8 kW车载动力电池直冷系统实验研究

电池冷却机组性能的优异对于动力电池在整车上安全、高效、可靠运行至关重要。基于制冷剂直接冷却的方式,本文设计并研制了一套8 kW动力电池冷却机组,并在某纯电动重卡上进行了实验验证及装车验证。结果表明:当电池底部的冷板表面温度在5～10℃时,电池芯体的最高温度能够降到35℃以下;采用双压缩机联合制冷方式,机组制冷性能达7.8 kW;采用分液头加毛细管的分液方式能够保证15块电池冷板进出口温差维持在5℃以内;通过循环充放电实验,在0.8C倍率充电、1C倍率放电的条件下,电芯温度皆可在40℃以下;在外界高温环境下,该机组能够在20 min内将电池芯体的平均温度降至28℃左右;此外,分析了制冷剂充注量、H型热力膨胀阀开度等因素对机组性能的影响,制定了机组的控制策略并加以评估。     

整体独立式冷藏车制冷机组的开发

阐述冷藏车制冷机组设计过程和性能测试结果。性能试验和数据分析表明,在箱内设定温度分别为-20℃(夏季)和-29℃(秋季)的情况下,箱体降温需要2 h左右。制冷机组停机时箱中后部最低温度仍然可以达到设定温度,即该冷藏车制冷机组可以满足物品的冷藏运输需求。     

小型烟气-热水型溴化锂吸收式制冷机组试验研究

探究适合于匹配小型分布式能源的烟气-热水型溴化锂吸收式制冷机组可降低设备初投资及拓展应用场景,选取某国产130kW烟气-热水型吸收式溴化锂制冷机组为研究对象,通过搭建与之匹配的试验台,测试了该机组冷冻水出口温度和冷却水进口温度对制冷量的影响,并测试了余热烟气进出口温度和热水温度、冷冻水进出口温度、吸收机制冷量、高低发温度随时间的变化规律。研究结果表明,冷冻水出口温度每升高1℃,制冷量提升3-4%,冷却水进口温度每增加2℃,制冷量降低2-6%。烟气进吸收机温度在280-440℃之间变化,出口烟气温度维持在65℃。冷剂泵开启后（约吸收机启动20min）,高压和低发溶液出口温度随时间逐步升高,分别稳定在108℃和57℃,冷冻水进出口温度维持在15/10℃左右。吸收机制冷量维持在100-115k W。误差分析得到制冷量和冷冻水出口温度误差分别为8.6%和0.5%,显示了较高的准确度。     

相变蓄冷保鲜库设计及温度场分析

目的 针对传统机械式制冷保鲜库能耗高、内部温度波动大等问题,研发一种小型可移动式、节能型相变蓄冷保鲜库.方法 通过安装制冷机组和100根蓄冷管道,在用电低谷时利用制冷机组为蓄冷管道和保鲜库提供冷源,在用电高峰时利用蓄冷管道内相变材料固-液相变时的吸热特性为冷库释冷,从而实现24 h循环保冷.结果 研究结果表明,在外环境平均温度30.9℃下,设定温度为2℃时,制冷机组工作时库内温度最大值为2.57℃,最小值为1.55℃,温度波动平稳;蓄冷管道释放冷量时库内温度最大值为3.45℃,最小值为1.98℃,夜间温度缓慢上升,维持时间大于14 h,且温度均匀性较好.结论 该保鲜库相较于传统机械式保鲜库能耗更低、温度更均匀,投资回报期为368 d.     

