Experimental and Numerical Analysis of the Flow Field in the Integrated Valve for the Control Rod Hydraulic Drive System

2018 ◽  
Author(s):  
Jiang Junfei ◽  
Qin Benke ◽  
Bo Hanliang
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Flow Resistance ◽  
Hydraulic Drive ◽  
Flow Channel ◽  
Drive System ◽  
Total Flow ◽  
Control Rod ◽  
Research Results ◽  
Flow Channels

Control Rod Hydraulic Drive System (CRHDS) is a new type of built-in control rod drive technology, and the Integrated Valve (IV) is the key control component of it. The pulse water flowing into the control rod hydraulic mechanism (CRHDM) is controlled by the IV to drive the hydraulic cylinders to move in a predefined sequence to make the control rod perform step-up, step-down and scram functions. Flow resistance of the IV flow channels is the key design parameter of IV which influences the step motion of the hydraulic cylinder and thus affects the performance of the CRHDS. Experiments on the flow resistance of IV flow channels at different working temperatures were conducted to obtain differential pressures of IV under various temperature and flow rate operating conditions. Based on the experimental conditions and results, three dimensional flow field analysis of the IV flow channels was carried out to get the flow field distribution and hydraulic parameters of the IV flow channels. Flow resistance of the IV flow channels at different working temperatures were obtained using the calculation results and agree well with the experimental results. It verified the correctness of the CFD model. On the basis of the numerical simulation results, the velocity and pressure distribution schemes in the IV flow channels under different working temperature conditions were compared and analyzed. The research results show that the flow resistance of the IV in-rod flow channels remains largely unchanged at different working temperatures, the peak flow velocity appears at the entrance of the valve core section which is also the main flow resistance loss area. The theoretical model was then applied to analyze the influence of the design parameters which include the valve core size, the angle between flow channels, etc., on the total flow resistance of IV at high temperatures. And the analysis results show that, the angle between flow channels has little influence on the flow resistance coefficient. The increase of valve core radius can significantly reduce the total flow resistance of IV flow channels. Numerical simulation on one out-rod flow channel is also carried out, which shows that the flow resistance in out-rod flow channel is much lower than the corresponding in-rod flow channels. The research results can give guidance for the design and optimization of the IV.

Analysis of Flow Resistance Influence on Step-Down Process of the Control Rod Hydraulic Drive System

2021 ◽  
Author(s):  
Linqing Yang ◽  
Benke Qin ◽  
Hanliang Bo
Keyword(s):  
Theoretical Model ◽  
Flow Resistance ◽  
Inflection Point ◽  
Great Influence ◽  
Hydraulic Drive ◽  
Hydraulic Cylinder ◽  
Drive System ◽  
Pressure Curve ◽  
Control Rod ◽  
Step Down

Abstract Control rod hydraulic drive system (CRHDS) is a new type of built-in control rod drive technology which is invented by INET, Tsinghua University. The integrated valve (IV) is the main flow control component of the CRHDS. Flow resistance of IV has a great influence on the control rod dynamic step-down process. The step-down performance experiments of CRHDS with different flow resistance of IV were conducted under room temperature conditions. Meanwhile, the theoretical model of hydraulic cylinder step-down process was established and combined with the relationship of the flow resistance of IV under the experimental conditions to get the dynamic response of the hydraulic cylinder. The calculation results of theoretical model agree well with the experimental data. On this basis, the theoretical model of hydraulic cylinder step-down process was applied to the high temperature working conditions with different flow resistance of IV. The analysis results show that at higher working temperature, with the increase of the flow resistance of IV control rod step-down average velocity decreases and step-down time increases correspondingly. There is an inflection point in the transient pressure curve and the pressure of the inflection point decreases gradually with the increase of the flow resistance. The pressure lag time after step-down also decreases. The research results lay the base for the design and optimization of the flow resistance of the IV for the CRHDS.

