Abstract Draining a viscous gas from a semi-sealed narrow conduit is a pore-scale problem of fundamental interest to primary fluid recovery from a petroleum reservoir as well as other applications. Such a drainage flow is entirely driven by the volumetric expansion of the gas and its mass flow rate is determined by the time-rate of decrease of the gas density within the conduit. It was found previously that when thermal effect is completely neglected, the drainage rate differs significantly from that based on the lubrication theory. The present work parametrically explores the influence of thermal boundary condition on the non-isothermal drainage flow from a narrow channel. It is found that as the wall transitions from adiabatic to isothermal condition, the excess density changes from a plane wave solution to a non-plane wave solution; and the drainage rate increases due to thermal damping on the wall, as a strong damping of the acoustic wave accelerates the process towards the final equilibrium. It is shown that when the exit is also cooled and the wall is non-adiabatic, the total recovered fluid mass exceeds the amount based on the isothermal theory determined by the initial and final density difference alone. The isothermal wall condition with the wall maintained at the initial gas temperature produces the most amount of fluid in the shortest time.

中文翻译：

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热边界条件对半封闭窄通道瓦斯抽采的影响

摘要 从半密封狭窄管道中排出粘性气体是一个孔隙尺度问题，对于从石油储层中回收一次流体以及其他应用具有根本意义。这种排放流完全由气体的体积膨胀驱动，其质量流率由管道内气体密度随时间下降的速率决定。先前发现，当完全忽略热效应时，排水率与基于润滑理论的有显着差异。目前的工作参数化地探讨了热边界条件对来自狭窄通道的非等温排水流的影响。发现随着壁面从绝热状态转变为等温状态，过剩密度由平面波解变为非平面波解；由于壁上的热阻尼，排水率增加，因为声波的强阻尼加速了朝向最终平衡的过程。结果表明，当出口也被冷却并且壁是非绝热的时，总回收流体质量超过了基于等温理论的单独由初始和最终密度差确定的量。壁面保持在初始气体温度的等温壁面条件在最短的时间内产生最多的流体。总回收流体质量超过基于等温理论的量，该量仅由初始和最终密度差确定。壁面保持在初始气体温度的等温壁面条件在最短的时间内产生最多的流体。总回收流体质量超过基于等温理论的量，该量仅由初始和最终密度差确定。壁面保持在初始气体温度的等温壁面条件在最短的时间内产生最多的流体。