国内外吸鱼泵研制现状

本文介绍了国内外研制的真空吸鱼泵、离心吸鱼泵、气力吸鱼泵、射流吸鱼泵等概况,着重就美国“ETI”公司生产的SILKSTREAM射流吸鱼泵的工作原理、结构、性能作了较详细的阐述,供今后研制开发参考。     

射流式鱼泵输送草鱼的性能研究

为了分析射流式鱼泵输送草鱼的性能及其损伤因素,文章设计了一台喉管直径为60 mm的射流式鱼泵,开展了草鱼输送实验,并采用高速摄影和计算流体力学方法进行了研究。结果显示,该射流式鱼泵在扬程2.24m时最高草鱼输送能力达918 kg·h~(-1),其所需水功率为2.83 k W。进一步的检测表明,部分实验鱼有鳞片脱落的情况,但未出现游泳异常,解剖后也未发现内脏受损等情况;实验鱼在过泵后呼吸频率及部分血液指标存在明显变化,但在24 h内基本可以恢复。数值模拟和高速摄影方法分析得出,剪切层是造成实验鱼泵内鳞片脱落的主要原因,撞击伤是由内流偏转诱导实验鱼撞击泵内壁面产生的,包含压力梯度在内的水力因素都可能使实验鱼产生应激反应。但由于鱼类在泵内时间极短,上述因素都不会致实验鱼死亡。     

文丘里(Venturi)吸鱼泵研究

介绍了文丘里(Venturi)射流吸鱼泵的结构、原理及应用。文丘里吸鱼泵无叶轮,靠水射流产生负压来抽送活鱼,输送过程中活鱼无损伤,每小时输送活鱼(鱼水混合)20 t,扬程5 m,效率高,适用于深水网箱养殖。     

吸鱼泵的主要结构型式及其应用前景分析

本文介绍了近年来国内外吸鱼泵的主要应用领域和发展前景,吸鱼泵作为远洋捕捞和网箱养殖业的机械化设备,可以快速输送渔获物,改变了过去人工处理费时费力的状况。确保鱼体无损伤并提高存活率是目前吸鱼泵研究的重点。本文讨论了离心式、真空式和射流式吸鱼泵主要机型的结构形式、技术特点和性能水平;并结合各种鱼泵的结构形式说明其优缺点,分析其在我国淡水养殖、深水网箱养殖、远洋捕捞以及渔业资源保护监测中的应用前景和改进措施,以期推进吸鱼泵在国内的普及应用,提高渔业机械现代化水平。     

国内外吸鱼泵研究进展

吸鱼泵是水产养殖和商业捕捞中用于渔获起捕、运输,提高生产效率的主要工具。确保鱼体无损伤并提高存活率是吸鱼泵研究的重点。本文介绍了国内外吸鱼泵的研究现状,讨论了离心式、真空式和射流式吸鱼泵主要机型的技术特点和性能水平;分析了美国、日本及欧洲等国在泵体结构优化、吸鱼泵扩展系统、吸虾泵和网囊泵吸系统等方面的研究进展。针对目前存在的鱼体损伤率高、效率偏低、机体笨重和能耗偏高等问题,提出了我国吸鱼泵技术的发展对策:需重点解决鱼体无损传输、增强通用性、提高智能化水平以及开发远洋渔业连续捕捞系统等问题。     

吸鱼泵的研究进展与发展建议

渔获的起捕是水产养殖和商业捕捞中的重要环节,人工操作不仅费时、费力,还会对鱼体造成较大的损伤。吸鱼泵作为渔业生产活动中重要的机械装备,具有操作简单、工作效率高、鱼体损伤率低等优点,越来越受到水产养殖和捕捞等行业的欢迎。介绍了常见的几种吸鱼泵的类型、工作原理及其主要的应用领域;分析了目前国内外吸鱼泵在基础研究、远洋捕捞、水产养殖捕捞以及智能控制方面的研究进展及其特点;结合国内外吸鱼泵研究特点,进行了对比分析,提出了今后吸鱼泵的功能定位及研究方向,以期为推进吸鱼泵在国内的普及应用,提高渔业装备的现代化水平提供参考。     

