多功能军用飞机地面液冷车研制与实验

为满足新型战机在地面待飞时对机载液冷系统的地面保障需求,本文设计开发并试制了飞机地面液冷车,分别对电源动力系统、冷却液输送系统、制冷加热系统（单级蒸汽压缩制冷循环+电加热器）、电气控制系统和车载底盘及厢体5部分进行了实验研究。结果表明：样车实现了液冷车补液、液冷车内循环、液冷车对机载液冷系统的加液/排液和外循环供液保障等功能。在环境温度为5 ℃的外循环制热和30 ℃的外循环制冷时,使机载液冷系统达到设定温度（制热时加热至15 ℃,制冷时冷却至10 ℃）,分别需要24min和20 min,冷却液循环流量为200 L/min,温度波动在±0.5℃以内。     

单相浸没式液冷箱体关键参数的仿真研究

随着数据中心冷却技术的发展，单相浸没式液冷技术表现出巨大的应用前景。在该冷却方式下，需将服务器浸没于液冷箱体内，通过冷却液的强制流动带走服务器热量。本文建立了1U服务器与液冷箱体模型，从服务器(局部)与液冷箱体(整体)两个角度出发，对影响其性能的关键参数进行了仿真研究。结果表明：选取高性能散热器，合理设计服务器内部结构，可以有效提升机柜的冷却性能；流量的增加可以改善液冷系统的冷却性能，但也会造成压力损失的增加；挡板可以强制冷却液流入服务器，显著降低CPU温度，增设挡板前后CPU温度相差19.8℃,这是影响该冷却技术性能最为关键的参数。     

CPU液体冷却器件及冷却液材料研究进展

综述了目前关于计算机CPU散热的3种液体冷却系统(大器件液冷循环系统、热管冷却系统和液体喷射冷却系统)及所采用的多种冷却液(水、液态金属和纳米流体)的研究进展;比较了3种液冷器件和3种冷却液的优缺点,指出热管冷却系统和纳米流体更加具有竞争优势;最后展望了CPU冷却器件和冷却液的发展前景。     

扩量程差压式蒸汽流量测量系统

本文提出了一种用于流量测量范围变化较大的差压式蒸汽流量测量系统,它采用了两套以标准孔板为节流装置,并设计了流量测量控制仪,根据不同流量值对流量测量管段进行控制测量,改善了差压式流量计量范围窄的缺点,对解决蒸汽用量变化大的蒸汽流量测量问题提供了技术措施。     

液冷散热器性能测试系统的研制

热阻和流阻是评价液冷散热器性能的主要参数。该文研制一套高精度的液冷散热器性能测试系统,由液冷散热器的进口流体温度控制单元、进口流量控制单元、模拟热源控制单元及测量单元组成。在台面温度测量方面,由于现有标准(GB/T 8446.2—2004)规定的温度测点位置不适应液冷散热器热阻测量,提出改进方法。开发相应的测试软件,具有系统控制、数据实时采集、测试报告输出等功能。并对某型号液冷散热器进行实验研究,通过实验数据对系统的测量不确定度进行分析,流阻测试的不确定度为0.48%,热阻测试的不确定度为2.4%。验证系统用于散热器流阻热阻测试的可靠性。     

流变仪液冷装置的设计研究

针对高温高压流变仪特点,设计了一种液冷装置,以解决流变仪外围机械部分的过热问题。该冷却装置采用了蒸汽压缩式制冷,以R410A为冷却工质,实现将流变仪的多余热量带离至室外,并运用温度传感器和变频器对各关键处温度、冷却液和制冷剂流量进行调节和控制。该系统有节能、可靠性高、结构紧凑、维护方便和换热效率高等优点。     

数字放映机使用维护小知识——放映机液冷系统小知识

正目前,很多数字放映机在影院已运行了很多年,它们都健康吗?例如,它们的液冷系统工作得怎样、应该怎样做维护是大家所关心的问题。一般中大型数字放映机的冷却系统是带有液冷的,它使用冷却液来给放映机关键成像部件-光引擎的DMD芯片和光路入口进行冷却散热用的,为保证放映机正常运行需要"食"用冷却液,它的主要成分为乙二醇和软化水,呈淡蓝色。可能你会听到,我家的放映机有一年多都没喝冷却液了,机器工作挺正常的,     

SCADA系统在天然气流量测量方面的新应用

天然气流量测量大都采用差压节流式流量测量法,其节流器具一般用孔板,状态参数测量用电动差压、静压、温度变送器来采集,利用数据采集与监视控制系统（SCA—DA系统）中的计算机或远程终端单元（RTU）或可编程逻辑控制器（PLC）处理速度快来积算流量,并利用存储量大的特点来存储实时参数、流量值和其他参数。流量测量一般用一套测量仪表,但是根据本文理论推导所知,     

利用机上传感器测量燃油流量的方法研究

主要介绍了在小型商用飞机无法加装流量传感器的情况下,利用机上传感器实现流量测量的方法,通过该方法完成了该飞机在各种状态下燃油流量的测量.     

