大型空间环模器热沉管网动态仿真技术

建立了大型空间环境模拟器热沉管网动态数学模型，介绍了热沉管网动态仿真技术的算法及软件结构，利用本文的软件对国内最大的空间环境模拟器热沉进行了动态仿真研究，并将结果与此前根据不考虑温度分布对流量分配影响的数学模型得到的仿真结果进行了对比，验证了该技术的可行性和先进性。     

热沉最佳稳定工况仿真技术

介绍了热沉最佳稳定工况的概念、数字模型及其计算机实现，并利用本文的软件对国内最大的空间环模器热沉进行了仿真研究，验证了该技术的可行性。热沉最佳稳定工况仿真研究对指导大型空间环境模拟器初期的调试试验有重要意义。     

基于水蒸发器的高速飞行器电子设备冷却性能研究

针对高速飞行器机载电子设备的高空冷却问题,提出了一种采用液态水作为主要热沉,防冻液作为辅助热沉的机载电子设备冷却方案.采用理论分析计算与计算机模拟仿真相结合的方法,建立了水蒸发器与电子设备换热仿真模型,对机载电子设备冷却系统进行性能分析.分析结果表明,在一定的飞行高度条件下,液态水作为主要热沉可以吸收大量的热量,满足机...     

核电汽轮机凝汽器运行参数动态特性仿真研究

汽轮机凝汽器是核电站重要的辅机设备,其运行参数动态特性直接影响汽轮机运行的经济性和安全性。基于分布式热动力学原理,在考虑不凝结气体对凝汽器换热特性影响的前提下,建立核电站表面式凝汽器动态参数模型。采用Adams多步仿真算法对AP1000核电凝汽器实时系统进行仿真。分析循环冷却水温度、流量、汽轮机排汽量阶跃变化对凝汽器运行参数动态特性的影响。研究表明:进汽量阶跃增加工况的仿真结果与实验值基本吻合,进汽量阶跃降低工况计算值略小于实验值,仿真模型计算精度较高。研究结果可为核电凝汽器变工况运行提供参考。     

叶脉型微通道热沉设计及散热特性分析

为改善相控阵天线多热源阵面温度的均匀性,基于植物叶脉优良的传质特性,提出一种用于相控阵多热源阵面的叶脉型微通道热沉。首先,对叶脉型微通道热沉的流动特性和散热特性进行仿真分析,得到热沉的热源温度分布。然后,以热源温度标准差最小化为目标,进一步优化叶脉型微通道结构,得到了非对称叶脉型微通道拓扑结构。最后,采用金属3D打印加工了铝基微通道热沉样件并进行散热性能测试。数值仿真结果表明,相比于传统平行微通道热沉,叶脉型微通道热沉不仅强化了传热,而且使得热源温度更均匀,压力损失更小;实验结果验证了叶脉型微通道热沉优良的散热性能。研究结论可为相控阵多热源阵面的热沉设计提供依据。     

舰用中冷回热燃气轮机装置动态性能分析

中冷回热循环（ICR）燃气轮机因其优越的全工况性能正日益受到船舶和工业领域的关注。通过分析ICR燃气轮机的变工况特性，采用模块化建模法仿真，对ICR燃气轮机进行动态性能分析，并与简单循环燃气轮机仿真结果进行比较。结果表明，换热器的热惯性对机组的动态性能影响较大，时间常数愈大，达到新平衡所需时问愈长；ICR燃气轮机不仅在设计工况点的效率和功率都有明显提高，而且在低工况下仍有良好的经济性，动力涡轮采用进口导叶面积可调可进一步改善ICR燃气轮机装置的部分工况性能。     

一种新型加热丝红外笼的设计及研究

设计研制了一种用于卫星组件热真空试验的新型红外加热笼,与传统加热带红外笼相比,具有覆盖系数低、降温速率快等特点.通过对三种不同覆盖系数的红外笼的仿真计算,分析了不同加热功率下的试件的温度特性.比较红外笼的试验测试结果与仿真结果,结果表明,受试验测试中热沉背景升温及控温策略影响,同工况下试件的温度均匀性及降温速率较仿真结...     

基于拉曼散射的分布式光纤传感系统真空低温热沉环境温度梯度测量

新型分布式光纤温度传感器具备电类温度传感器所不具有的独特优势，扩展了温度测量在真空低温环境中的应用领域。在真空低温热沉环境下使用分布式光纤温度传感器进行温度梯度测量。传统热电偶温度传感器和分布式光纤温度传感器布置在同一双层铝板结构中，铝板以及传感器放置在真空低温热沉环境中。铝板由加热片进行控温，以实现真空低温热沉环境下不同温度梯度的测量。对两类传感器所测铝板的温度数据进行分析，结果表明，基于拉曼散射原理的分布式光纤温度测量系统能够对真空低温热沉环境下的温度梯度实现精确测量，可以满足低温工况下工件的温度测量。     

