16MnR钢高温损伤后J_R阻力曲线实验研究

介绍了压力容器常用钢16MnR钢的经历高温损伤后的式样制备以及JR阻力曲线的测试结果。实验表明16MnR钢的断裂韧性与其经受的温度和经历的时间有着密切的关系。温度高材性会劣化,经历高温的时间短的材料断裂韧性会偏低。

A Novel Capacitive Pressure Sensor

A novel capacitive pressure sensor is presented, whose sensing structure is a solid-state capacitor consisting of three square membranes with Al/SiO2/n-type silicon. It was fabricated using pn junction self-stop etching combined with adhesive bonding,and only three masks were used during the process. Sensors with side lengths of 1000,1200,and 1400μm were fabricated,showing sensitivity of 1.8,2.3, and 3.6fF/hPa over the range of 410～ 1010hPa, respectively. The sensi- tivity of the sensor with a side length of 1500μm is 4. 6fF/hPa,the nonlinearity is 6. 4% ,and the max hysteresis is 3.6%. The results show that permittivity change plays an important part in the capacitance change.

Research on Volume Identification with the Method of Discharging at the Velocity of Sound

The method of volume identification in pneumatics was studied through theoretical analysis and experimental investigation. Regarding discharging from a container as a thermodynamic process with invariable index the dependence of the container’s volume on the pressure in the container and the index, during discharging at the velocity of sound, is deduced. Then through a lot of experiments, the value of index n of the process is found with a given precision and a specified volume range. Furthermore, the feasibility and practicability of this method are verified by experiments.

Calculations of plastic collapse load of pressure vessel using FEA

This paper proposes a theoretical method using finite element analysis(FEA) to calculate the plastic collapse loads of pressure vessels under internal pressure,and compares the analytical methods according to three criteria stated in the ASME Boiler Pressure Vessel Code. First,a finite element technique using the arc-length algorithm and the restart analysis is developed to conduct the plastic collapse analysis of vessels,which includes the material and geometry non-linear properties of vessels. Second,as the mechanical properties of vessels are assumed to be elastic-perfectly plastic,the limit load analysis is performed by em-ploying the Newton-Raphson algorithm,while the limit pressure of vessels is obtained by the twice-elastic-slope method and the tangent intersection method respectively to avoid excessive deformation. Finally,the elastic stress analysis under working pressure is conducted and the stress strength of vessels is checked by sorting the stress results. The results are compared with those obtained by experiments and other existing models. This work provides a reference for the selection of the failure criteria and the calculation of the plastic collapse load.

Research on reasonable winding angle of ribbons of Flat Steel Ribbon Wound Pressure Vessel

Flat Steel Ribbon Wound Pressure Vessels (FSRWPVs) are used in many important industry areas. There is no such kind of pressure vessel exploding on operation for its reasonable structure design. Many explosion experiments on Flat Steel Ribbon Wound Pressure Vessel showed that their limited load pressure is related to the winding angle of the steel ribbons. FSRWPVs with reasonable winding angle have better security and lower cost. Reasonable angels given at the end of this paper facilitate engineering design.

The General Design and Technology Innovations of CAP1400

A historical review of in-vessel melt retention （IVR） is given, which is a severe accident mitigation mea- sure extensively applied in Generation III pressurized water reactors （PWRs）. The idea of IVR actually originated from the back-fitting of the Generation 11 reactor Loviisa WER-440 in order to cope with the core-melt risk. It was then employed in the new deigns such as Westinghouse APIO00, the Korean APR1400 as well as Chinese advanced PWR designs HPRIO00 and CAP1400. The most influential phe- nomena on the IVR strategy are in-vessel core melt evolution, the heat fluxes imposed on the vessel by the molten core, and the external cooling of the reactor pressure vessel （RPV）. For in-vessel melt evolution, past focus has only been placed on the melt pool convection in the lower plenum of the RPV; however, through our review and analysis, we believe that other in-vessel phenomena, including core degradation and relocation, debris formation, and coolability and melt pool formation, may all contrib- ute to the final state of the melt pool and its thermal loads on the lower head. By looking into previous research on relevant topics, we aim to identify the missing pieces in the picture. Based on the state of the art, we conclude by proposing future research needs.

