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方管内固液两相流时均运动特性的数值研究 被引量:4
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作者 刘诚 沈永明 刘晓平 《泥沙研究》 CSCD 北大核心 2007年第4期10-16,共7页
应用三维k-ε-Ap两相湍流模型对垂直和水平方管内挟沙水流的固液两相时均运动特性和颗粒浓度分布规律进行数值研究,讨论了颗粒平均粒径和水流流速对固液两相流时均运动特性和颗粒浓度分布规律的影响。数值计算结果和试验实测结果吻合良... 应用三维k-ε-Ap两相湍流模型对垂直和水平方管内挟沙水流的固液两相时均运动特性和颗粒浓度分布规律进行数值研究,讨论了颗粒平均粒径和水流流速对固液两相流时均运动特性和颗粒浓度分布规律的影响。数值计算结果和试验实测结果吻合良好,准确得到了方管内固液两相流的时均运动特性。 展开更多
关键词 垂直(水平)方管 三维κ-ε-Ap模型 固液两相流 两相湍流模型 时均运动特性
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考虑管壁导热的方管内熔盐混合对流传热数值模拟
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作者 杨岑玉 孟强 +3 位作者 王乐 陈梦东 胡晓 徐桂芝 《储能科学与技术》 CAS CSCD 2019年第4期764-771,共8页
熔盐因具有传热能力强、工作温度高、使用温度广、系统压力低、经济适用等优点,成为太阳能热发电系统蓄热工质的理想选择。熔盐在实际应用中会因加热过程的非均匀性产生存在于固体表面和流体间的温差,造成流体工质中的密度梯度,因此出... 熔盐因具有传热能力强、工作温度高、使用温度广、系统压力低、经济适用等优点,成为太阳能热发电系统蓄热工质的理想选择。熔盐在实际应用中会因加热过程的非均匀性产生存在于固体表面和流体间的温差,造成流体工质中的密度梯度,因此出现重力导致的浮升力效应,其叠加到主流流动方向上即形成混合对流。管壁导热会对熔盐混合对流传热过程产生一定的影响。本文对熔盐在水平方管内非均匀加热条件下的单面加热的混合对流过程进行了数值模拟研究,在考虑壁厚的情况下研究了方管单面加热熔盐混合对流传热特性,分析了无量纲参数间的变化关系,并将结果与流型判定图和经典关联式进行对比。结果表明,非均匀加热时,浮升力效应会造成随流动距离增加主流核心区域的形状发生改变,且更加靠近加热壁面。Nu数随Re数、Ri数的增大而增大,局部Nux数随流动距离的深入先减小后增大。与忽略管壁导热数值模拟结果相比,主流核心区形状更加均匀,局部Nux更高且回升位置更加提前,流动特性和传热特性基本保持一致。 展开更多
关键词 熔盐 混合对流 水平方管 多面加热
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Noninvasive Flow Regime Identification for Wet Gas Flow Based on Flow-induced Vibration
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作者 华陈权 王昌明 +1 位作者 耿艳峰 石天明 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2010年第5期795-803,共9页
A novel noninvasive approach, based on flow-induced vibration, to the online flow regime identification for wet gas flow in a horizontal pipeline is proposed. Research into the flow-induced vibration response for the ... A novel noninvasive approach, based on flow-induced vibration, to the online flow regime identification for wet gas flow in a horizontal pipeline is proposed. Research into the flow-induced vibration response for the wet gas flow was conducted under the conditions of pipe diameter 50 mm, pressure from 0.25 MPa to 0.35 MPa, Lockhart-Martinelli parameter from 0.02 to 0.6, and gas Froude Number from 0.5 to 2.7. The flow-induced vibration signals were measured by a transducer installed on outside wall of pipe, and then the normalized energy features from different frequency bands in the vibration signals were extracted through 4-scale wavelet package transform. A "binary tree" multi-class support vector machine(MCSVM) classifier, with the normalized feature vector as inputs, and Gaussian radial basis function as kernel function, was developed to identify the three typical flow regimes including stratified wavy flow, annular mist flow, and slug flow for wet gas flow. The results show that the method can identify effectively flow regimes and its identification accuracy is about 93.3%. Comparing with the other classifiers, the MCSVM classifier has higher accuracy, especially under the case of small samples. The noninvasive measurement approach has great application prospect in online flow regime identification. 展开更多
关键词 flow regime identification wet gas flow flow-induced vibration wavelet package transform support vector machine
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Tumor Vascular Markers: Possibilities for Detection of Breast Carcinoma
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作者 Miroslava Bilecova-Rabajdova Peter Urban +3 位作者 Andrea Gresova Anna Birkova Alexander Ostro Maria Marekova 《Journal of Chemistry and Chemical Engineering》 2012年第2期118-123,共6页
