Water exchange of a standing column well with aquifer a Numerical Study

Part of groundwater circulating in the well conduct mass exchange with the aquifer. This part of exchange (the raw water exchange) is indicated the groundwater flow and heat transfer in a typical standing column well. In order to study the water exchange between the standing column well and the aquifer quantitatively, a mathematic model of flow in a standing column well and coupled heat transfer of well pipe, well hole and aquifer was developed. The model was verified by the field test of a standing column well, and results show that the simulated temper ature values of drawing water were in good agreement with the measured values both in the cooling and heating condition with the deviation less than 10% and the correlation coefficient up to 0.998. The raw water exchange of a standing column well was studied quantitatively by defining the raw water exchange ratio and the raw water exchange load ratio. For the typical example, the exchange ratio of raw water and the load ratio by raw water exchange were almost constant with the data of 29.6% and 23.4%, respectively.