卫星热控系统故障建模与仿真

为了简便、全面地研究各种热控系统故障对卫星各热控环节温度变化的作用和影响，将卫星热故障划分为热阻型、控制策略型和诱发型热负荷变化3种基本类型，建立了卫星外壳、辐射器、舱内环境和关键目标仪器4个主要热控环节温度变化的动态方程，应用热故障模拟模型，可以对各类热控系统发生故障时的热控环节温度变化规律进行较全面的仿真研究，从而为热控系统故障诊断及容错控制系统设计提供简便的数学模型和仿真方法。     

大型氦低温系统多变量控制

大型氦低温系统广泛应用于各类大科学装置中,运行中往往会产生热脉冲,通过负载端传导给制冷系统,对制冷系统产生热冲击。为了研究和应对热冲击,建立了一种多变量控制策略并得到了相关仿真和实验结果。首先以真实系统为基础建立了氦低温系统的动态仿真模型,同时建立了一个基于模糊神经网络的多变量协同控制策略,并将其应用在仿真液化器模型和一个真实的氦透平制冷系统上,得到了低温系统降温过程和控制过程的仿真和实验数据。仿真和实验结果显示本策略的偏差积分量为0.016 5,下降时间为102 s,上升时间为112 s。普通PID的的偏差积分量为0.026 9,下降时间为154 s,上升时间为170 s。通过仿真和实验过程的比较,验证了本文建立的动态仿真模型具有可用的精度,证明了本策略具有较好的控制效果。     

Distributed steady and dynamic modelling of dry-expansion evaporators: Modèlisation du régime stable et du régime transitoire des évaporateurs à détente sèche

A general distributed parameter model is presented to describe both steady and dynamic behaviors of dry-expansion evaporators. The homogeneous and three different non-homogeneous two-phase flow models are used to evaluate the impact of different flow models on the accuracy of the simulation. The experimental work was carried out on a full-scale refrigeration system with R-134a as the working fluid and without frost formation at the evaporator. Comparison between the modelling and experimental measurements shows that the drift flux flow models give satisfactory predictions. The simulation results indicate that an even air temperature distribution off the evaporator may be obtained by controlling liquid dry-out point at the two ends of the coil. The study also indicates that the counterflow configuration provides a higher heat exchange efficiency with a slower transient response compared with the cocurrent-flow configuration. A general distributed parameter model is presented to describe both steady and dynamic behaviors of dry-expansion evaporators. The homogeneous and three different non-homogeneous two-phase flow models are used to evaluate the impact of different flow models on the accuracy of the simulation. The experimental work was carried out on a full-scale refrigeration system with R-134a as the working fluid and without frost formation at the evaporator. Comparison between the modelling and experimental measurements shows that the drift flux flow models give satisfactory predictions. The simulation results indicate that an even air temperature distribution off the evaporator may be obtained by controlling liquid dry-out point at the two ends of the coil. The study also indicates that the counterflow configuration provides a higher heat exchange efficiency with a slower transient response compared with the cocurrent-flow configuration.     

模具温度对高光注射成型制品表面沉降的影响

以自主设计的车载高光蓝牙外壳为例,对模具温度对高光注射成型制品表面沉降影响规律,相同及不同模温条件下其他成型参数对制品表面沉降影响规律进行成型模拟研究。结果表明:高光成型制品沉降指数明显小于普通成型,且随模具温度的升高呈准线性减小趋势;模具温度设定情况下,保压压力对制品沉降指数影响最大,熔体温度、注射压力和保压时间影响效应相当,冷却时间几乎不具影响;随着模具温度的逐步升高,制品沉降指数随熔体温度的升高、注射压力增大呈减小趋势,随着其他参数的变化则呈波动变化趋势,且均在塑料热变形温度附近达极限值。     

Technical and economic working domains of industrial heat pumps: Part 2 – Ammonia-water hybrid absorption-compression heat pumps

The ammonia-water hybrid absorption-compression heat pump (HACHP) has been proposed as a relevant technology for industrial heat supply, especially for high sink temperatures and high temperature glides in the sink and source. This is due to the reduced vapour pressure and the non-isothermal phase change of the zeotropic mixture, ammonia-water. To evaluate to which extent these advantages can be translated into feasible heat pump solutions, the working domain of the HACHP is investigated based on technical and economic constraints. The HACHP working domain is compared to that of the best available vapour compression heat pump with natural working fluids. This shows that the HACHP increases the temperature lifts and heat supply temperatures that are feasible to produce with a heat pump. The HACHP is shown to be capable of delivering heat supply temperatures as high as 150 °C and temperature lifts up to 60 K, all with economical benefits for the investor.     

