共查询到20条相似文献,搜索用时 78 毫秒
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本文就管道内固体物料(气/固两相流)流速的相关测量技术进行了探讨和研究,并设计和制作了一种新型电容传感器、变换器、以及全软件式实时相关器(包括接口电路和相关软件),相关测速误差约±1%。 相似文献
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为了拾取气固两相流相关测量用随机流动噪声信号,研制了一种专用的高灵敏度抗干扰电容传感器,信噪比达40dB。 相似文献
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光-电检测法应用于气-固两相流微粒浓度的测量时,被测固体颗粒直径的变化对测量结果将产生明显影响.以致使测量结果与实际状态相反.本文分析了固体颗粒粒径对测量的影响,并提出了有效的修正方法. 相似文献
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以颗粒相在整个检测空间内均匀分布为前提,采用McClements理论和Bouguer-Lambert-Beer定律共同描述煤粉气-固两相流中超声衰减特性,建立超声衰减系数与气-固两相流相关参数的理论关系,通过数值模拟,分析超声衰减随着颗粒相体积分数、超声频率、颗粒粒径变化的规律。结果表明,超声频率越高衰减系数越大;声衰减系数随着颗粒相体积分数的增大线性递增;选用某固定频率检测,测得2个体积分数下的声衰减系数即可确定衰减-体积分数曲线斜率,从而实现任意衰减系数对应的颗粒相体积分数测量;在相同的体积分数下,煤粉颗粒粒径为10~200μm,声衰减系数随着颗粒粒径的增大单调递减,当煤粉颗粒粒径大于200μm时,声衰减系数对煤粉颗粒粒径不再敏感。 相似文献
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建立了FW-Φ150型强制涡卧式涡轮分级机内腔叶片之间气-固两相流的双流体理论模型熏并利用通用的流体力学计算软件进行了数值模拟。结果表明:该涡轮分级机在正常工作状态时,内腔流场遵循强湍流流动规律;粒子群的运动规律是,粒子的粒径越大,越易向叶片外边缘聚集,直至返回分级区;随着转速的增大,流场的涡流现象越来越强,相同粒径的粒子,当转速增大到一定的程度时,出现了反流现象,使已经分离出的细粒又返回到分级区,而影响分级机的分级效率。 相似文献
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通过实验研究了一体化自然循环反应堆压力壳上部自稳压气空间对于自然循环两相流系统启动过程中流动稳定性的影响。实验结果表明,较小的气空间有利于抑制流量振荡。依此提出在反应堆启动过程中提高流动稳定性的新途径:首先在较小的气空间体积下开始启动,当达到额定热工参数后将多余的水放出达到所需要的正确运行状态。 相似文献
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ᴌukasz Płociniczak Monika Maciejewska Andrzej Szczurek 《Inverse Problems in Science & Engineering》2017,25(4):555-579
In this work, we focus on a transient state of sensor as a source of chemical information. This problem deserves attention for many reasons. As an example, utilization of transient states may allow for faster and more accurate information acquisition. We have considered a transient state gas sensor response to test analyte applied for quantitative gas determination. We examined the inflection point which is a promising feature of a signal resulting from transient sensor responses. This particular feature was found to be linearly dependent on the target gas concentration. However, the applicability of inflection point method is dependent on the precision of its determination. It raises a number of issues related to signal regularization. The regularization problem was studied from a theoretical point of view. A number of a-priori estimates for regularization strategies were obtained yielding some practical algorithms for calculating the inflection point in a stable way. Next, they were validated using numerical simulations and real data analysis procedure. This work provides a rigorous mathematical evaluation of the inflection point method and it may contribute to the improvement of gas sensor performance. 相似文献
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设计了一种直径比为0.8的新型双锥流量计.在管道内径为50 mm、干度范围为0.002 5~0.04的工况下,采用该流量计对水平管道气液两相流流量的测量进行了实验研究.在水流量标准装置上对该流量计进行了标定,分析了其流出系数.基于均相流和James模型,提出了一种混合密度的修正方法.利用双锥流量计的差压信号,分别对均相流模型、James模型以及修正的模型进行气液两相流总流量测量误差分析.实验结果显示,经密度修正的模型对总流量测量的相对误差可控制在6%以内,均方根误差为2.94%,表明修正后的模型可对总流量进行有效的测量,双锥流量计用于气液两相流测量可以获得较好的效果. 相似文献
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利用塞贝克效应研制成功ZnO半导体气敏传感器。这种新型传感器能够输出0-100mV的直流电压,对于信号的放大与处理将十分方便。在实验中对20×10-6NO2气体进行检测,结果表明:传感器的输出电压(温差电动势),随着待测气体浓度而变化。因此,利用温差电效应制作气敏传感器是一条完全可行的新思路。 相似文献
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Zinc oxide (ZnO) is a versatile material for different commercial applications such as transparent electrodes, piezoelectric
devices, varistors, SAW devices etc because of its high piezoelectric coupling, greater stability of its hexagonal phase and
its pyroelectric property. In fact, ZnO is a potential material for gas sensor applications. Good quality ZnO films were deposited
on glass and quartz substrates by a novel CVD technique using zinc acetate as the starting solution. X-ray diffraction confirmed
the crystallinity of the zinc oxide film and SEM study revealed uniform deposition of fine grains. Undoped ZnO films were
used for detection of dimethylamine (DMA) and H2 at different temperatures by recording the change in resistivity of the film in presence of the test gases. The response
was faster and the sensitivity was higher compared to the earlier reported ZnO based sensors developed in our laboratory.
The main objective of this work was to study the selectivity of the ZnO film for a particular gas in presence of the others.
The operating temperature was found to play a key role in the selectivity of such sensors. 相似文献