基于SolidWorks的双流道吸鱼泵三维实体造型研究

吸鱼泵是鱼类起捕与输送的重要机械设备。确保鱼体无损伤并提高存活率是目前吸鱼泵研究的重点。鱼体在通过双叶片吸鱼泵的过程中容易受到叶片进口端的切割而损伤。双流道吸鱼泵的叶轮由两个空间通道组成,介质通过能力强,无堵塞性好,不会对鱼体造成损伤,是双叶片吸鱼泵的理想替代型式。双流道泵在工业领域中已被广泛使用,但在渔业方面至今仍是空白。介绍了双流道吸鱼泵叶轮及蜗壳的水力设计方法,结合实例详细阐述了采用Solid Works进行双流道吸鱼泵三维实体造型的过程。研究表明:采用Solid Works进行双流道吸鱼泵三维造型是切实可行的,对于深入开展双流道吸鱼泵研究,以及在深海网箱养殖和远洋渔业中进行推广应用双流道吸鱼泵具有重要意义。     

基于CFturbo的离心式吸鱼泵设计

传统的离心式吸鱼泵设计基本上是根据设计经验与相似泵推导设计,导致设计周期长且性能参数无法确定。为了更加快速、精确地设计出不同尺寸类型的吸鱼泵,并估算出离心式吸鱼泵的流量、扬程等性能参数,运用CFturbo设计软件进行参数化设计吸鱼泵,通过CFturbo软件建立吸鱼泵的三维模型,并通过软件内置经验函数优化设计,然后通过CFD流体动力学软件进行数值模拟仿真验证,最终设计出符合性能参数要求的离心式吸鱼泵,实现离心式吸鱼泵的快速研发。     

大型深水网箱连续式真空吸鱼泵的设计研究

大型深水网箱养殖,是最近十多年迅速发展起来的一种新型网箱养殖系统,已在挪威、智利、美国、丹麦、英国、加拿大、澳大利亚、日本等国普遍使用,而国内刚开始发展起来,潜力很大,所以研制和生产符合中国国情的大型深水网箱配套设备——吸鱼泵,供养殖户使用已成为必需,我们在间歇式真空吸鱼泵设计研究的基础上,研究开发了连续式真空吸鱼泵,该设备的研究开发已被列入国家十五“863”—“深海抗风浪网箱的研制”课题项目之中。一、连续式真空吸鱼泵工作原理吸鱼泵系统工作原理见示意图:吸鱼泵放于合适的位置,关闭吸鱼泵整个系统内腔的阀门,吸鱼…     

射流式浒苔打捞机的设计与试验

近两年青岛夏季沿岸浒苔(Enteromorpha prolifera)大量出现,为高效完成浒苔打捞工作,在现有船用离心泵和喷射泵的基础上,组装成射流式打捞机,从青岛市小麦岛浒苔收集处采集新鲜浒苔,在水池中进行浒苔打捞试验.结果表明,射流式浒苔打捞装置的工作效率达到7.2 t/h.为了进一步提高装置的工作效率,在原有设备的基础上,对离心泵和喷射泵均进行改进,喷射泵改为双吸口,位于泵体两侧,同时离心泵的入水口也作为浒苔吸口使用,并给出喷射泵主要设计参数.     

歧管式高压射流水下洗网机的设计

文章针对深水网箱养殖过程中岸电供应不便而给网衣的水下清洗带来极大困难的问题,研制了歧管式高压射流水下洗网机,克服了高压仓式洗网机水头损失大的缺点。通过水力学计算得到歧管式高压射流水下洗网机射流压力P=5．57MPa、喷嘴孔径d=2．6mm、射流速度v=104．1m·s。和射流功率P=12．3kW、射流反冲力F=234．96N。水下洗网机的海上清洗试验表明,在工作泵满足工作压力和设计流量条件下,歧管式高压水射流水下洗网机的综合性能达到了设计要求。     

水射流空化强化光催化氧化技术在养鱼污水处理中的应用初探

研究了水射流空化强化TiO2光催化氧化技术处理养鱼污水的效果,同时考察了单独的水射流空化处理、光解处理、光催化氧化处理的效果。试验结果表明:水射流空化强化TiO2光催化技术处理养鱼污水0.5 h后,杀菌率达97%;处理4 h后,氨氮和COD的去除率分别达25%和29%。在降解氨氮和COD方面,水射流空化技术和TiO2光催化氧化技术结合表现出明显的协同效应。水射流空化强化光催化氧化是一种绿色无污染的工艺,而且高速射流产生的冲击波对水体可以起到增氧的作用,有利于养殖鱼类的生长。     

