bluuebunny/crossref_metadata_2025_split huggingface dataset:
A high-fidelity polynomial chaos modified method suitable for CFD uncertainty quantification
Authors: Chen Jiangtao , Zhang Chao , Zhao Wei , Wu Xiaojun 
Published: August 2021

Abstract
There are many sources of uncertainty in the process of numerical simulation for engineering configure. Evaluating and quantifying the uncertainty of simulation results is very important for the design and evaluation process of the industrial department. The non-intrusive polynomial chaos method is a commonly used uncertainty quantification method, but a polynomial chaos with high accuracy requires a sufficient number of high-fidelity samples, which causes “dimension disaster” for high-dimensional problems. This paper proposes a modified method. First, a low-fidelity calculation model is used to generate a low-fidelity polynomial chaos, and then a small amount of high-fidelity calculation data is used to modify the low-fidelity polynomial chaos. This method is used to analyze the parameter uncertainty of the SA model in the RAE2822 airfoil calculation. Under the premise of effectively ensuring the accuracy, the calculation time is reduced by 60% compared with the method of using the full high-fidelity calculation model.
Research on a hydraulic displacement amplifier for a piezoactuator
Authors: Xu Youxiong , Zhou Hao , Zhu Songqing , Pan Ge 
Published: August 2021

Abstract
A piezoactuator-based hydraulic displacement amplifier with two flexible diaphragm spools and one rigid chamber is designed. The elastic characteristics and effective area of the diaphragm spool are theoretically and numerically analyzed. The influencing factors on the effective area of the diaphragm spool are studied by the finite element analysis method. On this basis, a proto-type is produced, and its measurement and control system is built. Experimental results show that the hydraulic amplifier prototype can achieve a stroke range of 540 μm and its amplification ratio is approximately 6.
Study on dynamic stress of pump turbine runner during power failure in pump mode
Authors: Lin Kai , Chen Funan , Wang Chao , Bi Huili , Luo Yongyao , Wang Zhengwei 
Published: August 2021

Abstract
The power failure process of pumped storage unit is one of the most dangerous transient processes. The unit enters the pumping braking mode and then generation mode after power failure. In this process, the rotating speed changes from the negative direction to the positive direction, and the hydraulic torque of the blade also changes rapidly, resulting in the great change of runner stress. In this paper, the amplitude of dynamic stress and the location of stress concentration of runner were calculated and analysed to evaluate the safety of runner in the process of power failure in pump mode. The coupling method of one-dimensional pressure wave calculation and three-dimensional flow simulation is used to predict the change of hydraulic loads and the fluid-structure-interaction method is used to calculate the dynamic characteristics of runner. It is found that the position of stress concentration changes in the process of rapid decrease of rotating speed to zero.
Study on Prediction and Optimization of Furnace Temperature Curve Based on Temperature Change Model
Authors: Ma Heng 
Published: August 2021

Abstract
For the furnace temperature curve when heating electronic components in the reflow furnace, with Fourier’s law, the Newton’s cooling law and the law of conservation of energy as the theoretical basis, combined with the relavant data, and based on heat conduction and thermal convection of the welding area, a temperature change model is established, and single objective optimization model is established as well. By using MATLAB and EXCLE to conduct ergodic search algorithm of solving, the ideal temperature curve and velocity of conveyor belt of the furnace is obtained.
Numerical Simulation of Converter Station Fire: A Study focus on the Fire Hazard of Valve Tower
Authors: Zhang Cheng , Mao Zhiyun , Zhang Bin , Song Quangang , Zhang Jiaqing 
Published: August 2021

