基于双热管新风机组温湿度独立控制空调系统试验平台设计

夏热冬冷地区夏季空气潮湿,除湿是空气调节的重点任务.针对温湿度独立控制空调系统中新风机组除湿能力不足的问题,采用双热管新风机组增强空调除湿能力.系统设计新风量为300 m^(3)/h,理论除湿能力为662.4 g/h,采用三级过滤器净化新风,满足除湿与卫生需求.该系统采用金属辐射吊顶处理室内空气温度,通过监测系统避免金属吊顶结露风险,可为温湿度控制及建筑节能提供参考.

新型双集热管多曲面槽式空气集热器在乌鲁木齐日光温室的应用研究

【目的】提高日光温室主动蓄热能力,使温室内热环境得到保障。【方法】提出一种新型双集热管多曲面槽式空气集热器,将此集热器与日光温室后墙结合构成主-被动式墙体体系,将此墙体体系应用于新疆日光温室,研究该集热器在日光温室中应用的可行性及应用效果。【结果】在集热器长度为16 m、集热器单支玻璃管接收器内空气流速为2.5 m/s的条件下,集热器出口温度可达75℃,集热效率可达50%。该集热系统通过日光温室墙体主动蓄热方式,在冬季实测期间累计可为日光温室提供约为2 400 MJ的太阳能。【结论】该结果可为集热器的推广应用提供参考。

乙烷双蒸发器低温回路热管的实验研究

介绍了一套双蒸发器低温回路热管样机的运行特性,包括次蒸发器辅助热管的降温启动性能和系统的传热能力。样机以乙烷作为工质,能够在次蒸发器上施加一定加热功率的情况下更快、更顺利地进入稳定工作状态。实验结果表明,该样机最高能够传递16 W的热量,最低传热热阻为1.3 K/W。

重力热管双循环空调在夏热冬冷地区应用的节能率分析

针对重力热管双循环空调的节能率,根据全国夏热冬冷地区10个典型城市的室外气象参数,提出了便于计算的统计求和简化算法。然后对长沙某数据中心的全年实际运行数据对计算模型进行了验证,结果表明,重力热管型双循环空调可比冷水机组节能约34%。计算模型的精度为12%,达到工程精度要求的范围。

热负荷分布对双蒸发器环路热管传热性能的影响

针对各自带液体补偿器的双蒸发器环路热管,采用模块化建模方式,数值模拟了不同热负荷分布下蒸发器毛细芯内的温度分布,确定了最优负荷分布模式以及系统传热极限。结果表明:施加于双蒸发器上的热负荷将同时影响双芯的温度变化,最优的热负荷分布模式为等热量分布。在一定的热沉温度下,并联双蒸发器环路热管的传热性能要明显优于单蒸发器环路热管,并以此求得该模型的传热极限为130 W,远大于同尺寸单蒸发器环路热管的传热极限37 W。

重力热管型双循环空调在夏热冬冷地区应用探讨

为实现2030年“碳达峰”与2060年的“碳中和”目标,节能的任务已经上升到国家战略层次,其工作刻不容缓。其重点在数据中心、5G网络等领域的节能能耗。而重力热管型双循环空调是利用自然冷源效率较高的一种机房空调。根据全国十个典型城市的室外气象参数,利用积分的方法,建立了机组混合制冷模式的计算模型。提出了便于计算的统计求和简化算法。然后与同类型的氟泵空调、水冷冷水机组加自然冷却板换模式进行了对比分析。结果表明:重力热管型双循环空调全年运行时长比氟泵空调多50.8%的时间。然后将长沙某数据中心的全年实际运行数据对计算模型进行了验证,重力热管型双循环空调可比冷水机组节能约34%。计算模型的精度为12%,达到工程精度要求的范围。重力热管型双循环空调在夏热冬冷地区使用是值得推广应用的一种方案。

全玻璃双真空太阳能集热管

本文简要叙述了在实际使用玻璃真空管中出现的问题,并系统阐述了全玻璃双真空太阳能集热管的原理、结构特点,突出了其优越性,说明其有很好的市场前景。

双模储水式电热水器温升测试及结果分析

目前市面上有两种类型的储水式热水器,一种是加热管在热水器内胆底部的单模储水式热水器,一种是两个加热管分别在内胆底部和出水口附近环绕的双模储水式热水器。本文主要对双模储水式电热水器进行了GB 4706.1-1998、GB 4706.12-2006标准的发热温升测试,给出了三种模式下有代表性的各个部件的温升,并推断出在第三种模式下,先令底部加热管工作至稳定再切换至上部电加热管工作至稳定,这种模式下的各部件的温升最高,温升测试也是最严酷的一种状态。

九州风神超强风冷显卡散热器

著名散热器生产厂商九州风神即将上市一款专门为显卡设计的热管散热器SNOWMANV6，它采用双热管设计，

An advanced turbulator with blades and semi-conical section for heat transfer improvement in a helical double tube heat exchanger

In present work,a helical double tube heat exchanger is proposed in which an advanced turbulator with blades,semi-conical part,and two holes is inserted in inner section.Two geometrical parameters,including angle of turbulator’s blades(θ) and number of turbulator’s blades(N),are considered.Results indicated that firstly,the best thermal stratification is achieved at θ=180°.Furthermore,at the lowest studied mass flow rate(m = 8 × 10^(-3) kg/s),heat transfer coefficient of turbulator with blade angle of 180° is 130.77%,25%,and 36.36% higher than cases including without turbulator,with turbulator with blade angle of θ =240°,and θ =360°,respectively.Moreover,case with N=12 showed the highest overall performance.At the highest studied mass flow rate(m = 5.842 × 10^(-2) kg/s),heat transfer coefficient for case with N=12 is up to 54.76%,27.45%,and 6.56% higher than cases including without turbulator,with turbulator with N=6,and with turbulator with N=9,respectively.

