液氮喷淋冷藏运输中液氮喷淋量,喷淋时间及传热系数的计算

本文主要介绍了液氮喷淋冷藏运输的特点着重探讨了液氮喷淋时间，喷淋量及传热系数的计算。     

液氮冷藏货柜车

当前、在冷藏食品的运输中,已广泛地使用冷藏汽车。在这些冷藏汽车中,几乎都使用压缩机制冷系统,并以小型汽油机或电动机作动力。下面拟介绍一种不须动力装置的直接膨胀式液氮冷藏货柜车。图一是液氮瓶直立放置的冷藏货柜车的示意图。这种货柜车是液态氮作为制冷剂,把液氮直接喷入货柜内制冷,使用后的氮气不回收,而排至大气中。其制冷系统主要部件有:盛装液氮的隔热钢瓶,(下称液瓶),喷咀系统,安全阀,温度控制机构等。图     

液氮冷藏集装箱的发展探讨

讨论了液氮冷源在冷藏技术中的应用优势，深入分析了液氮冷藏集装箱的发展优势，并对发展液氮冷藏集装箱存在的问题及对策进行了充分的探讨。     

液氮制冷在冷藏运输中的广阔前途

<正>六十年代初期,深冷技术首次应用于冷藏运输。应用表明,液氮制冷系统是唯一的、在商业上可与机械制冷系统相竞争的冷藏技术。在欧洲使用液氮制冷运送的货物已超过十万件。美国液氮制冷的车辆数以万计。液氮制冷系统的优点:可运送各种易腐货物,如新鲜水果蔬菜、肉类油脂、冻结货物及各种饮料;液氮制冷系统集中了冷藏运输和气调运输的优点,给车内创造了比较理想的环境,使易腐货物保持不变质,因为氮气对易腐货物的新陈代谢有抑制作用。国际铁路联盟科研所试验证明,     

液氮在食品速冻中的应用

用液氮速冻食品,一般可分为液氮浸渍冻结、液氮蒸气吹风冻结和液氮喷淋冻结三种方法。液氮浸渍冻结是使食品体跟液态氮浸渍接触,液氮吸收食品的显热和潜热而被蒸发,借以达到速冻食品的目的。液氮蒸气吹风冻结则是让液氮(利用食品热量)在特殊的蒸发器中蒸发,然后以很高的流速强制吹送至食品表面,从而使食品快速冻结。液氮喷淋冻结,则是将液氮喷淋到食品上,液氮吸收潜热气化,继后液氮的蒸气吸收显热升温,因而使食品迅速地冻结。这种方法的应用,远比液氮浸渍冻结和液氮蒸气吹风冻结广泛和普遍。下文着重讨论液氮喷淋冻结的工艺过程、设备、效果、传热学设计、经济性以及优缺点等。     

食品液氮速冻技术研究进展

液氮速冻技术能使食品快速穿过冰晶区实现食品的玻璃化或部分玻璃化,提高速冻食品的品质,在食品冷链中广泛应用。本文概括了食品液氮速冻技术的基本原理和经典传热模型,对比了液氮浸渍冻结、冷气循环冻结和喷淋冻结等速冻方式的特点,总结了速冻食品品质评价的研究进展和液氮速冻技术在食品加工中的应用范围,并展望了液氮速冻技术未来的研究方向。     

客车构件涂装前处理工艺

客车构件在涂装前通过脱脂、除锈、防锈、表调、磷化等工序 ,将工件表面的油污、锈蚀、疏松的氧化层、灰尘等除净 ,为整体涂装提供清洁表面 ,同时多孔性的磷化膜能显著提高涂膜附着力和耐蚀性。我公司采用喷淋式前处理生产线一年多来 ,积累了一些生产实践经验 ,介绍如下。1　前处理工艺流程(重锈蚀工件 )浸渍式除锈、除油→浸渍式水洗→浸渍式防锈处理→上挂 (一般锈蚀及油污工件直接从此上 )→喷淋预脱脂→喷淋脱脂→喷淋水洗 ( 1)→喷淋水洗 ( 2 )→喷淋除锈→喷淋水洗( 1)→喷淋水洗 ( 2 )→喷淋表调→喷淋磷化→喷淋水洗 ( 1)→喷淋水洗…     

