水体中溶解氧含量与其物理影响因素的实验研究

Experimental study on dissolved oxygen content in water and its physical influence factors

影响自然水体中溶解氧含量的因素包括化学因素、物理因素和生物因素,其中与水力学条件直接相关也易于进行调控的是物理因素。但现有对物理影响因素的研究中,关于水体流速对溶解氧含量及分布情况的系统性实验研究较为缺乏。本文通过搭建模拟河道,营造不同的水动力条件,探究流速、水深及水温对于河道内溶解氧含量及分布的影响。研究结果表明:在不考虑光合作用的复氧时,溶解氧在水体中的分层现象与流速和水深密切相关;对于地表Ⅲ类水,流速达到0.05 m/s时,溶解氧浓度相比于静止水体增加超过50%,饱和度达到90%左右;流速在0.05 m/s以下时,流速对于溶解氧浓度的影响占主导地位,流速超过0.05 m/s后,水温的影响占主导地位,溶解氧浓度随水温升高而降低,但溶解氧饱和度受水温影响不显著。

Factors affecting dissolved oxygen content in natural waters include chemical factors,physical factors and biological factors. Among them,physical factors are the ones that are directly related to hydraulic conditions and are easier to regulate. However,in the study of existing physical influencing factors,there is a lack of systematic experimental research on the flow rate of dissolved water and the distribution of dissolved oxygen. In this paper,a simulated river channel is built to create different hydrodynamic conditions and explore the effects of flow rate,water depth and water temperature on dissolved oxygen content and distribution. The results show that the stratification of dissolved oxygen in water is closely related to the flow rate and water depth without considering the reoxygenation of photosynthesis. For surface type III water,the flow rate reaches 0.05 m/s,the dissolved oxygen concentration increases by more than 50% compared to the stationary water body,and the saturation reaches about 90%. The flow rate is less than 0.05 m/s,and the influence of the flow rate on the dissolved oxygen concentration is dominant. When the flow rate exceeds 0.05 m/s,the influence of water temperature is dominant,and the dissolved oxygen concentration decreases as the water temperature increases,but the dissolved oxygen saturation is not affected by the water temperature.