不同送风方式下樱桃压差预冷的数值模拟

预冷时间对樱桃的贮藏期有着重要的影响,故合适的压差预冷方式成为预冷的研究重点。本文建立了水平送风与垂直送风的樱桃压差预冷数学模型,分析了两种不同送风方式下不同风速下包装箱内部的压力损失、预冷时间、均匀程度的变化情况。模拟结果表明:樱桃的预冷时间随送风速度的增加而减小,压力损失随风速的增加而增大,两者与送风速度的拟合关系均为幂函数;同时樱桃的不均匀度也受送风速度的影响,两者呈正相关;在送风速度6～16 m/s范围内的垂直送风的不均匀度仅为水平送风的75%左右。综合预冷时间、压力损失和均匀程度可以得到水平送风与垂直送风的最佳送风风速分别为9.3 m/s与12.7 m/s,压力损失分别为94.8 Pa与87.9 Pa,预冷时间分别为48.10 min与45.89 min,不均匀度分别为0.412与0.330。即垂直送风的预冷方式在樱桃压差预冷方面有一定的优势。     

果蔬差压预冷方式研究

介绍了差压预冷基本工作原理,并提出了几种不同的差压预冷方式,对预冷时的热量平衡进行了计算,导出了差压预冷时的基本热平衡方程。提高风速能缩短间隔式排列番茄的预冷时间,但是会增加包装箱两侧的压力差;在番茄的冰点温度以上,降低送风温度,缩短预冷时间,相对增加风速而言,包装箱两侧压力反而有减小的趋势。     

新疆赛买提杏加湿差压预冷试验研究

果蔬预冷处理是冷链的重要环节,有利于果蔬迅速去除田间热,并可为第二阶段冷藏做准备。为了延长赛买提杏的货架保鲜期,在差压预冷应用研究的基础上,提出了一种针对新疆赛买提杏的加湿差压预冷的方法。通过正交试验探讨了赛买提杏差压预冷过程中预冷时间、果实失水率、预冷均匀度的变化规律,得出新疆赛买提杏差压预冷设备的最佳参数。结果表明,电机转速1 350 r·min~(-1)(风机风量在130 m~3·h~(-1)),空气加湿器水汽量500 g·h~(-1),送风温度4℃时,预冷所需时间最短,为3.8 h;果实失水率最低,约为0.5%;预冷均匀度约为96%。本研究可为深入研究新疆赛买提杏冷藏贮存设备提供参考依据。     

差压预冷技术与装备在果蔬冷链物流中的应用

差压预冷技术是一种利用差压风机抽吸作用在果蔬包装箱内外两侧形成一定的压力差,促使冷空气通过包装箱上的通风孔进入到箱体内部,与果蔬进行对流换热,从而达到降低果蔬温度、延长贮藏期目的的空气预冷技术。该技术具有预冷速度快、冷却均匀、适用范围广等优点。本文对果蔬采后差压预冷关键技术及应用进行了阐述,并介绍了几种常用的差压预冷设备,以期为果蔬的差压预冷相关应用提供技术参考。     

日本果蔬保鲜设施与技术

1.温湿度管理及贮藏设施果品蔬菜收获后,靠消耗体内的养分进行呼吸作用,其呼吸强度直接影响其鲜度。因此,果品蔬菜保鲜最好的方法是从其收获到消费整个过程一直保持低温高湿条件,即保持冷链的连续性。日本1965年就开始进行果蔬预冷的研究和应用。1971年,长野县小沼农协利用冷藏车将预冷后的大白菜和甘蓝首次投放东京市场,销售一举获得成功。预冷的方式主要有强制通风冷却、差压通风冷却、冷水冷却和真空冷却等。许多试验已证明果蔬预冷品的货架期远比非预冷品长。最近日本开发出一种记录果温数据的小型装置,它对了解果品收获后到消费之间温…     

