共查询到20条相似文献，搜索用时 390 毫秒
1.
数据中心机房是能源消耗大户,通过改善其内部环境可以很好地减少能耗.本课题基于CFD 6Sigma软件对实际案例进行三维模型的构建,通过仿真分析模拟出机房内部的气流组织情况,同时利用K-means算法得出机柜负荷状态的聚类结果,建立出机柜的数学模型.通过其数学模型设计了基于机柜负荷变化的空调变风量模糊PID控制器,通过对... 相似文献
2.
针对越江联络通道温度场发展规律的不确定性,提出在联络通道开挖反方向位置,利用现场冻结盐水系统,开展原位冻结试验,以探究越江联络通道冻结温度场的发展规律。分别进行单孔、双孔、三孔原位冻结试验,并对试验结果对比分析。结果表明,在相同条件下三孔冻结模式冻结壁平均温度最低降到-11.74℃,冻结壁的极限厚度达到2.8 m。通过分析得到各冻结模式下冻结壁的极限厚度和冻结平均温度,确定在地下水渗流影响下三孔冻结能满足施工要求。结合冻结温度场控制微分方程,建立平面数值模型,进一步研究冻结温度场的扩展规律,与现场实测数据对比验证结果基本吻合。 相似文献
3.
胡月莲 《温州职业技术学院学报》2006,6(4):36-38
微通道传热技术是近几年发展起来的一门新兴的传热技术,具有传热效率高、结构紧凑等优点,是当前流动与传热研究的重要课题。运用计算流体力学程序(CFX)对环形微通道内单相水的流动与换热进行数值模拟,可以形象地描述出管内的流场和温度场,从中分析各种因素对流动与换热所产生的影响。 相似文献
4.
将设计的一套太阳能供暖系统在节能改造后的农宅（试验建筑）中应用,并与燃煤采暖炉供暖的农宅（对比建筑）进行冬季运行测试对比。室内温度和内墙壁温度分析结果显示,在同样的晴、阴天气条件下,试验建筑的室内平均温度都在16.5℃以上,温度波动幅度在3.8℃以下,而对比建筑室内平均温度在14.6~15.4℃,温度波动幅度达到6.6℃以上;试验建筑的内墙壁平均温度为12.9℃,温度波动幅度在1.0℃左右,而对比建筑的内墙壁平均温度为8.5℃,温度波动幅度在5.0℃以上。室内空气PM2.5和CO2浓度测试结果显示,试验建筑二者均在标准限值范围内,而对比建筑二者都远超出标准限值。整个冬季能耗测试结果显示,试验建筑比对比建筑节省电能3 390 kW·h,减少CO2排放量79.4%。因此,北方寒冷地区的农宅采用太阳能供暖其舒适性和节能环保效益都较好。 相似文献
5.
文章采用物联网技术管理网络机房,通过对物联网关键技术的分析,解决网络机房管理中存在的实际难题,为机房管理提供实时准确的信息.采用物联网的RFID技术是能够完成对机房数据的实时监控和记录,机房管理者在对这些实时传输的数据进行分析后,能够对机房内部设备整体运行的情况进行监测,一旦机房出现故障,能够形成快速响应,从而更加迅速的解决出现的问题. 相似文献
6.
王轲道 《中学语文教学参考(高中生版(学语文))》2004,(3)
长期以来,气候类型的判断一直是地理教学中较难讲授的内容,更是学生学习的难点。往往面对气候资料,大部分同学感到无从下手无法判断,甚至有些老师也感到困难。因此,探讨有效的气候类型判断方法很有必要。一、方法介绍1.依据最冷月平均温度,判断可能属于哪一个温度带通过气候资料,判断气候类型时,首先要看气候资料中的最冷月平均温度,如果最冷月平均温度低于- 2 0℃,则可暂定属于寒带;如果最冷月平均温度在- 2 0℃到0℃左右,则可暂定属于温带;如果最冷月平均温度在15℃～18℃以上,则可暂定属于热带。这样,根据气候资料中的最冷月平均温度,可… 相似文献
7.
