液体获取装置金属筛网内饱和液氢芯吸性能研究

Wicking Performance of Saturated Liquid Hydrogen Within Metallic Screens of Liquid Acquisition Devices

为了研究筛网通道式液体获取装置(LAD)对低温液氢推进剂的芯吸管理性能,采用绝热连续多孔介质模型,构建了计入筛网固体与周围气相环境热影响的蒸发修正芯吸模型,并采用液氮过热芯吸实验数据对构建的模型进行了有效性验证。针对常重力竖直芯吸过程,计算获得了绝热、过热条件下3种编织密度(200×1400、325×2300和510×3600)的荷兰斜纹筛网(DTW)内饱和液氢芯吸速度和芯吸高度的变化,并对比分析了筛网与气相环境过热度对低温芯吸性能的影响规律。结果表明:绝热条件下,筛网编织密度越小,芯吸速度越大,而最大芯吸高度越小;经丝方向芯吸性能始终优于纬丝方向;液氢芯吸过程的热敏感性极强,芯吸速度和最大芯吸高度均随过热度增大而显著衰减,筛网越密性能衰减幅度越大;气相环境过热度对液氢芯吸性能起决定性影响,低温下筛网固体自身的热影响相对微弱。

A modified evaporative wicking model based on the isothermal porous-continuum model is proposed to investigate the liquid wicking management performance of screen channel liquid acquisition devices(LADs)for cryogenic liquid hydrogen propellant.The model takes the thermal effects of both the solid screen and the vapor environment into account and is verified by the liquid nitrogen data of a superheated wicking experiment.For the vertical wicking processes with normal gravity,the development information of wicking velocity and wicking height of saturated liquid hydrogen in Dutch Twill weaves(DTW)with three woven densities(200×1400,325×2300 and 510×3600)are obtained under isothermal and superheated conditions.The thermal effects of screen solid and gas region on the cryogenic wicking performance are compared.Results show that under isothermal condition,the sparser the screen density is,the higher the wicking velocity and the smaller the maximal wicking height become;the wicking performance in warp direction is always better than that in shute direction;the wicking processes of liquid hydrogen has strong thermal sensitivity,both the wicking velocity and maximum wicking height remarkably decrease with the increase of superheating degree,and the degradation phenomenon is more significant within a finer mesh;the thermal effect of the gas environment plays a crucial role in the wicking performance of liquid hydrogen,while that of solid screen is very weak at the cryogenic temperature.