Numerical simulation of an advanced energy storage system using H2O–LiBr as working fluid, Part 2: System simulation and analysis

This paper is the second part of our study on the advanced energy storage system using H₂O–LiBr as working fluid. In the first part, the system working principle has been introduced, and the system dynamic models in the operation process have also been developed. Based on the previous research, this paper focuses on the numerical simulation to investigate the system dynamic characteristics and performances when it works to provide combined air-conditioning and hot water supplying for a hotel located near by Yangzi River in China. The system operation conditions were set as follows: the outdoor temperature was between 29 °C and 38 °C, the maximum air-conditioning load was 1450 kW, the total air-conditioning capacity was 19,890 kWh and the 50 °C hot water capacity for showering was 20 tons which needed heat about 721 kWh on a given day. Under these conditions, the system operation characteristics were simulated under the full- and partial-storage strategies. The simulation results predicted the dynamic characteristics and performances of the system, including the temperature and concentration of the working fluid, the mass and energy in the storage tanks, the compressor intake mass or volume flow rate, discharge pressure, compression ratio, power and consumption work, the heat loads of heat exchanger devices in the system and so on. The results also showed that the integrated coefficient of performances (COP_int) of the system were 3.09 and 3.26, respectively, under the two storage strategies while the isentropic efficiency of water vapor compressor was 0.6. The simulation results are very helpful for understanding and evaluating the system as well as for system design, operation and control, and device design or selection in detail.     

基于RBF神经网络的自动包装机温度控制算法研究

目的针对传统热封工艺中温度调节PID算法参数过度依赖人工经验的缺点,提出一种RBF神经网络与PID算法相结合的具有参数自适应的热封温度控制算法。方法使用控制系统的输出误差作为代价函数,采用最小均方误差(LMS)调整权值与偏置参数,并通过中心自组织算法实现径向基函数中心和中心宽度的动态调节,在Matlab软件中的Simulink子系统中建立仿真模型进行算法验证,并与传统PID控制算法进行比较。结果仿真结果表明,径向基神经网络与传统PID算法的结合使得系统输出响应在动态性能和静态性能方面均优于传统PID,在系统上升时间、调节时间等方面均优于增量式数字PID。结论将RBF神经网络PID算法应用于自动包装机,避免了传统热封工艺中PID控制算法参数不能适应于复杂变换控制环境的问题,神经网络PID算法的自适应性强,实现了热封温度变化下PID参数的自动调整,在一定程度上提升了生产效率和包装设备的智能化水平。     

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。     

芯片封装均温板壳体的传热特性研究

高热流密度、微型化芯片的发展使传统金属材料的热扩散能力受限.本文设计加工了一款具有微针筋的均温板,应用于芯片封装壳体,实验研究了充液率、芯片尺寸、散热器运行参数(水流量、温度)对均温板壳体(VC IHS)传热性能的影响,并与同工况条件下芯片封装金属铜壳体(Cu IHS)的传热性能进行对比.结果表明:VC IHS的充液率...     

The compression/absorption cycle – influence of some major parameters on COP and a comparison with the compression cycleLe cycle à compression–absorption: influence de certains paramètres importants sur le COP et comparaison avec le cycle à compression

This article concerns two main studies: a parameter study and a comparison. In the parameter study, the CAHP is focused upon. Its COP sensitivity to changes in the absorber and desorber falling-film tube length, heat exchanger area distribution, and concentration change of the solution in the absorber is studied. The relative distribution between the desorber and absorber is found to have little impact on COP. The area distributed to the solution heat exchanger and the concentration change in the absorber is found to have a large impact on COP when examined separately, but when they are studied together, and with optimized concentration change for each area distribution, the total impact is low. It is shown that the falling-film tubes should be designed to be as long as possible in order to increase the COP.The comparison involves a new procedure for comparing the performance (COP) of a compression/absorption heat pump (CAHP) with that of a compression heat pump (CHP). In the procedure local heat transfer coefficients and pressure drop are taken into account. Further, the comparison is performed for various heating applications and with specified investment level. The heating applications are typically industrial or district heating cases and are chosen to study impact of three different kinds: size of the sink and source temperature change (glide), temperature lift for a given sink and source glide and temperature level for a given sink and source glide. Ammonia/water is used as working fluid in the CAHP and isobutane in the CHP. A relevant industrial design is assumed for the CHP (including an indirect economizer coupling, suction gas heat exchanger, sub-cooler and surface enhancements in evaporator and condenser), which is not the case in previous comparisons of this type. The absorber and desorber in the CAHP are modeled as vertical falling-film tube-and-shell heat exchangers. The main results for the comparison study are: (1) the COP of the CAHP is as good as that of the CHP when the sink and source glides are 10 K; (2) when the glide of the sink and source is increased to 20 K, the CAHP has a 12% better performance than the CHP; and (3) an increased temperature lift and an increased temperature level give the CAHP a relatively worse COP. Some COP-increasing design parameters to be studied further are proposed for the CAHP.     

Technical and economic working domains of industrial heat pumps: Part 1 – Single stage vapour compression heat pumps

A large amount of operational and economic constraints limit the applicability of heat pumps operated with natural working fluids. The limitations are highly dependent on the integration of heat source and sink streams. An evaluation of feasible operating conditions was carried out considering the constraints of available refrigeration equipment and a requirement of a positive net present value of the investment. Six heat pump systems were considered, corresponding to an upper limit of the sink temperature of 120 °C. For each set of heat sink and source temperatures the best available technology was determined. The results showed that four different heat pump systems propose the best available technology at different parts of the complete domain. Ammonia systems presented the best available technology at low sink outlet temperature. At high temperature difference between sink in- and outlet, the transcritical R744 expands the working domain for low sink outlet temperatures.