Finite element modeling for analysis of cracked cylindrical pipes

The characteristic properties of shell element with similar shapes are used to generate a so-called super element for the analysis of the crack problems for cylindrical pressure vessels. The formulation is processed by matrix condensation without the involvement of special treatment. This method can deal with various singularity problems and it also presents excellent results to crack problems for cylindrical shell. Especially,the knowledge of the kind of singular order is not necessary in super element generation; it is very economical in terms of computer memory and programming. This method also exhibits versatility to solve the problem of kinked crack at cylindrical shell.

A Controlled Study on Comparing Differences in CT Perfusion Imaging between Rabbits inoculated with VX2 Lung Tumor and Patients with Squamous Cell Carcinoma of the Lung

OBJECTIVE By analysis and evaluation of the perfusion images and perfusion parameters of the rabbits with VX2 lung tumor, the association between the perfusion parameters and tumor angiogenesis of patients with squamous cell carcinoma of the lung has been studied in order to establish a non-invasive and effective way to detect tumor blood supply, which is be able to exhibit hemodynamic data in tumors during cancer treatments. METHODS Fifteen Netherlands rabbits inoculated with VX2 lung tumor （rabbit group） and 25 patients with squamous cell carcinoma of the lung （patient group） received a multi-slice spiral CT perfusion imaging test using the Netherlands PHILIPS Brilliance 16-slice spiral CT and a U.S. MEDRAD binocular highpressure syringe. Image postprocessing was done using the special perfusion software and EBW 4.0 Workstation. Perfusion volume （PV）, peak enhanced increment （PEI）, transit time peak （TTP）, and blood volume （BV） were measured and analyzed. RESULTS In the rabbit group, the values of the PV, PEI, TTP, and BV of the tumor margin were （53.89 ± 13.38） mL/（min.mL）, （45.71 ± 15.52） Hu, （39.29 ± 10.10） sec, and （31.45 ± 18.19） mL/100 g, respectively; these values of the tumor center were （36.57 ± 14.17） mL/（min.mL）, （28.64 ± 11.74） Hu, （39.00 ＋ 9.78） sec, and （19.76 ± 13.95） mL/100 g, respectively; the values of the muscles were （12.45± 4.38） mL/（min.mL）, （10.98 ± 5.03） Hu, （38.86 ± 10.04） sec, and （5.38 ±2.87） mL/100 g, respectively. The values of the relative perfusion volume （RPV）, relative peak enhanced increment （RPEI）, and relative blood volume （RBV） of the tumor margin were 4.38 ± 1.45, 3.96± 1.45, 9.99 ± 11.7, respectively; these values of the tumor center were 2.14 ± 1.08, 1.83±1.45, 4.17 ±3.39, respectively. The values of the PV, PEL BV of the tumor margin vs. the values of the muscles developed t-values, which were 15.028, 10.79, and 5.88, respectively （P ≤ 0.01）, with statistical significance; the values of the PV, PEI, BV of the tumor center vs. the values of the muscles produced t-values, which were 8.67, 7.49, and 4.55, respectively （P 〈 0.01）, with statistical significance. The values of the TTP of the tumor margin vs. TTP values of the muscles, and the TTP values of the tumor center vs. TTP values of the muscles developed t-values, which were 1.7 and 0.806, respectively （P ≥ 0.05）, without statistical significance. In the patient group, the values of the PV, PE, TTP, and BV of the tumor margin were （88.95 ± 30.89） mL/（min.mL）, （61.87 ± 27.31） Hu, （37.72 ± 12.53） sec, and （18.38 ± 7.2） mL/100 g, respectively; these values of the tumor center were （39.77 ± 18.29） mL/（min.mL）, （14.57 ± 8.1） Hu, （35.64 ± 12.41） sec, and （11.22 ± 6.02） mL/100 g, respectively; these values of the muscles were （12.45 ± 6.5） mL/（min.mL）, （6.14 ± 2.66） Hu, （35.68± 12.35） sec, and （2.23 ± 1.11） mL/100 g, respectively. The values of the RPV, RPEI, and RBV of the tumor margin were 8.05 ± 5.04, 8.87 ± 4.32, and 12.16 ± 8.49, respectively; these values of the tumor center were 2.39 ± 1.68, 2.97 ± 2.1, 3.53 ± 2.82, respectively. The values of the PV, PEI, BV of the tumor margin in the patient group vs. the values of the muscles produced t-values, which were 13.8, 10.85, and 12.22, respectively （P 〈 0.01）, with significant differences; these values of the tumor center vs. the values of the muscles developed t-values, which were 9.158, 6.26, 8.654, respectively （P 〈 0.01）, with significant differences. The TTP value of the tumor margin vs. that of the muscles produced t-value, which was 0.371, and the TTP value of the tumor center vs. that of the muscles developed t-value, which was 1 （P 〉 0.05）, without statistical difference. CONCLUSION CT perfusion imaging technics demonstrates directly dynamic changes of blood flow to tumors, which assists in identifying tumor growth and necrosis, therefore, this research provides an evidence-based guidelines for the treatment of human lung squamous cell carcinoma and has far-reaching clinical significance.

