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2020

Numerical simulation

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Full-Text Articles in Engineering

High Fidelity Computational Modeling And Analysis Of Voice Production, Weili Jiang Dec 2020

High Fidelity Computational Modeling And Analysis Of Voice Production, Weili Jiang

Electronic Theses and Dissertations

This research aims to improve the fundamental understanding of the multiphysics nature of voice production, particularly, the dynamic couplings among glottal flow, vocal fold vibration and airway acoustics through high-fidelity computational modeling and simulations. Built upon in-house numerical solvers, including an immersed-boundary-method based incompressible flow solver, a finite element method based solid mechanics solver and a hydrodynamic/aerodynamic splitting method based acoustics solver, a fully coupled, continuum mechanics based fluid-structure-acoustics interaction model was developed to simulate the flow-induced vocal fold vibrations and sound production in birds and mammals. Extensive validations of the model were conducted by comparing to excised syringeal and …


Freezing Temperature Field Characteristics Of Multi-Loop Pipers Under Different Working Conditions At The Interface Of Deep Thick Sand And Clay, Yang Qing, Rong Chuanxin, Li Mingjing, Yang Guobing Dec 2020

Freezing Temperature Field Characteristics Of Multi-Loop Pipers Under Different Working Conditions At The Interface Of Deep Thick Sand And Clay, Yang Qing, Rong Chuanxin, Li Mingjing, Yang Guobing

Coal Geology & Exploration

When drilling in a complex heterogeneous formation, due to the limitation of bit crown shape, the cutters of each part of the bit are subjected to non-uniform force, and the cutters at the local location are subjected to large impact load, which lead to the occurrence of bit vortex. In order to solve the problem, a “multi-level force balance” cutter circumferential arrangement scheme is proposed. By establishing the rock breaking finite element simulation model of the bit, the mechanical characteristics of the cutter and the bit under three circumferential cutter distribution modes(clockwise, counterclockwise and “multi-level force balance”) are analyzed. Simulation …


Mathematical Modelling And Numerical Simulation Of Mass Transfer During Deep-Fat Frying Of Plantain (Musa Paradisiacal Aab) Chips (Ipekere), James Abiodun Adeyanju, John Oluranti Olajide, Emmanuel Olusola Oke, Akinbode A. Adedeji Dec 2020

Mathematical Modelling And Numerical Simulation Of Mass Transfer During Deep-Fat Frying Of Plantain (Musa Paradisiacal Aab) Chips (Ipekere), James Abiodun Adeyanju, John Oluranti Olajide, Emmanuel Olusola Oke, Akinbode A. Adedeji

Biosystems and Agricultural Engineering Faculty Publications

This study developed a mathematical model following the fundamental principles of mass transfer for the simulation of the oil and moisture content change during the Deep-Fat Frying of plantain (ipekere) chip. The explicit Finite Difference Technique (FDT) was used to conduct a numerical solution to the consequential governing equation (partial differential equation) that was used to describe the mass transfer rate during the process. Computer codes that were computed in MATLAB were used for the implementation of FDT at diverse frying conditions. Samples of the plantain were cut into portions of 2 mm thickness, and these sliced portions …


Stability Analysis Of An Underground Powerhouse On The Left Bank Of The Baihetan Hydropower Station Based On Discrete Element Simulation And Microseismic Monitoring, Hao-Yu Mao, Nu-Wen Xu, Biao Li, Yi-Lin Fan, Jia-Yao Wu, Guo-Tao Meng Dec 2020

Stability Analysis Of An Underground Powerhouse On The Left Bank Of The Baihetan Hydropower Station Based On Discrete Element Simulation And Microseismic Monitoring, Hao-Yu Mao, Nu-Wen Xu, Biao Li, Yi-Lin Fan, Jia-Yao Wu, Guo-Tao Meng

Rock and Soil Mechanics

To investigate the stability of the surrounding rock during excavation process of the underground caverns at the Baihetan hydropower station, effects of excavation unloading on the deformation and failure of the surrounding rock using the numerical simulation software 3DEC based on DEM (discrete element method) are analyzed. The microseismic monitoring technology is introduced to monitor and analyze micro-fracture evolution inside the surrounding rock of the caverns in real time, and the numerical simulation results are compared with the microseismic monitoring data. In order to verify the accuracy of numerical simulation and microseismic monitoring results, the spatiotemporal evolution law of the …