Constructing stage discharge relationship with numerical simulation including hydraulic resistance

2020 ◽  
Author(s):  
atsuhiro yorozuya
Keyword(s):  
Numerical Simulation ◽  
Risk Assessment ◽  
Shear Stress ◽  
Flow Field ◽  
Flow Resistance ◽  
River Flow ◽  
Flow Simulation ◽  
Flood Risk Assessment ◽  
The One ◽  
Flow Stage

<p>A flood risk assessment has implemented with an inundation map or with other simulated results; e.g., a rainfall-runoff simulation. In order to conduct the flood risk assessment, it is usual that the case with maximum floods are subject for discussion. At the same time, it is usual that observed data of the maximum floods are not available, since the maximum floods has not experienced, or observation have not conducted. Estimation of the discharge values are not simple, since the river flow at the targeted cross section are affected by river shape, or roughness changes. Both of them are sensitive with different flow stage.</p><p>The present study discusses about constructing the stage discharge relationship with numerical simulation. For this purpose, the author implements the 2-D depth integrated flow simulation including the flow resistance. The flow resistance is one of the traditional studies of the sediment hydraulics. It deals with the changing of resistance with different micro-scale bed forms as the bed shear stress changes. Similar with the one by Engelund (1966), the relationship with grain shear stress and total shear stress are constructed in qualitative manner by Kishi and Kuroki (1973). It is useful to obtain the bed roughness with different flow stage. The author implements the changes of the roughness in the 2-D depth integrated flow simulation and obtains the flow field in actual river flow in order to obtain the discharge values.</p><p>The authors conducted the numerical simulation in steady flow condition. In order to construct the stage-discharge relationship based on the results, 10 different cases with appropriate ranges of stage were conducted. The domain of the simulation is 5 times longer than the width of the targeted section. In order to construct the initial condition, bathymetry data in the one point in 5 m with the laser technique, and sediment size distribution at the different location; e.g., at center of flow, top of the dune and etc., were obtained. The calculated results were compared with observed flow field by float measurements and other non-contact current meter. The results indicate that the numerical stage-discharge relationship shows some good agreements and few disagreements with the one created based on observation. For example, at the water stage which represents the dune I, the simulated results are similar with observed. However, at the stage of dune II, simulated velocity shows smaller velocity than observed. As Hirai (2015) suggested, shape of micro-bed form classified as Dune II is unstably changes between Dune and flat bed. Therefore, velocity at the stage is sensitively changes as well. From this aspect, the authors concluded that not only the numerical simulation but also field measurement are necessary in order to construct good stage-discharge relationships, in particular if the shear stress at the targeted discharge involves the Dune II.</p>

Deceleration Performance and Parameter Influence Analysis of the Control Rod Hydraulic Deceleration Device for Control Rod Hydraulic Drive System

2019 ◽  
Vol 5 (3) ◽  
Author(s):  
Qin Benke ◽  
Li Leishi ◽  
Bo Hanliang
Keyword(s):  
Internal Control ◽  
Three Dimensional ◽  
Hydraulic Drive ◽  
Drive System ◽  
Field Analysis ◽  
Control Rod ◽  
Design And Optimization ◽  
Main Components ◽  
Technology Control ◽  
The Impact

Control rod hydraulic drive system (CRHDS), which is invented by INET, Tsinghua University, is a new type of internal control rod drive technology. Control rod hydraulic deceleration device (CRHDD), which consists of the plug, the hydraulic deceleration cylinder, etc., is one of the main components of the CRHDS. The CRHDD performs the rod dropping deceleration function through the interworking of the plug and the deceleration cylinder, which is filled with water, and reduces the rod dropping peak acceleration and the impact force acting upon the control rod to prevent the control rod cruciform blade from being deformed or damaged. The working mechanism of the CRHDD is presented and analyzed. The theoretical model of the control rod dropping process, which is based upon force analysis of the control rod during scram process, three-dimensional flow field analysis, and flow resistance calculation of the hydraulic deceleration cylinder, the kinematics and dynamics analysis of the control rod, is built whose results are compared and validated by the CRHDS scram test results. Then the model is used to analyze the influence of the key parameters, including the fuel case gap, the plug design clearance, the working temperature, etc. on the CRHDD working performance. The research results can give guidance for the design and optimization of the CRHDD.

