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1.
垂直埋管土壤源热泵供热供冷实验与分析   总被引:7,自引:1,他引:6  
张开黎  王如竹  于立强 《流体机械》2001,29(9):57-60,53
论述了垂直埋管周围土壤温度场随时间的变化以及垂直埋管土壤源热泵供热供冷性能同土壤温度变化的关系,采用有限元法利用所建理论模型对垂直埋管周围土壤温度场进行了数值模拟,模拟结果与实际测试结果较为吻合。  相似文献   

2.
A method for performing magnetic resonance imaging (MRI) and producing field-focusing hyperthermia sequentially in phantoms and rat tissues with a grounded hyperthermic probe and a commercial MRI scanner was demonstrated. In the treatment mode the MRI scanner was used as a radiofrequency (RF) power source, and an invasive, electrically grounded, tuned probe was used to produce hyperthermia in phantoms via induced eddy current convergence. Temperature increases of 4.5 degrees C/5 minutes in a dielectrically uniform phantom and 5.0 degrees C/6 minutes in the peritoneum of a rat were measured in the vicinity (3-5 mm) of the grounded probe with the transmitter of the MRI scanner working at 2 per cent duty cycle. The advantage of this combined diagnostic and therapeutic approach is that the position of the hyperthermic probe can be monitored before each treatment, with observation of the tumor during and after treatment, if desired. In addition, the total cost is significantly less than that of both an MRI scanner and an RF hyperthermia treatment system.  相似文献   

3.
In the course of constructing an apparatus suitable for studies of nuclear magnetic resonance at high temperatures and high fields we developed a furnace with a new heating element which has been applied for the first time to NMR studies. The furnace can work in a 8-T field of a superconducting magnet system at temperatures up to 2200 K. Because of its geometrical form the heating element does not cause any measurable disturbing magnetic fields resulting from the heating current, and has many advantages compared to conventional heating elements. The temperature at which, up to this moment, we could observe NMR in external fields of 8 T amounts to 1200 K. The specifically adapted NMR probe works at radio frequencies up to 50 MHz. With this apparatus we carried out measurements of the magnitude, sign, and temperature dependence of the Knight shift of Mo in molybdenum metal.  相似文献   

4.
碳纤维电热元件辐射强度分布的数值模拟   总被引:4,自引:0,他引:4  
建立碳纤维电热辐射管辐射强度分布的数学模型,基于MATLAB软件模拟不同类型碳纤维电热元件的辐射强度分布,并讨论其空间辐射特性。模拟结果表明:结构参数对碳纤维电热元件辐射强度分布的影响较大,随管径的变化,空间辐射强度存在一个最佳值,辐射强度分布的不均匀性随管径的增加而增加。对比不同类型电热元件的辐射强度分布特性,相同规格电热元件的辐射强度分布场基本一致,而辐射强度值随元件类型而变化。碳纤维电热元件的辐射强度明显高于普通金属加热元件,并且双侧涂覆红外涂料可使其辐射强度明显地提高。调整涂料的配方可以改变红外辐射的频谱分布以满足特殊的加热要求。试验证明:测试数据与模拟结果基本一致,为后期辐射场的设计提供了依据。  相似文献   

5.
张姝  郑茂余 《流体机械》2012,40(8):69-74
提出了空气源蓄热式土壤源热泵系统,该系统将夏季自然空气热量蓄存于土壤中,冬季再由热泵取出供热,即实现了可再生能源的移季利用又能解决严寒地区应用土壤源热泵引起的土壤全年总取热量与总排热量失衡的问题.为研究系统运行特性,建立了系统全年仿真模型,并以哈尔滨某建筑为例进行了模拟计算.结果表明,经移季蓄热埋管管壁处土壤温度升高了3.2℃,显著改善了热泵运行条件,使得供暖保证率达到了99.5%,热泵性能系数为3.99,系统全年供热性能系数为2.56.证明了该系统在严寒地区应用是可行的.  相似文献   

6.
针对空气加热器内部电加热管位置对其出口温度影响较大这一问题,采用蒙特卡罗(Monte-Carlo)方法分析并编制了计算机程序,完成了对加热管位置的随机布置,然后采用有限元方法并结合仿真分析软件ANSYS对加热器内的温度场进行了数值模拟,得到使其出口温度达到预定值时所需的最少加热管数目和各个管的合理位置,从而实现了用计算机辅助设计空气加热器,为工程设计提供了理论依据。  相似文献   