Physical Experimental Study On Excavation Disturbance Of Tbm In Deep Composite Strata, Lin-Ken Shi, Hui Zhou, Ming Song, Jing-Jing Lu, Chuan-Qing Zhang, Xin-Jing Lu Nov 2020

Physical Experimental Study On Excavation Disturbance Of Tbm In Deep Composite Strata, Lin-Ken Shi, Hui Zhou, Ming Song, Jing-Jing Lu, Chuan-Qing Zhang, Xin-Jing Lu

Rock and Soil Mechanics

In view of the alternating change of soft and hard rock mass in the work face, physical model test and numerical simulation were conducted to investigate the dynamic response of tunnel surrounding rock during the process of TBM excavation in composite strata at the Lanzhou water source construction project. Similar composite rock mass materials with different strength ratios of surrounding rock were prepared by performing analogous proportion experiments. The fiber grating technology was used to capture the strain evolution law of surrounding rock in composite strata during tunnel excavation, and the macroscopic fracture morphology of the surrounding rock of the …


Simulation Of The Cutter Arrangement Pattern Of The Arc Pdc Drill Bit, Ju Pei, Wang Chuanliu Oct 2020

Simulation Of The Cutter Arrangement Pattern Of The Arc Pdc Drill Bit, Ju Pei, Wang Chuanliu

Coal Geology & Exploration

When drilling in a complex heterogeneous formation, due to the limitation of bit crown shape, the cutters of each part of the bit are subjected to non-uniform force, and the cutters at the local location are subjected to large impact load, which lead to the occurrence of bit vortex. In order to solve the problem, a “multi-level force balance” cutter circumferential arrangement scheme is proposed. By establishing the rock breaking finite element simulation model of the bit, the mechanical characteristics of the cutter and the bit under three circumferential cutter distribution modes(clockwise, counterclockwise and “multi-level force balance”) are analyzed. Simulation …


Development And Application Of Contact Algorithms For Rock Shear Fracture Surface, Qiu-Feng Ma, Yue-Ping Qin, Tian-Bai Zhou, Xiao-Bin Yang Sep 2020

Development And Application Of Contact Algorithms For Rock Shear Fracture Surface, Qiu-Feng Ma, Yue-Ping Qin, Tian-Bai Zhou, Xiao-Bin Yang

Rock and Soil Mechanics

To overcome the inefficiency of existing numerical algorithms in calculating the contact slip law of complex fracture surfaces, a new numerical calculation algorithm was proposed by adoption of the idea of boundary element method. In this algorithm, all nodes were located at the boundary of rock blocks, and the interaction force between rock blocks and the displacement of rock blocks were calculated by using the explicit differential method. The algorithm was validated by two simulation experiments, i.e. “ball sliding on paraboloid” and “dumbbell on the inclined plane”. The results show the algorithm can accurately describe the contact between objects and …


Error Correction Methods In Numerical Simulation For Unilateral Constraint Dynamics, Haitao Gao, Yali Han, Youxiong Xu, Songqing Zhu, Zailuo Wu Sep 2020

Error Correction Methods In Numerical Simulation For Unilateral Constraint Dynamics, Haitao Gao, Yali Han, Youxiong Xu, Songqing Zhu, Zailuo Wu

Journal of System Simulation

Abstract: Aiming at problem of calculation errors and constraint violation in numerical simulation for dynamics of unilateral constraint such as contact and collision, the error projection correction methods were put forward. On the basis of dynamical behavior of unilateral constraint described by linear programming model, mixed linear complementarity dynamics was built. Numerical simulation methods for the mixed linear complementarity dynamics were derived. In order to reduce calculation error and constraint violation caused by this error in the numerical simulation, an error correction method was built for correcting position and velocity error of numerical solution on the base of bilateral …


