共查询到20条相似文献,搜索用时 31 毫秒
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谱带吸收式光纤温度传感器 总被引:8,自引:1,他引:7
本文提出了一种新颖的半导体谱带吸收式光纤温度传感器系统结构.分析了半导体谱带吸收式光纤温度传感器的原理,推导了其数学模型.该传感器用反射式传感结构,以砷化镓半导体材料作为温度敏感元件,并利用除法器消除了传感器光源的波动及光纤的连接损耗,使传感器具有结构简单、抗环境干扰、高可靠性特点.文中对传感器的整个系统进行了设计和分析,并进行了实验测试,实验结果显示:该传感器在-20~110℃的温度范围内有1℃的测量精确度,并且温度从110℃降到15℃时的时间响应为25s. 相似文献
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基于光滑粒子流体动力学方法, 分别采用实测样品几何缺陷模型和简化V形沟槽模型对铅的微喷射过程进行了模拟. 重点分析了金属表面几何缺陷微细结构对微喷射特性的影响, 并将数值计算结果与相应的实验测量值进行对比. 结果表明, 基于实测样品几何缺陷模型计算的最快喷射速度和累积喷射量与实验测量结果符合得很好. 进一步研究发现, 在实测样品几何缺陷诱导的微喷射过程中存在“二次汇聚喷射”现象, 与单次喷射相比, 该过程会诱导产生更高的喷射速度并显著影响微喷物的空间密度分布. 这说明除了受扰动波长、深度影响外,表面几何缺陷微细结构也是影响金属微喷射过程的重要因素. 相似文献
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《Heat Recovery Systems and CHP》1995,15(3):249-256
The optimal performance of an absorption heat transformer, i.e. a type II absorption heat pump, is investigated by using the cyclic model with continuous flow. The effect of thermal resistances between the heat transformer and the heat reservoirs is considered in the model. A general expression related to the rate of heat-pumping, the coefficient of performance and the overall heat transfer area of the heat transformer is derived. The expression is used to optimise the main performance parameters of the heat transformer. The maximum rate of heat-pumping and the corresponding coefficient of performance are calculated. For a given overall heat transfer area of the heat transformer, the optimal relation of the heat transfer areas of the heat exchangers is obtained. The problems concerning the optimal choices of other performance parameters are discussed. The results obtained here can not only enrich the theory of finite time thermodynamics, but also provide some new theoretical bases for the optimal design and operation of real absorption heat transformers. 相似文献
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多绕组干式整流变压器作为托卡马克装置加热系统中高压电源的一个重要设备,其性能优良与否直接关系到高压电源的输出品质。开展变压器的功率损耗与散热分析研究,减少变压器因温度上升造成的性能影响,对保证变压器的良好工作状态是十分重要的。通过MATLAB对干空气下的比热容、传热系数等热物理性质与温度的关系进行拟合分析,得到相关的关系方程,对变压器的对流传热与热辐射进行分析计算,得到仅在空气自然对流和热辐射的情况下,不能使变压器的温度控制在满足性能的温度范围之内。在强迫空气对流的情况下,实现了变压器良好的散热。进一步利用ANSYS对变压器的温度场分布进行分析,利用温度场的分布趋势图观察强迫风冷相对于自然冷却的优点,强迫风冷降低了整体的温度,使热量更快地散发到周围大气中,减少了变压器受高温的危害。 相似文献
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《Heat Recovery Systems and CHP》1992,12(1):49-55
A heat transformer can upgrade heat to a higher temperature. A two-stage heat transformer has a greater temperature upgrading potential than a single-stage heat transformer, e.g. heat can be upgraded from a level of about 130–140°C to temperatures of about 200°C. A practical method to select suitable hydrides to be used in a two-stage heat transformer is presented. The example discussed shows that the selected alloys result in a reasonable operation of the two-stage heat transformer. Three different evaluation criteria viz. coefficient of performance, alloy output and temperature output, are introduced to compare the operational characteristics of heat transformers with different alloys; the influence of some metal hydride properties on the operational characteristics is also discussed. 相似文献
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《Heat Recovery Systems and CHP》1994,14(3):265-272
An absorption heat transformer using the working pair trifluoroethanol-pyrrolidone (TFE-Pyr) is described. Trifluoroethanol is used as the working fluid and pyrrolidone is used as the absorbent. A computer simulation model is developed for the thermodynamic analysis of the heat transformer. By the verification of a group of experimental measurements, the model is used to investigate the influences of various operating conditions, design parameters and component dimensions on the performance of the heat transformer. Conclusions on the heat transformer are made according to the results of the thermodynamic assessment. 相似文献
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立式升温型溴化锂吸收式热泵的设计与变工况研究 总被引:1,自引:0,他引:1
