巨型水电机组励磁系统环形热管整流柜的研制与应用

针对巨型水电机组励磁整流柜散热问题，介绍了利用环形热管散热的工作原理和自冷型环形热管整流柜的研制改进过程，分析了一体式环形热管散热器和水平对称结构的优势及其在乌东德水电站的应用。结果表明，采用完全自冷方式的环形热管励磁整流柜可在现场长期稳定运行，从设计原理上解决了灰尘、噪声、工作电源、维护等一系列问题，提高了设备的安全可靠性和自动化水平，同时降低了能耗，节能环保效益显著。     

流溪河发电公司2号机励磁系统改造

简要介绍2号机励磁系统改造前、后的运行情况,并通过介绍新励磁系统一些常见试验的方法及注意事项和一些常见的故障处理方法,说明新励磁系统完全满足我厂机组需要。     

充气热管空气预热器的设计及应用

文章介绍充气热管空气预热器的开发应用。采用平界面模型,确定充气热管冷却段的有效长度。通过实际工程应用,结果认为采用充气热管换热器具有十分良好的防腐蚀及防堵灰性能。     

充气热管空气预热器的设计分析及应用

对充气热管空气预热器的结构进行分析和应用介绍,采用平界面模型,确定充气热管冷却段的有效长度。在原始参数相同的条件下,对充气和不充气的热管换热器进行试验,分析热管最低控制工作温度、排烟温度和换热面积之间的差异。工业试验和实际应用结果表明：在变工况和高硫煤(5％-7％)的条件下采用充气热管空气预热器具有十分优良的防腐蚀和防积灰的性能。     

TA2管子管板自动TIG焊工艺研究

采用自动TIG焊对TA2管子管板进行试验,通过焊前清理、焊接工装、坡口形式、焊接参数、焊接顺序、焊后无损检测、宏观检测及力学性能等试验,对焊接接头进行研究,结果表明：焊前使用无水乙醇对换热管与管板焊接区域及周围母材进行清理;焊接时使用大直径喷嘴进行保护,同时结合气体保护工装对换热管内部进行保护;采用J型坡口可保证焊接接头根部良好熔合;在保证根部充分熔合的情况下,使用小电流焊接参数进行焊接;焊接时在周围换热管内部插入冷却工装,采用跳焊的焊接方式进行焊接;通过上述措施可保证TA2管子管板焊接接头质量,可用于产品生产制造。     

热管式聚光光伏冷却集热装置的应用研究

文章设计了一种热管式聚光光伏冷却集热装置,利用热管原理来改变翅片式风冷光伏散热器、管路式水冷光伏散热器的设计思路,通过将热管端蒸发段的介质输送到冷凝端进行换热的相变过程,使得光伏基板的热量迅速传递到冷凝端水箱中,达到降温和集热的双重效果。热管式聚光光伏冷却集热装置不仅能够对光伏组件进行快速冷却,使整个光伏组件换热面温度分布均匀,提高光伏系统的发电效率,还可将多余热量进行收集利用,提高发电收益,在聚光光伏发电领域中具有广阔的市场前景。     

螺旋板式热管重油冷却器的试验研究

本文针对燃用高粘度重油的火电厂回油冷却难的问题,在研制翅片式热管重油冷却器取得成功经验的基础上,利用螺旋板换热器的优点,提出了螺旋板式热管重油冷却器,并进行了小型实验。实验证明,这种结构的重油冷却器冷却效果更佳,优点更为突出。     

百米热管新技术

<正> 近年来热管大部分被用于电器的冷却和热交换器的元件上。其长度仍停留在数十厘米,最长的也只有几米。从热能输送角度来看,研制长热管,用于长距离输送热能,已势在必行。 1.百米长热管的研制 1.1 长热管的研制作为长距离输送能量的方式,通常是利用     

聚光型光伏电池的冷却方式

在聚光型光伏发电系统中,冷却方式是必须考虑的问题,各种冷却方式的优缺点和适用场合各不相同,合理的冷却方法不仅可以降低电池温度,平衡光斑不均匀性,还应该具有安装方便、功耗低、可靠性高等特点。介绍了目前较为常用的风冷和水冷方式,以及研究中较有前途的微通道、射流冲击、热管和液浸冷却技术。由于不同结构光伏发电系统的冷却要求不同,选择何种冷却方法也是设计中重要的环节。最后简要分析了冷却方法的选择问题。     

燃气轮机冷却技术综述

详细地阐述了对气膜冷却、内部强化换热以及热管冷却等的影响因素,目前的应用状况以及发展前景.重点集中在内部强化换热和热管冷却.本文可以使刚开始接触燃气轮机冷却技术的人员对冷却技术有个整体的了解,还可以对研究设计人员提供必要的参考依据.     

