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Copyright of Atomic Energy Science & Technology is the property of Editorial Board of Atomic Energy Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Rotordynamic characteristics of a high temperature sodium liquid (HTSL) seal were studied in this paper by using CFD software. Compared with the water liquid seal, the HTSL seal has a larger leakage flow rate and a lower drag power loss. The HTSL seal has a larger direct stiffness coefficient and the effective stiffness coefficient Keff is also larger than the water liquid seal, which means the HTSL seal has a better stiffness capacity. The HTSL seal possesses a positive effective damping coefficient Ceff in the whole whirling frequency range, which means better stability for the rotor system especially in high rotor speeds [ABSTRACT FROM AUTHOR]

Copyright of Atomic Energy Science & Technology is the property of Editorial Board of Atomic Energy Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Atomic Energy Science & Technology is the property of Editorial Board of Atomic Energy Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of CT Theory & Applications is the property of Editorial Department of CT Theory & Applications and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Atomic Energy Science & Technology is the property of Editorial Board of Atomic Energy Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Mine Automation is the property of Industry & Mine Automation Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Petrochemical Universities / Shiyou Huagong Gaodeng Xuexiao Xuebao is the property of Journal Editorial Department Of Liaoning Shihua University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Atomic Energy Science & Technology is the property of Editorial Board of Atomic Energy Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Atomic Energy Science & Technology is the property of Editorial Board of Atomic Energy Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Atomic Energy Science & Technology is the property of Editorial Board of Atomic Energy Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Harbin University of Science & Technology is the property of Journal of Harbin University of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Harbin University of Science & Technology is the property of Journal of Harbin University of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

[Introduction] In order to find an economic and effective solution to the improvement of the hydrodynamic performance of floating offshore wind turbines, this paper studies the design scheme of heave plates to improve the hydrodynamic damping performance and anti-rolling effect of the floating body, and finally improve the stability of the output power of floating offshore wind turbines. [Method] Taking a 10 MW semi-submersible floating wind turbine as an example, this paper discussed the effect of different design parameters of the heave plate structure on improving the hydrodynamic damping using the method of computational fluid dynamics, and found an optimal design scheme. [Result] After optimized design, the heave damping of the heave plate structure is increased by 14.9%, and the roll damping is increased by 19.1%, and while the heave damping of the “quincunx-shaped” edge heave plate is increased by 36.98% compared with the original model. [Conclusion] This paper reveals the formation mechanism of the generation of vortex vents and the improvement of the hydrodynamic damping of the heave plate, and puts forward the “quincunx-shaped” heave plate structure in an innovative manner that can effectively improve the damping performance of the heave motion of the floating body. The above conclusions provide important references for the research and design of the foundation structure of the floating offshore wind turbines of this kind in the future.

Helical coil steam generator has the advantages of compact structure, high heat transfer efficiency, strong resistance to thermal expansion stress, and has been widely applied in energy and power engineering, chemical industry and other fields. As the energy transfer facility between firstsecond loops and the isolation barrier for radioactive working medium, the inner structure of helical coil steam generator is extremely complicated, hence its structural integrity and operation reliability are necessary guarantee for the nuclear power plant safety. In this paper, the porous media method was adopted to simplify the complex structure of the multilayer helical coil domain in heat exchange assemblies, a shell side working fluid flow heat transfer characteristics analysis model was established, and the tube side watersteam two phase flow boiling heat transfer characteristics analysis model was established based on the homogeneous flow hypothesis. The gridnode data mapping method was applied to realize the coupled heat transfer simulation between shell side and tube side, and a three-dimensional full-scale thermalhydraulic characteristics analysis code HeTAF for the helical coil steam generator was developed based on the open source CFD platform OpenFOAM. The validation was performed against flow boiling heat transfer experiment of helical tube by Santini, and the calculation results of heat transfer coefficient variation with quantity are in good agreement with the measured data, indicating that the adopted model package are capable for accurate prediction under high mass flux rate and heat flux experimental condition. The helical coil oncethrough steam generator in high temperature gas cooled reactorpebble module was selected as the research object. The simulation of single heat transfer assembly under full power operating condition was performed using HeTAF. The distributions of thermalhydraulic parameters including tube side and shell side fluid temperatures, heat transfer coefficient, heat transfer power, void fraction and equilibrium quantity along tube length were obtained, and the transition process of each phase state and dominant heat transfer mechanism in the helical tube was predicted. The calculation results of helium and steam outlet temperature are fixed well with the design value with absolute errors of 5.29 K and 5.76 K respectively, which illustrates that the HeTAF can effectively predict the thermalhydraulic characteristics of both shell side and tube side of single heat transfer assembly. The work in this paper has significance reference for the design and safety analysis of helical coil steam generator. In the future, based on the existing methodology and simulation strategy, the fullscale coupled thermalhydraulic characteristics analysis of the helical coil steam generator will be conducted, and supplementary validation and subsequent optimization of HeTAF code will be carried out continuously.

