侧向有界条件下垂向环流井水动力场模拟

Numerical simulation of vertical circulation well under lateral boundary conditions

分析现有的侧向无界条件下垂向环流井水动力场数学模型与解析解,基于MODFLOW建立侧向有界条件下的数值模型,模拟多组不同抽注流量和抽注段间距的情景,绘制水头误差分布图、前向追踪流线图和地下水流量占比图,通过对比分析论证了侧向边界对水头、流线形态和流量占比的影响。结果表明:随着流量增大以及抽注段间距增大,垂向环流井水动力场循环范围增大,边界对垂向环流井水动力场影响逐渐明显,流线越接近侧向边界,其形态由椭圆形趋近于矩形,且最外围均衡区内地下水交换量占比降低趋势明显;提出无量纲参数,进一步定量地分析侧向边界对流场的影响。

The influence of the lateral boundary conditions on the hydrodynamic field of the vertical circulation well is focused on.The mathematical model and analytical solution under the existing lateral unbounded conditions are analyzed.Based on MODFLOW,the numerical model under the condition of lateral boundedness is established,which simulates the multiple sets of different pumping flow and sampling intervals.The error distribution map,the forward trace streamline diagram and the groundwater flow ratio map show the influence of the lateral boundary on the head,streamline morphology and flow ratio,respectively.The results show that:with the increase of flow rate and the spacing of the pumping section,the circulation range of the hydrodynamic field of the vertical circulation well increases,the influence of the boundary on the hydrodynamic field of the vertical circulation well is gradually obvious,the flow line is closer to the lateral boundary,the shape is close to a rectangle by an ellipse,and the proportion of groundwater exchange in the outermost equilibrium zone is reduced.The influence of the lateral boundary on the flow field is further analyzed quantitatively by proposing dimensionless parameters.