Analysis of Leakage in Bolted-Flanged Joints Using Contact Finite Element Analvsis

The evolution of leakage is studied using detailed contact finite element analysis. The distribution of stress at the gasket is analyzed using a contact condition based on slide-line elements using ABAQUS, a commercial finite element code, Slide-line elements also take into account pressure penetration as contact that is lost between flange and gasket. Results are presented for a particular flange, a raised face flange sealed by a mild steel gasket. A comparison of the results from the gasket contact analysis and the contact conditions specified by the ASME Boiler and Pressure Vessel Code, Sections VIII, Division 1 shows that the conditions specified in the ASME Code predict leakage relatively accurately.

Blast Pressure Mitigation by Surface Explosion Using Water in a Walled Container

Mitigation of blast pressure using water in a walled container was evaluated. A PETN （pentaerythritol tetranitrate） pellet of 1.4 g near the model wall was detonated on a steel plate. A water-filled container was placed between the explosive and the wall. The pressure histories at six points, which corresponded to Hopkinson scaled distance of from 3.6 m·kg^-1/3 to 21.7 m·kg^-1/3 were evaluated along with dependence of mitigation effects on the amount of water and the position of the container. The presence of the water and the wall mitigated the peak overpressure near the explosion points and the positive impulse along all points. The mitigation effect was equivalent to 20-30% reduction of explosive weight based on discussion of the equivalent ratio. The presence of the water along the wall （not very close to the explosive） also mitigated the blast pressure.

Seismic Isolation of Reactor Assembly for a Fixed Base Accelerator Driven System Reactor Building

In the SILER （Seismic-Initiated events risk mitigation in LEad-cooled Reactors） Project, it is interesting to apply seismic isolation technology for the reactor assembly of the fixed base reactor building for ADS （Acceleration Driven System） heavy liquid reactor MYRRHA （Multipurpose Hybrid Research Reactor for High-Tech Application） which contains the most critical safety related components, such as reactor vessel, safe shutdown and control rod mechanisms, primary heat exchangers, primary pumps, spoliation target assembly and fuel assemblies, etc. The purpose of this paper is to investigate the possibility of an application of a partial seismic isolation to the safety critical components only, here, the reactor assembly. This paper presents the preliminary analysis results of the isolated reactor assembly and compares these with those of seismic isolated ADS reactor building. The analysis results show the reduction of the seismic acceleration response but the increase of the relative displacement for the reactor assembly. Some safety issues, especially, coolant＇s incapable covering the reactor core make difficult to apply for the partial seismic isolation of the ADS reactor assembly due to large relative displacement occurring the partial isolation system. Further study on the partial seismic isolation application of the critical safety components are also discussed.

