Alpha Radioactivity Monitor Using Ionized Air Transport Technology for Large Size Uranium Waste: Part 2—Simulation Model Reinforcement for Practical Apparatus Design

2010 ◽  
Author(s):  
Takatoshi Asada ◽  
Yosuke Hirata ◽  
Susumu Naito ◽  
Mikio Izumi ◽  
Yukio Yoshimura
Keyword(s):  
Ion Transport ◽  
Simulation Model ◽  
Cfd Simulation ◽  
Transport Model ◽  
Model Simulation ◽  
Ion Density ◽  
Transport Simulation ◽  
Simulation Results ◽  
Alpha Radioactivity ◽  
Ionized Air

In alpha radioactivity measurement using ionized air transportation (AMAT), conversion from ion currents to radioactivity accurate is required. An ion transport simulation provides ways of complementarily determining conversion factors. We have developed an ion transport simulation model. Simulation results were compared with experiments with air speeds, faster than 1 m/s, achieving good agreement. In a practical AMAT apparatus, the air-flow at the alpha source may be slower than 1 m/s, and ion loss is likely to be large. Reinforcement of the ion transport model to cover the lower air speed region is effective. Ions are generated by an alpha particle in a very thin column. Since the ion density at this temporal stage is high, the recombination loss, proportional to the square of ion density, is dominant within a few milli-seconds. The spatial and temporal scales of this columnar recombination are too small for CFD simulation. We solve an ion transport equation during the period of columnar recombination with diffusion and recombination terms and incorporated the relation between ion loss and turbulent parameters into CFD. Using this model, simulations have been done for various air speeds and targets. Those for simulation results agree with experiments, showing improvement of simulation accuracy.

Pollutant Transport Model and Numerical Simulation in Landfill Site

2012 ◽  
Vol 443-444 ◽  
pp. 424-429
Author(s):  
Ying Zhao ◽  
Qiang Xue ◽  
Lei Liu ◽  
Bing Liang
Keyword(s):  
Numerical Simulation ◽  
Control System ◽  
Simulation Model ◽  
Landfill Leachate ◽  
Transport Model ◽  
Control Measure ◽  
Underground Water ◽  
Seepage Control ◽  
Simulation Results ◽  
The One

The simulation model for describing the transportation and transformation of landfill leachate pollutant in landfill, soil and underground water was established. Taking Wuhan Changshankou landfill for example, the numerical simulation was carried out. The simulation results showed that if there’s no any seepage control measure, the groundwater and soil under landfill will be polluted seriously after MSW was filled; the highest pollutant concetration in landfill was about 25000, and the one in groundwater and soil was about 20000; at the thirtieth year, the pollutant concetration in groundwater and soil still remained up to 10000 although the one in landfill was about 0. The simulation results also showed that the vertical stonewall can’t be used as a nature, and artificial seepage control system must be used.

Analysis of Dynamic Characteristics of Automatic Transmission Shifting Control

2014 ◽  
Vol 643 ◽  
pp. 42-47 ◽  
Author(s):  
Yan Xiao Fu ◽  
Liang Yi Cui ◽  
Xiang Yang Xu ◽  
Peng Dong
Keyword(s):  
Simulation Model ◽  
Control Strategy ◽  
Model Simulation ◽  
Automatic Transmission ◽  
Test Results ◽  
Shift Quality ◽  
Impact Function ◽  
Automatic Transmissions ◽  
Simulation Results ◽  
The Impact

Basing on the fact that requirements for shift quality in automatic transmissions have been increasing rapidly necessitates the establishment of a suitable shifting control strategy in order to facilitate smoothness of different processes, this paper introduces a simulation model of an 8-speed automatic transmission for front-drive vehicles with respect to detailed shifting strategies and relative parameters. The transmitted torque of the oncoming shift elements before synchronization point can be reduced by an impact function in order to damp the impact and thus make the gear shifting process more smooth. This paper makes a systematic introduction of the structure of 8AT, theoretical basis of control strategy, the establishment of the simulation model and the comparison between test results and simulation results. The conclusion shows that with an accurate dynamic model, simulation results and test results are neighborhood data, the simulation model can be used to help realizing the ultimate goal of better shift quality with higher efficiency, lower shift loads and improved shifting comfort.