天然气计算机流量测量系统的改进

天然气流量测量大多采用差压节流式流量测量法,其节流器具一般用孔板,状态参数测量用电动差压、静压、温度变送器来录取,利用计算机或远程终端单元(RTU)或可编程逻辑控制器(PLC)处理速度快的特点来积算流量,利用存储量大的优势来存储实时参数、流量值和其他参数。流量测量一般是用一套测量仪表,但是根据理论推导可知,实际工况参数值越接近测量仪表的量程,状态参数测量值的不确定度对流量测量不确定度的影响就越小。本文在分析基础上提出了变送器采用低、中、高不同量程的仪表测量状态参数值,以提高天然气流量测量的准确度。一、流量测量…     

An analytical investigation of heat and mass transfer under conditions of film cooling of bodies

An analytical investigation is performed of heat and mass transfer under conditions of film cooling by liquids which exhibit the properties of abrupt variation of dynamic viscosity with a moderate variation of temperature (by three to five orders of magnitude with the temperature varying by 150–200 degrees). The coolant under constant pressure on the inner boundary of the body is filtered through specifically organized pores and forms an evaporating liquid film on the outer boundary. This organization of heat shielding makes it possible to automatically control the feed of coolant depending on the varying external heat fluxes and related temperatures of the body and coolant, as well as to maintain the initial geometry of the body (no carry-over of mass of the body material occurs). A simplified mathematical model of heat shielding is suggested, and analytical solutions are obtained for the body temperature and for the rates of coolant flow rate and evaporation. The relevant results are discussed.     

层间微通道液体冷却3D-ICs的仿真研究

近年来,随着半导体工业的迅速发展,芯片特征尺寸逐渐减小逐渐接近极限,为此提出三维集成电路(3D-ICs),集成度显著提高,但同时也造成芯片功率密度成倍增加,层间微通道液体冷却因其结构紧凑、传热效果较好、压降低等优点成为备受关注的焦点。本文采用仿真工具3D-ICE建立带有层间微通道液体冷却的不同通道类型的3D-ICs模型,模拟分析层间通道的物性参数如通道壁厚/针肋直径、通道高度、制冷剂流速/达西速度对三维芯片温度分布的影响情况。结果表明,给定条件下,热点温度随通道壁厚/针肋直径的增加而减少,在50~100变化快,温降最高可达1.309℃,随后趋于稳定;热点温度随通道高度变化的变化因通道类型而异,矩形直通道Tmax在0~1间迅速降低,随后逐渐升高,线性微针肋Tmax在一定范围内较矩形直通道平缓下降,随后缓慢升高或趋于平稳;热点温度随制冷剂流速/达西速度的增加而降低,且变化逐渐平缓。     

气淮两相流流型BP网络识别

解决气液两相流流型的客观、自动识别一直是工业界和学术界所关注的问题。本以U型科垂直上升段内空气水两相流为例,采用压力、压差波动的不同特征参数的组合,深入研究了对流型自适应BP网络识别的准确率的影响,获得了能够满足工种精度要求的参数波动特征组合方式,本的结果表明,该方法需要建立大量的流型特征的数据库,适用于流型的离线识别。     

A novel cooling scheme for superconducting power cables

Long distance transmission of electrical power with superconducting cables is likely necessary for energy conservation and effective utilization of renewable energy sources. The performance and cost of such superconducting lines is as significantly influenced by cryogenic issues as by superconductor performance. One significant cryogenic issue is that in the usual method of cooling using sub-cooled cryogen flow there is a limited cable length before the cryogen needs to be re-cooled. This adds complexity and cost to the cable system. Here we address this problem by utilizing the latent heat of the cryogen without the complication of multi-phase flow. The cryogen is distributed to the superconducting components by spraying it through small holes in a pressurized line. The pressurized liquid exiting the holes turns into mixed liquid and vapor with a temperature near the boiling point of the cryogen at the pressure of the space surrounding the superconducting components. The pressure in the space surrounding the superconducting components is then kept near atmospheric by maintaining short distances to a vent. The sprayed liquid accumulates but rapidly vaporizes in response to the heat load, providing even cooling power at a fixed temperature for the entire length of the line. Our work indicates that it may be possible to implement a cooling system with much simplified cryogenic stations at the cable ends and allowing cable lengths of up to 100 km with no intermediate cooling stations.     

