| 中西方减压贮藏研究概述 |
|
Stanley P. Burg郑先章
（1.美国 VacuFresh 公司 迈阿密 33133；2.扬州通利冷藏集装箱有限公司 扬州 225000）
摘 要 减压贮藏系统用调节大气压力控制O2浓度,其技术与效果与CA完全不同。低压下，空气进入真空室会膨胀，使其中的CO2、C2H4及挥发性污染物浓度减少99%；增强气体扩散及减弱呼吸，使不同物品能忍受0.1%～0.2% 的O2浓度。气体扩散增强还促进CO2、NH3和C2H4从物品内部逸出，连续换气将其排到室外。在1.33～2.67 kPa极低压力下，物品呼吸热少相应的能蒸的水分就少，高湿度和防止对流及辐射减少物品失水。极低压时O2极稀薄，园艺品呼吸热和传热能力因对流抑制了90%。极低压防止细菌和霉菌生长，杀灭昆虫，抑制C2H4生成量>90%，防止CO2伤害，抑制有毒的琥珀酸盐形成，限制Vc损失，阻止C2H4形成酶，因此减压设备极有利于园艺品贮藏。概述西方减压研究成果与发展，评价中西方在减压研究上存在的重要差异。
关键词 食品包装与贮藏；低压贮藏；热传递；失水；昆虫检疫；呼吸；乙烯 |
|
Summary of Hypobaric Research in China and the West
Stanley P. Burg☆ and Zheng Xianzhang
☆ VacuFresh Co.,Miami,Florida, 33133, USA AbstractA hypobaric storage system controls the O2 concentration by regulating the atmospheric pressure, but its technology and effect differ from CA entirely. At a low pressure the CO2, C2H4, and volatile contaminant concentrations present in the incoming air decrease by up to 99% when the air expands during entry into the vacuum storage chamber, and increased gaseous diffusion and respiratory inhibition cause different commodity types to tolerate 0.1%-0.2% O2. Increased gaseous diffusion also promotes the escape of CO2, NH3 and C2H4 from within the commodity, while continuous air-changes flush these gases from the storage chamber. During ultra-low pressure hypobaric storage at 1.33-2.67 kPa a high relative humidity and the prevention of convective and radiant heat uptake by the commodity limit its water loss to the amount that can be evaporated in response to the small amount of respiratory heat it produces. O2 is so scarce that a horticultural commodity`s respiratory heat production and ability to transfer heat by convection are inhibited by 90%, An ultra-low pressure prevents bacterial and mold growth, kills insects, prevents CO2-damage, inhibits ethylene production by >90%, inhibits toxic succinate formation, limits ascorbic acid loss, and inactivates ethylene forming enzyme. Therefore, the hypobaric equipment is the most beneficial for horticultural commodity storage. The paper will summarize hypobaric research results and the development of LP systems in the West, and evaluate important differences between hypobaric research in China and the West.
Keywords Food package and storage; Low-pressure storage; Heat-transfer; Water-loss; Insect-quar antine; Respiration; Ethylene |
| 多联式空调(热泵)系统的作用域 |
石文星 邵双全 彦启森
(清华大学 北京 100084) |
|
摘 要 提出多联式空调（热泵）系统的作用域概念，指出其作用域包括安全性作用域、经济性作用域和调节性作用域，是三种作用域的交集；阐明三种作用域的影响因素，并以复杂管网制冷系统仿真模型为工具，定量分析采用HCFC22为制冷剂的多联式空调（热泵）系统的作用域范围。
关键词 市政工程；多联式空调（热泵）系统；作用域；安全性；经济性；调节性 |
|
Effective Region of Multi-connected Air-conditioner (Heat pump) System
Shi Wenxing, Shao Shuangquan and Yan Qisen
☆ Tsinghua University, Beijing, 100084, China
AbstractThe“effective region” of multi-connected air-conditioner (heat pump) system was proposed, which includes the safety region, the efficiency region and the adjustability region. Based on the system simulation model, the factors that influence the three effective regions were investigated. Moreover, the quantitative regions are presented for the system charged with HCFC22.