Numerical and Experimental Analysis of the Control Rod Hydraulic Deceleration Device for the Control Rod Hydraulic Drive System

2017 ◽  
Author(s):  
Qin Benke ◽  
Li Leishi ◽  
Bo Hanliang
Keyword(s):  
Internal Control ◽  
Room Temperature ◽  
Three Dimensional ◽  
Hydraulic Drive ◽  
Drive System ◽  
Field Analysis ◽  
Control Rod ◽  
Design And Optimization ◽  
Main Components ◽  
The Impact

Control rod hydraulic drive system (CRHDS), which is invented by INET, Tsinghua University, is a new type of internal control rod drive technology. Control rod hydraulic deceleration device (CRHDD), which consists of the plug, the hydraulic deceleration cylinder, the hydraulic buffer, etc., is one of the main components of the CRHDS. The plug is connected with the top of the control rod driving shaft and moves along with the control rod inside the hydraulic deceleration cylinder. The CRHDD performs the rod dropping deceleration function through the interworking of the plug and the deceleration cylinder which is filled with water, and reduces the rod dropping peak acceleration and the impact force acting upon the control rod to prevent the control rod cruciform blade from being deformed or damaged. The working mechanism of the CRHDD is presented and analyzed. The rod dropping performance of the CRHDS was tested experimentally under room temperature. The theoretical model of the control rod dropping process, which is composed of the three dimensional flow field analysis and flow resistance calculation of the hydraulic deceleration cylinder, the kinematics and dynamics model of the control rod, is built whose results are compared and validated by the CRHDS scram test results under room temperature. Then the model takes into account of the influence of the fuel assembly box on the control rod scram process under high temperature working conditions, and is used to analyze the influence of the key parameters, including the helical spring stiffness inside the deceleration cylinder and the working temperature on the CRHDD working performance. The research results can give guidance for the design and optimization of the CRHDD.

Improved Thermal Uniformity by Introducing Tree-Like Flowing Channels in a PEMFC Flow-Field Plate

2017 ◽  
Author(s):  
Yuxin Jia ◽  
Rui Zhu ◽  
Bengt Sunden ◽  
Gongnan Xie
Keyword(s):  
Fuel Cells ◽  
Flow Field ◽  
Proton Exchange Membrane ◽  
Numerical Study ◽  
Flow Characteristics ◽  
Flow Channel ◽  
Proton Exchange ◽  
Field Plate ◽  
Flow Channels ◽  
Exchange Membrane

Thermal uniformity in the flow field plate of proton exchange membrane fuel cells (PEMFCs) is crucial for their power generating efficiency and reliability and therefore, has attracted much attention. The present numerical study is an attempt to optimize the flow channels via replacement of convectional zigzag continuous channels by tree-like bifurcated channels radially outwards. The numerical model is validated by experimental data available in the open literature. The effects of included angles and length ratios among the channels on thermal uniformity are analyzed based on detailed fluid flow characteristics. Results show that tree-like channels outperform conventional ones. It is found that tree-like flow channels can improve thermal uniformity of proton exchange membrane fuel cells. Within limits, with smaller angle between bifurcated flow channels and length ratio 2−1/3 between higher flow channel and lower flow channel, PEMFC can obtain the most uniform temperature distribution in Y shape tree-liked flow field.

Numerical Analysis of Minicar Radiator Flow Resistance

2011 ◽  
Vol 383-390 ◽  
pp. 4916-4921
Author(s):  
Chuan Bo Liu ◽  
Yi Min Mo ◽  
Ming Li
Keyword(s):  
Numerical Simulation ◽  
Surface Roughness ◽  
Numerical Analysis ◽  
Flow Field ◽  
Flow Resistance ◽  
Coolant Flow ◽  
Outlet Section ◽  
Water Tank ◽  
Local Resistance ◽  
Slowing Down

In order to seek methods of reducing the coolant resistance of radiators in mini-vehicle, the resistance distribution in minicar radiators was obtained by carrying out numerical simulation to coolant flow field of the radiators. The analysis indicated that the coolant resistance mainly composed of two parts: the resistance along radiating pipes, the inlet and outlet resistance of the water tank. Reducing the surface roughness of coolant pipes could lower the resistance along pipes. Slowing down the changes of the inlet and outlet section could reduce the local resistance.

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