Development Characteristics Of Freezing Temperature Field Of Coastal Soft Soil Strata, Chen Junhao, Zhuang Yan, Chen Bijian, Zhao Zhenwei, Wang Qiyun Aug 2020

Development Characteristics Of Freezing Temperature Field Of Coastal Soft Soil Strata, Chen Junhao, Zhuang Yan, Chen Bijian, Zhao Zhenwei, Wang Qiyun

Coal Geology & Exploration

In order to research the temperature fields and development law of freezing in the construction of connected aisle in coastal soft soil stratum, based on connected aisle between Luoxiu road station and Baise road station of Shanghai subway Line 15, the thickness and average temperature of frozen curtain, and the freezing process were analyzed. The temperature fields and development law of freezing were predicted by the three-dimensional numerical model of the connected aisle and the temperature data which were analyzed. The results show that the inherent pressure in soft soil causes initial pressure in the pressure relief hole. A lot …


Overburden Failure Simulation Under Double Coal Seams Mining In A Coal Mine In North Shaanxi Province, Sun Xueyang, Zhang Qi, Li Cheng, Zhang Lei Aug 2020

Overburden Failure Simulation Under Double Coal Seams Mining In A Coal Mine In North Shaanxi Province, Sun Xueyang, Zhang Qi, Li Cheng, Zhang Lei

Coal Geology & Exploration

Under the conditions of multi-seam mining, the overburden failure of coal seams has unique characteristics, which affects the mine production arrangement. Taking a mine in northern Shaanxi Province as an example, based on the geological and mining conditions of the mine, the influence of double-seam mining on overburden rock damage was analyzed by using the method of similar material simulation experiment and numerical simulation. The results show that the height of the caving zone and the height of the fractured zone in the overburden of coal seam obtained by using similar material simulation and numerical simulation with different widths of …


Simulation Study On External Explode Of Large Equivalent Charge On Large Buildings, Weiping Zhao, Xiankun Ge, Chuanwu Liu, Fengchun Zhu Aug 2020

Simulation Study On External Explode Of Large Equivalent Charge On Large Buildings, Weiping Zhao, Xiankun Ge, Chuanwu Liu, Fengchun Zhu

Journal of System Simulation

Abstract: The particle algorithm in AUTODYN, Smoothed Particle Hydrodynamics (SPH), was used to simulate dynamic damage of the external explosion on large buildings, which provided a visual effect. The dynamic damage details of reinforced concrete and brick masonry structure at different time were proposed by the simulation of single component. Additionally, the overpressure of shock wave, caving velocity and kinetic energy were obtained. It shows that the caving can speed up to a maximum value of 152 m/s with the kinetic energy of 18 000 J, that means a great damage to personnel and equipment in the building. Under …


Study Of Synchronization For Fractional-Order Hyperchaotic System And Its Application In Secure Communication, Xue Wei, Jinkang Xu, Hongyan Jia Aug 2020

Study Of Synchronization For Fractional-Order Hyperchaotic System And Its Application In Secure Communication, Xue Wei, Jinkang Xu, Hongyan Jia

Journal of System Simulation

Abstract: A unidirectionally coupled synchronization method was adopted to design and implement the synchronization for the reported commensurate fractional-order hyperchaotic system, and its correctness and effectiveness were analyzed in theory. Moreover, taking an example of 3.6-order hyperchaotic system, analog circuits were designed to implement the fractional-order hyperchaotic system and its unidirectionally coupled synchronization with the frequency-domain approximation method based on Bode diagram. By conducting the circuit implementation, it is found that the results of the circuit implementation are in good agreement with those of the numerical simulation, which demonstrates the feasibility of the synchronization. On this basis, a secure communication …


Dynamic Simulation Of Single Abrasive Grain Cutting Tc4 Based On Sph Method, Wang Yan, Wang Shuai, Jianguo Liu, Xiong Wei Aug 2020

Dynamic Simulation Of Single Abrasive Grain Cutting Tc4 Based On Sph Method, Wang Yan, Wang Shuai, Jianguo Liu, Xiong Wei