KeywordsMunicipal engineering; Multi-connected air-condition (heat pump) system; Effective region; Safe region; Efficient region; Adjustable region |
| 带亲水层波纹翅片管换热器空气侧特性的参数影响分析 |
|
张圆明 丁国良 马小魁
（上海交通大学 上海 200030） |
|
摘 要 为了确定翅片间距、管排数和入口空气相对湿度等参数对析湿工况下带亲水层波纹翅片空气侧特性的影响，对7个带亲水层的波纹翅片管换热器进行了试验研究，并分别以Colburn换热因子和Fanning摩擦因子来反映空气侧换热和压降特性。结果表明，换热和摩擦因子都随着翅片间距的减小而增大。换热因子随着管排数的增加而减小，而摩擦因子受管排数的影响不显著。当入口相对湿度增大时，换热因子增大，而摩擦因子则几乎不变。入口水温越低，则入口空气相对湿度对换热因子的影响越显著。 关键词 热工学；空气侧特性；试验研究；波纹翅片；析湿工况；亲水层 |
|
Influence of Parameters on Airside Performance of Wavy Fin-and-tube Heat Exchangers with Hydrophilic Coating under Dehumidifying Conditions
Zhang Yuanming☆, Ding Guoliang and Ma Xiaokui
☆ Shanghai Jiao Tong University, Shanghai, 200030, China
AbstractThe effects of space of fins, number of tube rows and relative humidity of incoming air on airside performance of wavy fin with hydrophilic coating under dehumidifying conditions were experimentally explored for seven wavy fin-and-tube heat exchangers with hydrophilic coating. The Colburn factor and the Fanning friction were applied to describe airside heat transfer and friction characteristics, respectively. The test results indicate that the Colburn factor and the friction factor increase with the decrease of space of fins. The Colburn factor decreases when number of tube rows increases while the effect of number of tube rows on the friction factor is small. When inlet relative humidity increases, the Colburn factor increases and the friction factor almost remains unchanged. Inlet relative humidity has a more significant effect on the Colburn factor when the inlet water temperature is lower.
KeywordsPyrology; Airside performance; Experimental; Wavy fin; Dehumidifying conditions; Hydrophilic coating |
| 环境温湿度对制冷陈列柜性能影响的实验研究 |
|
谢 堃1 陈天及1 余克志1 杨 宁1 严志刚2 李雪艳2
（1.上海水产大学 上海 200090；2.北京富连京制冷机电有限公司 北京 100038） |
|
摘 要实验测试了内藏机组的立式敞开式冷藏陈列柜在不同室内温湿度工况下的运行性能，包括柜内各层的温度分布，蒸发器的结霜凝水特性和制冷系统的功率消耗等。研究表明，当环境温度从25℃升高到30℃、相对湿度从40%升高到90%时，柜内各层温度升高6～10℃，蒸发器析水量增加1.88倍，功率消耗增加21%。指出了立式敞开式冷藏陈列柜（设计柜温3～7℃）需根据环境气候合理设定运行周期和调整食品陈列区域，可显著降低能耗并提高陈列食品的品质。
关键词 热工学；陈列柜；内藏机组；性能；环境温湿度 |
|
Experimental Investigation on Effect of Ambient Temperature and Relative Humidity on Performance of Refrigerated Display Cabinet
Xie Kun☆, Chen Tianji, Yu Kezhi, Yang Ning, Yan Zhigang and Li Xueyan
☆Shanghai Fisheries University, Shanghai, 200090，China
Abstract The operation performance of a refrigerated vertical open display cabinet system with internal located refrigeration unit was tested, including the temperature distribution at each layer in the cabinet, the frosting and water condensing characteristics of the evaporator and the power consumption of the refrigeration system, at different indoor temperature and relative humidity. The result shows that when the ambient temperature rose from 25℃ to 30℃ and relative humidity increased from 40% to 90%, the temperature of each layer in the cabinet rose 6-10℃；the weight of condensing water in the evaporator increased by 188%；the power consumption increased by 21%. It seems that for small food store the power consumption can be reduced markedly and the displayed food quality can be improved by setting the operation cycle properly and regulating the food display area according to the ambient climate.