陈作义 《广东教育学院学报》2013,(3):53-57
翅片管束发生凝结换热对换热效果影响重大.选定含湿混合气体(温度75～94℃和水蒸气质量分数12%～20%),对该气体横掠翅片管束的凝结换热进行了实验研究.通过对实验数据的分析,得到混合气体进口温度、混合气体流速、不凝性气体质量分数对凝结换热过程的影响,并拟合得到凝结换热Nu数的准则关系式. 相似文献
8.
《实验室研究与探索》2017,(3):55-58
设计了某型号笔记本电脑水冷散热系统,通过热力学理论散热模拟计算设计制造出的换热器散热效率为90%,水冷散热系统的峰值温度为70℃。用鲁大师软件监测了计算机中央处理器(CPU)和显卡的温度,比较分析了其散热效果。结果表明:在大型游戏连续运行2 h内,水冷散热系统下,CPU温度最高达75℃,显卡温度达到80℃;风冷散热系统下,显卡和CPU达到80℃左右,相对于水冷散热系统,散热较慢;而在大型单机游戏运行结束时,水冷系统下显卡和CPU突降为50℃,在非大型游戏电脑正常工作状态下,显卡和CPU温度维持在50℃左右。而风冷散热系统下大型游戏运行2 h结束90 min后,CPU温度降至55℃左右,显卡温度降至50℃以下。 相似文献
9.
每年10月下旬至11月中旬这段时间,北方气温明显下降,昼夜温差大,加之不到供暖期,室内偏冷,日平均温度有时只有3℃～4℃;有时提前供暖,室内温度又骤升至20℃左右。在这秋冬交替气候多变的时期,幼儿往往表现出诸多不适应。这段时间易发生感冒、肠胃炎等流行病,轻者吃药打针,重者住院治疗,给患儿及患儿家长带来痛苦和麻烦,也给幼儿园教育管理带来不利。因此,入冬初期保育工作十分繁重。经过多年实践,我们注重把好衣着厚薄、温度湿度、进食饮水、消毒防病四关。衣着关根据气候变化,注意适时增减幼儿衣着,做到冷厚热薄;冷多热少,不迟不早。俗话说“春焐秋冻”,意思是告诫人们入冬时衣服不要一下子穿得太 相似文献
10.
《浙江大学学报(A卷英文版)》2020,(2)
目的:面向液体火箭发动机再生冷却,针对较高亚临界压力下单个垂直微小通道中液氮的流动沸腾传热特性开展实验研究,讨论并分析热流密度、密流和入口压力对沸腾曲线和局部换热系数的影响,以获得液氮在微小通道中较高亚临界压力下的流动沸腾传热机理及实验关系式。创新点:1.通过工况参数对沸腾曲线和局部换热系数的影响分析,得到液氮在微小通道中较高亚临界压力下的流动沸腾传热机理;2.提出微小通道中较高亚临界压力下的流动沸腾传热修正关系式。方法:1.通过实验方法,得到液氮在微小通道中较高亚临界压力下的沸腾曲线和局部换热系数;2.通过实验与理论分析相结合,得到液氮在微小通道中较高亚临界压力下的流动沸腾传热机理;3.通过理论分析,将实验结果与六种预测关系式进行比较,并根据实验数据提出一种改进的实验关系式(表7)。结论:1.热流密度对换热系数有较大影响,随着热流密度的增大,出现了三种变化趋势;2.在实验范围内,密流的增大抑制了核态沸腾,并且降低了环状流的局部换热系数;3.入口压力的增大在较大干度范围内增大了局部换热系数,直到局部蒸干的出现;4.综合考虑核态沸腾和局部蒸干两种主导传热机理,在Tran关系式的基础上提出了一种适用于较高亚临界压力条件下微小通道中液氮流动沸腾的修正实验关系式(平均绝对误差为19.3%)。 相似文献
11.
