| Industrialized aquaculture is an important area of fishery in China.It is a modern,high-density and intensive breeding mode.It is more and more developed by the aquaculture enterprises in the environment of serious environmental pollution and lack of water resources.Is the main trend of aquaculture development.Factory farming uses circulating water cultivation mode,through the culture of waste water for physical filtration,biological filtration and other steps to ensure the quality of water conditions,to achieve the recycling of aquaculture water to achieve 0 emission 0 pollution efficient farming model.The core of the circulating water culture model is water treatment technology.At present,the treatment of water treatment in the pond mainly involves the removal of solid waste,the removal of soluble contaminants and the disinfection and oxygenation of water.And solid waste,which is the primary pollution of aquaculture water quality factors,how to timely and efficient remove is an important means to improve water quality conditions.In this paper,the flow characteristics of the shrimp culture pond and the fish pond were investigated by means of the combination of experiment and numerical simulation.The flow field distribution characteristics and the accumulation of soil were studied under different jet angle and jet velocity,and provide reference for the engineering design of the circulating water tank.The main conclusions of this paper are as follows:(1)The characteristics of the pollution and the distribution of the flow field of the shrimp pond in different jet angles(0°、10°、20°、30°、40°、50°)and jet flow velocity(10cm/s、15cm/s、20cm/s、22cm/s、24cm/s、28cm/s)were explored by the test method.It is found that the velocity of the cross section of the square rounded cut pond is "V",and the flow velocity near the pool is larger and then decreases first and then increases.But when the jet angle of more than 40 °,according to the effect of pollution can be inferred,the flow will be messier.Also,there is a difference in the surface fluidity and the underlying flow regime of the pond.The high flow velocity area of the surface flow field is mainly in the vertical and horizontal section close to the wall of the wall,and the high velocity area of the bottom flow field mainly appears in the jet mouth and its downstream section.The pollution effect of the square round cut angle breeding pond is affected by the jet angle and the jet velocity.The study found that the jet angle of 40 °,the most conducive to the pool of dirt accumulation.The greater the jet flow rate,the better the pollution effect.(2)By means of numerical simulation,study the distribution law of velocity distribution,radial velocity and tangential velocity,the influence of different jet angle α(0°、10°、20°、30°、40°、50°)and jet velocity u(10cm/s、15cm/s、20cm/s、22cm/s、24cm/s、28cm/s)on the flow field distribution in the pond.The results show that the overall flow velocity decreases with the increase of the depth distance,and the flow velocity of the bottom flow field is the smallest due to the influence of the bottom friction.The distribution characteristic of flow rate at each depth was small in the middle and big outside,the longitudinal speed near the center of pool is obvious.The tangential velocity distribution of each depth plane is a relatively symmetrical "M" distribution,which has the characteristics of big in the middle and small outside.There is no obvious regularity of the radial velocity distribution,but it is important to analyze the characteristics of the effluent in the bottom of the factory.With the increase of the jet velocity u,the flow field of the surface flow field and the bottom flow field increase obviously,and the rotation effect of the water body in the pool is improved with the increase of the flow velocity.The jet angle α has a significant effect on the flow field.When the jet angle α is 0 °,the flow velocity in the tank is small in general,and the water rotation effect in the pool is poor.With the increase of the jet angle,the overall flow field effect becomes better,the overall flow rate becomes larger,reaches the best effect at 40 °,and then increases with the angle,the effect is worse.(3)The effects of jet flow velocity(0.2 m/s、0.3m/s、0.4m/s、0.5m/s、0.6m/s、0.7m/s),jet angle(0°、10°、20°、30°、40°、50°)and suction mode(bottom suction mode and side suction mode)were studied by means of experimental method.Combined with jet flow test,jet angle test and suction test,study the characteristics of dirt collection of tube jet,taking into account a variety of factors,we recommend the sewage collection mode of circulating water culture system in the pool,can be set for the bottom of the suction Mode,the edge of the jet tube angle of about 40 °,jet flow rate should be not less than 0.3m / s.For the larger particles of dirt,strong cohesive situation,can increase the jet flow rate to obtain the desired effect,the specific flow rate can be determined through a special study. |
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