共查询到19条相似文献,搜索用时 171 毫秒
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二、差压传感器特性鉴定系统 为了能够运用“群特性”进行“软补偿”,必须建立与三维校验法相配套的传感器特性鉴定系统。我们在差压变送器的高压腔和低压腔同时用同一压力源加载就可以在零差压条件,测出不同温度时、不同静压下的附加误差n'_(spo),由于采用同一压力源加载, 相似文献
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介绍基于LabVIEW软件开发平台的直压检漏系统组成及工作原理.建立了描述直压检漏系统被测容腔内气体压力、温度以及等效传热系数、漏率之间关系的数学模型.基于该模型并根据试验实际所测压力和温度数据获得等效传热系数和漏率在不同温度变化过程中的变化规律.试验结果表明,负压状态下被测容腔内气体压力、温度和泄漏量相互影响,微泄漏对容腔内气体的温度变化影响较小,容腔漏率随容腔内气体压力和温度升高而变小,随容腔内气体压力和温度降低而变大.等效传热系数随容腔内气体温度上升和容腔内外温差增大而减小,随容腔内气体温度下降和容腔内外温差减小而增大.本研究为直压检漏系统温度校正深入研究奠定了一定的基础. 相似文献
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为提高双腔串联压电泵的输出性能,对泵的进口腔与出口腔的容积比进行了优化设计。分别设计了容积比为1.9、1.5、1.3三种串联压电泵样机,并对样机进行了试验测试。试验结果显示,采用增加容积比的方式可以提高双腔串联压电泵的输出流量,但不能提高其输出压力;对每个不同腔体容积比的双腔串联压电泵在异步驱动和同步驱动下进行了输出性能测试,测试结果显示,当输送气体时,两种驱动方式均有很好的流量输出,且输出结果比较接近,但仅有异相驱动时才能输出液体。分析结果为提高双腔串联压电泵的输出性能提供了很好的依据。 相似文献
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基于热力学第一定律、质量守恒定律和气体状态方程,综合考虑工作腔的两种内泄漏以及工作腔壁面与介质气体之间的传热,构建了无油涡旋压缩机的热力学模型。运用欧拉法求解所建立的热力学模型,得到了气体在吸气-压缩-排气全过程中容积、温度、压力和质量随主轴转角的变化情况,并对比分析了不同传热和泄漏的影响规律。对研制开发的无油涡旋压缩机进行了变转速性能测试,分别测试了不同排气压力下的温度、排气量、功率。结果表明:传热对压力和温度的影响最大,而泄漏对工作腔质量的影响最大。随着转速的增大,温度、排气量、功率都呈明显的增大趋势。该热力学模型对无油涡旋压缩机的研发和性能分析具有一定的指导和借鉴作用。 相似文献
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Transient analysis for compressible fluid flow in transmission line by the method of characteristics
Transient analysis for compressible fluid flow has been conducted to evaluate the dynamic characteristics of the dead-ended or volume-terminated transmission lines following a sudden pressure change at its entrance. The two partial-differential equations, based on the conservation of mass, energy and momentum, were derived for the one-dimensional adiabatic compressible flow with friction and entrance head loss. The governing equations describing the present transient-state flow are hyperbolic, and the boundary conditions include a fixed volume termination at the exit and sinusoidal disturbance in the sudden pressure change at tube entrance. The method of characteristics is used to transform the partial differential equation into the particular total differential equations, which can be integrated along the characteristic lines. The present result shows good agreements with the existing results. The effects of tube length. tube diameter and end volume are evaluated on the responses of the pressure and on the damping factor. 相似文献
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In this paper, the control design with distributed model of pipelines is proposed to make the cylinder side be free of pressure sensors. In this research, long connected pipelines are used. The pipeline is designed as a one dimensional distributed model. The model of pipelines is based on the discretization of four equations, as state equation of air, motion equation, continuity equation, and energy equation. The distributed model estimates the pressure losses and time delay through long connected pipelines in real time. To confirm the control method with distributed model of pipelines, a simulation model of the whole system is designed. Compared simulation and experimental results, it has been found that the model represents the real system well. In the experiments, the pressure values in the cylinder chambers estimated by the distributed model in real time played as control signals. Compared with the estimated and measured pressure values in the cylinder chambers, it is found that with this distributed model, the pressure values in the cylinder chambers is precisely estimated in real time using the measured values at the control ports of the servo valve. The experimental results demonstrate that the position accuracy is almost the same with that of using the measured pressure signals in the cylinder chambers. The cylinder side is free of pressure sensors with the proposed control method. 相似文献
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A Reynolds' equation, using Winer's viscoplastic model to express the non-Newtonian fluid property, is derived for line-contact EHL problems. The numerical solutions are obtained to the incorporated Reynolds', elasticity, and energy equations for pressure, film thickness, and temperature distribution between two surfaces simultaneously having rolling and sliding motions. The results are presented for thermal non-Newtonian lubrication, to observe the difference between Winer's equation and Trachman's expression on temperature distribution, pressure, and film thickness. The variation in friction coefficient with slip shear rate is in agreement with other experimental data. 相似文献
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通过建立轴向柱塞泵配流副的几何模型,利用雷诺方程推导了配流副的油膜压力方程,采用有限差分法和松弛迭代法求解雷诺方程。利用FORTRAN语言编程求解,利用MATLAB语言对油膜厚度、压力、温度分布进行了仿真研究。结合油膜厚度方程、雷诺方程、能量方程、弹性变形方程、黏温黏压方程和密度温压方程,仿真微观织构配流副的热弹流润滑特性。研究表明:配流副油膜厚度增大,最大油膜压力减小,最高温度值减小;配流副的热-流-固耦合效果随油膜间隙收敛逐渐明显,在最小油膜厚度处达到最大,并且,油膜压力值达到最大;加工微观织构可以显著改变配流副的油膜压力和温度分布。 相似文献