Keywords Pyrology; Display cabinet; Internal located refrigeration unit; Performance; Ambient temperature and relative humidity
|
| R-134a在水平直管和螺旋管内凝结换热特性的实验研究 |
邵 莉 韩吉田 潘继红
（山东大学 济南 250061） |
|
摘 要 对替代制冷剂R-134a在水平直管和螺旋管内的凝结换热特性进行了实验研究。在三个不同的冷凝温度（35 ℃、40 ℃和45 ℃）、制冷剂R-134a 的质量流量变化范围为100～400kg/(m2?s)和制冷剂的干度范围为0.1～0.8的条件下，实验得到了R-134a在水平直管和螺旋管内的凝结换热系数随R-134a的质量流量和干度的变化关系，并将水平直管和螺旋管内的凝结换热特性数据进行了对比。实验结果表明，R-134a在螺旋管内的凝结换热系数比直管的大4%～13.8%。
关键词 工程热物理；R-134a；螺旋管；凝结换热；两相流与换热 |
|
Condensation Heat Transfer of R-134a in Horizontal Straight and Helically Cooled Tubes
Shao Li☆, Han Jitian and Pan Jihong
☆ Shandong University, Jinan, 250061, China
Abstract The characteristics of condensation heat transfer for R-134a in horizontal straight tubes and helical tubes were experimentally investigated. The experimental were carried out at three saturation temperatures(35℃, 40℃ and 45℃) with the refrigerant mass flux from 100 to 400 kg/(m2?s) and the vapor quality from 0.1 to 0.8. The effects of vapor quality and mass flux of R-134a on the condensation heat transfer coefficient were obtained, and the heat transfer characteristics for straight and helical tubes were compared. The results indicate that the condensation heat transfer coefficients in the helical tubes were 4%-13.8% higher than those in the straight tubes.
Keywords Engineering Thermophysics; R-134a; Helical tube; Condensation heat transfer; Two-phase flow and heat transfer |
| 机械泵驱动两相冷却系统特性分析和实验研究 |
刘 杰1 裴念强2 郭开华1，2 何振辉2 李庭勋2 顾建明1
（1.上海交通大学 上海 200030；2.中山大学 广州 510725） |
|
摘 要 以热管和环路式热管为主要形式的两相流冷却技术凭借其良好的冷却能力和较低能耗的特点在空间冷却中已经有了多年的实验研究和太空飞行记录。随着热源发热量增加、热流密度的增大以及散热回路日趋复杂，用机械泵为驱动力的两相冷却系统逐渐引起各国热控科研人员的重视。通过对机械泵驱动的两相流冷却技术同毛细力驱动的环路式热管及机械泵驱动单相冷却技术的工作原理和主要的性能进行分析比较，可以看出该系统切实可行，并且在启动，散热能力和结构设计上有明显优势。以CO2为循环工质对该新型系统的散热特性进行试验研究，结果证明机械泵驱动的环路式热管系统具有低能耗、高控温精度和结构紧凑的特点。 关键词 动力机械工程；机械泵热管；两相流；空间；冷却 |
|
Theoretical and Experimental Investigation on Characters of Mechanical Pumped Two Phase Cooling System
Liu Jie☆, Pei nianqiang, Guo Kaihua, He Zhenhui，Li Tingxuen and Gu Jianming
☆ Shanghai Jiao Tong University，Shanghai,200030,China
Abstract A brief review of two-phase cooling applications was presented. The differences between MPLHP (Mechanical Pumped Loop Heat Pipe) and LHP/CPL( Loop Heat Pipe /Capillary Pumped Loop )or Mechanical Pumped Single-phase Cooling Loop were discussed according to working mechanism and heat transfer characters. The characters of MPLHP system using CO2 as a working fluid were investigated theoretically and experimentally. The results show that the loop heat pipe driven by a mechanical pump has obvious advantages, such as lower power consumption, higher control accuracy, and compactness.