Journal of System Simulation

Abstract: Considering the negative effects of mesh distortion on calculation accuracy in FEM simulation, a novel mesh free method named Smoothed Particle Hydrodynamics (SPH) method was employed to simulate the process of single CBN abrasive grain cutting TC4. Establishing a SPH model of TC4 workpiece and a FEM model of single abrasive grain with cutting edges similar to the real abrasive grain, the influences of cutting depth on grinding forces and chip formative process were studied systematically. The simulation results state that grinding forces enlarge with the increase of cutting depth, while grinding force ratio decreases. And TC4 chip formative …


Fire Reconstruction Method Based On Les And Linear Programming, Guangyao Yao, Peizhong Yang, Tan Xun Jul 2020

Fire Reconstruction Method Based On Les And Linear Programming, Guangyao Yao, Peizhong Yang, Tan Xun

Journal of System Simulation

Abstract: A method based on LES and linear programming was proposed for the numerical construction of fire accident. In the simulation with LES method, all the quantities were decomposed into large-scale components and small-scale components. For large-scale components, the direct simulation method was used. For small-scale components, the subgrid model was used. The LES method could improve the simulation accuracy. In the linear programming method, the parameters were locally linearized to solve the optimization problem. It could improve the simulation efficiency. The method was applied to the numerical reconstruction of a wholesale market fire in Shanghai. The spread of fire …


Numerical Simulation Of Hot And Cold Fluids Mixing In A Tee-Junction, Wenli Wei, Yunfei Hong, Shipeng Shao, Yuling Liu Jul 2020

Numerical Simulation Of Hot And Cold Fluids Mixing In A Tee-Junction, Wenli Wei, Yunfei Hong, Shipeng Shao, Yuling Liu

Journal of System Simulation

Abstract: Flow and heat transfer model in tee junction was established and the 3D RNG k-ε turbulence model was completed to simulate the process of mixing and capture the information of velocity and temperature. The simulation results and measured data of the mean value of velocity and temperature were analyzed and compared, and are in a good agreement, which indicates that the RNG k-ε model combined with the heat transfer model can well simulate the hydraulic characteristics and heat transfer mechanism of hot and cold fluids in a tee junction. Furthermore, the upstream segment of a tee junction has two …


Numerical Simulation About Fuel Injection Source Location Impacting On Turbulent Combustion Process, Sun Hui, Guangcheng Cai, Jiang Lin, Shibo Wang Jul 2020

Numerical Simulation About Fuel Injection Source Location Impacting On Turbulent Combustion Process, Sun Hui, Guangcheng Cai, Jiang Lin, Shibo Wang

Journal of System Simulation

Abstract: Fuel injection source location has very important influence on combustion process. It determines the location of the furnace flame. The three dimensional model of the furnace was established by the numerical simulation method. Under different conditions, the fuel injection source location on the temperature field within the furnace, the pollutant concentration field, and the flow field distribution inside the furnace combustion process were investigated. The results were compared and analyzed. After analysis, the results show that the fuel injection source location from 1.1 ~ 1.5 meter process of change, the average temperature within the furnace continue to rise, the …


Numerical Simulation And Experimental Study Of Three-Dimensional Flow Field On Roots-Type Power Machine Based On Dynamic Mesh Technique, Yanjun Xiao, Yuxiang Liu, Dayuan Wang, Feng Hua, Chunxia Li Jul 2020

Numerical Simulation And Experimental Study Of Three-Dimensional Flow Field On Roots-Type Power Machine Based On Dynamic Mesh Technique, Yanjun Xiao, Yuxiang Liu, Dayuan Wang, Feng Hua, Chunxia Li

Journal of System Simulation

Abstract: A new roots-type power machine was recommended. As for it, the working fluid of low pressure waste heat according was simulated to both the different operating conditions and the different intake and exhaust pressure and flow, and the changing process of internal flow field over time period using dynamic mesh technique was simulated when the power machine was in rotating work. The pressure field, velocity field and mass flow rate with the simulation results were analyzed, thus reaching the optimum operating conditions and the key parameters of the roots-type power machine. A test platform and conducted field tests was …


Numerical Simulation For Influence Of Baffle Length On Hydraulic Characteristics In Radial Sedimentation Tanks, Wenli Wei, Zewei Zhang, Yunfei Hong, Yuling Liu Jul 2020