Heat pipe cooling technology for desktop PC CPU

As Pentium-IV, a high-performance PC CPU, emerges, CPU’s thermal design power shows sharp increase. Since conventional cooling method, aluminum extruded heat sink has disadvantages like poor cooling performance, acoustic noise increase and weight rise, cooling module in the form of remote heat exchanger using heat pipe is developed. Especially, using system fan exhausting heat inside to cool CPU reduces acoustic noise with lowered quantities of fan and makes it possible to reduce manufacturing unit price. This paper proposes cooling using heat pipe, recommends Pentium-IV CPU cooling module on change of fan revolution speed, and looks for possibility of reducing acoustic noise.     

热管用于笔记本电脑智能温控散热的分析

随着笔记本电脑性能的不断提升,传统的单一风冷散热已经满足不了要求,传热性能优越的热管便应用于笔记本电脑散热。分析了热管用于智能温控散热系统的传热机理,并建立了传热模型．分析了用于笔记本散热的热管的热阻和总传热系数,结合实例进行了定量计算。计算结果表明热管配合智能温控风扇,能很好满足笔记本散热的要求。     

Heat pipe with PCM for electronic cooling

This article experimentally investigates the thermal performances of a heat pipe with phase change material for electronic cooling. The adiabatic section of heat pipe is covered by a storage container with phase change material (PCM), which can store and release thermal energy depending upon the heating powers of evaporator and fan speeds of condenser. Experimental investigations are conducted to obtain the system temperature distributions from the charge, discharge and simultaneous charge/discharge performance tests. The parameters in this study include three kinds of PCMs, different filling PCM volumes, fan speeds, and heating powers in the PCM cooling module. The cooling module with tricosane as PCM can save 46% of the fan power consumption compared with the traditional heat pipe.     

Dynamic test strategy for diagnosing a heat pipe cooling module

This article experimentally develops a dynamic test strategy for efficiently diagnosing a heat pipe cooling module in order to improve the time-consuming conventional steady-state test. The first step is to investigate the performance of a heat pipe by measuring its thermal resistance, and the next step is to examine the influence of the parameters on the temperature response of the heat pipe cooling module. The experimental parameters include the press force, preheating temperature, heating power, and starting time of the fan. The results show that the thermal performance of a heat pipe, the contact condition between the heat pipe and the base plate, and the heat dissipation ability of a heat sink, are diagnosed within 30 seconds. During the dynamic test, both the startup and the ability to reach uniformity of temperature of the heat pipe can be observed. In addition, the temperature response of a heat pipe cooling module based on a lumped model matches the experimental data.     

风扇罩及串并联影响散热模块换热的试验研究

为解决车辆冷却系统中散热器模块常出现的散热能力不足的问题,对某型车辆的散热模块在风洞测试平台上进行试验研究;试验散热器模块为水散油散匹配不同直径的风扇罩,水散油散变换串并联方式,分别进行风洞试验,试验结果表明,风扇罩直径和串并联方式显著影响散热模块的散热和阻力性能,可以通过调整散热器匹配的风扇罩直径和变换串并联方式来提...     