Breast cancer is one of the world's most urgent health problems. The first symptoms of mammary malignancies are manifested only at an advanced stage with significant mortality. Detecting this disease at an early stag... Breast cancer is one of the world's most urgent health problems. The first symptoms of mammary malignancies are manifested only at an advanced stage with significant mortality. Detecting this disease at an early stage gives the majority of patients a better chance of survival. The aim was to search for changes in gene expression of specific tumor vascular markers like death receptor 6 (Dr6) and glycoprotein M6B (Gpm6B) in the blood of patients with breast cancer. All subjects were divided into two groups. First group with patients are with different grades of breats tumors (n = 30). Second group consists from healthy women (n = 15). After isolation of mRNA from blood, RT-PCR was followed by gel electrophoresis. For statistical analysis one-way ANOVA was used with Student's T test using GraphPad InStat software. Significant changes in mRNA levels of gene Dr6 in all grades of first stage breast cancer were detected. The mRNA levels of Dr6 showed a rising tendency from GI (116% higher value than control) to G3 (198% higher than control). During monitoring of the mRNA level of Gpm6B, a weaker increase was observed than in Dr6. The difference in GI was only 8% higher compared with controls and 44% at G3. From our results it can be concluded that DR6 is a more suitable marker for the diagnosis of breast malignancies in the early stages than Gpm6B. In our work, a non-invasive method for more timely and precise determination of the earlier stages of breast cancer is described, which could also contribute to monitoring the effectiveness of treatment, or regression of this disease. 展开更多
关键词 RT-PCR Dr6 Gpm6B gynecological malignancies breast cancer.
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单面加热方管混合对流换热特性实验研究 被引量:1
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作者 王孟春 吴声敏 +2 位作者 张秀婷 种道彤 刘继平 《工程热物理学报》 EI CAS CSCD 北大核心 2012年第1期105-108,共4页
本文对单壁面加热水平方管通道内混合对流换热进行了实验研究,其中加热面分别为底面、侧面、顶面,Re=1514~3028,Gr*=2.06×10^6—8.22×10^6;通过对加热面温度进行曲线拟合减小壁面温度测量误差,得到考虑轴向导热的局部... 本文对单壁面加热水平方管通道内混合对流换热进行了实验研究,其中加热面分别为底面、侧面、顶面,Re=1514~3028,Gr*=2.06×10^6—8.22×10^6;通过对加热面温度进行曲线拟合减小壁面温度测量误差,得到考虑轴向导热的局部Nusselt数的变化规律。实验结果表明侧面加热和底面加热时,局部Nusselt数要明显高于顶面加热的情况;局部Nusselt数在管道前段受Re的影响较大,在后段受Gr*的影响较大。 展开更多
关键词 混合对流 水平方管 NUSSELT数
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New experimental method for inundation effect of film condensation on horizontal tube bundle 被引量:3
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作者 MA ZhiXian ZHANG JiLi SUN DeXing 《Science China(Technological Sciences)》 SCIE EI CAS 2012年第10期2856-2863,共8页
Theory of film condensation heat transfer(FCHT) for vapor condensed on horizontal tube bundle(HTB) is vital to many industry processes.Meanwhile,the inundation effect is the key to model the film condensation heat tra... Theory of film condensation heat transfer(FCHT) for vapor condensed on horizontal tube bundle(HTB) is vital to many industry processes.Meanwhile,the inundation effect is the key to model the film condensation heat transfer coefficient(CHTC) on HTB.This paper proposed a new experimental method,homologous method,to obtain the inundation effect precisely.Based on the requirements of the new test method,a new test facility was designed and established.Then,the superiority of homologous method for inundation effect was investigated based on experiment result and theoretic analysis.The results showed that the homogenous method can effectively control the experimental error of inundation effect,which is less than 50% of the error of CHTC,and less than 30% of the error of the inundation effect gained by routine method.The new test facility built for the homogenous method is excellent in obtaining the accurate inundation effect of film condensation on HTB.All the result is a foundation of the theoretical development of the FCHT on HTB. 展开更多
关键词 horizontal tube bundle film condensation inundation effect experimental method experimental error
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