| Summary: | 碩士 === 國立成功大學 === 資源工程學系碩博士班 === 98 === The groundwater flowmeters in recent years are often used to investigate groundwater flow in pollution site and groundwater flow investigation. The heat-flow flowmeter is one of groundwater flowmeters, which has the superiority of simple and convenience. The thesis is proposed to discuss instrument disturbance and influence of measurement by laboratory sand tank. We focus on four influence factors with sponge filters, packing ring, well screens, as well as groundwater quality and specific heat accompanying with laboratory sand tank. Finally, application on the field site is also presented in order to validate groundwater velocity and direction of measurement of heat-flow flowmeter.
The results show that the measurement variation of groundwater velocity and direction using different sponge filters is insignificant, and the difference of measurement velocity and direction is less 10% and 10 degrees, respectively. It indicated that the measurement difference of velocity and direction is within the instrument error scope. As considering the sponge filter installed, the values of velocity of measurement without packing ring has lower 20 ~ 30% than those with packing ring. It also indicated that the variation of measurement flow direction within the well was related to the relative position between well screens and groundwater direction, and the difference degree of flow direction is less 30 degrees. Furthermore, the variation of measurement velocity within the well was related to the relative position between well screens and groundwater flow. The relative position also affects the situation of water inflow well resulting in the difference of measurement velocity. Since the specific heat of salt water affects the velocity of measurement, the results showed that as the specific heat is smaller, the velocity of measurement is smaller.
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