Analysis of Pb-Bi Vessel Wall Ablation Experiment with High Temperature Liquid by MPS Method

In a severe accident of a light water reactor, ablation of the RPV （reactor pressure vessel） lower head by corium is a key phenomenon, which affects progression of the accident. The MPS （moving particle semi-implicit） method is one of particle methods that calculate behavior of incompressible fluid by semi-implicit method. In preceding studies, the MPS method has been extensively studied and developed for simulations of different phenomena involved in severe accident of nuclear reactors. This paper aims to investigate whether the MPS method is capable of analyzing the lower head ablation phenomenon. The small-scale experiment carried out at CRIEPI （Central Research Institute of Electric Power Industry） using Pb-Bi vessel and silicone oil was analyzed for the validation of the MPS method. The MPS analysis well reproduced the experimental phenomena qualitatively. However, with respect to some quantitative results, more investigation such as influence of the calculation particle size is necessary.

RANS （Reynolds Averaged Navier-Stokes） and LES （Large Eddy Simulations） of the Air-Water TOPFLOW-PTS Experiment

The occurrence of a PTS （pressurized thermal shock） in a reactor vessel is an important phenomenon for assessing nuclear reactor safety. New experiment was conducted at HZDR （Helmholtz-Zentrum Dresden-Rossendorf）, focused on thermal mixing processes in the cold leg and the downcomer of two-phase PTS case. Present work reports CFD （computational fluid dynamics） ana｜ysis of steady-state air-water case. CFD analysis was conducted with two turbulence-modeling approaches, RANS （Reynolds Averaged Navier-stokes） and LES （large eddy simulations）. Multiphase situation was modeled with VOF （volume of fluid） approach. Simulations were performed using the FLUENT 12 package. Comparison of computed temperatures results and measurements along the thermo-couple lines revealed results depend on the turbulence model used.

Numerical Simulations of Upper Plenum Thermal-Hydraulics of Monju Reactor Vessel Using High Resolution Mesh Models

In order to evaluate the effects of the FHs （flow holes） on the inner barrel, which were installed in the upper plenum of the Monju reactor vessel, a high resolution meshes around the FHs was constructed. Using this model, it was mainly clear that in the 40% rated operational conditions, the shape of the FHs on the inner barrel did not change largely to the upper plenum thermal-hydraulics. The effect of the FHs on the honeycomb structure in the upper structure was also investigated in these calculations. The results indicated that the height of thermal stratification interface became lower than that evaluated from the test data.

Flexible and transparent capacitive pressure sensor with patterned microstructured composite rubber dielectric for wearable touch keyboard application

The development of pressure sensors with highly sensitivity, fast response and facile fabrication technique is desirable for wearable electronics. Here, we successfully fabricated a flexible transparent capacitive pressure sensor based on patterned microstructured silver nanowires(AgNWs)/polydimethylsiloxane(PDMS) composite dielectrics. Compared with the pure PDMS dielectric layer with planar structures, the patterned microstructured sensor exhibits a higher sensitivity(0.831 kPa^-1, <0.5 kPa), a lower detection limit,good stability and durability. The enhanced sensing mechanism about the conductive filler content and the patterned microstructures has also been discussed. A 5×5 sensor array was then fabricated to be used as flexible and transparent wearable touch keyboards systems. The fabricated pressure sensor has great potential in the future electronic skin area.

