20W@80K空间大冷量脉冲管制冷机试验研究

空间应用对于80K温区的冷量需求日益增加，然而国内空间大冷量脉冲管制冷机的研究起步较晚，目前制冷机的冷量不能满足红外探测的发展需求。为了进一步提高脉冲管制冷机的制冷量，研制了一台由线性压缩机驱动的小型脉冲管制冷机。通过试验研究了调相机构、充气压力、输入功率等因素对脉冲管制冷机制冷性能的影响规律，并测试了降温速率，探究了调相机构对压缩机输出功率的影响等。研制出的制冷机在输入电功率为350 W，热端温度为300 K时，在80 K获得了20.5 W的制冷量，整机的相对卡诺效率达到了16.1%。     

13W@80K空间大冷量脉冲管制冷机的模拟设计与试验验证

目前,空间红外探测领域对80K温区的冷量需求越来越大,然而为其提供冷源的大冷量的空间脉冲管制冷机相对缺乏。为了提高空间脉冲管制冷机的制冷量,基于Sage平台,建立大冷量的同轴型脉冲管制冷机的整机模型,通过模拟计算,对制冷机的蓄冷器尺寸、脉冲管尺寸、惯性管调相与导流结构等进行设计。依据设计结果,加工了同轴型脉冲管制冷机的冷指,并通过试验研究了调相机构、充气压力、热端导流结构、蓄冷器丝网目数、输入电功率等因素对脉冲管制冷机的影响规律。将试验与模拟结果进行对比,两者具有较好的一致性,从而验证了该大冷量脉冲管制冷机整机模型的准确性。研制出的制冷机在输入电功功率为300W,热端温度为300K时,在80K获得了13W的制冷量,相对卡诺效率可以达到11.9%。且该工程样机已应用到空间项目中。     

一种新型机床冷却系统的研究

介绍了一种基于脉冲管制冷技术的机床冷却系统。该系统以脉冲管制冷机为冷源 ,将制冷的脉冲管置于切削刀具内 ,通过脉冲管的冷端将切削区的热量带走 ,达到降低刀具的切削温度、提高刀具耐用度的目的     

超高频同轴型脉冲管制冷机研究

超高频脉冲管制冷机体积小、重量轻,在空间应用中备受关注,近几年来成为该领域的一个前沿发展方向.由于直线型脉冲管制冷机结构简单、方便调试,在模拟计算的基础上加工直线型试验样机,根据直线型试验样机的优化结果设计加工同等尺度的同轴型原理样机,其冷指外径仅有9 mm,长度40mm,质量为250 g.同轴型样机经过压缩机的匹配和双向进气结构的优化,采用谐振频率为50 Hz高频压缩机工作在90 Hz驱动,80 w电功率输入下可获得46.4 K无负荷最低温度,在80 K可获得2.1 w制冷量.由于冷指尺寸小、运行频率高,冷头降温速度快,2 min即可从室温降至工作温区80 K,且冷头温度不受重力影响.     

多级斯特林型脉管制冷机中过渡蓄冷器试验优化

多级脉冲管制冷机中的过渡蓄冷器因结构简单,其对整机性能的影响通常被忽略。目前,国内有报道的大多数使用过渡蓄冷器结构的多级脉冲管制冷机均没有对过渡蓄冷器进行系统的研究和优化,但过渡蓄冷器作为多级脉冲管制冷机整机PV功消耗的重要部件之一,其效率的高低直接影响整机性能优劣。分别从过渡蓄冷器回热填料(丝网)填充方式、过渡蓄冷器直径以及长度三个方面对其进行优化研究。结果表明：优化过渡蓄冷器相关参数后,制冷机在20K的制冷量相较优化前提高了19.01%。     