冷藏车内温度场和湿度场的数值模拟研究

应用流体力学（CFD）软件Fluent,采用k-ζ流模型和非稳态求解方法,对加入货物冷藏车的温度场和湿度场进行了三维非稳态数值模拟计算．得到了冷藏车蒸发器区、中心区、货物区以及边壁等处的温湿度分布。冷藏车内流场的数值模拟结果可以为监测与控制冷藏车内的环境提供技术依据。     

Application Based on DSP of FPS200 in Embedded System

以甘蓝、花椰菜、大白菜为试材,在冷库中采用地垛式、货架式、差压式3种方法进行预冷,比较了不同预冷方式的预冷速度对蔬菜口感、颜色、新鲜度、腐烂率的影响.结果表明,采用差压预冷方式的预冷时间为7 h左右,比地垛式预冷缩短7～10 h,比货架式预冷缩短3～5 h;经差压式预冷模拟贮藏运输的蔬菜鲜嫩爽口,腐烂率低.差压预冷方式在果蔬保鲜领域中具有潜在的优势.     

机械式冷藏集装箱内温湿度场的数值模拟及其试验研究

以配置了上送风管的机械式冷藏集装箱为研究对象,采用番茄为试验物料,建立三维k-ε紊流计算模型,结合多孔介质模型及组分输运模型,采用非稳态求解方法,计算装载货物情况下集装箱内部的动态温湿度场;同时对该模型相应点的温湿度变化过程进行试验验证研究。结果表明,果蔬在冷藏集装箱运输过程中,自身的呼吸作用及通过箱壁从外界传入的热量对温度场的影响较大,造成货物内部与靠壁面处的温度较高;由于货物区温度较高,且热湿空气被水分含量较低的冷空气取代,致使在同等水蒸气含量下货物区的相对湿度较周围空气区低。模拟计算结果与试验验证结果能较好地吻合,建立的模拟模型可为果蔬冷藏集装箱内温湿度的监测与控制提供技术依据。     

新型保鲜剂在果蔬贮运中的应用

果蔬贮运保鲜的配套技术包括制冷设备、气调设备、减压贮藏与减压预冷设备、保鲜包装、各种类型的保鲜剂，以及贮运过程中所采用的温度、湿度、气体成分、预冷方式等，其中保鲜剂对果蔬的贮运起着极其重要的作用。[编者按]     

果蔬差压预冷实验包装箱相关参数的研究进展

为了研究包装箱对果蔬差压预冷效果的影响,综述了国内外果蔬差压预冷包装箱参数及相关方面的研究。发现研究重点主要集中在预冷实验箱的单个参数（开孔形状、开孔大小、开孔率、三维尺寸）上,而预冷包装箱材料的选取及各参数对预冷效果的综合影响方面的研究相对较少,预冷包装箱最佳三维尺寸的确定、预冷包装箱材料和厚度的选择、预冷包装箱与储存包装箱的通用性等问题都还需要深入研究。     

Exploration of Positive Pressure Mechanical Air Supply System

The problems are discussed in positive pressure mechanical air supply system design, when the actual status is far different from what figures in the code based. Expressions must be used to determine the supply air rate. The rate between length and width of rectangle air channel should be less than 6. To avoid some uncertain factor, correction factor for absolute coarseness should choose the bigger figure. The smoke control and extraction design of smoke controlling stair hall must be divide into two parts: The overground and the underground. When setting positive pressure mechanical air supply system in smoke controlling stair hall, the outer window in the hall must be fixed. To insure the inner surface of smoke controlling stair hall keep compact and lubricity, communion should be done with governor of builders.     

Design and Analysis of the Air Flow and Distribution of Laminated Air Conditioning in Summer in the Powerhouse of Sanxia Hydropower Station

Around the design of air flow and distribution about the laminated air conditioning in summer in the powerhouse of Sanxia hydropower station, the system division, air flow pattern, air supply state and volume etc have been analyzed separately. Based on the existing domestic achievements, the relative calculation model has been established and the application method has been explored. From this the program named as AFDC/LACS has been compiled with language FORTRAN77 and the calculation on the airflow and distribution of the place mentioned above has been done with several design conditions. Thus some batches of the technical parameters have been provided to plan the test conditions in the heat simulated test..     