Research into tritium and helium-3 contents distributions in steel wall of spherical pressure vessel

The tritium quantity stored in a steel pressure vessel decreases with time because of helium-3 decay and permeation of tritium into the steel wall of the pressure vessel.Meanwhile,the tritium quantity permeating into the steel wall also decreases with time due to helium-3 decay and diffusion in and out of the wall of tritium.Tritium and helium-3 in the steel wall will cause hydrogen and helium embrittlement of the wall material,respectively,and thereby change the carrying capacity of the vessel.Taking contemporarily both decay and permeation of tritium within the vessel and decay and diffusion of tritium having permeated into the wall into consideration,the governing equations of tritium and helium-3 contents in the wall were established and solved,and relevant formulas were deduced.Through analytical calculations,curves of tritium and helium-3 contents versus radius and time were theoretically plotted,the contents spatio-temporal distributions laws were obtained,and a law about helium-3 contents distribution in steel wall of a spherical pressure vessel was discovered which was called the law of double helium-3 content.

Numerical and experimental investigations for an air cannon optimization

Air cannon is a kind of de-clogging device which produces impulse force by instantly releasing the compressed air deposited in a pressure vessel. Air cannons are widely used in the transport pipes of warehouses, docks, furnaces and coal mines. In this paper, the theoretical analysis with isentropic flow hypothesis is firstly conducted on a simplified mode/ to deduce the theo- retical maximum of impulse force. And numerical study is carried out to predict the steady and unsteady impulse forces via simulating the whole exhausting process of the air cannon. The results demonstrate that the impulse force can be improved via increasing the piston sleeve inlet length and increasing the nozzle diameter. Laval nozzle can also increase the impulse force of the air without increasing the air mass flow. The optimization of the air cannon is then conducted on the basis of the theoretical and numerical analyses. Experimental measurements indicate that the computations well simulate the working process of the air cannon and the impulse force of the optimized design is 50% higher than the original model. For the cases with working pressure of 0.8 MPa, the optimized design is 60% higher than the original one.

A Rapid Evaluation Method of the Heat Removed by a VCS before Rise-to-Power Tests

Before rise-to-power tests, the actual measured value of heat released from the Reactor Pressure Vessel(RPV) or removed by the Vessel Cooling System(VCS) cannot be obtained. It is difficult for operators to evaluate the reactor outlet coolant temperature supplied from the High Temperature Engineering Test Reactor(HTTR) before rise-to-power tests. Therefore, when the actual measured value of heat released from the RPV or removed by the VCS are changed during rise-to-power tests, operators need to evaluate quickly, within a few minutes, the heat removed by the VCS and the reactor outlet coolant temperature of 30 MW, at 100% reactor power, before the temperature achieves 967℃ which is the maximum temperature limit generating the reactor scram. In this paper, a rapid evaluation method for use by operators is presented. The difference between the experimental and analytical results was within 30(k W) and it is appropriate that the presented evaluation method can be applied; therefore, operators can analyze the heat removed by the VCS quickly, within a few minutes, before and during Rise-to-Power Tests.

A new method of rapid quality detection of vacuum insulation panels

A new method of measuring gas pressure in vacuum insulation panels(VIPs)is reported in this study,which provides a fast and efficient quality control option of production.Although there are different methods of measuring gas pressure for VIPs,connecting an internal measurement gauge to external data acquisition units is problematic.The thin high barrier film covering the panel’s core usually prevents external electrical wires or mechanical devices being connected to the inside of the VIPs.To solve this problem,a micro capacitive pressure sensor with 0 to 250 Pa detection range is developed to detect the vacuum pressure.The sensor has high linearity and a sensitivity of 10 mV/Pa.Moreover,through the communication mode study,an ultrasound communications system for VIPs is designed.It shows from operation that this system is stable and reliable,and quick for communication speed.This new method enables the quality detection of VIPs to be completed within 1 second.The minimum detectable pressure of VIPs is below 1 Pa,and the measurement error can be controlled around 5%.