scholarly journals Study on the Cooling Effect of Attached Fins on PV Using CFD Simulation

Energies ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 758 ◽  
Author(s):  
Jaemin Kim ◽  
Yujin Nam
Keyword(s):  
Simulation Model ◽  
Cfd Simulation ◽  
Hot Spot ◽  
Cooling Effect ◽  
Dynamics Simulation ◽  
Solar Simulator ◽  
Cooling Performance ◽  
Electrical Efficiency ◽  
Pv Module ◽  
Simulation Results

The issue of efficiency decrease according to temperature increase is a pending problem in the PV market. Several active and passive technologies have been suggested but few quantitative studies on the estimation of the cooling effect have been carried out. In this study, a CFD (computational fluid dynamics) simulation model was developed to analyze a passive cooling technology using fins attached to the back of the PV module. Furthermore, a method to improve airflow at the back of the PV module by forming slits in the frame was analyzed. The simulation model reproduced the indoor test that uses a solar simulator and the cooling performance was analyzed according to the shape of the fins and the presence of slits. In the simulation results, the surface temperature and expected electrical efficiency without cooling were 62.78 °C and 13.24% respectively under nominal operating cell temperature conditions. Moreover, the temperature reduced by approximately 15.13 °C because the fins attached at the bottom of the PV module increased the heat transfer area with airflow. Thus, the electrical efficiency according to the PV module temperature was predicted as 14.39%. Furthermore, when slits were installed between the fins, they increased the airflow velocity and accelerated the formation of turbulence, thereby improving the cooling performance of the fins. The simulation results showed that the temperature could be further reduced by approximately 8.62 °C at a lower air velocity. As the fins and slits can also reduce the non-uniformity of the temperature, they are expected to supplement the efficiency and durability reduction of the PV modules caused by the hot spot phenomenon. In addition, it was shown that slits in the frame could further improve the cooling performance of the fins at a low-velocity airflow.

A Study of Simulation Model of Doubly-Fed Motor Based on Matlab/Simulink

2013 ◽  
Vol 816-817 ◽  
pp. 625-628
Author(s):  
Xian Biao Chen
Keyword(s):  
Simulation Model ◽  
Model Simulation ◽  
Regulation System ◽  
Motor Simulation ◽  
Unity Power Factor ◽  
Two Phase ◽  
Speed Regulation ◽  
Simulation Results ◽  
Doubly Fed ◽  
The Mathematical Model

This paper introduces the characteristics of doubly-fed motor. The mathematical model in the two-phase synchronous rotating coordinate system d-q of doubly-fed motor is given, and a simulation model is constructed by Matlab S-function based on the model. Simulation of doubly-fed motor on stator unity power factor vector control is carried out through the model and simulating waveforms are given. The simulation results illustrate that the doubly-fed motor simulation model by S-function has the characteristics of simple, fast and high precision. It provides a convenient pathway for the research of doubly-fed speed regulation system.

scholarly journals Dynamic Analysis of Bottom Hole Assembly With External Vibrating Force Excitation

2013 ◽  
Author(s):  
Lei Wang ◽  
Stephen Butt ◽  
Jianming Yang
Keyword(s):  
Cfd Simulation ◽  
Model Simulation ◽  
Fluid Pressure ◽  
Rock Interaction ◽  
Bottom Hole ◽  
Bottom Hole Assembly ◽  
Computational Fluid Dynamics Cfd ◽  
Simulation Results ◽  
Force Excitation ◽  
Valve Part

