挂壁式变频空调器热舒适性的数值模拟及实验研究

结合挂壁式房间空调器的使用特点,运用CFD方法模拟室内空调热环境,对空调送风温度的影响进行了分析.利用房间环境热舒适实验结果,对模拟结果进行对比和分析,验证数值计算模型的准确性.     

挂壁式空调器导风板的优化设计

挂壁式空调器的送风系统中导风板的设计较大地影响着空调的热舒适性,尤其在寒冷的冬季更加明显,本文采用CFD仿真模拟分析与试验验证相结合的方法对挂壁式空调器导风板单层与双层方案进行对比分析和优化设计,研究结果表明:在相同工况下双层比单层方案送风噪声平均低0.5 dB(A),房间中下部平均温度提高7.7℃,较好地提升了热舒适性。     

基于负压强制通风散热的变频空调器电控系统热设计

电子元器件良好的散热性能是空调器可靠性的重要保证之一,且对空调器的高温制冷舒适性影响极大。本文对变频空调器室外机模块散热过程以及强制风冷散热方案进行分析,提出一种基于负压强制通风散热的电控系统散热方案,该方案通过全新的散热风道设计、散热器设计以及电器盒特殊结构设计,大幅度提高元器件的散热性能。试验结果表明,该散热方案能够有效降低变频模块的温度,提高高温制冷量,室外环境温度50℃时制冷量提升6%;室外环境温度60℃时保持稳定可靠的持续制冷,高温制冷舒适性效果明显。     

过渡季节两种采暖方式室内温度场的实验研究

使用IMP数据采集系统,对过渡季节西安地区集中采暖房间和变频空调采暖房间温度进行测试.结果显示,与集中采暖相比,变频空调采暖房间工作区域的温度场的温度梯度为2.35℃和同一水平面上温度不均匀性较大,其最大差值有1.2℃.因此,对过渡季节西安地区房间的热舒适性而言,集中采暖比变频空调采暖优越.     

半导体制冷床垫睡眠热平衡系统模拟与性能分析

通过营造局部非均匀空调环境,可以实现人体睡眠热舒适与节能的双重目的。本文提出并搭建了基于半导体制冷床垫的睡眠热平衡系统,通过半导体制冷与人体热负荷耦合传热模型,对半导体制冷床垫系统的热特性进行了参数化分析、优化设计与节能性评价。结果表明：通过增加制冷床垫的半导体数量,减小电流输入,可以扩大室内允许的舒适空气温度范围,同时降低结露风险。半导体制冷床垫系统的节能率与室内温度、半导体工作电流以及房间面积直接相关。通过对比参考工况（空调设定26 ℃）、工况1（空调设定27 ℃）与工况2（空调设定28 ℃）,可知工况1与工况2可实现最高10.26%与23.37%的节能率。     

多元VRV空调系统性能研究

提高舒适性与降低能耗是空调系统的发展方向.在现代建筑中,在同一时刻,有的房间需要制冷,有的房间需要制热,甚至有的房间既不需要制冷也不需要制热,传统的空调系统只能所有房间同时供热或同时制冷,本文提出了一种新型的多元热回收VRV空调系统.此系统由一个室外机和多个室内机构成.系统通过变频压缩机和电子膨胀阀自动调节各室内机的制冷剂流量以满足各个房间的负荷的需要,通过电子膨胀阀与电磁三通阀的切换实现多个房间同时制冷和制热的要求.制热房间的室内机作为冷凝器,制冷房间的室内机作为蒸发器,而室外机可能是冷凝器也可能是蒸发器.这样,由于冷凝热与蒸发热同时被利用,系统能效比大大提高,与得到相同冷热量的分散机组相比,室外机的容量和能耗都大大降低.与传统的空调系统相比,此系统用较低的能耗提供有较高的舒适性,适用于住宅或商业建筑使用,有制冷、热泵和热回收等五种运行模式,可在全年内运行.     

家用变频空调与公用电网谐波污染

变频空调因为省电,舒适性好等优点,市场占有率不断提高,但是目前市场上变频空调产品层次参差不齐.本文通过总结当前家用变频空调技术现状,分析当前市场上仍采用交流变频技术的家用空调器运行过程中对电网的谐波污染的机理和其产生的危害,在技术上总结了一些谐波污染的防治措施,并指出了出台相应技术法规规范变频空调器市场的急迫性.     

夏季办公室空调房间气流组织的数值模拟

为了描述和分析在夏季使用分体落地式空调器来制冷的办公室室内的气流组织,根据实际情况建立其物理和数学模型,应用CFD方法对办公室空调房间上送下回的送风方式下的气流组织进行三维数值模拟。通过Fluent软件来进行数值解算,给出室内速度场和温度场的分布状况。通过对不同空间位置的速度矢量图和温度等值线图的分析,得到了该室内气流组织的合理性和人员所处不同区域的热舒适性,并以此来指导办公室内空调通风的设计和改进。     

教你如何辨别真假变频空调

正山东王先生:天气越来越热,想换个空调,听说变频的好用又省电,但听说这种空调有冒牌货,选购的时候应该怎样区分呢?小编解答:变频空调也有真假?是的,这是说的真假变频空调并不是指商家的假冒伪劣产品,而是在变频空调的一些技术控制上往往容易转空子,让你买了变频空调,却不一定能享受到变频空调的真正使用效果。下面正品鉴别网就来教你如何区分真假变频空调。变频空调舒适性极佳,是定频空调所不具备的。相对十定频空调而言,变频空调的舒适性主要体现在精确温度、合理湿度、     

房间空调器恒温暖房技术实验研究

针对普通热泵空调在制热除霜过程房间温度波动约6℃~10℃,用户使用过程感到忽冷忽热的问题,设计了一款在低温环境下制热除霜过程中持续制热、恒温暖房的空调器;通过实验验证,实现制热除霜过程房间温度波动约0.6℃~1.6℃,解决了用户使用过程中忽冷忽热的感受,提高了热泵空调系统在低温环境下使用的舒适性。     

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.……     

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.     

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.     

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 ...