异侧布置竖缝式鱼道紊流结构试验研究

鱼道是辅助鱼类克服障碍物,实现产卵洄游、索饵洄游和越冬洄游的通道。全球目前已建鱼道中,鱼类能够溯游通过的鱼道尚不足50%,大多数鱼道的水力设计仅考虑平均流速,忽略了鱼道内的紊流结构,探究鱼道的水力特性尤其是紊流结构,对改进其设计具有重要的指导意义。通过在大比尺水槽模型中试验研究异侧布置竖缝式鱼道的紊流结构,利用声学多普勒测速仪(ADV)实测竖缝式水池内每一点的三维瞬时流速,剖析流场的三维时均流速分布、流动特征、旋涡特性、纵向和横向紊动强度分布、不同水平面的雷诺应力分布等,考虑了两种典型流量(Q1=20.62 L/s,Q2=30.75 L/s)和3个特征水平面(h/3,h/2和2h/3),提出了三维流速分布的半理论半经验公式、流场矢量图及各点的旋度,并与自由壁面射流进行比较。结果表明,异侧布置竖缝式鱼道前半池内纵向流速具有壁面射流的特征,后半池由于受下游隔板的阻挡则偏离壁面射流规律;水池内存在顺时针方向的水平旋涡,其旋度随流量的增大而增强;前半池壁面射流区的紊动强度存在峰值区,后半池的紊动强度峰值区由水槽左侧移至右侧;壁面射流区的雷诺应力变幅较大,而在旋涡区则较小,有利于洄游鱼类在鱼道上溯和歇息。     

High fluid shear strain causes injury in silver shark: Preliminary implications for Mekong hydropower turbine design

The Lower Mekong Basin is facing unprecedented threats to fish diversity from hydropower development. There is increasing pressure on developers and construction authorities to design solutions to improve fish survival through turbines, thus protecting the resources in regions being developed for hydropower. A hydraulic characteristic of hydropower turbines with known fisheries impacts is fluid shear stress. Elevated shear stress occurs where rapidly flowing water passes near spillways, screens and within turbine draft tubes. Shear stress can have adverse impacts on fish, but no work has assessed whether this holds true for Mekong River species. A flume was used to determine critical tolerances of silver shark, Balantiocheilos melanopterus (Bleeker), to shear stress rates at a high‐velocity jet which simulated a hydropower turbine. Fish were assessed for injury or mortality following exposure. Results were compared against a no‐shear control. Injury and mortality were greater at higher shear stress exposures. Injuries occurred at all shear exposure levels with mortality at shear levels higher than 600/s. This approach should help design future hydropower turbines if data on other species demonstrate similar results. If the likelihood of adverse impact is high, then shear stress will need to be considered in the design of future hydropower facilities.     

不同干燥方式对卵形鲳鲹鱼片风味的影响

为探究不同方式干燥卵形鲳鲹鱼片的风味差异,实验选取冰鲜卵形鲳鲹为原料,采用热风干燥、热泵干燥和冷冻干燥3种方式干制卵形鲳鲹鱼片,分别测定并分析其TBA值、呈味核苷酸含量、游离氨基酸含量和挥发性风味物质等指标。结果显示,干燥后的卵形鲳鲹鱼片中TBA值与K值均显著上升,其中冷冻干燥鱼肉的TBA值仅比冰鲜鱼片增加1.6倍,但热泵干燥和热风干燥则分别增加了5.5和4.5倍。干燥后鱼肉中的总游离氨基酸含量及味精当量较冰鲜卵形鲳鲹鱼片显著降低,其中热风干燥鱼肉的味精当量则下降了50.83%。热泵干燥鱼肉中苦味氨基酸含量和鲜味氨基酸含量分别占总氨基酸含量的19.11%和7.37%,而冷冻干燥组鱼肉中甜味氨基酸相对百分含量最高,为53.62%。3种干燥方式中,热泵干燥卵形鲳鲹的味精当量最高,为4.47谷氨酸钠(MGS)/100 g,表明热泵干燥卵形鲳鲹鱼片的鲜味程度最高。就挥发性风味成分而言,热泵干燥鱼肉酯类和酮类较多,其主要呈现果香味和焙烤坚果味;热风干燥中烃类和芳香类的相对含量约占70%,醛类和酯类相对含量达20%;而冷冻干燥中烃类与芳香类相对含量占到90%以上,醛类和酯类相对含量不足8%,其风味...     

