greater influence on the droplet evaporation rate,which grows with temperature.Within the falling distance of two meters,with the ambient temperature riseing by every 100 K in the range from 100 to 300 K,the relative evaporation increases about 18%.The higher the gas flow speed reaches,the higher the droplet evaporation rate gets at equal time due to the stronger convection heat transfer,but the evaporation capacity decreases because of limited evaporation distance.Under above conditions,the relative evaporation is 5%~6% within the flow speed range of 10~30 m/s.Bigger droplet has bigger absolute evaporation capacity but smaller relative evaporation capacity,and the droplet evaporation rate rises with the ambient pressure.
      作者: 阮一逍 [1] 薛绒 [1] 赖欢 [2] 刘秀芳 [1] 侯予 [1]
      Author: RUAN Yixiao [1] XUE Rong [1] LAI Huan [2] LIU Xiufang [1] HOU Yu [1]
      作者单位: 西安交通大学能源与动力工程学院,710049,西安 西安交通大学能源与动力工程学院,710049,西安;中国空气动力研究与发展中心设备设计及测试技术研究所,621000,四川绵阳
      刊 名: 西安交通大学学报 ISTICEIPKU
      年,卷(期): 2017, 51(6)
      分类号: TK121
      在线出版日期: 2017年7月6日
      基金项目: 国家自然科学基金资助项目,中国博士后科学基金资助项目