本文对立式升温型溴化锂吸收式热泵循环和各部件建立了数学模型,并设计了85℃热水驱动产110℃热水的立式降膜升温型溴化锂吸收式热泵,吸收器输出功率为50 kW。然后对其在热源热水温度和流量变化、冷却水入口温度和流量改变等非设计工况下的工作特性进行了计算与分析研究,得到变工况对于机组性能系数,效率和机组负荷的影响关系图。发现在我们的研究范围内,热源水参数的变化对机组性能的影响要大于冷却水。并且在热源水参数变化过程中,机组性能存在性能急剧变化的拐点,实际运行中应当避免。 相似文献
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《Heat Recovery Systems and CHP》1990,10(5-6):549-553
The coupling between a single-stage heat transformer and finite heat sources and sinks is considered. A simple lumped-parameter mathematical model shows that the performance is noticeably reduced in comparison with the simpler case of an infinite (constant temperature) heat source. The best performance is obtained when the evaporator and the generator are fed in series, the evaporator being placed upstream. 相似文献
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《Heat Recovery Systems and CHP》1991,11(5):361-369
Derived thermodynamic design data, including Carnot coefficients of performance, enthalpy-based coefficients of performance with and without an economizer heat exchanger and flow ratios for possible combinations of operating temperatures, are calculated for absorption heat transformers operating on a system in which water is used as the working fluid and aqueous lithium iodide solution as absorbent. The effects of operating temperatures as well as economizer heat exchanger on the performance of the absorption heat transformer are illustrated graphically. 相似文献
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《Heat Recovery Systems and CHP》1988,8(5):445-450
High performance absorption heat transformers based on improved configurations can be proposed with the aim of widening the range of operation of the single stage heat transformer (SSHT). In this paper a two stage heat transformer arranged by coupling the absorber of the first stage to the evaporator of the second stage (TSHT) is analyzed by means of a lumped-parameter mathematical model, written with reference to the water-sulphuric acid system.The computed values of four different indexes of performance show that the proposed TSHT allows one to noticeably increase the gross temperature lift obtainable with a SSHT, while saving a large fraction of the input energy. 相似文献
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《Heat Recovery Systems and CHP》1990,10(5-6):527-537
An adsorption heat transformer can raise the temperature level of a fraction of waste heat by rejecting the remaining heat to a low temperature level. In this work some alternatives in the design of an adsorption heat transformer, such as a 2-tank system, 3-tank system and 4-tank system, are evaluated using zeolite-water vapour as the adsorbent-adsorbate pair. The values of coefficient of performance (COP) are computed for each system for various temperatures of waste heat source at which the heat is available and heat sink at which the heat is delivered.It is found that an adsorption heat transformer can be used for a gross temperature lift as high as 50°C with a fairly good COP value. Moreover the 4-tank system gives a much improved COP value as compared to the 2-tank and 3-tank systems for the same operating conditions. It is also found that the effect of temperature driving force for heat transfer on the COP value is quite pronounced. 相似文献
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《Heat Recovery Systems and CHP》1988,8(5):451-457
An innovative heat transformer can be derived from the TSHT discussed in Part I. Its configuration is essentially based on a serial arrangement of the two absorbers (“double absorption heat transformer”, DAHT) and allows a drastic reduction of the number of items necessary for the TSHT.The performance of a DAHT operated with the water-sulphuric acid system was computed by means of a lumped-parameter mathematical model and expressed in terms of the four indexes of performance previously used for the TSHT examined in Part I. The results show that the DAHT reaches its optimum performance at values of gross temperature lift intermediate between those optimal for the SSHT and the TSHT, respectively. 相似文献