Abstract
The fire hazard of a valve tower in converter station fires were investigated by using the Fire Dynamics Simulator (FDS). The 2 m2, 5 m2 and 10 m2 transformer oil pool fires with the calculated heat release rate (HRR) of 2.02, 6.23 and 13.78 MW were considered in the simulations, and the smoke propagation process, smoke temperature and visibility were mainly concerned. The results showed that the whole valve tower was immersed in the fire smoke at about 600 s in 2 m2 fire condition, and the maximum temperature rise inside the valve hall was about 20ºC. In the 5 m2 fire condition, the smoke layer height descended to the bottom of the valve tower at about 300 s, and the visibility around the valve modules was lower than 5 m at about 450 s. The maximum smoke temperature inside the valve hall was over 60ºC, and the temperature of smoke around the valve modules ranged from 43 to 52ºC. In the 10 m2 fire condition, the valve tower was immersed in the fire smoke at about 210 s, and the visibility around the valve modules was lower than 5 m at about 300 s. The smoke temperature beneath the ceiling of the valve hall was over 100ºC, and the temperature at the height of valve towers ranged from 65 to 80ºC. It was observed that the larger the fire size was, the higher the fire hazard of the valve tower would be found. In the 5 m2 and 10 m2 pool fire conditions, the thermal damage to the valve tower was non-negligible. The normal operation of the electrical components in the valve tower might be affected, and the failure of electrical components might be occurred.
Analysis of flow characteristics in pumped storage unit during start-up in turbine mode
Authors: Liu Tao , Wang Chao , Chen Zhiming , Chen Funan , Bi Huili , Luo Yongyao , Wang Zhengwei 
Published: August 2021

Abstract
During the start-up, the unit enters into speed-no-load from static state. The runner is full of complex vortex, which hinders the water flow into the runner, and even leads to the failure of starting up. It is necessary to study the vortex and flow state to evaluate the stability of start-up. In this paper, the coupling method of one-dimensional pipeline system and three-dimensional flow inside the unit is used to simulate the startup process and analyse the three-dimensional flow state in runner. The flow instability during the start-up process is deeply studied by analysing the pressure distribution, streamline and turbulent kinetic energy. The results show that the turbulence intensity in the runner decreases with the increase of discharge. During start-up, the vortices in the runner occupy the whole blade passage, and then disappear. With the decrease of discharge, the turbulent kinetic energy at the runner inlet rises and small vortex appears at runner inlet.
Study on the Aerodynamic Characteristics of Top-Mounted Inlet with Different Lip Angles
Authors: Xiao Lianghua , Ge Changjie , Shang Yinhui 
Published: August 2021

Abstract
The stealthy performance is an important factor to be considered in the design of the modern UAV, and the inlet is the strong RCS scattering source, which needs to be paid more attention. The inlet with lip angle is beneficial to the stealth performance, but unfavorable to the aerodynamic characteristics of the inlet. In this paper, three inlets with different lip angles are studied, and the characteristics of the inlets are obtained by using CFD and experimental methods. Results indicate: 1) data obtained by CFD well predicts the vortex in the inlet, and it’s very close to the experimental value, which shows that CFD method can be used for analysis; 2) the lip angle has a great influence on the characteristics of the inlet under ground running, and the circumferential distortion index of the inlet increases rapidly with the increase of the lip angle; 3) the effects of the lip angle on the characteristics of the inlet can be ignored under the condition of the high incoming Mach number.
Turbulence characteristics of large factory building and its influence on airship transport process
Authors: Liu Yuan , Ye Hu , Zhang Yongdong , Zhang Li , Li Min , Huang Taiqin 
Published: August 2021

Abstract
Aiming at the problem that the stability of airship’s posture is destroyed by turbulent flow when the airship leaves the large factory building, a Computational Fluid Dynamics (CFD) numerical simulation method is used to analyse the characteristics of large factory building disturbance under different inflow angles. The transport process of airship is simulated, and the equivalent force and moment of airship in variation with transport distance are acquired. The results show that the wind field changes along the transport path of the airship, which makes the equivalent force and moment acting on the airship body center fluctuate. In 60 degrees of the incoming flow, compared with other inflow angles, the turbulence at the exit of large factory building is severe, and the distance affected by the turbulent flow of large factory building is shorter, and the equivalent force and moment acting on the airship body center are larger in the process of airship transport. The simulation results provide an effective reference for the safety of airship transport process.
Symmetric and asymmetric bifurcations of natural convection inside circular cavity in the route to chaos
Authors: Chen Jilai , Zhang Jishuo 
Published: August 2021

