Prototype Engineering Test Platform of ITER Magnet Gravity Support

ITER magnet gravity support （GS） has been redesigned as a structure of pre- assembled nmlti-flexible plates instead of the original welded structure. In the past several years, engineering tests of the new structure have been proposed. A prototype engineering test plat- form is being developed. In order to apply the loads/load combinations onto the test mock-up, seven hydraulic bolt tensioners in three directions have been applied to simulate various loads （forces and moments）, through which the deformation of bolts, flexible plates and clamp blocks, the stress distribution in the flexible plates, the friction between the contact surface, etc. can be monitored/tested. The measurement and control system includes seven sets of synchronization controller, a 16-channel strain gauge, 25 sets of displacement sensors, etc. Principles of EDC220 digital controller and development of multi-channel control software are also demonstrated.

120-ton Thrust Liquid-Oxygen/Kerosene Engine Passed Acceptance Test

On May 28, the 120-ton thrust liquid-oxygen/kerosene engine developed by the Academy of Aerospace Liquid Propulsion Technology (AALPT) passed the acceptance test organized by China National Space Administration (CNSA). The 120-ton thrust liquid-oxygen/kerosene engine is a non-pollution, non-toxic, high performance and reliable basic pro-

Numerical simulation of tritium behavior under a postulated accident condition for CFETR TEP system

China Fusion Engineering Test Reactor(CFETR)is China's self-designed and ongoing next-generation fusion reactor project.Tritium confinement systems in CFETR guarantee that the radiation level remains below the safety limit during tritium handling and operation in the fuel cycle system.Our tritium technology team is responsible for studying tritium transport behavior in the CFETR tritium safety confinement systems of the National Key R&D Program of China launched in 2017,and we are conducting CFETR tritium plant safety analysis by using CFD software.In this paper,the tritium migration and removal behavior were studied under a postulated accident condition for the Tokamak Exhaust Processing system of CFETR.The quantitative results of the transport behavior of tritium in the process room and glove box during the whole accident sequence(e.g.,tritium release,alarm,isolation,and tritium removal)have been presented.The results support the detailed design and engineering demonstration-related research of CFETR tritium plant.

3D fluid model analysis on the generation of negative hydrogen ions for negative ion source of NBI

A radio-frequency(RF) inductively coupled negative hydrogen ion source(NHIS) has been adopted in the China Fusion Engineering Test Reactor(CFETR) to generate negative hydrogen ions.By incorporating the level-lumping method into a three-dimensional fluid model,the volume production and transportation of H^(-) in the NHIS,which consists of a cylindrical driver region and a rectangular expansion chamber,are investigated self-consistently at a large input power(40 k W) and different pressures(0.3–2.0 Pa).The results indicate that with the increase of pressure,the H^(-) density at the bottom of the expansion region first increases and then decreases.In addition,the effect of the magnetic filter is examined.It is noteworthy that a significant increase in the H^(-) density is observed when the magnetic filter is introduced.As the permanent magnets move towards the driver region,the H^(-) density decreases monotonically and the asymmetry is enhanced.This study contributes to the understanding of H-distribution under various conditions and facilitates the optimization of volume production of negative hydrogen ions in the NHIS.

Optimization of technical measures for improving high-temperature performance of asphalt-rubber mixture

Asphalt-rubber pavements often become dam-aged in high-temperature regions and appear rutted or wavy, and experience slippage. To improve the high-temperature performance of the asphalt-rubber mixture, technical measurements, such as, the optimal adjustment of gradation, technique of composite modification, and control of compaction were investigated. An optimal adjustment of aggregate gradation based on stone matrix asphalt improves the high-temperature stability of the asphaltrubber mixture significantly. Through composite modifi- cation, the effect of asphalt-rubber modification was enhanced, and the dynamic stability and relative defor- mation indices of the asphalt-rubber mixture were improved significantly. Furthermore, compaction parame- ters had a significant influence on the high-temperature stability of the asphalt-rubber mixture. The rolling times for compacting the asphalt-rubber mixture should be controlled to within 18-20 round-trips at a molding temperature at 180℃; if the rolling time is a 12 round-trip, the compaction temperature of the asphalt-rubber mixture should be controlled between 180 and 190℃.

Preparation and Characterization of Zireonia Oxygen Sensors

A thimble zirconia oxygen sensor electrolyte and their interface were observed with was prepared with YSZ. The surfaces of the Pt electrode, a scanning electron microscope （SEM）.The sensor was examined with engine bench test to evaluate the essential performance. The basic function such as electromotive force output and response time was discussed. The oscillograph trace was also obtained and analyzed with four different frequencies. The experimental results reveal that the oxygen sensor has high performances meeting the demands of practical applications..

Research on cooling-temperature control strategy of fuel-cell engine test bench

As one of the important ways to utilize hydrogen energy,fuel cells are receiving more and more attention and research from countries and institutions.To meet the practical needs of testing the performance of high-power fuel-cell systems and simulate the actual application environment as much as possible,a fuel-cell system test bench is usually used to test the system performance,in which the cooling-temperature control of the test bench has a great impact on the results of the performance of the fuel-cell system.This paper studies the cooling-temperature control strategy of a 150-kW-class fuel-cell engine test platform,proposes a new test-bench cooling-system structure with a thermostat and heat exchanger as the main heat-dissipation components,and compares and analyzes the impact of coordinated thermostat and heat-exchanger control on the fuel-cell system test performance.The test results show that the control strategy of the coordinated operation of a thermostat and heat exchanger can maintain the steady-state error to within±0.3℃and maintain the temperature variation to within±1.5℃during the loading-condition test,so as to avoid the limitation of system output performance due to excessive cooling-temperature fluctuation and ensure that the fuel-cell engine performance-test process is carried out smoothly and efficiently.

Influence studyof flow separation on the nozzle vibration response

In the present paper,the vibration response difference of the upper stage nozzlewith higher expansion ratio between ground and altitude simulation hot-firing test is analyzed.lt indicates that the acceleration response of the nozzle under ground hot-firing test is muchhigher than that of the altitude condition.In order to find the essential reason,the experimentaland numerical simulation studies of the flow separation are developed by using the test enginenozzle.The experimental data show that the nozzle intemal flow occurred flow separation andthe divergence cone intemal wall pressure pulsation increased significantly downstream fromthe separation location.The numerical simulation and experimental results indicate that theincrease of internal wall pressure and turbulence pulsating pressure are the substantial reason ofvibration response increasing aggravatingly during the ground firing test.

Model-Based Embedded Compiled Software Fault Positioning

Software fault positioning is one of the most effective activities in program debugging. In this paper, we propose a model-based fault positioning method to detect the faults of embedded program without source code. The system takes the machine code of embedded software as input and translates the code into high-level language C with the software reverse engineering program. Then, the static analysis on the high-level program is taken to obtain a control flow graph（CFG）, which is denoted as a node-tree and each node is a basic block. According to the faults found by the field testing, we construct a fault model by extracting the features of the faulty code obtained by ranking the Ochiai coefficient of basic blocks. The model can be effectively used to locate the faults of the embedded program. Our method is evaluated on ST chips of the smart meter with the corresponding source code. The experiment shows that the proposed method has an effectiveness about 87% on the fault detection.