Influence of fan setting height on the cooling performance of a plate‐fin‐type heat sink with microprocessor

The cooling performance of a plate‐fin‐type heat sink equipped with a cooling fan was investigated experimentally. The heat sink was 80 mm long, 43 mm wide, and 24 mm in height (including the 4‐mm‐thick base). The cooling fan was 40 × 40 × 15 mm and was set to direct the air flow vertically in the downstream half of the heat sink. We focused on the influence of the height (which varied from 5 to 20 mm) that the fan was set at, on the heat transfer coefficient of the heat sink. The maximum value of the heat transfer coefficient was achieved at a setting height of 5 mm. At this height, the volumetric heat transfer coefficient was 1.8 times as high as that in a parallel flow under the same fan power. This result indicates that the cooling performance of heat sinks with a cooling fan can be improved by using this kind of compact structure. © 2001 Scripta Technica, Heat Trans Asian Res, 30(6): 512–520, 2001     

利用汽车发动机余热的溴化锂吸收式制冷研究

根据现有汽车空调的制冷系统和发动机冷却水及排气系统的结构特点,结合溴化锂吸收式制冷系统的工作原理,提出将汽车排气管和发动机冷却水箱进行结构改造作为溴化锂吸收式制冷系统的发生器,代替传统的汽车空调的制冷和采暖系统及发动机冷却系统。并对该溴化锂制冷系统进行了热力计算和传热面积的计算,计算结果表明,溴化锂制冷系统充分利用了废气余热和冷却水余热,减少了汽车油耗,并且改造后的排气热交换器和冷却水箱传热面积小,结构简单紧凑。     

Investigation of a piezoelectric fan embedded in a heat sink

Previous studies show that the performance of a piezoelectric (PZT) fan is strongly affected by length, vibrating frequency, and fan amplitude. This study examines a cooling system, which is composed of a heat sink made of aluminum and a piezoelectric fan. An oscillating airflow can be generated and induced by the fan deformation. The piezoelectric fan between two fins may break the thermal boundary layer and enhance the heat dissipation rate of the cooling system with forced convection. In order to estimate the optimum design of the cooling system, the effects of operating frequency, fan amplitude, fan arrangement, Ri (Gr/Re_pzt²), and power consumption are analyzed. Moreover, the relationship between the dimensionless PZT-convection number (M_p) and Ri has been investigated to analyze the performance of the cooling system. A three-dimensional, transitional model has been built to account for the flow field of the cooling system. The optimum cooling system shows the M_p reaches 2.3.     

Performance prediction of an improved air-cooled steam condenser with deflector under strong wind

For an air-cooled steam condenser (ACSC), environmental wind can cause a large flow rate reduction in the axial fans mainly near the windward side of the air-cooled platform due to cross-flow effects, resulting in a heat transfer reduction. This leads to an increase of turbine back pressure, and occasional turbine trips occur under extremely gusty conditions. A new method is proposed in this paper to remove the strong wind effect by adding deflecting plates under the air-cooled platform, which contributes to forming a uniform air mass flow rate in the axial fans by leading enough cooling air to the fans in the upwind region. Numerical simulation is made of the thermal-flow characteristics and heat transfer performance of the improved ACSC with deflectors. A heat exchanger model is used for simulating the flow and heat transfer in the ACSC, in which the heat exchanger is simplified to a porous medium and all flow losses are taken into account by a viscous and an inertial loss coefficient. A fan model is used for reaching the flow condition at the heat exchanger inlet with the actual performance curves of the fan. It is found that the improved ACSC with deflector shows a significant enhancement in both the cooling air mass flow rate and the heat rejection rate compared with the conventional ACSC. The higher the wind speed is, the larger the heat transfer enhancement of the improved ACSC is. The effect of the plate inclination is also investigated, and the inclination angle of 45° is found to be the optimum value for the arrangement of the deflector.     

An efficient solar-powered adsorption chiller and its application in low-temperature grain storage

A novel solar-powered adsorption cooling system for low-temperature grain storage has been built, which consists of a solar-powered water heating system, a silica gel–water adsorption chiller, a cooling tower and a fan coil unit. The adsorption chiller is composed of two identical adsorption units, each of them containing an adsorber, a condenser, and an evaporator/receiver. The two water evaporators have been incorporated into one methanol evaporator by the use of the concept of a gravity heat pipe. In order to improve the system efficiency and achieve continuous cooling production, the adsorbers are operated out-of-phase, and heat and mass recovery processes have been used. During the period from July to September of 2004, the system was put into experimental operation to cool the headspace (i.e., the air volume above the grain) of a grain bin. Three months of operation showed promising performance. The chiller had a cooling power between 66 and 90 W per m² of collector surface, with a daily solar cooling coefficient of performance (COP_solar) ranging from 0.096 to 0.13. The electric cooling COP was between 2.6 and 3.4.