7.
地下水源热泵代替燃油锅炉供热的经济性分析   总被引:1,自引:0,他引:1  
刘东  由世俊 《流体机械》2004,32(10):64-66
以胜利油田某供暖小区为例,对燃煤锅炉、燃油锅炉、电锅炉、地下水源热泵为热源的几种方案进行了分析比较,认为用地下水源热泵系统代替燃油锅炉是可行的,而且是经济的;介绍了工程设计和运行的具体情况,指出了地下水源热泵系统的特点和使用时的限制条件。  相似文献   

8.
A glove box adaptation of a high resolution atomic emission spectrometer (AES) is reported employing sequential radial viewing of an inductively coupled plasma (ICP) source for determination of trace metallic elements in plutonium bearing samples. The original compact ICP-AES unit was converted into separate units. All electronic and optical components were placed outside radioactive containment. The entire assembly of the ICP torch, radiofrequency coil, nebulizer, spray chamber, peristaltic pump, and drainage system were placed inside the glove box for the analysis of radioactive samples. All these modifications were achieved without any compromise on the analytical performance of the spectrometer. Operational experience of the instrument for analysis as well as additional information for the upkeep and maintenance of the same is described. Proper optical alignment of the ICP source and detection system was performed.  相似文献   

9.
地源热泵供热水-空调冷热联供综合系统的实验研究   总被引:4,自引:0,他引:4  
介绍了作者自主设计实施的地源热泵热水-空调冷热联供系统,运用单因素方法,研究地埋管总深度、地埋管及空调的循环介质流量等对热泵系统运行特性的影响,提出土壤源制热水和冷热联供两种工况下的合理运行方式。研究结果表明土壤源制热水间歇运行时既满足生活热水需求,又避免土壤源长期过度取热;夏季采用空调冷凝热为建筑制冷的同时制取生活热水,机组综合能效比达1:7以上,使热水系统全年运行成本大大降低。  相似文献   

10.
地源能在城市和工业厂区供暖供冷领域已经呈现出了蓬勃发展的趋势。结合在分布式能源系统中地源热泵装置的实际应用,来实现工业园区的分布式能源冷热能的互补。该文主要研究了地源热泵装置在工业园区能源系统中,实现“一键启停操作”的自动调节的控制策略,简化了操作,通过运算调节控制,实现降本增效、节能环保的目的,具有重大的现实意义。  相似文献   

11.
The finite element approach is applied to predict crack patterns in a single or composite material under loadings. Crack patterns are represented as variations of a field variable. These variations are determined from the solution of a coupled system of equations consisting of an Allen-Cahn or Ginzburg-Landau type field equation and elasticity equations based on phase field theory. This representation does not require tracking crack tips as in the conventional finite element approach for the modeling of crack propagation problems. For a numerical solution for the system, a finite element algorithm is proposed and implemented into the finite element program “FEAP”. Several numerical simulations are performed and analyzed to predict the crack patterns in 2D single or composite materials under the loadings.  相似文献   

12.
单根真空集热管和复合抛物面聚光器(CPC)组成的接收器(单管接收器)对线性菲涅尔式聚光系统的镜场布置有特殊要求。本文根据单管接收器的特点,提出了利用CPC最大接受半角控制镜场高宽比实现镜场无阴影布置的方法。利用几何关系推导了镜场无阴影布置的数学表达式,并给出了数值计算方法。通过算例,将一次反射镜和镜场中心的距离与镜场地面覆盖率相结合对镜场布置进行了优化。研究结果表明:对于CPC最大接受半角为45°、反射镜宽度为380mm、而反射镜列数为21的镜场,当系统无阴影工作时间确定为6h时,相邻一次反射镜间距最大为537mm较为合理,而此时地面覆盖率为73.28%。该方法对于单管接收器线性菲涅尔聚光镜场的布置具有普适性,对线性菲涅尔式聚光系统的设计具有较好的指导意义。  相似文献   

13.
以沈阳地区典型民用住宅建筑为例,对太阳能-地源热泵与热网互补供暖系统进行仿真研究。利用TRNSYS软件,建立太阳能-地源热泵与热网互补供暖系统仿真模型和地源热泵与热网互补供暖系统仿真模型,对2种系统的蒸发器进出水温度、热泵机组COP,及热网加热量进行对比分析,结果表明:太阳能-地源热泵与热网互补供暖系统相比地源热泵与热网互补供暖系统的平均出水温度提高了50.41%;平均进水温度提高了53.08%;平均COP由3.167增加到4.65;热网运行时间由1540h增加到2032h;热网供暖季的平均换热量由114566.62kJ/h减少到101257.27kJ/h。  相似文献   