Abstract
Natural convection occurs when pipe floating at the water surface during night, which can be regarded as a circular cross-section enclosure heated from below and cooled from the top. Numerical investigation is carried out with focuses on the flow configurations in the route to chaos. When Ra is lower than 103, convection is neglectable and conduction dominate the heat transfer. The flow becomes chaos and unsteady when Ra increases to 108. In the route to chaos, the number of cell increase with the decrease of the cell size. It is found that a symmetric to asymmetric bifurcation of flow configuration followed by a asymmetric to symmetric exist for Ra between 103 to 106.
Dynamic characteristics analysis of a hydraulic valve by FEM and CFD method
Authors: Huang Xiaoli , Liu Qian , Wei Qiang , Deng Xiaohe 
Published: August 2021

Abstract
The dynamic characteristic of the flood valve is an important index to ensure its safety and reliability. In this paper, CFD computational fluid dynamics (CFD) method is used to model and simulate the three-dimensional unsteady internal flow field of the valve during its working process, so as to obtain the dynamic distribution of the internal flow field parameters of the valve under specific working conditions. The modal analysis of the valve body is carried out to provide a calculation method and data support for the evaluation of the vibration and noise level during the operation of the valve.
Investigation on Fluid-Structure Interaction of a Steel Truss Aqueduct under Seismic Force
Authors: Chang Haocheng , Wu Zhigang , Zhu Yu , Ma Rujin 
Published: August 2021

Abstract
Aqueduct, one special kind of bridge, has quite different loads from traditional bridge. In this paper, we study the fluid-structure interaction characteristics of a steel truss aqueduct under seismic force using finite element method (FEM). The additive mass method is used to get the acceleration of key sections under E2 earthquake wave. Then the acceleration is applied on the FSI model to obtain the influence of unbalance hydrodynamic load and hydrodynamic pressure on structure. A simplified linear relationship between earthquake acceleration and pressure on the wall is also proposed. The conclusions and approach provided by this study could serve as significant references for anti-seismic design and control of similar steel truss aqueducts.
Research on the influence of the number of holes in porous ventilated plate on the jet length
Authors: Xu Zhenyuan , Ma Wenjing , Yang Kaike , Xiang Yong , Chen Liangming , Zhang Junwei 
Published: August 2021

Abstract
The influence of porous ventilation plate on the smoothing effect of filtered gas is mainly reflected in the jet length after the airflow passes through the porous ventilation plate. The shorter the jet length is, the less the influence of the uniform flow on the subsequent equipment is. In order to solve the problem that different number of openings of porous ventilation plate has different length of jet flow in the downstream, a small size unit module of porous ventilation plate is selected for research, and its geometric shape is reproduced truly. Under the premise of keeping the aperture constant, the opening rate of the porous ventilation plate is indirectly changed by changing the number of openings on the porous ventilation plate, and the influence law of different number of openings on the downstream jet flow is analyzed and studied. In this paper, the incompressible N-S equation and the RNG k-e turbulence model are used to simulate the jet flow field distribution of the porous ventilation plate module. Through simulation calculation, the influence law of different number of openings on the jet length and velocity under the same aperture is obtained. Further, by comparing and analyzing the velocity variation curve in the center area of the porous ventilation plate, the basic research ideas and theoretical basis are provided for the design, selection and research of the opening of the porous ventilation plate, which has a certain reference value to guide the engineering design and application of the porous ventilation plate.
Computation of aerodynamic performance for horizontal axis wind turbine considering the rotation effects
Authors: Liu Guoyan 
Published: August 2021

Abstract
The blade element momentum theory is lack of estimating the wind turbine performance changes caused by rotation. The paper analysis the impact of airfoil flow by centrifugal force and the Coriolis force which generated by the rotating blades and defines the airfoil performance at separated changing flow region by numerical simulation. This paper calculates the aerodynamic performance with centrifugal correction model using a commercial wind turbine as an example, The numerical model and results are verified by comparing with the actual measurement. The results show that the correction model considered the rotation effect to estimate the wind turbine power is more accurate and closer to the measured value.
Numerical Simulation of Turbulent Flow for non-Newtonian Fluid in two kinds Complex Annulus Channel
Authors: Zhang Yi , Li Nan 
Published: August 2021