Novel lateral insulated gate bipolar transistor on SOI substrate for optimizing hot-carrier degradation

A novel lateral insulated gate bipolar transistor on a silicon-on-insulator substrate SOI-LIGBT with a special low-doped P-well structure is proposed.The P-well structure is added to attach the P-body under the channel so as to reduce the linear anode current degradation without additional process.The influence of the length and depth of the P-well on the hot-carrier HC reliability of the SOI-LIGBT is studied.With the increase in the length of the P-well the perpendicular electric field peak and the impact ionization peak diminish resulting in the reduction of the hot-carrier degradation. In addition the impact ionization will be weakened with the increase in the depth of the P-well which also makes the hot-carrier degradation decrease.Considering the effect of the low-doped P-well and the process windows the length and depth of the P-well are both chosen as 2 μm.

Theoretical and experimental studies on fabrication of two-layer aluminum−copper pipe by friction stir additive manufacturing

Using a friction stir additive manufacturing(FSAM)process,the fabrication of a two-layer aluminum−copper pipe was studied experimentally and numerically.For this purpose,by presenting a 3D thermo-mechanical model in ABAQUS software,the temperature and strain distributions during the process were studied.The simulation results show that,although the rotational-to-traverse speed ratio with a good approximation can predict the heat input during welding,it is not a precise measure to predict the occurrence of defects in the weld cross-section.There is a good agreement between the predicted and experimental thermal results,and the maximum relative error is 4.1%in estimating the maximum temperature during welding.Due to heat and severe plastic deformation in the stir zone,the aluminum−copper intermetallic compounds(CuAl_(2) and Cu_(9)Al_(4))are formed.The maximum hardness in the stir zone is 301.4 HV_(0.1) in sample welded with an overlap of−0.5 mm.The ultimate tensile strength and elongation of the two-layer pipe fabricated by friction stir additive manufacturing are(319.52±2.31)MPa and 19.47%,respectively.

Oscillation heat transfer dynamic model for new type oscillation looped heat pipe with double liquid slugs

In order to explain the oscillation heat transfer dynamics of closed loop oscillation heat pipe (CLOHP) with two liquid slugs,analysis on the forces and heat transfer process of the partial gas-liquid phase system involving multiple parameters was carried out,and a new type oscillation heat transfer dynamic model of the CLOHP was set up based on conservation laws of mass,momentum and energy.Application results indicate that its oscillation heat transfer dynamics features depend largely on the filling rate,pipe diameter and difference in temperature.Besides,oscillation intensity and transfer performance can be improved to a large extent by increasing the temperature difference properly and enlarging the pipe diameter within a certain range under a certain filling rate.

SGTR事故SG满溢分析扩展研究

采用热工水力系统程序进行核电厂蒸汽发生器传热管破裂(SGTR)事故蒸汽发生器(SG)满溢分析,验证在该事故下SG不会发生满溢;对SGTR事故进行扩展研究,考虑多种传热管破裂情况,包括单根传热管双端断裂、多根传热管双端断裂和传热管破口,并将3种情况的分析结果进行比较,给出SGTR事故最极限的工况。研究结果表明,单根传热管双端断裂工况下,SG不会发生满溢,且与其他2种工况相比满溢裕量最小,在所有分析工况中最极限。

Simulation of Thermocapillary Convection in a TwoLayer Immiscible Fluid System Using a Boundary Element Method

A boundary element method for simulating thermocapillary convection in a two-layer immiscible fluid system with flat and free interface has been developed.The divergence theorem is applied to the non-linear convective volume integral of the boundary element formulation with the pressure penalty function.Consequently,velocity gradients are eliminated and the complete formulation is written in terms of velocity.This avoids the difficulty of convective discretizations and provides considerable reductions in storage and computational requirements while improving accuracy.In this paper,we give the influence of different parameters(Marangoni number, Reynolds number)on thermocapillary convection in cavity with two-layer immiscible fluids.As shown by the numerical results,when the physical parameters between liquid encapsulant and melt are chosen appropriately, the detrimental flow in the bottom melt layer can be greatly suppressed.The influence of the free interface on thermocapillary convection is also shown.

Rigid Sensor Allocation and Placement Technique for Reducing the Number of Sensors in Thermal Monitoring

Using embedded thermal sensors, dynamic thermal management(DTM) techniques measure runtime thermal behavior of high-performance microprocessors so as to prevent thermal runaway situations. The number of placed sensors should be minimized, while guaranteeing accurate tracking of hot spots and full thermal characterization. In this paper, we propose a rigid sensor allocation and placement technique for determining the minimal number of thermal sensors and the optimal locations while satisfying an expected accuracy of hot spot temperature error based on dual clustering. We analyze the false alarm rates of hot spots using the proposed methods in noise-free, with noise and sensor calibration scenarios, respectively. Experimental results confirm that our proposed methods are capable of accurately characterizing the temperatures of microprocessors.