KeywordsPower machinery and Engineering;Mechanical Pumped Loop Heat Pipe；Two-phase；Space；Cooling |
| 电子膨胀阀在低温装置上降温特性的试验研究 |
|
徐 波 陈儿同 周 冰 林美英（上海理工大学 上海 200093） |
|
摘 要 为了研究电子膨胀阀在低温条件下的应用特性，研制了低温试验台，并在试验台上并联安装了电子膨胀阀和热力膨胀阀，对两种膨胀阀在相近工况下进行降温特性的对比性试验。根据实验结果进行分析研究，可以看出电子膨胀阀在低温条件下的控温曲线是非常平稳的，并可调节电子膨胀阀的不同开度，达到不同的降温速率及终温。另外通过改变电子膨胀阀开度，研究了在变开度情况下，对制冷系统循环参数的影响。
关键词 热工学；电子膨胀阀；节流元件；降温特性；低温装置 |
|
Study on Temperature Characteristic of Electronic Expansion Valve on Low-tempera ture Devices
Xu Bo☆, Chen Ertong, Zhou Bing and Lin Meiying
☆ University of Shanghai for science and Technology, Shanghai,200093, China
Abstract A low-temperature test system was set up to investigate temperature characteristic of electronic expansion valves on low-temperature devices. In the system, a thermostatic expansion valve and an electronic expansion valve were installed in parallel. The experimental results show that the temperature control curves are smooth and steady with the electronic expansion valve at the low-temperature conditions. In addition, different temperature drop rates and final balanced temperatures can be achieved by changing the open degree of the electronic expansion valve.
Keywords Pyrology; Electronic expansion valve; Throttling device; Temperature characteristic; Low-temperature device |
| 空气循环热泵除湿技术的理论和实验分析 |
王智超
（中国建筑科学研究院空气调节研究所 北京 100013） |
|
摘 要 研究了空气热泵（逆布雷顿）循环应用于干燥的可行性，建立了相对简单的模型对比热泵干燥技术与传统的空气通风加热干燥技术的能量效率，应用综合性能指标和热力学关系对系统各个部件进行建模。通过实验和模拟分析的方法表明，与传统的通风加热干燥技术相比，空气循环热泵式干燥机的能量利用效率有显著提高。
关键词 热工学；空气循环热泵；干燥；能源利用效率 |
|
Theory and Experimental Analysis on Air Cycle Heat Pump Dry Technology
Wang Zhichao☆
☆ China Academy of Building Research Air-condition Institution，Beijing,100013,China
AbstractThe feasibility of air cycle heat pump dry technology was analyzed. A simple theoretical model was set up and the energy efficiency of ventilation heating dry technology was compared with that of air cycle heat pump dry technology. Mathematic models for all thermodynamic parts were set up using integrate performance coefficients and their thermodynamic relations. The experiment and simulation results show that the energy efficiency of air cycle heat pump dry technology is greatly higher than that of the ventilation heating dry technology.
Keywords Pyrology；Air cycle heat pump；Dry technology；Energy efficiency |
| 双毛细管卧式冷藏冷冻箱制冷循环的有效能分析 |
|
何茂刚1 宋新洲1,2 张 颖1 张建涛1
(1.西安交通大学 西安 710049；2.河南新飞电器有限公司 新乡 453002) |
|
摘 要 针对采用传统蒸气压缩制冷循环的冷藏冷冻箱的冷藏室换热温差大、有效能损失大的缺陷，提出了一种新的串联式双毛细管冷藏冷冻箱制冷循环。该循环系统是在常规的制冷循环的冷藏蒸发器和冷冻蒸发器之间增加一个毛细管，以提高冷藏蒸发温度，从而减少传热温差，进而降低冷藏室的有效能损失。利用PR方程计算制冷剂的热力学性质，编写了蒸气压缩制冷循环的有效能分析程序，分别对传统和新提出的冷藏冷冻箱制冷循环进行了计算。结果表明：传统冷藏冷冻箱制冷循环在制冷剂为R12、R134a时，有效能效率分别为21.20%、20.57%；双毛细管冷藏冷冻箱制冷循环在制冷剂为R12、R134a时，有效能效率分别为23.97%、23.44%；同比提高13.07%和13.95%。 关键词 热工学；双毛细管系统；有效能分析；卧式冷藏冷冻箱 |
|
Available Energy Analysis of New Double-capillary Tube Refrigeration System of Refrigerator-freezer
He Maogang☆, Song Xinzhou, Zhang Ying and Zhang Jiantao
☆ Xi`an Jiaotong University,Xi`an, 710049,China
Abstract A new double-capillary tube refrigeration system for refrigerator-freezers was proposed. A capillary tube was added between the two evaporators in the fresh and frozen food storage chests to raise the evaporation temperature of the fresh food, and reduce the heat exchange temperature difference and the available energy loss. PR equation was adopted to calculate the thermodynamic properties of the refrigerants, and the available energy analysis for the vapor compression refrigeration cycle was programmed to calculate thermodynamic performances of the new and the conventional refrigeration cycle of the refrigerator-freezer. The calculation results show that the available energy efficiency of the conventional refrigeration cycle of the refrigerator-freezer is 21.20% and 20.57%, respectively when the refrigerant is R12 and R134a while that of the double-capillary tube refrigeration cycle of the refrigerator-freezer is 23.97%and 23.44%, respectively. By comparison, the available energy efficiency of the new refrigeration system increases by 13.07% and 13.95%, respectively.