Laboratory Simulation to Remove Petroleum Pollutant in Groundwater by Using Air Sparging

Based on the stratigraphic configuration of the oil-contaminated sites in Northeast China, the efficient and best experimental conditions to remove oil pollutants in a relatively heterogeneous aquifer using air sparging were investigated. The results show that for Complex formation, the remediation of AS technology is efficient. It was shown that when air flow rate was 300ml/min, the removal rate of benzene, naphthalene were 99.54% and 11.58%, respectively. When the medium was layered heterogeneous porous media, the removal rate of continuous air sparging is superior to intermittent air sparging. In the whole experiment, the removal efficiency of naphthalene was very low which may be own to its structure and properties and the heterogeneous of the medium. When the Semi-volatile contaminants exist, considering the use of other combined remediation technique was necessary.     

Analysis on Influencing Factors of Indoor Air Quality and Measures of Improvement

Nowadays,IAQ(Indoor Air Quality) becomes a topic of general interest.This paper discusses the definition and influencing factors of IAQ and puts forward some measures for improving indoor air quality.     

Model Experiment and Primary Research of Laminated Air Conditioning in the Powerhouse of Three-Gorges Hydropower Station in Summer

In this paper, the model experiment of laminated air conditioning in the powerhouse of Three-Gorges Hydropower Station was introduced. To assure the effect of air conditioning, the influence of different roof temperature, air supply velocity and Ar number on air distribution was analyzed and studied. Some conclusions have been drawn.     

濮阳市最高气温和最低气温非对称变化趋势分析

提要：运用1960-2008年以来濮阳逐月和年平均最高、平均最低以及平均气温和相应的极端气温资料,借助线性分析和年代跃变分析的方法,研究其长期变化趋势和年际变化,结果表明：濮阳的夏季平均最高气温呈下降趋势、冬季最低气温和年平均气温呈现明显上升趋势,冬季增温主要在夜间,夏季降温主要在白天。全年的平均增温主要是由冬季夜间引起的。     

Winter Air-conditioning I-d Pattern Design of Fan-coil Units

For the most common fresh air handling way supplying fresh air directly into the rooms after it has been handled in fan coil with outdoor air systems, the paper gives the design method of i d pattern in winter air conditioning operating mode, which determines the state of supply air of fan coil units and the final parameter of winter fresh air througn the ratio of fresh air. For selecting the final parameter of fresh air after it has been handled,the authors gives three conditions:Winter fresh air is handled to room enthalpy;Winter fresh air is handled between room enthalpy line and room temperature line; Winter fresh air is handled to room temperature or a little lower than room temperature. The comparing result show that the second method is desirable after comparison.     

立式气箱径向通风试验报告

本试验取鉴径向通风的基本原理,采用立式气箱和复壁导流管相结合的通风设计,基本上实现了中小型房式仓散储粮堆的“不揭膜”通风工艺,取得了较为理想的均衡通风效果.     

Evaluation and Analysis of Bacteria Pollution in Dwelling Indoor Air

Tests and study were carried out on indoor air bacteria pollution in dwelling house inChongqing city. Based on the data of measured bacteria concentration of the indoor air,the reasons for indoor air pollution were analyzed. Ith was found that the bacteria seriously polluted the indoor air. The main factors influencing the indoor air bacteria pollution are moisture, natural ventilation and lighting conditions. The construction forms and decoration of the dwelling house are the secondary reasons for indoor air bacteria pollution. Measures and suggestions of preventing the indoor air bacteria pollution and improving the indoor air quality and environmental quality were presented.     

利用粮堆微气流熏蒸高大立筒仓储粮害虫的试验

根据粮堆内部微气流的运行方向，在高大立筒仓粮面或仓底施药，可以得到很好的杀虫效果，具有经济、安全、简单、快速的特点。