It is promising to simultaneously develop multiple products through the combined utilization of sea-water by solar chimney technology. A small scale experimental system was set up. The collector temperature, the seawater temperature, and the temperature and humidity of the airflow under the collector were measured. Thermal network analysis of the system was carried out. The results show that the airflow is nearly saturated at the entrance of the chimney, and the mean dry-bulb and wet-bulb temperatures of the airflow have increased by 8.4℃ and 9.6℃ respectively. The radiation heat transfer between the collector and the sky is the biggest heat loss in the system, which is up to 29.1% on average of the solar energy. However, the water evaporation heat is about 23.6% on average of the solar energy. To reduce the heat loss and enhance the water evaporation, it is necessary to reduce the emissivity and thermal conductivity of the collector and increase the evaporation areas. 相似文献
12.
将热管系统的蒸发器作为连铸结晶器,通过测试蒸发室及熔融室内的温度,揭示热管运行温度和熔融室温度的关系。结果表明：在普通环境温度下和物质熔融温度为160℃时．热管工作温度为50-70℃,热管系统蒸发器面积和冷凝器面积之比从1：15增加到1：30时。热管工作温度降低较快,下降约23％;当面积比从1：30增加到1：60时,下降约8％：将热管系统运用于连铸生产时．增大热管系统的冷凝器面积,可以降低热管工作温度。但降低程度随面积比的增大而减小;当用于镁合金连铸时,热管的运行温度将超过100℃． 相似文献
13.
分析液氮冻结的现场实施情况,结合工程背景资料建立数值分析模型,通过计算分析并与现场实测成果验证,系统研究液氮冻结过程中竖直方向与水平方向温度场分布特征及其变化规律。结果表明：液氮冻结通过沸腾吸热与对流换热方式达到降温冻结的效果,相较于盐水循环冻结方式,液氮冻结效率高,周期短;但其冻结温度场分布不均匀,在竖直方向上存在较大温差,温度最低区域分布在液氮沸腾区范围,而水平方向上分布较为均匀;温度场中低温区域并不在两排冻结管之间均匀发展,冻结区域向连续墙方向发展的速度比土体方向发展速度快。基于研究成果,提出了液氮冻结加固设计、施工的优化建议,为今后液氮冻结工程提供理论依据与技术参考。 相似文献
14.
为研究一种新型强化传热管的传热效果,对光管、普通翅片管和螺旋槽式翅片管在不同流量条件下的传热特性进行了比较研究.实验中管程工质为水蒸气,壳程通入饱和液态水作为冷源.结果表明,螺旋槽式翅片管的换热量明显高于光管和普通翅片管,并且随着流体流量的增加,传热效率的提高也更加明显.当蒸汽温度140℃时,螺旋槽式翅片管沸腾传热系数... 相似文献
15.
Indoor air quality and thermal comfort are important features of indoor environment, In this paper, a numerical simulation based on the k-ε model of CFD is used to analyze factors such as loading, exterior-protected construction, blowing-in rate that play an important role in the temperature field and airflow field of the displacement ventilation system. Exterior-protected construction has little influence on indoor temperature distribution of displacement ventilation systems and the influence is limited only in a small area near the external wall when the indoor heat source is the main cooling load. The height of a room has little influence on indoor temperature field, and the temperature gradient of active region is basically unchanged. In the system combined with a displacement ventilation system and a cooling system, the height also has little influence. When the cooling load is high,the indoor heat source creates a strong convective plume, which will make the average indoor air age lower, the ventilation efficiency higher and the elimination of pollutant easier. Air supply rate plays an important role in displacement ventilation systems. The increase of air supply rate that can be realized by increasing the air supply velocity and enlarging the area of air inlet will increase the mass capability of the system and diminish the vertical temperature gradient. From the comparison between simulations and experiments, it is concluded that this simulation are creditable. 相似文献
16.