Abstract
During the polymer flooding multi-layered injection process, it is difficult to achieve large pressure drop and small viscosity loss at the same time in the injection allocators. To address this issue, two kinds of flow channel structures are designed. They are ring groove structure and spindle groove structure. CFD software FLUENT is used to simulate the flow characteristics of non-Newton fluid flowing in the above structures, which are complex annular channels. By comparing the pressure drop, velocity contours and turbulent kinetic energy, the spindle groove structure is preferred. It has large throttle depressurization and big solution viscosity retention rate within a limited length. The influence from different flow channels structure on pressure drop is limited, but the impact on viscosity loss is great.
Study on Passive Acoustic Fuze in Wake Field of Ship with High Precision Recognition for High-Speed Small Target
Authors: He Xiaohui , Liu Zhongle , Yuan Zhiyong , Su Ruiqun 
Published: August 2021

Abstract
It is proposed to adopt a new way against the incoming high-speed small target in the wake field of ship. The passive acoustic fuze composed by a ternary array can detect and receive a large number of signals with characteristic information, among which the intersection process between the incoming target and the acoustic fuze is regarded as the important characteristic information. Through analysis of delay estimation and the delay error according to the characteristics information received from the passive ternary array, such as the distance, the azimuth and the energy envelope, to improve the accuracy of location and azimuth. By means of the modified polynomial least square fitting method to eliminate outliers and interference from signals to improve the sharpness of the curve, to further fit the curve and to eliminate the negative impact from the change of data. An optimal initiation strategy is proposed based on the two above-mentioned aspects. Finally, it proved by tests that the proposed method has a certain value for reference.
Analysis of the influence of the tubes constrained structure of contra-flow vertical shell and tube heat exchanger on heat transfer ability with natural circulation
Authors: Peng Kangwei , Wang Xiaoding , Song Guangdong , Liu Mengmeng 
Published: August 2021

Abstract
In order to verify the effect of the combined restraint form of straight strip and corrugated strip on the heat transfer capacity of shell-tube heat exchanger with natural circulation. The physical model and mathematical model of the local heat exchange section of the heat exchanger are established by using ICEM and Fluent to carry out numerical simulation. The calculation results of three-dimensional flow field and temperature field of the heat exchange section are solved and analysed to obtain the resistance characteristics of the tube bundle of shell-and-tube heat exchanger under the restriction of corrugated strip and straight strip with natural circulation and the influence at the temperature field.
Noise Study of Small Ships during Sailing in Near-wake Field based on Body Force Model
Authors: He Xiaohui , Liu Zhongle , Yuan Zhiyong , Ruan Yingying 
Published: August 2021

Abstract
Noises of ships during sailing and in the near-wake field are both important factors in the ship design, which is of great significance to the ship structure and personnel health. A convenient body force model is adopted to replace the action of a real propeller through the computational fluid dynamics (CFD) method, meanwhile, FW-H equation is used to calculate the radiated noise in the near-wake field of small ships and forecast the noise characteristics of small ships during sailing in the near-wake field. The variation law of noise spectrum at different monitoring points during the evolution of the near-wake field is analyzed, and the simulating results are in good agreement with the testing data. Research proves that the body force model is efficient and feasible to the noise characteristics of small ships during sailing in the near-wake field, which can provide some reference for the design of small ships and also for the noise prediction in the near-wake field.
Controllable Pitch Propeller Performance Comparison of Different Speed and Pitch Matches at non-cavitation condition
Authors: Xi Peng , Meng Lu , Huang Zheng , Wang Zhanzhi 
Published: August 2021