Numerical Simulation For Influence Of Baffle Length On Hydraulic Characteristics In Radial Sedimentation Tanks, Wenli Wei, Zewei Zhang, Yunfei Hong, Yuling Liu

Journal of System Simulation

Abstract: The VOF (volume of fluid) method was applied to track the free water surface, and the RNG turbulent model was used to close the two-phase flow time-averaged equations. The influence of inlet vertical baffle with different lengths on hydraulic characteristics in radial sedimentation tank was simulated and analyzed. The control equations were discretized using the finite volume method. Velocity and pressure were solved using the PISO (Pressure-Implicit with Splitting of Operators) algorithm. The research results show that: the long length feed flow baffle model has a smaller recirculation zone, better velocity field distribution than short length baffle, and the …


Study On Diffraction Effects Of Planar Underwater Shock Interaction With Rigid Quadrilateral Structure, Yuchun Li, Zhenru Gao, Bin Feng, Liu Qiang, Shen Wei Jul 2020

Study On Diffraction Effects Of Planar Underwater Shock Interaction With Rigid Quadrilateral Structure, Yuchun Li, Zhenru Gao, Bin Feng, Liu Qiang, Shen Wei

Journal of System Simulation

Abstract: Finite element simulation using LS-DYNA was performed to investigate the interaction of underwater planar shock wave and rigid quadrilateral structure. The characteristics of diffraction waves on both front and back surface of the rigid structure were analyzed and trace lines were gained. Vortex was formed near the corner of the structure diffracted by underwater shock with a void part of zero pressure existing in the local fluid region. Bulk cavitation near fluid-structure interface leads fluid pressure to drop to negative value, which is an important damage factor to merged structures. A derived pressure formulas of diffraction wave to rigid …


Surface Efficient Gas Extraction Mode Based On Full Coverage Of Working Face, Fang Jiawei, Han Baoshan, Zhou Jiajia, Wang Zhengxi, Zhang Dingliang, Liu Jia, Xu Jianjun Jun 2020

Surface Efficient Gas Extraction Mode Based On Full Coverage Of Working Face, Fang Jiawei, Han Baoshan, Zhou Jiajia, Wang Zhengxi, Zhang Dingliang, Liu Jia, Xu Jianjun

Coal Geology & Exploration

Aiming at the problems of soft and broken coal seam, low permeability, difficulty in gas extraction and low drainage efficiency in working face, a full-coverage mode for gas extraction in working face through the horizontal well group with staged fracturing roof at both ends is proposed. Taking a mine in Suxian mining area of Huaibei coalfield as an example, based on the characteristics of in-situ stress and working face distribution, combined with the analysis of gas geological conditions and coal seam mechanical properties in the area, the cross section dipole sonic logging method was used to optimize the orientation of …


Development Characteristics Of Water Conducted Fracture Zone Based On Overburden Structural Effect, Cao Zubao, Wang Qingtao Jun 2020

Development Characteristics Of Water Conducted Fracture Zone Based On Overburden Structural Effect, Cao Zubao, Wang Qingtao

Coal Geology & Exploration

In order to study the roof water disaster caused by coal mining in Huanglong coalfield, taking mining failure of layered overburden as research object, four typical composite structural models for coal-soft rock-hard rock-soft rock-hard rock(combination I), coal-soft rock-soft rock-hard rock-hard rock(combination Ⅱ), coal-hard rock-soft rock-hard rock-soft rock(combination Ⅲ) and coal-hard rock-hard rock-soft rock-soft rock(combination IV) were generalized. Numerical simulation and theoretical calculation were used to analyze the mining failure characteristics of different overburden combinations and correlation between water conducting fissures and lithologic combination structure of overburden. The law of the effect of overburden structure on the development height of water …


Influence Factors And Formation Properties Of Temperature Field In The Frozen Wall Of Double Ring Pipes, Li Huaixin, Lin Bin, Wang Peng Jun 2020

Influence Factors And Formation Properties Of Temperature Field In The Frozen Wall Of Double Ring Pipes, Li Huaixin, Lin Bin, Wang Peng

