共查询到19条相似文献,搜索用时 703 毫秒
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本文针对恶劣条件下滑动弧等离子体放电稳定性问题,搭建了高气压交流旋转滑动弧放电实验系统,开展了高气压下交流旋转滑动弧放电特性实验,并对其放电特性、电弧运动特性、光谱特性进行了分析.研究结果表明:随着介质气体压力的升高,滑动弧放电的电压、电流、能量均呈现增大趋势,当介质气体压力升高到0.52 MPa时,滑动弧放电的能量从常压下的84.74 J增大到147.13 J;且随着介质气体压力的升高,电弧的击穿频率并不是单调变化,而是在0.2 MPa时达到最大为26.55 kHz;高气压下电弧运动过程中会出现“弧道骤变”现象;随着介质气体压力的升高,滑动弧放电的整体光谱发射强度呈现变强趋势;通过两谱线法对滑动弧放电的电子激发温度进行了计算,常压下滑动弧放电的电子激发温度为0.8153 eV,随着介质气体压力的升高,电子激发温度呈现升高趋势,当介质气体压力达到0.4 MPa时,滑动弧放电的电子激发温度升高至5.3165 eV. 相似文献
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轮背空腔-密封气对CAES向心涡轮变工况流动损失的影响 总被引:1,自引:0,他引:1
本文以国内首套MW级压缩空气储能(CAES)系统末级向心涡轮为研究对象,通过数值模拟分析了变工况条件下轮背空腔-密封气对等熵效率和流场结构的影响.结果表明:在求解中考虑轮背空腔-密封气结构能够使等熵效率数值解的偏差减小0.7%;随涡轮进口压力增加,轮背空腔泄漏流由叶片吸力面中部叶高区域逐渐向轮毂转移,流动损失先增加后减小;合理降低轮背空腔泄漏气体的轴向速度,能够减弱轮背空腔-密封气结构对等熵效率的负面影响,使向心涡轮在较宽的变工况范围内都保持高效运行. 相似文献
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高压气体吸收光谱特性的研究是可调谐半导体激光吸收光谱技术应用于爆轰发动机等高压燃烧环境的重要基础.为了解气体吸收光谱随压力的变化规律特别是在高压下的吸收光谱特性,本文以CO2为气体介质对其在高压环境下近红外波段1.58μm处的吸收光谱进行了理论分析与试验研究,并给出一种高压气体浓度的计算方法.在1—10.13×105Pa压力环境下,对1.58μm处CO2吸收光谱进行了数值模拟,搭建了高压环境气体在线测量试验系统,对CO2在波段1578.1—1579.7 nm的吸收光谱进行了试验测量.利用线性回归拟合将试验所得光谱吸收率与模拟吸收率进行对比,对高压环境下气体浓度进行了计算.结果表明,试验所得吸收光谱与数值模拟结果相吻合,1—10.13×105Pa压力环境下利用线性拟合寻优法计算气体浓度最大误差为5.5%,平均误差2.6%. 相似文献
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光纤光栅(FBG)传感器具有灵敏度高,测量量程大,抗电磁干扰能力强,耐高温能力强等诸多优点,在爆炸冲击测试领域具有广泛的应用前景。针对空腔爆炸压力变化历程对压力传感器的性能要求,设计了一种抗冲击FBG压力传感器。传感器采用圆平膜片作为承压面,利用均匀压力作用下的挠度拉伸FBG产生位移。对传感器的力学模型进行了理论计算,并进行了有限元仿真,理论分析与数值模拟计算结果误差小于2%。使用标准压力源对传感器进行了标定,获得最终的压力灵敏度为545.187 kPa/nm,线性度相关度为99.998%。根据空腔爆炸现场防护需求,设计了有效的抗爆防护装置,并将该传感器成功用于空腔爆炸爆后气体压力变化历程测量,取得很好的测试效果。 相似文献
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The mean flow of gas in a pipe past a cavity can excite the resonant acoustic modes of the cavity--much like blowing across the top of a bottle. The periodic shedding of vortices from the leading edge of the mouth of the cavity feeds energy into the acoustic modes which, in turn, affect the shedding of the next vortex. This so-called aeroacoustic whistle can excite very high amplitude acoustic standing waves within a cavity defined by coaxial side branches closed at their ends. The amplitude of these standing waves can easily be 20% of the ambient pressure at optimal gas flow rates and ambient pressures within the main pipe. A standing wave thermoacoustic heat pump is a device which utilizes the in-phase pressure and displacement oscillations to pump heat across a porous medium thereby establishing, or maintaining, a temperature gradient. Experimental results of a combined system of aeroacoustic sound source and a simple thermoacoustic stack will be presented. 相似文献
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E. A. Bondarev I. I. Rozhin V. V. Popov K. K. Argunova 《Journal of Engineering Thermophysics》2018,27(2):221-231