溴化锂制冷机的串联运行

目前，国内厂家生产的双效溴化锂制冷机冷媒水进出制冷机的温差一般在４～５℃，对于制冷量较大的制冷系统，冷媒水的循环量相当大。不仅要消耗大量的电能，而且要有足够粗的大口径外管，否则将会由于冷媒水的流量不够造成制冷机进出压差达不到要求，而使制冷机组自动保护报警而无法运行。 为了解决这一问题，我们提出将两台溴化锂制冷机冷媒水串联运行的设想，原理如图１所示。将第一台溴化锂制冷机冷媒水出水由管道泵适当加压后经旁通管进入第二台溴冷机冷媒水的进口。第二台机组在第一台已经降温４—５℃的基础上再降４－５℃，最终达７…     

热声热机技术的研究进展

首先简要地介绍热声热机(包括热声发动机和热声制冷机)的基本工作原理和热声技术特点,指出热声热机是基于热致声效应和声制冷效应两类热声效应而工作的,它完全没有机械运动,采用惰性气体工作,是一种可靠性高和环保的新型的能源转换机械.然后重点介绍近十几年来国内外在热声技术研究方面所取得的重要进展,主要包括在热声发动机和热声制冷机两个方面.在热声发动机研究方面,简要回顾热声效应的发现和驻波热声发动机的研究进展,接着介绍行波热声发动机的提出和迅速发展历程,重点介绍热声转换效率达到30%的热声斯特林发动机和压比达到1.3(采用氦气)、效率达到32%的聚能型热声发动机研究工作;在热声制冷技术方面,分别介绍热声驱动脉冲管制冷获取低温的研究工作以及热声驱动室温制冷机获得高效率、大冷量等方面的研究工作,并重点介绍采用声压放大器获得液氢温度以下的完全无运动部件热声驱动脉冲管制冷机(低于20 K),以及在-20℃获得了300 W以上的制冷量的双行波流程的热声驱动室温热声制冷机.最后,扼要地介绍热声理论方面的研究进展,并对热声技术的问题和该研究领域的发展方向进行展望.     

航天用双驱动对置式斯特林制冷机驱动控制系统研究

介绍了作者研制的航天用双驱动、对置式斯特林制冷机的驱动控制系统。由于该制冷机由两台压缩机和两台膨胀机两两对置而成，为达到最佳制冷性能和最大减振目的，必须同时对两台压缩机活塞和两台膨胀机活塞的运动行程、位置、相位、频率以及对置相位进行 坟驱动控制。本系统采用闭环反馈控制，利用单片微处理器作为主控制器，通过Ａ／Ｄ，Ｄ／Ａ实现对制冷机的稳定、可靠控制。该系统能适应航天工作环境是其特点之一。还给出了系统的     

蒸汽两效溴化锂吸收式制冷机之一——基础知识

蒸汽两效溴化锂吸收式制冷机,由于能直接和有效地两次利用热能,具有高的热力效率,被誉之为省能机型。这种机型在国外发展很快,应用很广;在国内,一机部通用机械研究所和六机部七○四所已成功地研制了典型样机,并已在轻纺行业中得到应用。目前,轻纺、石油化工、冶金、旅游业和影剧院等许多部门都呼吁尽快大力发展这种机型,提供先进的省能的空调制冷设备。由于有关蒸汽两效溴化锂吸收式制冷机尚无专著,资料较少,本刊应读者要求,从本期开始以蒸汽两效溴化锂吸收式制冷机为题,系统地介绍基础知识、工作原理、设计计算、典型结构、性能及调节、自动控制以及操作保养等有关问题,以供参考。     

用于冷却HTc SQUIDs的脉冲管制冷机系统的设计分析

设计出一套以冷却HTc SQUIDs(高温超导量子干涉仪)为目的的基于Stirling型同轴脉冲管制冷机的低噪声低温系统并进行了系统化的试验。为消除制冷机产生的复杂干扰并实现与器件的直接耦合,所有处于SQUIDs拾波线圈附近的制冷机部件都由无磁、非金属和电绝缘的材料制作。详细描述了制冷机部件材料的选择以及制冷系统的设计与优化,并对系统的综合性能进行了分析与评价。初步试验显示系统的制冷性能和干扰特性满足冷却HTc SQUIDs的基本要求。     