我国铁路液氮冷藏车首次重载运行试验

研究用液氮的铁路冷藏车是我国铁路冷藏运输的紧迫需要,具有重大的经济效益和社会效益。本文报导了液氮冷藏车在我国首次运行的情况,介绍了用淘汰的B16型保温车改装为液氮冷藏车的结构,静止试验以及重载运行试验的结果。     

液氮冷藏集装箱的箱型选择与结构设计

介绍了国际集装箱的应用与发展状况，针对我国集装箱运输的现状及未来的发展，提出了开发兴氮冷藏集装箱的优选箱型，并就液氮冷藏集装箱绝热材料选择，绝热层制作及其有关问题进行了分析研究。     

液氮冷源在冷藏运输中的应用

论述液氮冷源、液氮冷藏车(箱)的优越性;并就开发液氮冷藏运输中存在的几个问题,提出一些参考意见。     

激光设备冷却系统设计研究

本文以某激光设备为例,探讨了激光设备的液体冷却方式,首次使用了蓄冷方式的冷却方式。在车载方式下使用蓄冷方式冷却,蓄冷水箱设计是一个关键,本文重点对蓄冷水箱的设计进行了设计研究,同时在冷却系统中引用了节能供水方式,采用PID模糊控制技术,保证供水温度,达到对激光设备冷却的目的。     

LNG汽车冷能回收在低温冷藏车中的应用

LNG(液化天然气)作为绿色汽车燃料,可以减少汽车尾气排放造成的空气污染。此外,LNG在汽化、温升的过程中释放大量的冷能。本文提出利用乙二醇溶液做冷媒的蓄冷系统对该冷能进行回收。并将回收的冷能用于低温冷藏链中的冷藏运输过程。系统参数计算结果表明:回收的冷能满足中短途小型冷藏车的冷负荷需求。     

蒸发温度自动调节技术及其在冷藏车上的应用

针对现有食品冷藏车由于蒸发温度不可自动调节而导致冷鲜果蔬结冰、冻伤和脱水等问题,提出一种蒸发温度可以根据设定温度自动调节的解决方案,其通过改变膨胀阀流量实现不同的蒸发温度.具备蒸发温度可以自动调节制冷系统的冷藏车,不但高效节能,还可以从根本上解决一车多用和一车多温的问题,降低油耗和排放.     

Cold spraying of Cu‐Al‐Bronze for cavitation protection in marine environments

High strength metal coatings are promising for reducing the cavitation damage of ship rudders. Cold spraying offers the opportunity to produce coatings that have similar properties as respective bulk material. In this study, conditions for cold spraying CuAl10Fe5Ni5 bronze are evaluated for the use at ship rudder applications. The spray parameter sets were varied with respect to nozzle type, process gas pressure and temperature. Single particle impact morphologies were investigated by scanning electron microscopy and categorized into different classes to obtain information on the deformation behavior. Within the selected parameter regime, coatings were processed with deposition efficiencies of up to 70%. The coating microstructures were analyzed by optical microscopy to gain information on spraying conditions for minimum porosity. For the higher parameter sets, porosities of less than 2% were obtained. Coating performance was investigated by cavitation test procedures. These first results show that cold sprayed bronze coatings still faces challenges with respect to powder properties. With further optimization, respective coatings could have a high potential for ensuring a good performance in rudder protection.     