The paper is devoted to simulation of the initial stage of natural gas hydrate underground storage: gas injection into aquifer just below permafrost rocks. It is based on the mathematical model of multiphase non-isothermal real gas and water flow in porous media. The model takes into account the transformation of gas and water into hydrate at certain temperature, which depends on gas flow pressure. The dynamics of hydrate and water saturation as well as the pressure and temperature fields in a reservoir with given porosity, permeability, and initial values of pressure, temperature and water saturation were studied. An implicit finite-difference scheme is used to approximate the original boundary-value problem. The finite-difference equations are solved using simple iteration and sweeping algorithms. Several examples of calculations corresponding to real cases are given. Calculations have revealed that the final result strongly depends on the combination of porosity and permeability of a reservoir. 相似文献
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引射式压力恢复系统是化学激光系统应用中的一个重要组成部分,为了提高引射器引射效率,减小整个系统尺寸,可以采用主动降低光腔出口气流温度的方法。通过数值模拟,开展了用热交换器降低光腔出口气流温度的研究。给出了混合气体的热物理性质、热交换器建模方法及数值模拟条件,比较了不同条件下热交换器性能的差异,发现由于出口气流密度很低,热交换器的总传热系数、压力损失比常规条件下有较大幅度的减小。此时适当增大椭圆管尺寸,采用高翅片换热管,可以有效地提高热交换器的换热能力。 相似文献
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针对周围是均匀岩石介质的地下化学爆炸,研究爆炸后爆室内气体的泄漏规律.利用量纲分析,得到影响气体泄漏时间的主要物理量,包括气体动力学粘度、爆室内超压、围岩孔隙率及围岩厚度的平方与渗透率的比值等,并初步给出它们之间的函数关系.然后基于达西定律,推导计算气体泄漏时间的解析公式.得到的气体泄漏时间计算公式与通过量纲分析得到的定性函数关系式完全相符,二者从不同的角度对同一问题给出了相容的结果.可为地下化学爆炸气体泄漏的理论分析和规律性研究提供研究思路和工具,为地下爆炸有关的工程估算提供参考依据. 相似文献
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A gas distribution function for a 2D nanopore was derived, making possible calculations of thermodynamic characteristics such as pressure and heat capacity. The dependence of pressure and heat capacity on the least nanopore size was considered suggesting the presence of specific phase transitions in the gas in a certain temperature range. The phase transitions are associated with size quantization which results in “effective” interaction (attraction) between gas molecules. 相似文献
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L. Pátý 《Czechoslovak Journal of Physics》1960,10(8):603-611
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This paper deals with the inertial cavitation of a single gas bubble in a liquid submitted to an ultrasonic wave. The aim was to calculate accurately the pressure and temperature at the bubble wall and in the liquid adjacent to the wall just before and just after the collapse. Two different approaches were proposed for modeling the heat transfer between the ambient liquid and the gas: the simplified approach (A) with liquid acting as perfect heat sink, the rigorous approach (B) with liquid acting as a normal heat conducting medium. The time profiles of the bubble radius, gas temperature, interface temperature and pressure corresponding to the above models were compared and important differences were observed excepted for the bubble size. The exact pressure and temperature distributions in the liquid corresponding to the second model (B) were also presented. These profiles are necessary for the prediction of any physical phenomena occurring around the cavitation bubble, with possible applications to sono-crystallization. 相似文献