Based on the Downhole Oscillating Device (DOD) newly developed for purpose of improving drilling efficiency, Computational Fluid Dynamics (CFD) simulation is conducted. The axial vibration force created by the DOD is thoroughly investigated. The simulation is focused on the valve part which generates the fluid pressure pulsations. Fluid flow rate and/or back pressure is applied to the model as boundary conditions. The DOD’s application will also induce the inertia phenomenon of the fluid column above the tool. This phenomenon is also studied based on parametric analysis. Within the simulation results, a dynamic model is developed to further investigate the effect of the oscillating force generated by the DOD on drilling efficiency. Nonlinearities in the bit-rock interaction are taken into account in the model. Simulation results show that application of the DOD in drilling may improve the ROP at least by 5%.

scholarly journals Macro Modeling of V-Shaped Electro-Thermal MEMS Actuator with Human Error Factor

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 622
Author(s):  
Dongpeng Zhang ◽  
Anjiang Cai ◽  
Yulong Zhao ◽  
Tengjiang Hu
Keyword(s):  
Neural Network ◽  
Simulation Model ◽  
Bp Neural Network ◽  
Human Error ◽  
Calculation Model ◽  
Fuzzy Mathematics ◽  
Ansys Simulation ◽  
Macro Modeling ◽  
Error Factor ◽  
Simulation Results

The V-shaped electro-thermal MEMS actuator model, with the human error factor taken into account, is presented in this paper through the cascading ANSYS simulation model and the Fuzzy mathematics calculation model. The Fuzzy mathematics calculation model introduces the human error factor into the MEMS actuator model by using the BP neural network, which effectively reduces the error between ANSYS simulation results and experimental results to less than 1%. Meanwhile, the V-shaped electro-thermal MEMS actuator model, with the human error factor included, will become more accurate as the database of the V-shaped electro-thermal actuator model grows.

scholarly journals Numerical Investigation for the Resin Filling Behavior during Ultraviolet Nanoimprint Lithography of Subwavelength Moth-Eye Nanostructure

Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 799
Author(s):  
Yuanchi Cui ◽  
Xuewen Wang ◽  
Chengpeng Zhang ◽  
Jilai Wang ◽  
Zhenyu Shi
Keyword(s):  
Simulation Model ◽  
Nanoimprint Lithography ◽  
Cfd Simulation ◽  
Boundary Slip ◽  
Accurate Analysis ◽  
Inlet Velocity ◽  
Filling Height ◽  
Proposed Model ◽  
Good Consistency ◽  
Computational Fluid Dynamics Cfd

Accurate analysis of the resin filling process into the mold cavity is necessary for the high-precision fabrication of moth-eye nanostructure using the ultraviolet nanoimprint lithography (UV-NIL) technique. In this research, a computational fluid dynamics (CFD) simulation model was proposed to reveal resin filling behavior, in which the effect of boundary slip was considered. By comparison with the experimental results, a good consistency was found, indicating that the simulation model could be used to analyze the resin filling behavior. Based on the proposed model, the effects of process parameters on resin filling behavior were analyzed, including resin viscosity, inlet velocity and resin thickness. It was found that the inlet velocity showed a more significant effect on filling height than the resin viscosity and thickness. Besides, the effects of boundary conditions on resin filling behavior were investigated, and it was found the boundary slip had a significant influence on resin filling behavior, and excellent filling results were obtained with a larger slip velocity on the mold side. This research could provide guidance for a more comprehensive understanding of the resin filling behavior during UV-NIL of subwavelength moth-eye nanostructure.

Optimization of Structure and Calculation of Flow-Force on Poppet Valve under Converging Flow

2011 ◽  
Vol 339 ◽  
pp. 148-151 ◽  
Author(s):  
Shu Juan Zheng ◽  
Long Quan
Keyword(s):  
Cfd Simulation ◽  
Internal Flow ◽  
Poppet Valve ◽  
Converging Flow ◽  
Simulation Results

This paper optimizes the structure of the poppet valve based on the internal flow. The flow-force on poppet valve in the case of the converging flow is simulated and studied by CFD. Simulation results represent that the traditional formula for computing the flow-force can be used only in the certain range, so the formula is modified based on the simulation result.

Sign in / Sign up

Export Citation Format

Share Document