Keywords Pyrology; Double-capillary tube; Available energy analysis; Chest refrigerator
|
| 六流道喷嘴涡流管能量分离特性的研究 |
|
王远鹏1 聂荣华2 林明峰1
(1.西安交通大学 西安 710049；2.西北工业大学 西安 710072) |
|
摘 要 涡流管具有结构简单、无运动部件、价格低廉、可靠性高等优点，但管内发生的能量转换却极为复杂。以压缩空气为工作介质，对涡流管能量分离特性进行了实验研究，获得了涡流管制冷、制热效应随入口压力、冷端流率之间的关系，研究结果表明，进口压力越高，六流道喷嘴涡流管的制冷、制热效应越好,但获得最大制冷、制热效应时的冷端流率均有减小的趋势。 关键词 热工学；涡流管；能量分离；喷嘴；温度效应 |
|
Performance Study on Energy Separation in Vortex Tube with Six Channels
Wang Yuanpeng☆，Nie Ronghua and Lin Mingfeng
☆ Xi`an Jiaotong University, Xi`an ,710049, China
Abstract The performances of energy separation in a vortex tube were experimentally studied with compressed air to be the working medium and the influences of inlet pressure and cold mass flow fraction on cooling effect and heating effect of the vortex tube were obtained. The results show that the cooling effect and the heating effect of the vortex tube with the nozzle of six flow passage increase with the increase of the inlet pressure, and the cold mass flow fraction decreases at the biggest cooling effect and heating effect.
KeywordPyrology; Vortex tube; Energy separation; Nozzle; Temperature effect
|
| 蒸发器建模仿真与试验的比较 |
|
尹 斌1,2 丁国良2 欧阳惕1
（1. 广东申菱空调设备有限公司 顺德 528313；2. 上海交通大学 上海 200030）
摘 要 采用稳态分布参数模型对R134a单元机的蒸发器进行仿真。使用改进的Kattan模型对R134a在光滑管内的流动形式进行划分，从而得出流型图。根据流型图，应用不同表达形式的关联式计算管内局部沸腾换热系数。C C Wang的模型用于计算百叶窗形翅片管式蒸发器的表面换热系数及压降。析湿系数通过试验数据建立的数据库确定。在仿真过程中，应用隐式三次多项式拟合模型计算R134a的物性。将仿真结果与试验数据对比发现，仿真值能够较为真实的反映机组的运行状态。通过误差分析得出制冷量的平均相对误差为1.12％，出风干球温度的平均相对误差为1.25％，出风焓的最大相对误差为0.88％，R134a出口温度的平均相对误差为4.0％。 关键词 热工学；蒸发器；稳态分布参数模型；试验 |
|
Comparison Between Model-established Simulation and Experiment for Evaporators
Yin Bin☆, Ding Guoliang and Ouyang Ti
☆ Guangdong Shenling air-conditioning equipment Co.,Ltd, Guangdong, 528313, China
Abstract The simulation on an evaporator of an R134a air-conditioning unit was conducted with a steady state distribution parameter model. Using the update Kattan model, R134a flow patterns inside smooth tubes were divided, and then the flow pattern map was obtained. Based on the flow pattern map, local boiling heat transfer coefficients were calculated with different correlations. The surface heat transfer coefficient and the pressure drop of louver fin evaporators were calculated with C C Wang`s model. The moisture separation coefficient was determined from the database established with test data. During simulation, implicit cubic polynomial curve-fitting model was used to calculate R134a thermodynamic properties. The results show that the simulation values are in agreement with the experiment data. The average relative error of refrigeration capacity, dry bulb temperature of outlet air, and R134a outlet temperature is 1.12%, 1.25%, and 4.0%, respectively. Moreover, the maximum relative error of outlet-air enthalpy is 0.88%.
