为给养殖对象提供适宜生长条件,本文探究了冷水团养殖工船养鱼水舱水体温度、舱底流态与进水流速的关系。利用CFD(Computational fluid dynamics)技术模拟养鱼水舱的传热和流态,设计水舱保温方案,确定最佳进水流速,通过理论计算分析水舱保温效果。研究表明:在无保温层情况下,养殖水体温度与进水流速呈现函数关系:y=-1.75lnx+293.25,外界环境对舱内水体温度影响较大;保温层厚度为30和50mm时,两者均有良好的保温效果。流态模拟表明,该进排水条件下,池中心存在一定规模死水区,最小进水流量为76.3m3/h,此时池底水体旋转速度为17.2cm/s。经分析,可采用硬质聚氨酯泡沫作为水舱保温材料,玻璃钢内衬作为养殖舱壁。理论计算表明设计的保温方案可长时间满足养殖对象对水温的需求,但在高温时段舱盖板应及时关闭。通过温度场和流场数值模拟验证,模拟值与实测值对比,温度误差小于9.1%,速度模拟值和实验值可较好吻合。研究结果表明,所选湍流模型能对养鱼水舱温度场和流场准确模拟,外界温差13℃条件下,养鱼水舱保温层厚度为30mm,设计的保温方案具有良好保温效果,养殖水体水力停留时间应小于1.9h。

In order to provide suitable growth conditions for the raised object,we explored the relationship among water temperature and bilge and influent flows in cold water mass aquaculture boat.Using computational fluid dynamics(CFD),we simulated the heat transfer and flow simulation of fish tank,designed the thermal insulation scheme of water tank,determined the optimum water rate of water,and analyzed the heat insulation effect of water tank through theoretical calculation.Our findings indicated that there was a certain functional relation(y=-1.75 lnx+293.25)between temperature and velocity of inlet in the absence of insulation layer;the external environment has a great influence on the water temperature in tank;and both have good insulation effect when insulation layer thickness was 30 and50 mm.Flow simulation showed that the pool center had a certain scale of dead zone under drainage condition;the minimum water inflow was 76.3 m3/h,and the bottom average rotational velocity was 17.2 cm/s.Through analysis,we found that rigid polyurethane foam can be used as water tank insulation material;and glass fiber reinforced plastic as the bulkhead.The theoretical calculation showed that the scheme can meet the demand of the water temperature for a long time;and the hatch cover should be closed in time during the high temperature period.Through verification of numerical simulation of temperature and flow field,simulation value compared with measured value,the temperature error was within 9.1%,the speed simulation and the experimental value can be matched.The results showed also that the selected turbulent model can simulate fish tank temperature and flow fields accurately.At the outside temperature of 13 ℃ and fish tank insulation layer thickness of 30 mm,the insulation scheme had a good heat preservation effect.Aquaculture water hydraulic retention time should be less than1.9 h.