低温储罐预冷过程预测

为了能输送和存储单相低温液体,保证输送管道和低温储罐的安全,预冷过程不可或缺。对预冷时间、预冷介质消耗量进行预测有利于指导实际操作。从热力学基本理论出发,采用稳态与变热导率的热力学分析方法,建立储罐预冷时间与预冷介质消耗量数学模型,推导了储罐温度随时间的变化关系,探讨进口流量与预冷时间、预冷介质消耗量之间的相互影响。将不同的计算方法相结合,指导选取最佳预冷流量。     

A novel concept of rapid cooling method of refrigeration system

This paper describes a novel cooling method of enhancing refrigeration capacity during short time (order of 1 min) by storing low-temperature liquid refrigerant. This method actively controls the refrigerant mass flow rate for the evaporator. The compressor of the refrigerator, therefore, does not have to be oversized to cope with intermittent large cooling load of the system. During a short period of time, a higher cooling capacity than that of the steady operation is achieved by the increased mass flow rate of liquid refrigerant. An experimental apparatus was designed and fabricated to validate the proposed cooling methodology. Two reservoirs as temporary sequential storages of the refrigerant were set up before and after the evaporator. Several on/off solenoid valves were installed to control the refrigerant flow. From the experimental results, we confirmed a successful operation of rapid cooling process as designed. This rapid cooling methodology shall be useful for temporarily enhancing the refrigeration capacity in other low-capacity refrigeration systems. The practical system must optimize the design of refrigerant reservoirs to reduce the whole system size.     

Safety system consideration of a supercritical-water cooled fast reactor with simplified PSA

The probabilistic safety of the supercritical-water cooled fast reactor (SCFR) is evaluated with the simplified probabilistic safety assessment (PSA) methodology. SCFR has a once-through direct cycle where all feedwater flows through the core to the turbine at supercritical pressure. There are no recirculation loops in the once-through direct cycle system, which is the most important difference from the current light water reactor (LWR). The main objective of the present study is to assess the effect of this difference on the safety in the stage of conceptual design study. A safety system configuration similar to the advanced boiling water reactor (ABWR) is employed. At loss of flow events, no natural recirculation occurs. Thus, emergency core flow should be quickly supplied before the completion of the feedwater pump coastdown at a loss of flow accident. The motor-driven high pressure coolant injection (MD-HPCI) system cannot be used for the quick core cooling due to the delay of the emergency diesel generator (D/G) start-up. Accordingly, an MD-HPCI system in an ABWR is substituted by a turbine-driven (TD-) HPCI system for the SCFR. The calculated core damage frequency (CDF) is a little higher than that of the Japanese ABWR and a little lower than that of the Japanese BWR when Japanese data are employed for initiating event frequencies. Four alternatives to the safety system configurations are also examined as a sensitivity analysis. This shows that the balance of the safety systems designed here is adequate. Consequently, though the SCFR has a once-through coolant system, the CDF is not high due to the diversity of feedwater systems as the direct cycle characteristics.     

冷凝器冷却水通道声传递特性

为阐明冷凝器冷却水通道的声传递特性、提高循环水系统声学设计能力,将换热方程和一维平面波方程耦合,推导得到换热管内冷却水声传递矩阵,针对冷凝器几何结构建立总传递矩阵并求解得到其冷却水通道声传递损失。建立试验系统验证了冷凝器冷却水管路声传递损失计算结果。根据换热管双向流固耦合分析计算结果,管外蒸汽绕流对换热管内冷却水脉动压力的影响可以忽略,冷凝器进出口管内水声和管壁振动测试结果也表明,该系统内冷却水脉动和管壁振动耦合紧密,管内流体脉动是管壁振动的主要激励源。研究结果还表明,通过调整冷凝器冷却水通道结构参数可以调节冷却水声传递损失。     

An alternative observation on the orifice pulse tube cryocooler and analysis through the unified model of cryocoolers

A new observation of the orifice pulse tube (OPT) cryocooler is proposed and analyzed on the ground of the unified model of cryocoolers. The elementary temperature reduction mechanism is modeled and verified through the measurements of Mikulin and others. This analysis refers to the upper limit performance for zero phase shift between the pulses of pressure and flow rate at the cold end. The lowest attainable temperature is formulated and pointed out as central characteristics of an OPT cooler. It dominates the closed form expressions for cooler's cooling capacity, COP and FOM as function of the compression ratio, the size of regenerator, the species of coolant and average flow rate. The so obtained upper limit of COP and FOM is about half of that in literature. Performance is also compared with Solvay and Gifford-MaMahon cryocoolers.