大唐克旗空分装置1#机组增压机检修总结

正一、事故经过2013年5月5日晚21:49分,空分1#机组跳车,此前汽轮机于21:33分开始启动升速,21:48分汽轮机达到额定转速。此时增压机3级非驱动端轴瓦(支承轴承:报警值110℃、跳车值118℃)温度TI232-1从36℃升高到91℃,而且还在持续上升,到21:49分,该温度值升高到118℃,达到的高高报跳车值(118℃),导致机组     

复合式露点间接蒸发冷却空调机组在敦煌机场某食堂的应用

介绍复合式露点间接蒸发冷却空调机组在敦煌机场某食堂的应用情况,并进行测试分析。结果表明,在室外平均干/湿球温度为30℃/17.7℃,机组进风干/湿球温度为25℃/14℃时,风量为10 000 m~3/h的机组出风干球温度为13℃,温降近15℃,机组平均湿球效率为110%;风量为20 000 m~3/h的机组出风干球温度为17℃,温降仅8℃,机组平均湿球效率为70%。建议适当提高机组的二/一次风量比,以提高机组的效率。     

一种变频空调电控箱体降温模块的研究

本文根据变频热泵机组系统特点和制冷循环热传导原理设计了一种变频空调电控箱体的降温模块,该降温模块的U型散热装置与制冷剂配管接触弧度为3/4圆弧结构,接触点切线成45°斜角,放置在空调系统中出储液器到进入电子膨胀阀之间的管路部分,使制冷剂经过该散热装置的温度处于40℃～50℃之间最佳温度范围。在环境温度43℃、出水温度15℃的制冷工况下,通过实验分析和验证了增加该散热装置和自然冷却两种状态下系统的性能。结果表明:加装制冷剂散热装置机组运行时变频器功率器件产生的热量可以通过制冷剂散热装置带走,降温效果较为明显。同时,通过理论计算和实验测试对比了变频器功率发热部件温度与制冷剂进口温度之间温度差变化情况,验证了加装制冷剂散热装置的效果。     

轨道交通设备用房的空调机组选择分析

目前在轨道交通设备用房的空调机组选型中往往采用舒适性空调机组,通过分析认为不应采用,应采用机房空调机组。比较了送风温度与露点温度,并研究了蒸发温度下降对机组的影响、冷水机组供水温度的选择。研究与结果表明显热比高的机房空调应采用机房空调机组,冷水机组供水温度应为10℃。     

低环温空气源热泵外流场模拟及换热性能影响分析

空气源热泵作为一种高效、节能装置,具有广泛的应用前景和市场价值。建立了低环境温度空气源热泵物理模型,对1×1机组、3×4阵列以及4×6阵列低环温空气源热泵外流场进行三维数值模拟,分析水平风速、机组布置、墙面阻碍等因素对机组平均入口空气温度和机组换热性能的影响。结果表明,水平风速越大,机组布置数目越多,有墙面阻碍下的低环温空气源热泵机组平均入口空气温度越低。当水平风速增大到5m/s,无墙面阻碍下1×1机组、3×4阵列以及4×6阵列平均入口空气温度与环境温差分别为0.92℃、1.16℃和1.57℃;有墙面阻碍下温差分别为0.92℃、1.4℃和1.98℃。对于单一机组热泵,水平风速越大,机组换热量越大。对于阵列机组,水平风速越大,机组平均换热量出现先增大后下降的趋势。特别的当水平风速大于2.5m/s后,背风侧阵列机组入口空气温度降低,阵列机组平均换热量开始下降,有墙面阻碍下24台机组平均换热量为原来机组换热量的91.9%。阵列机组布置时,应增大机组距墙间距,减小墙面对风机出口冷空气扩散的阻碍。进行具体定量分析对实际工程和系统研究具有重要意义。     

吸收式制冷机的新型节能循环设计研究

针对双效溴化锂吸收式制冷机串联系统高压发生器排烟温度偏高，存在一定的余热资源浪费这一实际问题，采用并联增加一个低压发生器的方法，对原有系统进行改进，形成的一个新型循环系统。对该新型系统的工作原理及循环流程进行了介绍；就第二低压发生器排烟温度分别为160℃，140℃，120℃和不增设第二低压发生器这四种情况对机组进行设计研究，得出相应排烟温度下机组的制冷量、热力系数和各换热设备的换热面积及外形尺寸，并绘制出排烟温度与制冷量、热力系数及机组总换热面积之间的关系曲线，研究结果对于溴化锂吸收式制冷机的设计有一定的参考价值。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...