Coal Geology & Exploration

In order to research the change law of the temperature field of the frozen wall of double-circle pipes, an auxiliary shaft in Huainan coalmine was taken as the research object, the FLAC3D software was used to numerically simulate the formation process of the temperature field of the frozen wall of double-circle pipes and the influence of different factors on average temperature of frozen wall based on the relevant geological parameters. The research results show that temperature of the soil in the double-circle pipes is the lowest, and temperature on both sides increases gradually, the interval between frozen holes is …


Design And Numerical Simulation Of Multi-Layer Bit With Extra-High Matrix, Sun Qibin, Shen Lina, Yang Gansheng, Tian Guoliang, Ruan Hailong, Chen Xi Jun 2020

Design And Numerical Simulation Of Multi-Layer Bit With Extra-High Matrix, Sun Qibin, Shen Lina, Yang Gansheng, Tian Guoliang, Ruan Hailong, Chen Xi

Coal Geology & Exploration

Aiming at the problem that the life of the diamond bit is limited by the height of the bit matrix, an optimized design scheme of an impregnated diamond bit with extra-high multi-layer matrix was proposed. In the design of the bit, eccentric staggered cutting teeth, alternate waterways and water baffles were introduced to ensure the cooling and effective drilling of the bit. Through strength and hydraulic flow field simulation, the strength of the drill bit was checked, the rationality of the waterway structure was verified, and the finished product of the drill bit was further realized. The drill bit breaks …


Flow Simulation Considering Adsorption Boundary Layer Based On Digital Rock And Finite Element Method, Yong Fei Yang, Ke Wang, Qian Fei Lv, Roohollah Askari, Qing Yan Mei, Jun Yao, Jie Xin Hou, Kai Zhang, Ai Fen Li, Chen Chen Wang Jun 2020

Flow Simulation Considering Adsorption Boundary Layer Based On Digital Rock And Finite Element Method, Yong Fei Yang, Ke Wang, Qian Fei Lv, Roohollah Askari, Qing Yan Mei, Jun Yao, Jie Xin Hou, Kai Zhang, Ai Fen Li, Chen Chen Wang

Michigan Tech Publications

Due to the low permeability of tight reservoirs, throats play a significant role in controlling fluid flow. Although many studies have been conducted to investigate fluid flow in throats in the microscale domain, comparatively fewer works have been devoted to study the effect of adsorption boundary layer (ABL) in throats based on the digital rock method. By considering an ABL, we investigate its effects on fluid flow. We build digital rock model based on computed tomography technology. Then, microscopic pore structures are extracted with watershed segmentation and pore geometries are meshed through Delaunay triangulation approach. Finally, using the meshed digital …


Numerical Simulation Of Cavitation And Failure Analysis In Hydraulic Loader, Mo Li, Yang Qi, Yumei Wang Jun 2020

Numerical Simulation Of Cavitation And Failure Analysis In Hydraulic Loader, Mo Li, Yang Qi, Yumei Wang

Journal of System Simulation

Abstract: Using software CFX with SST κ-ω model and Rayleigh-Plesset cavitation model, the numerical simulation of 3-D steady flow with water liquid and water vapour two phases in whole flow passage of hydraulic loader was conducted. The influences of different parameters (inlet flow rate, rotational speed and blade angle) on cavitation of hydraulic loader were studied. The results show that, under small flow rate, large blade angle (≥60°) and low speed (≤3 000 r/min), cavitation is light. At different working conditions, where cavitation appears in radial direction of position is the same. The cavitation mainly distributes where the r/R …


Numerical Simulation Of Aluminum Foam Cushion Performance Analysis On Set-Forward Overload Of Fuze, Kuahai Yu, Xuhui Zhang, Hongyu Xu, Li Rong, Xingguo Kang Jun 2020

Numerical Simulation Of Aluminum Foam Cushion Performance Analysis On Set-Forward Overload Of Fuze, Kuahai Yu, Xuhui Zhang, Hongyu Xu, Li Rong, Xingguo Kang

