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Li J.,North China Electrical Power University | Zhou T.,North China Electrical Power University | Ju Z.,North China Electrical Power University | Huo Q.,North China Electrical Power University | Xiao Z.,CNNC Key Laboratory on Nuclear Reactor Thermal Hydraulics Technology
Annals of Nuclear Energy | Year: 2014

Construct the predicting model of CHF based on BP neural network. The sensitivity coefficients of different parameters could be calculated by solving partial differential of the predicting model. With the method of neural network connection weight sensitivity analysis and the data from other researchers' experiments, the sensitivity of different factors to the critical heat flux (CHF) is analyzed. The result shows that, ΔGmax/G0 has the largest sensitivity coefficients to CHF and the inlet temperature has the smallest sensitivity coefficients in the test range. The sensitivity of ΔGmax/G0 could be 20 times of that of the inlet temperature. The BP predictions of CHF fit well with the experimental data, and the errors fall in the margin of 5%. The BP predictions of the influences of ΔGmax/G0 and τ to CFm fit well with Kim's formula, and the largest error is 12.5%. © 2014 Elsevier Ltd. All rights reserved. Source


Liu H.,Chongqing University | Pan L.,Chongqing University | Deng J.,Chongqing University | Yuan D.,CNNC Key Laboratory on Nuclear Reactor Thermal Hydraulics Technology | Huang Y.,CNNC Key Laboratory on Nuclear Reactor Thermal Hydraulics Technology
Hedongli Gongcheng/Nuclear Power Engineering | Year: 2016

Based on the model of VOF (Volume of Fluid) and UDS (User Defined Scalar), this paper builds the simulation model of using conductivity probe measuring two-phase flow parameters. The process of using double-sensor probe measuring two phase flow was simulated. The electric field distribution was obtained when the probe pierced the bubbles. The results show that the probe piercing the bubbles cause the distinct change of the distribution of current and voltage. As the process of simulation is not influenced by noise signal, bubble shape variation and signal response delay, the ideal signal is obtained such as the square wave signal of current and voltage. The simulation results truly reflect the basic process of the measurement by using the double-sensor probe for gas liquid two-phase flow. © 2016, Yuan Zi Neng Chuban She. All right reserved. Source


Hong G.,Shanghai JiaoTong University | Hong G.,CNNC Key Laboratory on Nuclear Reactor Thermal Hydraulics Technology | Yan X.,CNNC Key Laboratory on Nuclear Reactor Thermal Hydraulics Technology | Yang Y.-H.,Shanghai JiaoTong University | Xiao Z.-J.,CNNC Key Laboratory on Nuclear Reactor Thermal Hydraulics Technology
International Journal of Thermal Sciences | Year: 2012

Subcooled flow boiling is a commonly applied technique for achieving efficient heat transfer. Although numerous works have been done on two-phase flow phenomena, most of these works focus on land-based channels. Therefore, for identifying the heat transfer phenomena in the barge-mounted system, it is necessary to know the local flow condition in an oscillating acceleration field. In this study, forced convection subcooled water boiling experiments are conducted in narrow rectangular channels at low frequency oscillations. The bubble size, bubble velocity and bubble number density have been statistically analyzed under different heaving conditions and at different flow rates. The results of the bubble size distribution have been presented as cumulative distribution functions, which exhibit in reality a very wide spread of bubble size. The results show that an increase of the oscillation frequency causes an increase fluctuation of bubble size, bubble velocity and bubble number density. Under the same heaving condition, an increase of mass flow rate leads to a decrease fluctuation of bubble size and bubble velocity. A correlation has been sought for the fluctuation of bubble diameter due to heaving motion. The proposed model agrees well with the experimental data within the averaged relative deviation of ±19.2%. © 2011 Elsevier Masson SAS. All rights reserved. Source


Huang J.,CNNC Key Laboratory on Nuclear Reactor Thermal Hydraulics Technology | Huang Y.-P.,CNNC Key Laboratory on Nuclear Reactor Thermal Hydraulics Technology | Wang Y.-L.,CNNC Key Laboratory on Nuclear Reactor Thermal Hydraulics Technology
Hedongli Gongcheng/Nuclear Power Engineering | Year: 2013

Based on 170 density wave oscillation experimental data from parallel round tube and narrow rectangular channel, the experiment method, identification method of oscillation and analysis method of experimental data have be uniformed, and the oscillation boundary of round tube and narrow rectangular channel have be analyzed. The investigation results show that the oscillation boundary is not affected by the channel section forms with identical equivalent diameter with pressure 1.0~19.2 MPa, mass flux 101.9~1200.0 kg·m-2·s-1 and inlet sub cooling 18.0~85.2°C. Source


Hong G.,CNNC Key Laboratory on Nuclear Reactor Thermal Hydraulics Technology | Hong G.,Shanghai JiaoTong University | Yan X.,CNNC Key Laboratory on Nuclear Reactor Thermal Hydraulics Technology | Yang Y.-H.,Shanghai JiaoTong University | And 2 more authors.
Nuclear Engineering and Design | Year: 2012

A visual study of bubble departure size in forced convective subcooled boiling flow under static and heaving conditions was presented. High-speed digital images of flow boiling phenomena were obtained, which were used to measure bubble departure diameter. Experiments were conducted at atmosphere pressure in a narrow rectangular channel, with mass flux ranging from 300 to 710 kg/m 2 s, heat flux ranging from 65 to 298 kW/m 2 and inlet subcooling ranging from 20 to 40 K. The heaving frequency, which is generated by a six degrees-of-freedom platform, ranged from 0.2 to 0.61 Hz. The results indicated that decreasing mass flux and increasing heat flux had a tendency to increase bubble departure diameter under static condition. In heaving motion, bubble departure size was affected by additional heaving acceleration and flow rate fluctuation. A bubble departure model was proposed to predict the bubble departure diameter under static and heaving conditions by considering the additional acceleration and flow rate fluctuation. The proposed model agreed well with the experimental data within the averaged relative deviation of ±17.5%. © 2012 Elsevier B.V. All rights reserved. Source

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