KeywordsPyrology; Evaporator; Steady state distribution parameter model; Experiment |
| 低温冷风机结霜特性的研究及其融霜方法的改进 |
|
刘恩海 南晓红 何 媛
（西安建筑科技大学 西安 710055）
|
|
摘 要 以华中地区某禽类加工厂冻结间的冷风机为研究对象，建立数学模型，对结霜工况下冷风机运行特性进行了理论分析。模型和实验测得的霜层厚度的平均偏差8.99%，吻合较好。阐述了随着霜层的生长，空气冷却器的传热面积、传热系数以及空气侧压降的变化规律。进一步分析了冻结间内空气相对湿度、冷风机进口空气干球温度以及迎面风速等对霜层生长的影响。并遵循尽量减少初投资、节能、实用为选择改进的原则，结合企业生产工序及冻结间运行的实际情况，对原融霜方式提出改进方案。 关键词 工程热物理；冷风机；结霜特性；霜层生长；融霜；节能 |
|
Investigation of the Frosting Performance and Improvement of the Defrosting Method for an Air-cooler under Low Temperature Condition
Liu Enhai☆, Nan Xiaohong and He Yuan
☆ Xi′an Univ. of Arch. ＆ Techn., Xi′an, 710055, China
Abstract A theoretical analysis was carried out and a mathematical model was proposed for air-cooler frosting performance. The comparison of the calculated thickness of the frost layer shows good agreement with the experimental data. The average difference is 8.99%. Further studies were carried out on the factors affecting heat transfer surface, the coefficient of heat transfer and the air side pressure drop during a frosting process. The characteristics of frost growth were analyzed under different inlet air temperature, relative humidity and velocity. The calculated results show that the inlet air temperature and the relative humidity of the inlet air have obvious influence on the frosting. Disadvantages of the present defrosting methods were analyzed. In order to reduce the first cost and energy consumption of the refrigeration system for a cold-storage enterprise, an improved method of defrosting for an ammonia air-cooler was proposed. It was proved that the improved method is practical for improving the energy saving, lowering manufacture cost and enhancing economical benefits.
Keywords Engineering thermophysics;Air-cooler；Frosting performance；Frosting rate；Defrosting；Energy saving |
| 苹果真空冷冻干燥工艺参数对耗电量影响的研究 |
郭树国1,2 刘 强1 付广艳1 刘 群1 郭北涛1
(1.沈阳化工学院 沈阳 110142；2.沈阳农业大学 沈阳 110161) |
|
摘 要 研究了苹果真空冷冻干燥工艺参数（干燥室压力、物料厚度、加热温度）对耗电量的影响规律。试验结果表明，影响试验指标的主要因素是物料厚度，试验因素主次排列为物料厚度、干燥室压力、加热温度。其较优组合为干燥室压力为140Pa、物料厚度为12mm、加热温度为30℃。 关键词 食品包装与贮藏；真空冷冻干燥；工艺参数；耗电量 |
Effects of Technological Parameters on Power Consumption in Apple Vacuum Freeze
Drying Guo Shuguo☆, Liu Qiang, Fu Guangyan, Liu Qun and Guo Beitao
☆ Shenyang Institute of Chemical Technology，Shenyang,110142,China
Abstract The influence of technological parameters of apple vacuum freeze drying (pressure in drying room, material thickness, heating temperature) upon the power consumption of product were explored. The experiment results show that the most important factor affecting power consumption is the material thickness and then the pressure in the drying room and the heating temperature. It is likely that the optimized combination of the factors is teh pressure in the drying room of 140Pa, the material thilkness of 12mm and the heating temperature of 30℃.
Keywords Food package and storage;Vacuum freeze drying; Technological parameter; Power Consumption |
{newsCommentContent} [{commentNickName},{commentTime}]