14.
利用单一结构元素对遥感图像进行形态学边缘检测时,可能会出现边缘不完整、抑制噪声能力差等问题。为此,提出了一种基于可变结构元素的遥感图像形态学边缘检测方法。首先,依据遥感图像目标的多样性,构造不同尺度和包含多方位的结构元素,以此可变结构元素为基础,构建相应的形态学运算,对遥感图像进行Top-hat和Bottom-hat变换,抑制目标背景中的噪声,突出图像目标边缘;然后利用构造的可变结构元素进行形态学边缘检测,获得多幅具有不同尺度和方位边缘特征的图像;最后对各个方向边缘进行加权求和得到图像边缘,运用最小二乘法对其边缘进行拟合,从而精确地定位出目标边缘轮廓。实验结果表明,本文方法能够检测到完整的遥感图像边缘信息,边缘检测精度较高,抗噪性能优越,相比经典边缘检测算子和单一结构元素的形态学边缘检测方法,图像边缘检测效果较好,检测精度达到95%。  相似文献   

15.
一种MOCCII通用电流模式滤波器的实现   总被引:2,自引:3,他引:2  
提出一种结构简单、易于实现的基于 MOCCII(多输出端第二代电流传输器 )的单输入多输出的通用电流模式滤波器电路 ,该滤波器电路仅由 3个 MOCCIIs及 6个接地 RC元件构成 ,能同时输出低通、带通、高通、带阻及全通五种滤波形式 ,具有很低的无源灵敏度 ,且所有的 RC元件均接地。给出了硬件电路的实验结果。  相似文献   

16.
The design of a setup for crystal growth by the hydrothermal method under conditions of a rotating heat field is described. A temperature control system with a device for the dynamic switching-on of the heating elements of the growth furnace is described. The amplitude–frequency characteristics of the heat fields in the empty autoclave are presented.  相似文献   

17.
In this study, a standardized finite element model for the carbody structures of various railway vehicles made of sandwich composites was suggested. The standardized finite element model for composite carbody structures was introduced and proposed by comparing the results of real structural tests under vertical, compressive, twisting load and natural frequency tests of various railway vehicles. The results showed that the quadratic shell element was suitable to model the reinforced metal frame used to improve the flexural stiffness of sandwich panels compared to beam elements, and layered shells and solid elements were recommended to model the skin and honeycomb core of sandwich panels compared to sandwich shell elements. Also, the proposed standard finite element model has the merit of being applied to crashworthiness analysis just by minor modifications, such as contact conditions and constraint equations.  相似文献   

18.
针对快速变模温注塑成型模具热响应分析复杂问题,对电热式变模温注塑模具热响应作了研究,采用随形加热系统设计方法,将复杂的电热式变模温注塑模具简化为单个加热细胞单元,以电热元件的规格和布局为设计变量,以加热时间和型腔表面温差为热响应指标,结合Matlab图形界面开发模块和ANSYS有限元分析软件,开发了基于加热细胞单元的电热式变模温注塑模具热响应辅助分析程序,并对其准确性做了验证分析。研究结果表明,该辅助分析程序可以较好地预测模具的加热效率和型腔表面温度均匀性,可为电热式变模温注塑模具的设计、分析一体化提供一条快捷和高效的途径。  相似文献   

19.
针对公用车辆运行数据人工采集和录入效率低且不可靠等问题,提出了无线射频数据通信的设计。给出了采用SM5964单片机和NRF905单片射频收发器来实现车辆运行数据的无线采集传输的设计方案,包括车载机模块、无线发射和接收模块以及单片机和PC机之间的串行通信模块。该设计方案可推广应用于其他需要无线通信的数据采集系统。  相似文献   

20.
针对长三角地区气候特点,设计了一种冷凝热回收型地源热泵恒温恒湿空调系统,分别就夏季和春季,建立恒温恒湿空气处理的数学模型,对冷凝热回收型地源热泵恒温恒湿空调系统和常规电加热型地源热泵恒温恒湿空调系统的耗能进行理论计算与分析。结果表明:冷凝热回收型地源热泵恒温恒湿空调系统回收的冷凝热足以把降温除湿后的冷空气加热到所需温度范围,与常规电加热型地源热泵恒温恒湿空调系统相比,此系统在夏季节能40.2%,在春季节能77.4%。  相似文献   

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