叶轮式增氧机对鱼池溶氧日变化影响的模拟模型初步研究

针对鲜有鱼池溶氧模型考虑增氧机对鱼池溶氧日变化影响的现实,在传统的描述鱼池水温和溶氧日变化多层模型的基础上,通过分析叶轮式增氧机水跃和液面更新对鱼池多层水体中各能量要素和溶氧变化因子的影响,构建了能反映叶轮式增氧机增氧效果的鱼池水温和溶氧日变化模拟模型。通过实验数据对模型的校参和验证,发现溶氧逐小时模拟值与观测数据的均方根误差为0.267(晴天)和0.420(阴天),Nash-Stucliffe效率系数为0.957(晴天)和0.967(阴天),证明该模型能准确反映溶氧质量浓度的变化规律。同时运用模型模拟数据进行分析,结果显示:叶轮式增氧机增氧1 h后,其影响会持续12 h左右,而且效果主要集中在鱼池中下层,表层水层因高溶氧值和复氧原因,其增氧效果不明显;晴天一天之中最佳开机时间为0:00~10:00;阴天增氧效果不是很理想。

Simulation model study on the effect of impeller aerator on dissolved oxygen diurnal variation in fish ponds

The aerator is the necessary equipment that raising the dissolved oxygen values in fish ponds,especially in high-density breeding ponds.Aim at the facts that no fishpond dissolved oxygen model has considered the effect of aerator on diurnal variation of dissolved oxygen in fish pond.The paper analyzed the effects of hydraulic re-aeration and liquid level renewal on the energy factors and dissolved oxygen change factors in the multi-layer water body of the fishpond.Based on the traditional multi-layer model describing the diurnal variation of water temperature and dissolved oxygen in fishpond,established the model that could simulate the effect of the impeller aerator on the diurnal change of water temperature and dissolved oxygen.Through the calibration and verification of the model based on the experimental data,and found that the root-mean-square error of the hourly simulation value of dissolved oxygen and the observed data was 0.267(sunny day)and 0.420(cloudy day).The nash-stucliffe efficiency coefficient was 0.957(sunny day)and 0.967(cloudy day),which proved the model was correct,and could accurately reflect the dissolved oxygen concentration changing.Analyzed using model simulation data,result showed that the aerating effect of the impeller aerator was evident in the middle and lower layer of the fishpond,no effects at the surface layer of water.The best boot time on a sunny day was from 0∶00 to 10∶00am.The effect of increasing oxygen on cloudy days was very poor.These conclusions were the same as those analysis based on the experimental data.The model considering the effect of the aerator on dissolved oxygen could provide theoretical support for fish pond planning,aerator performance and prediction of low oxygen stress in the fish pond.