车用发动机润滑油冷却器传热和阻力特性的研究

选取国内生产车用发动机润滑油冷却器的4个主要厂家生产的同一型号的8个冷却器进行了传热和阻力特性的实验研究，实验结果表明，由于采用不同生产工艺，冷却器的传热性能和阻力特性有较大的差异。根据冷却器传热性能和阻力特性的实验数据拟合了换热量、阻力随润滑油流量的变化关系，可为车用润滑油冷却器的结构设计及选型提供依据。     

Performance investigation of capillary tubes for machine tool coolers retrofitted with HFC-407C refrigerant

The machine tool coolers are the best managers of coolant temperature in avoiding the deviation of spindle centerline for machine tools. However, the machine coolers are facing the compressed schedule to phase out the HCFC (hydro-chloro-floro-carbon) refrigerant and little attention has been paid to comparative study on sizing capillary tube for retrofitted HFC (hydro-floro-carbon) refrigerant. In this paper, the adiabatic flow in capillary tube is analyzed and modeled for retrofitting of HFC-407C refrigerant in a machine tool cooler system. A computer code including determining the length of sub-cooled flow region and the two phase region of capillary tube is developed. Comparative study of HCFC-22 and HFC-407C in a capillary tube is derived and conducted to simplify the traditional trial-and-error method of predicting the length of capillary tubes. Besides, experimental investigation is carried out by field tests to verify the simulation model and cooling performance of the machine tool cooler system. The results from the experiments reveal that the numerical model provides an effective approach to determine the performance data of capillary tube specific for retrofitting a HFC-407C machine tool cooler. The developed machine tool cooler system is not only directly compatible with new HFC-407C refrigerant, but can also perform a cost-effective temperature control specific for industrial machines.     

A study of the fouling characteristics of EGR coolers in diesel engines

Diesel emission regulations have recently become more severe. An important goal in diesel engine research is the development of methods to reduce the emissions of NOx and PM (particulate matter). Cooled EGR (exhaust gas recirculation) system has been widely used to reduce the NOx and PM emissions of light-duty diesel engines. In this study, numerical analyses, rig tests and engine tests were performed to assess how changes in internal shape characteristics can improve the heat exchange efficiencies of EGR coolers. The heat exchange efficiencies of EGR coolers have been numerically and experimentally measured during a fouling process. The results show that the second type of oval EGR cooler tested (oval #2) exhibited better heat exchange efficiency than either the first type of oval EGR cooler was tested (oval #1) or the shell and tube cooler examined. The turbulence generated in exhaust gas flows by the wavy-finned design of the oval EGR coolers facilitated PM desorption that allows these coolers to self-purify. With respect to the two similar oval EGR coolers, the cooler with fin pitch 4 mm has better efficiency than the cooler with fin pitch 6 mm due to differences in the heat transfer areas of these coolers. Both CFD analyses involving extreme conditions of engine operation and engine fouling tests involving conditions experienced during vehicular operation indicate that the two oval coolers differed by less than 4% with respect to both initial heat transfer efficiency and heat transfer efficiency after a 78-hour fouling test.     

