二滩水库水温结构及其影响因素研究

应用MIKE 3建立三维水温模型，对二滩水库水温结构进行数值模拟，发现该水库水温垂向分布呈现单温跃层和双温跃层两种型式。 气象要素、库区来水流量和水体温度、水库出流位置及流量大小等是影响水温结构的主要因素。夏季二滩水库随着上游来水水温的升高，水库水温相应升高，但在温度异重流和紊流扩散的双重作用下，是水库中层均温层水体温度同步升高。大坝出水位置的改变，将使库区流态发生变化，随着出水口位置的下移，水库来水和出流形成的纵向水流随之向库底下潜，水库中层均温层垂向厚度增加，对库底水温的干扰增强。

Water temperature structure and influencing factors in Ertan Reservoir

The software MIKE 3 was applied to establish the three dimensional modal of water temperature distribution in reservoir for simulating the water temperature structure in the reservoir of Ertan Hydro Project. The parameters of the model were calibrated by observation data. The simulation result shows that the water temperature distribution along the water depth of the reservoir exhibits the characteristic of single thermoeline or double thermocline. The main factors influencing the temperature structure are weather, flow rate and water temperature of inflow, outlet position and discharge. The water temperature of the reservoir in summer rises as the inflow water temperature rises, but only the temperature of the uniform-temperature-layer of the middle stratum of the reservoir water increases synchronously due to density current and turbulent diffusion. When the outlet position is changed, the flow regime in reservoir will vary. Along with down-shift of the outlet position, the longitudinal stream formed by reservoir inflow and outflow descends to the bottom of the reservoir, the thickness of uniform temperature layer increases and the disturbance of water temperature at reservoir bottom will be enhanced.