共查询到18条相似文献,搜索用时 187 毫秒
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《节能技术》2016,(3)
在非能动核电站当中,PRHR(非能动余热排出,Passive Residual Heat Removal)是非能动安全系统的重要组成,是事故后、尤其是全厂断电事故后,用于载出堆芯衰变热的重要途径。在高度比例降低的整体试验中,要保证PRHR中的现象与原型的相似性,需要通过理论分析和推导,从理论上证明模拟的准确性,并得到相关的设计准则,才能保证整体试验结果的准确性。通过对事故进程中PRHR主要物理过程和现象进行识别和分析,并进行PRHR的比例分析,得到PRHR在整体试验台架进行事故模拟过程时所需满足的关键比例准则。对不同缩比尺度的比例分析和失真评价结果表明,缩比台架中PRHR的相似准则不能同时得到满足,需要根据试验目的进行选择和取舍;台架整体的高度比(长度比)越接近1,则失真越小。 相似文献
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比例化的反应堆热工水力整体试验台架广泛应用于核电站的安全评估试验。比例试验台架往往存在储热释放比例过高从而造成瞬态过程或现象模拟失真。本文从基本控制体热量传递模型出发,分别通过微分方法、流道控制体方法、以及功率积分法分别对储热进行比例分析,分析表明在满足自然循环比例分析准则的条件下,在确定的高度比下选取合适的管径比例和壁厚,能够实现释热过程的瞬态相似模拟。为了简化实际工程设计的分析难度,可采用功率积分法以确保总体储热量满足功率比例要求。最后对ACME台架的储热分析表明其储热释放比例在合理范围内。本文可为相关热工水力试验中有关储热问题的分析和解决方法研究提供一定的参考。 相似文献
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对汽轮发电机组-基础系统模化过程的动力特性相似准则关系进行研究,作者根据相似理论,分别采用量纲分析法和方程分析法建立了模型和原型之间的动力特性相似准则关系。依据相似准则关系,设计并建立了某电厂600MW汽轮发电机线-基础系统的1:20模型,并对该模型进行了模态试验和动力响应试验等动力特性研究工作;根据模型和原型之间的动力特性相似准则关系,推算出该汽轮发电机组-基础系统原型的动力特性参数,从而达到了研究汽轮发电机组-基础系统动力特性的目的。 相似文献
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流化床的放大效应十分显著,使得流化床的试验研究在大型工业流化床设计中的应用发生问题。近年来在国外发展起来的流化床模拟放大技术是从流态化现象的基本控制方程出发,根据相似原理导出一组无量纲相似准则数。这些准则数建立了不同条件下(结构尺寸、温度、压力和床料特性等)的流化性能间相似的内在关系,对流化床的试验研究及设计实践有重要的指导意义及应用前景。 相似文献
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《International Journal of Hydrogen Energy》2019,44(30):15949-15961
In order to investigate dynamic characteristics of pressure fluctuation and thermal efficiency of a liquid hydrogen (LH2) storage system during depressurization process under microgravity condition, a transient CFD model of LH2 tank is established. Based on the assumption of lumped vapor, a UDF code is developed to solve phase change and heat transfer between liquid phase and vapor one. The thermal efficiency is provided for assessing the performance of different pressure control methods. Results show that raising the injection velocity and decreasing the temperature of the injection liquid can enhance the effect of fluid mixing and shorten the depressurization time. Increasing the pressure lower limit can also improve the efficiency of depressurization process. The model can predict the tendency of pressure changes in the tank, and provide theoretical guide to design LH2 tank and optimize its parameters for space application. 相似文献
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一种应用于谐波检测的三相锁相环 总被引:1,自引:0,他引:1
为准确检测负载谐波电流,针对瞬时无功功率理论检测方法(iP-iQ)在电网电压不平衡、畸变等条件下谐波检测的不足,提出了一种新的基于双同步旋转坐标变换及交叉解耦的三相锁相环消除二倍频分量,实现更高的锁相精度、有效消除纹波。通过与传统锁相环(SRF-PLL)运用于(iP-iQ)法进行谐波检测的仿真对比,结果表明在电网电压不平衡和畸变条件下,新的三相锁相环(IDDSRF PLL)提取到的基波畸变率分别降低了1.18%和1.42%,从而提高了(iP-iQ)法的谐波检测性能。 相似文献
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白曙 《柴油机设计与制造》2015,(4):1-4
为了比较湍流模型对缸盖鼻梁区换热计算结果的影响,采用三种湍流模型对简单的T型截面刚体进行数值模拟计算,并与实验数据进行了对比。结果表明,在相同边界条件下,不同湍流模型的计算结果有很明显的差别。在沸腾状态下,对于换热问题的计算,采用AKN模型和SST模型都比较合适。其中AKN模型的计算值与实验值的偏差最小。 相似文献
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In this paper are described some results of an investigation of the transient burning rate and critical pressure decay rate required to cause extinction of a steadily burning solid propellant subject to sudden depressurization. The analysis takes into account the finite times associated with the conduction process and the variation of condensed phase heat release in the solid during a transient. It is postulated that composition of the solid decomposition products,is oxidizer-rich immediately after the start of depressurization and fuel-rich afterwards. The theoretically calculated transient burning rates qualitatively agree with experimentally measured values, reported by Norton and Schultz [1]. Yin and Hermance [2], and Fletcher and Bunde [3]. A stability analysis under the linear approximation predicts the existence of a minimum burning, surface temperature below which stable combustion of the solid propellant is not possible. The analysis correctly predicts the critical depressurization rate required to extinguish a burning solid propellant by sudden preventing of the combustion chamber. 相似文献
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《International Journal of Hydrogen Energy》2007,32(10-11):1537-1541
From production to end-users, the choice of suitable hydrogen delivery and storage systems will be essential to assure the adequate introduction and development of these facilities. This article describes the main options for hydrogen storage when produced from renewable energy, and explains different criteria to be considered in the design and building-up of stationary hydrogen storage systems, with special attention to exergy issues. An example of exergy analysis is done using data from the solar hydrogen storage facility of the Spanish Instituto Nacional de Técnica Aeroespacial (INTA).As expected, the main conclusions of this analysis show the advantage of low pressure hydrogen in comparison with other available methods to store hydrogen. Another interesting option, from the exergy efficiency point of view, is the storage of hydrogen in metal hydride systems. The last option, and the most inefficient, is the high pressure hydrogen storage. 相似文献