搅拌对微波加热过程中热点形成的影响研究

目前,微波作为一种新型的加热手段已经被广泛应用于化学各个领域中,微波加热过程中由于热点现象存在而造成的危险不容忽视.文中利用有限元方法联合求解了包括电磁场方程、流体力学方程和热传导方程在内的多物理场方程组,研究了搅拌速度的变化对微波加热去离子水过程中热点形成的影响.分析结果显示：搅拌并不能完全消除微波加热过程中的热点.     

地板辐射采暖系统的热舒适性评价

通过热舒适平衡方程、热平衡评价指标（PMV）及用来表示热舒适不满意百分率的（PPD）指标对地板辐射采暖的热舒适性进行评价．从而得出采用地板辐射采暖系统,当室内设计温度在14-17℃,人们就会感觉比较舒适,不但降低了室内设计温度,也达到了节能的目的。     

Operation Performance of Central Solar Heating System with Seasonal Storage Water Tank in Harbin

This paper presented a preliminary research on the central solar heating system with seasonal stor-age(CSHSSS)used in cold climate in China.A mathematical model of the solar energy seasonal storage water tank used in the central solar heating system was firstly developed based on energy conservation.This was fol-lowed by the simulation of the CSHSSS used in a two-floor villa in Harbin,and analysis of the impacts on storage water temperature of tank volume,solar collector area,tank burial depth,insulation thickness around the tank,etc.The results show there is a relatively economical tank volume to optimize the system efficiency,which de-creases with increasing tank volume at the constant collector area,and increases with increasing collector area at the constant tank volume.Furthermore,the insulation thickness has obvious effect on avoiding heat loss,while the tank burial depth doesn't.In addition-the relationship between the solar collector efficiency and storage wa-ter temperature is also obtained,it decreases quickly with increasing storing water temperature,and then in-creases slowly after starting space heating system.These may be helpful for relevant design and optimization in cold climates in China and all over the world.     

Numerical Study of Thermal Performance of Phase Change Material Energy Storage Floor in Solar Water Heating System

The conventional solar heating floor system contains a big water tank to store energy in the day time for heating at night,which takes much building space and is very heavy.In order to reduce the water tank velume even to cancel the tank,a novel structure of integrated water pipe floor heating system using shape-stabi-lized phase change materials (SSPCM) for thermal energy storage was developed.A numerical model was devel-oped to analyze the performance of SSPCM floor heating system under the intermittent heating condition,which was verified by our experimental data.The thermal performance of the heating system and the effects of various factors on it were analyzed numerically.The factors including phase transition temperature,heat of fusion,ther-real conductivity of SSPCM and thermal conductivity of the decoration material were analyzed.The results show that tm and kd are the most import influencing factors on the thermal performance of SSPCM floor heating sys-tem,since they determine the heat source temperature and thermal resistance between SSPCM plates and indoor air,respectively.Hm should be large to store enough thermal energy in the day time for nighttimes heating.The effects of KP can be ignored in this system.The SSPCM floor heating system has potential of making use of the daytime solar energy for heating at night efficiently in various climates when its structure is properly designed.     

1MHz/4kW超高频感应加热电源的研究与实现

采用V-MOS场效应管桥式串联谐振、高频变压器隔离方式,设计了一种频率为1MHz、功率为4kW的超高频感应加热电源.该装置采用扫频拦截方式启动,采用锁相环频率跟踪和相位锁定方式进行恒功率反馈控制.为提高逆变频率,采用了桥臂推挽变压器驱动,为保证逆变电路中桥臂上下两器件不同时导通,用门电路构成死区形成电路.经检测该电源各项性能指标良好.     

太阳能电池组件层压机加热系统的设计与试验

在研究太阳能电池组件层压机加热系统性能要求的基础上,设计了一种能够独立控制加热温度,利用热油反向流动自动补偿温度差的双向控温太阳电池组件层压机加热系统,有效地改善现有电加热系统、油加热系统和工作台之间的传热效果,提高工作台表面温度均匀性。     

倾斜煤层开采对底板突水影响的数值模拟

为了研究倾斜煤层开采条件下的突水规律,在考虑原岩应力、地质构造、地下水、采动影响等因素基础上,从应力场和渗流场共同作用的角度出发,研究含底板岩体在内的采场岩体系统的变形与破坏。研究结果表明,随着工作面的推进,底板岩层的破坏深度和范围加速增加。研究结论将数值模拟结果与工程实际进行比较分析,为寻求安全、经济的开采方法提供了理论依据。     

计量供热系统适量调控管网技术的分析

在热源供热量与热用户的需热量基本匹配的基础上,对供热系统的水力计算、管网的调节性和稳定性、管网的优化等方面进行分析和探讨,为改变计量供热系统的被动调节提供一些方法。     

功率超声致煤层瓦斯升温机理

为了分析功率超声对煤层瓦斯抽放率的影响,基于线性超声学原理,推导了功率超声在煤层瓦斯中传播的吸收致能量损耗公式及热传导诱发的能量损耗公式,并进而推导了功率超声下煤层瓦斯升温计算公式.利用试验资料研究了煤体升温对瓦斯吸附/解吸的影响,在瓦斯吸附量.温度的拟合关系式基础上,建立了功率超声诱发煤层瓦斯升温致瓦斯解吸量的计算公式.研究表明,功率超声致煤层瓦斯升温作用能提高煤层瓦斯的解吸率和抽放率.     

北方地区浅埋人防工程热负荷特点

为提高北方地区浅埋人防工程空调系统设计计算精度,以动态负荷的观点,探讨该类型工程的热负荷特征.采用统计方法分析了北方4城市(哈尔滨、长春、沈阳和北京)的典型气象年参数.以位于沈阳的某人防工程为例,运用二维数学模型计算了工程围护结构全年8 760 h的逐时传热量.计算过程中首先模拟计算了周围岩土层的温度,以该结果作为围护结构传热量计算的初始条件.热负荷的其他组成项中,假定人员和设备负荷为静态值,新风负荷则进行了动态计算.计算结果表明,北方地区浅埋型地下工程热负荷受工程外气象参数变化影响,也呈现出年周期性波动和日周期性波动.