工厂化对虾养殖池管式射流集污水力特性

工厂化养殖池内水体的流场分布特性直接决定了其对残饵、粪便等的排污性能。本实验研究了管式射流驱动模式下,射流角度与射流流速对养殖池内水体流场与污物聚集特性的影响。养殖池流场特性采用点式流速仪进行布点测量,利用MATLAB软件对流场特性进行分析。采用相机采集的养殖池集污效果图像,并利用Photoshop软件与自行开发的不规则图形面积分析软件对图像进行分析。研究表明,流速从池心向外呈"V"型变化,在射流角度固定的情况下,射流速度越大,池心低流速区域越小,污物向池心的聚集效果越好;在流速固定的情况下,存在一个最佳的射流角度,本实验在24 cm/s流速条件下,射流角度为40°时,池内污物聚集效果最优。结论认为在保证养殖对象生长的前提下,可尽量提高射流流速;在24 cm/s流速条件下,最佳射流角度在40°左右。本研究成果可为工厂化养鱼池、养虾池等管式射流水力驱动系统的优化设计提供参考依据。     

Numerical analysis of the effects of gas-phase properties on the internal characteristics and wear in a centrifugal pump

Centrifugal pumps are indispensable in aquaculture engineering. The existence of bubbles is inevitable in a centrifugal pump and may affect the performance of the pump which delivers solid-liquid two-phase flow. Thus, this study aims to analyze the effects of gas-phase properties on the internal characteristics of a centrifugal pump by using a computational fluid dynamic code based on Eulerian multiphase mode and a standard k–ε two-equation turbulence model. Results show that gas-phase properties, such as concentration and diameter, affect the absolute pressure and the phase distribution in the centrifugal pump. The gas-phase distribution on the working faces of blades is greater than forces on the back face of the blades. The larger the diameter of the gas-phase is, the easier it is to be concentrated; Thus, the working face of the blades is prone to cavitation and corrosion, and with the increase of the bubble size, the cavitation corrosion of the back surface of the impeller becomes more serious. The solid-phase velocity and static pressure distribution increase with increasing concentration or diameter of gas-phase. The solid-phase is more easily leave the impeller area and enter the volute because of the existence of gas-phase, which may lead to abrasion of volute. The existence of gas makes the solid velocity distribution in the centrifugal pump more uneven, which may cause uneven wear of the centrifugal pump. The obtained results by this method can reveal the effects of gas-phase properties and wear on the internal characteristics in centrifugal pumps and are helpful for improvement and empirical correction in the hydraulic design of centrifugal pumps.     

A case study: Impacts of deviating from model research design to the commercial industry for split-pond aquaculture

A case study is presented to compare the results of design and management including circulation and dissolved oxygen management at a modified split-pond facility in west-central Alabama to the recommended design. Modifications included: the use of and a propeller pump instead of a slow-moving paddlewheel, lack of baffle in the waste cells, waste cell to fish cell ratio size, and improperly positioned aerators and DO sensing probes.Over a three year time period, the modified split-pond facility had net yields of hybrid catfish (Ictalurus punctatus ♀ x I. furcatus ♂) that reached up to 11,416 kg/ha/year; however, this includes several reports of fish kills. The present study experienced a minimum 15% reduction in net production compared to the recommended design values with a maximum potential loss of 54%. Ponds used an axial pump to transfer water between a 6:1 ratio of waste treatment area to fish grow-out area. Water flowed from the fish cell to the waste cell at a rate of 31.2 m³/min and from the waste cell back to the fish cell at a rate of 0.78 m³/min. Aerators used 5619–7492 kW-hr/ha which is more than the electrical use in traditional ponds (2238 kW-hr/ha). Even with the extra aeration, this study had at least one fish cell and one waste cell drop below a dissolved oxygen concentration of 2.5 mg/L. These specific modifications may lead to poor survival and production in split-pond aquaculture and are discussed with best management practices of the recommended design.     

Physiological Stress in Channel Catfish,Ictalurus punctatus,Harvested by Lift Net,Vacuum Pump,or Turbine Pump

Stress in freshwater fish results in an increase in serum cortisol and glucose and a decrease in serum electrolytes. These physiological indicators of stress were measured in fignerling and food-size channel catfish, "Ictalurus punctatus," before harvest, immediately after harvest, and for several days after the fish were harvested. Fingerlings were harvested in spring with either a turbine fish pump or a traditional boom-and-basket lift net. Food-size fish were harvested in winter, spring, and summer by a turbine fish pump, a vacuum fish pump, or a life net. Elctrolyte concentrations were very stable and did not show consistent effects of harvesting. Cortisol and glucose were the most sensitive to harvesting, and both increased during harvesting in all months tested. Recovery of the serum concentrations to pre-harvest levels was generally completed by the fifth day after harvest. Stress responses were similar among the different harvesting techniques, which suggests that the method of choice may be based on other factors, such as cost of available facilities.