Abstract
The paper took one controllable pitch propeller as study model. Open water performance at different pitches were calculated based on FLUENT. On this basis, rotational speeds that match P/D = 1.5, 1.3, 1.15, 1.0 at 21kn were obtained according to characteristic curve of navigation. Propeller efficiency and pulsing pressure were carried out and compared at different matches. The result shows that pulsating pressure is both influenced by speed and pitch. It is non-linear relationship between pitch ratio and cavitation and efficiency and is inconsistent with the character of propulsion efficiency. Hence it brings adverse effect on pulsing pressure if the match of speed and pitch is selected only according to propulsion efficiency. The paper recommends comprehensive consideration about pulsing pressure and propulsion performance should be taken to choose match of speed and pitch at non-cavitation condition.
Research on the Application of Astrophysics in Magnetohydrodynamics under Big Data
Authors: Ma Chuantao 
Published: August 2021

AbstractBased on the background of big data, the paper establishes the evolution equation of electromagnetic fluid state parameters over time called Magnetohydrodynamics (MHD). Compared with kinetic theory, magnetohydrodynamics is much simpler in mathematical processing, and there are many processes in plasma. For some other phenomena in plasma, such as Landau damping, instability in velocity space, etc., the theory of magnetohydrodynamics is unable to describe. The thesis starts from the dynamic equations and establishes the magnetohydrodynamic equations.
Application of Celestial Mechanics Theory in Spacecraft Orbit Design
Authors: Gong Yanxiang 
Published: August 2021

Abstract
This paper systematically studies the application of orbital dynamics theory in spacecraft orbit design. In this paper, two linearized equations with J2 relative term perturbation are introduced firstly, and their advantages and disadvantages are compared and analyzed. On this basis, an improved method is proposed and applied to the design of hovering orbit and fast flying orbit, and good results are obtained in some cases. The traditional numerical solution algorithm for ballistic design is innovated and improved, and the improved Newton iterative method is comprehensively applied to ensure that the algorithm can still converge quickly under the condition of inaccurate initial value; The simulation results show that the orbit integrated rapid design method studied in this paper is reliable, fast and accurate, and can be applied to the rapid orbit design of spacecraft.
Numerical Simulation of Multi-puffing Process of Electronic Atomizer
Authors: Wu Jinlu , Huang Jiejie , Gao Yihan , Gao Naiping 
Published: August 2021

Abstract
The thermodynamic behaviors of electronic atomizer during the multi-puffing process have an important influence on the product performances. Exploring the thermodynamic mechanisms behind the vaporization phenomena is helpful for engineers and consumers to understand electronic atomizer. The theoretical modelling and simulation of the multi-puffing process for the electronic atomizer were carried out in this study. During 1∼10 puffing number, the mass fraction of propylene glycol in the residual e-liquid reduced when the puffing number increased. Meanwhile, the mass fraction of vegetable glycerin in the residual e-liquid increased gradually. The total particulate matter of aerosol generated from the electronic atomizer decreased with the puffing number increasing. The maximum vaporization temperatures of the residual e-liquid rose gradually in the multi-puffing process.
Analysis of working characteristics of throttle speed regulating valve
Authors: Han Zhiyin , Zhang Yunxiu , Li Yanfang 
Published: August 2021

Abstract
In this paper, combined with the working requirements of throttling speed regulation in the circuit, the structure principle and working characteristics of speed control valve in flow control valve are analyzed, the speed regulating performance and characteristics of speed regulating valve in hydraulic system are expounded, It is pointed out that the relationship between speed and load of speed regulating valve is rigid in the process of speed regulating of hydraulic system, that is to say, the speed regulating valve is suitable to be used in the case of large load variation, high speed stability requirements of the occasion.
Gas Diffusion Model and Its Application based on CFD Theory
Authors: Zhou Yanbing , Liu Beibei , Tang Qi , Qing Ping , Li Han , Zhang Xiaohong 
Published: August 2021

Abstract
In order to reduce the loss and impact of the unexpected leakage of hazardous chemicals, the paper makes use of the computational fluid mechanics theory and applies the commercial software, FLOVENT, to imitate the steady state and transient state of six scenes of the diffusion scope and concentration change of NH3 and H2 in different wind directions and leak location; furthermore, it takes the simulated result as the basis to analyze the diffusion length and impact scope of the characteristic concentration, both of which will be the evidence for occupants evacuation.