Based on a three-step kinetic mechanism, a one-dimensional, time dependent, numerical model is presented forthe smoldering propagation in a horizontally packed bed of cellulosic material. The kinetic processes include pyrolysis andoxidation degradation of fuel and oxidation of char. Heat transfer between solid and gas is taken into account, and the diffusioncoefficient varies with the temperature. Radiative heat transfer is included by using the diffusion approximation. The effectsof airflow velocity and oxygen concentration are simulated on the smoldering velocity and the averaged maximum temperatureof smoldering fuel. The results indicate that the spread rate varies linearly with increasing airflow velocity, and the inlet airvelocity has little effect on the maximum temperature. The evolutions of gas species and solid compositions are predicted.The effects of frequency factors (A1, A2 and A3) are analyzed. Simulations show that the smoldering spread rate increaseswith increasing A2 (fuel oxidation), but decreases with A1 (fuel pyrolysis) and A3 (char oxidation). 相似文献
17.
针对锂离子电池电化学产热机理复杂、热分析建模参数多等问题,引入集总模型思想,建立单体方形电池少参化产热模型。通过大量实验、数据分析,辩识电池热物性参数,获得基于真实物理参数的热行为仿真集总模型。对比单体电池在不同放电倍率下温度场的实验数据和仿真结果发现：在0.2、0.5、1 C恒流放电工况下,集总模型对电池表面温度的预测误差均低于0.55℃,误差率小于1.94%,达到实际工程预测精度要求。该研究结果可为商业化锂离子电池热行为分析提供参考。 相似文献
18.
刘辉敏 《中国现代教育装备》2012,(5):12-14
为改善教学效果,将ANSYS引入传热学多媒体课程。介绍了传热计算相关理论,以典型的传热过程为例,采用ANSYS对其温度场进行了分析。采用ANSYS能够调动课堂气氛,有利于学生对知识点的掌握。 相似文献
19.
A one-dimensional column is set up to study the mass transfer during air sparging process for methyl tertiary butyl ether(MTBE) removal in saturated soil and groundwater, with the condition of different airflow and soil penetrability. It is shown that the removal rate of MTBE can reach 80%, 90% and 95% when airflow is 0.05 m3/h, 0.085 m3/h and 0.10 m3/h, respectively. Increasing airflow will help to increase the removal rate of dissolved MTBE, but eventually a threshold removal rate is reached, above which further increasing air injection rates does not increase the removal rate. Fine sand allows the injected air to travel in bubble form, while coarse sand and medium sand allow the injected air to travel in the form of discrete channels; the greater the soil grain size is, the more extensive the channel net work forms, which in turn leads to higher removal rate. A tailing effect of lingering residual contaminant concentrations occur within the fine sand. About 20% of MTBE cannot be removed. 相似文献
20.
A cooling system consisting of several heat exchange modules is a necessary part of an automobile, and its performance has a direct effect on a vehicle’s energy consumption. Heat exchangers, such as a charged air cooler (CAC), radiator, oil cooler, or condenser have different structures and can be arranged in various orders, and each combination may produce different effects because of interactions among them. In this study, we aimed to explore the principles governing interactions among adjacent heat exchangers in a cooling system, using numerical simulation and experimental technology. 3D models with different combinations were developed, compared, and analyzed comprehensively. A wind tunnel test platform was constructed to validate the computational results. We found that the heat dissipation of the modules was affected slightly by their relative position (the rules basically comply with the field synergy principle), but was independent of the modules’ spacing within a certain distance range. The heat dissipation of one module could be effectively improved by restructuring, but with a penalty of higher resistance. However, the negative effect on the downstream module was much less than expected. The results indicated that the intensity of heat transfer depends not only on the average temperature difference between cold and hot mediums, but also on the temperature distribution. 相似文献