Journal of System Simulation

Abstract: Buffering protect of fuze under high-speed impact was realized using aluminum foam gasket with special pore structure, and numerical simulation method to achieve the buffer validity analysis. Numerical model of three-layered concrete target projectile penetration was established, and the numerical model was validated to be accurate by comparing the fuze acceleration curves of simulation and experiment results. Numerical simulations were completed to predict the cushioning effect for different foamed aluminum structures. The result reveals that foamed aluminum cushioning can reduce the load of the fuze, and the foam's void ratio and thickness will significantly affect the cushioning performance, and …


Modeling And Numerical Simulation Of Micro-Tube Scale Effects In 3dp Process, Congping Chen, Xiaoyun Wang, Jieguang Huang, Li Bo Jun 2020

Modeling And Numerical Simulation Of Micro-Tube Scale Effects In 3dp Process, Congping Chen, Xiaoyun Wang, Jieguang Huang, Li Bo

Journal of System Simulation

Abstract: Wall slip and viscous dissipation are two main scale effects in 3DP (Three dimensional printing) process, which has influences on the material's flow properties and thermophysical properties and the printing quality. According to the two phenomena above, theoretic models of wall slip and viscous dissipation were established, respectively, and the software Polyflow was used to study the two scale effects and their interactions with molten ABS in micro-tubes of different radius. Simulation results show that wall slip level increases with the slip coefficient decreasing, and material's velocity decreases with the increase of tube radius; Viscous dissipation level decreases …


Numerical Simulation On Hydraulic Characteristics Of Free Hydraulic Jump On Corrugated Beds Of Stilling Basin, Wenli Wei, Yunfei Hong, Yuling Liu Jun 2020

Numerical Simulation On Hydraulic Characteristics Of Free Hydraulic Jump On Corrugated Beds Of Stilling Basin, Wenli Wei, Yunfei Hong, Yuling Liu

Journal of System Simulation

Abstract: The VOF (volume of fluid) method was applied to track the free water surface, and the RNG k–ε turbulent model was used to close the two-phase flow time-averaged equations. The conditions properties of free hydraulic jumps on corrugated beds with a stilling basin under 9 kinds of conditions were studied by numerical simulation. Simulation research results show: There are vortexes generated by corrugated beds surfaces, rotating in the clockwise direction. The pressure distribution on corrugated beds in hydraulic jump region appears a wavy change, and the difference between the pressure values at adjacent crest and trough gradually decreases along …


Numerical Simulation Of Diffusion Regularity Of Co In Fire Smoldering Phase In Aircraft Cabin, Jiaquan Lin, Ruiting Wang, Pi Jun, Ma Min, Jianzhong Yang Jun 2020

Numerical Simulation Of Diffusion Regularity Of Co In Fire Smoldering Phase In Aircraft Cabin, Jiaquan Lin, Ruiting Wang, Pi Jun, Ma Min, Jianzhong Yang

Journal of System Simulation

Abstract: In order to study the impact of the cabin air conditioning supply velocity on CO diffusing in the fire smoldering phase and the effect of the transportation of CO to human body, a simulation model of A320 aircraft cabin was established, and velocity field and CO concentration field under the different air supply velocity were simulated based on the fluid dynamics control equations. The relationship between the air conditioning supply velocity and the value of CO concentration as well as the diffusion area was obtained by the analysis of the transportation of CO in different directions. The drainage efficiency …


Inertia Effect In Dynamic Tensile Tests Of Concrete-Like Materials, Zhang Shu, Yubin Lu, Dongmei Zhao, Chen Xing Jun 2020

Inertia Effect In Dynamic Tensile Tests Of Concrete-Like Materials, Zhang Shu, Yubin Lu, Dongmei Zhao, Chen Xing

Journal of System Simulation

Abstract: The different understanding on the influential degree of the inertial effect does exist among researchers, and it has not been uniformly defined in dynamic tensile tests. The finite element numerical simulation method was employed to analyze the three typical dynamic tensile tests, without considering the real strain-rate effect in these models, where a constitutive model only considered the influence of hydrostatic pressure was used for modeling the specimen in these models. It is found that the dynamic tensile strength of concrete specimens in the three models mentioned is strengthened with the increase of loading strain-rate, owing to the …