转轮式两级蒸发冷却空调机组的试验研究

提出了一种低空调能耗,新、排风能量回收的转轮式两级蒸发冷却空调系统,第一级采用转轮式间接蒸发冷却器,第二级采用填料式直接蒸发冷却器,排风侧采用的散热方式:排风经过填料式直接蒸发冷却器降温后进入转轮回风侧,并制作出试验样机。对试验样机各功能段的性能进行了测试。结果表明,在试验测试范围内,转轮间接蒸发冷却段的最佳排风、新风风量比β为1.1,整机联合运行时,机组最终出风温度19.9℃,低于入口新风的湿球温度21.9℃,机组温降可达到12.5℃。     

EGR冷却器对柴油机NOX排放的影响

本工作针对某公司PEMS排放试验中NOX排放超标问题,对其发动机在2020年和2017年两种不同EGR冷却器的情况下的发动机排放进行比较,分析得到2020年发动机所存在的问题为EGR冷却器冷却效率不足导致NOX的排放量超标。本工作基于现有EGR冷却器进行了结构改进,冷凝隔板由原来的8层改成为9层。通过对改进后的样件与原有的EGR冷却器排放实验结果对比中发现使用了改进后的EGR冷却器的发动机NOX排放量基本稳定在1.7~2.4 g/kW·h,符合国家标准(≤4 g/kW·h),对现阶段PEMS排放超标的问题提供了可行性方案。     

Design of an energy saving oil cooler system using hot gas

According to the development of machine tools to higher speed and multi axes, thermal error which is known to account for about 70% of the total error of machine tools is becoming a serious issue. To reduce thermal error, the heat generating parts of machine tools are cooled down by direct contact with a cooling medium. The medium in most cases is oil, thus, the cooling device is called oil cooler. In this study, an oil cooler system employing hot gas bypass method was developed to improve the performance including energy efficiency of the oil coolers used for ultra-precision machine tools. Through tests, the developed system exhibited high temperature control accuracy of ±0.1°C, and less energy consumption than conventional on/off type (equipped with heater for preventing excessive cooling) by about 45%. The proposed oil cooler system is applicable to semiconductor process, ultra-precision injection molds, as well as ultra-precision machine tools to improve product quality and energy efficiency of production facilities.     

船用增压空冷器维护保养方法探讨

增压空冷器是船用柴油机增压系统的重要组成部分,其性能状态不良将导致柴油机和增压器联合运行工况曲线偏移和恶化,为此探讨增压空冷器维护保养方法,确保增压空冷器处于良好状态,使得保证柴油机和增压器联合运行工况正常。     

Improvement of temperature accuracy in oil cooler systems with gas bypass

In keeping with the development of machine tools with higher speed, more axes, and a greater degree of sophistication, thermal deformation is becoming an important factor in the precision of machine tools. It has been found that thermal error accounts for about 70% of the total error in machine tools. As such, oil coolers which absorb heat from heat generating parts with cold oil are being used to reduce the error caused by thermal deformation. The gas bypass type oil coolers used in ultra-precision (temperature accuracy within ±0.1°C) machine tools are simple in structure and precise in terms of their temperature control performance; however, they have a limitation as regards temperature control due to the instability of their performance under light load conditions. In this study, an oil cooler system equipped with dual electronic valves was developed to solve the problems of the single electronic valve system and achieve more precise temperature control. To verify the performance of the developed system, its performance under the operating conditions of rated load, DIN 8602 standard, and ISO/DIS 230-3 operational mode was compared and analyzed. The proposed oil cooler system is applicable to semiconductor equipment, ultra-precision injection molds, and ultra-precision machine tools, and improves the quality of the products.     

无翅片椭圆不锈钢波纹管管束空气冷却器的研究

空气冷却器采用无翅片椭圆不锈钢波纹管管束替代传统的翅片管管束，是空气冷却器设计制造的技术革新。实验数据证明，此项发明专利技术基本成熟，可使空气冷却器的耐久性、可靠性、耐腐蚀性、耐污染性等各项性能指标有大幅度提高，具有非常广阔的应用前景。     

柴油机废气再循环系统冷却器的数值模拟

柴油机废气再循环(EGR)技术能有效降低NOx有害排放,而EGR冷却器的结构优化是提高冷却器效率,减少NOx排放的有效手段.应用FLUENT软件对柴油机废气再循环系统冷却器的数值模拟,为柴油机废气再循环系统冷却器的设计和优化提供理论依据.