相变蓄冷技术在食品冷链运输中的研究进展

目的 概述相变蓄冷技术在食品冷链运输中的研究进展,为冷链运输发展提供一定的研究思路。方法 综述相变蓄冷技术在蓄冷式冷藏车、蓄冷保温箱及其他冷链运输设备中的应用,主要对其相变蓄冷材料、蓄冷技术与保温材料的结合、运输过程内部温度分布的影响因素及其新型的运输方式进行论述。结果 相变蓄冷技术在食品冷链的各种运输设备中都有广泛的应用领域和较大的发展空间。结论 相变蓄冷技术是提高能源利用效率的有效手段,在冷链运输系统中具有广阔的应用前景。相变蓄冷材料、保温材料以及运输过程中温度稳定分布的研究及多温共配技术是今后的研究方向。     

Table grapes and refrigeration: fumigation with sulphur dioxideLe raisin de table et le froid: fumigations de dioxyde de soufre

Long-term storage of dessert grapes requires fruit which is free from rotting, efficient means of rapid cooling and cold storage, prompt initial fumigation with sulphur dioxide, and periodic disinfection with the correct dosage, uniformly distributed.The distribution of gas in the cold store or in the transport vehicle depends on the type of package used, the tightness of the pack, the use of pallets, and of course, on the system of air circulation employed. All these factors are very important in the control of deterioration, free from risk of damage due to exposure to excessive concentrations of SO₂. Fumigation of packaged produce with diverse mixtures of sodium or potassium bisulphite gives further protection to fruit in transit for more than ten days.     

Table grapes and refrigeration: fumigation with sulphur dioxide

Long-term storage of dessert grapes requires fruit which is free from rotting, efficient means of rapid cooling and cold storage, prompt initial fumigation with sulphur dioxide, and periodic disinfection with the correct dosage, uniformly distributed.The distribution of gas in the cold store or in the transport vehicle depends on the type of package used, the tightness of the pack, the use of pallets, and of course, on the system of air circulation employed. All these factors are very important in the control of deterioration, free from risk of damage due to exposure to excessive concentrations of SO₂. Fumigation of packaged produce with diverse mixtures of sodium or potassium bisulphite gives further protection to fruit in transit for more than ten days.     

A model for the design of zone control automated guided vehicle systems

An analytical modelling strategy is proposed as a screening device for use prior to the simulation phase in the design of zone control automated guided vehicle systems (AGVS). The proposed model predicts the effects of the major AGVS design variables on system-performance measures including maximum throughput capacity and risk factors associated with shop locking. This is done through a process which specifically evaluates the system operating dynamics associated with vehicle fleet size, guidepath layout, workstation storage capacity, routeing, and, to a less precise extent, vehicle dispatching. Operating dynamics are defined to include vehicle blocking resulting from guidepath contention and variation of in-process storage levels. The objective of the analytical model is to reduce the extent of simulation modelling necessary to design a zone-control AGVS for a given materials-handling workload. The model is illustrated for a sample AGVS with variation in the fleet size, workstation storage capacity and dispatching rule demonstrated.     

Supersonic Cold Spraying for Energy and Environmental Applications: One-Step Scalable Coating Technology for Advanced Micro- and Nanotextured Materials

Supersonic cold spraying is an emerging technique for rapid deposition of films of materials including micrometer-size and sub-micrometer metal particles, nanoscale ceramic particles, clays, polymers, hybrid materials composed of polymers and particulates, reduced graphene oxide (rGO), and metal–organic frameworks. In this method, particles are accelerated to a high velocity and then impact a substrate at near ambient temperature, where dissipation of their kinetic energy produces strong adhesion. Here, recent progress in fundamentals and applications of cold spraying is reviewed. High-velocity impact with the substrate results in significant deformation, which not only produces adhesion, but can change the particles' internal structure. Cold-sprayed coatings can also exhibit micro- and nanotextured morphologies not achievable by other means. Suspending micro- or nanoparticles in a liquid and cold-spraying the suspension produces fine atomization and even deposition of materials that could not otherwise be processed. The scalability and low cost of this method and its compatibility with roll-to-roll processing make it promising for many applications, including ultrathin flexible materials, solar cells, touch-screen panels, nanotextured surfaces for enhanced heat transfer, thermal and electrical insulation films, transparent conductive films, materials for energy storage (e.g., Li-ion battery electrodes), heaters, sensors, photoelectrodes for water splitting, water purification membranes, and self-cleaning films.