During the normal operation of cooling towers in nuclear power plants, water vapor with a certain temperature is discharged through the outlet of the cooling tower, which mixes with the surrounding air. A portion of this vapor condenses and forms visible plumes. This paper uses Computational fluid dynamics (CFD) numerical simulation software to simulate six nuclear power units and their supporting cooling towers at a nuclear power plant site, and studies the impact of plumes emitted from the six cooling towers under different wind directions on the radioactive diffusion of the nuclear power plant discharge. The research results indicate that when the arrangement direction of the cooling towers is consistent with the wind direction，the influence of the cooling towers on the environmental flow field extends to a distance of approximately 1 500 m in the downwind direction. When the cooling towers are located in the downwind direction of the reactor unit, the emission from the cooling towers increases the pollution diffusion factor within a 1 000 m range of the chimney. As the environmental wind speed increases, the impact of the cooling tower emissions on the diffusion of pollutants from the chimney decreases.

The risk of hydrogen explosion accident in solution reactor system is high, because both hydrogen and oxygen are released simultaneously from the solution reactor vessel during normal operation. Once hydrogen explosion accident occurs, the overpressure and temperature loads induced by explosion could threaten the integrity and security of radioactive containment boundary. Thus, the structural safety assessment in the event of a hydrogen explosion accident is a key question, which is highly concerned by both designers and nuclear safety reviewers. In this paper, a multi-subject coupling analytical process of structural safety assessment under hydrogen explosive load was presented, which considered chemistry, thermodynamics and mechanics, and this multi-subject coupling analytical process was applied to the structural safety assessment of solution reactor system successfully. Firstly, the governing equation numerical simulation was built up based on computational fluid dynamics (CFD) method and combustion model to simulate hydrogen explosion behaviors. Considering the solution reactor system consisted of vessel and pipelines, the hydrogen explosion behavior in a narrow channel experiment and in a large-scaled vessel experiment was simulated respectively, and the numerical simulation results, such as overpressure and flame front speed, were compared with experimental data to verify the reasonableness and accuracy of numerical simulation method. Then, the authors established the full-scaled numerical model of solution reactor system and simulated the overpressure and temperature rise in the event of a hydrogen explosion accident, using the numerical method above. The initial hydrogen volume concentration, pressure and temperature derived from accident analysis, two ignition positions (the outlet of reactor vessel and the end of pipeline) were taken into account. Furtherly, the overpressure and temperature induced by hydrogen explosion were applied to the radioactive containment boundary, and the structural dynamic response of solution reactor under hydrogen explosive load was obtained. The results show that the validation of the simulation of hydrogen explosion in narrow channel experiment and large-scaled vessel experiment is verified, and the calculated result can fit well with experimental data. It proves that the numerical method above is accurate and is applicable to solution reactor system. The simulation of hydrogen explosion in solution reactor system presents that a significant overpressure and temperature rise occurs within the radioactive containment boundary. The explosive hazard is greater when the ignition position is located at the end of pipeline. However, even the worse explosive load is unable to undermine the integrity of radioactive containment boundary, the solution reactor system can maintain safety in the event of hydrogen explosion accident.

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Drainage & Irrigation Machinery Engineering / Paiguan Jixie Gongcheng Xuebao is the property of Editorial Department of Drainage & Irrigation Machinery Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Aerosols in advanced reactors are considered the primary carriers of radioactive nuclides, and the motion behavior of aerosol particles in the near-wall region of reactors is of significant importance for reactor safety analysis. For example, for a high-temperature gas-cooled reactor (HTGR), the graphite dust generated due to the operation of spherical fuel elements may move in the primary circuit under the drag action of the coolant, which will result in deposition, resuspension and then affects the reactor performance. The aerodynamic drag produced by the interaction between fluid and particles during the near-wall motion of aerosols was studied, and the computational fluid dynamics method for near-wall drag numerical calculation was employed in this paper. In order to construct the model for non-spherical particles, several spherical particles (3-5) were combined into non-spherical particles according to the rod-shaped dust particle samples obtained from samples in high-temperature gas-cooled reactor. Based on the geometric model of the particle, the Realizable k-ε turbulence model was used to simulate the Reynolds stress of the mainstream fluid, and the enhanced wall treatment model was used to calculate the turbulent viscosity in the near-wall and around particle region. The three-dimensional incompressible steady SIMPLE algorithm was employed for the computations. The results show that the drag force exerted by the airflow on the particles can be divided into two components, namely, the pressure difference drag force and the shear drag force. Compared to the drag force on the particle under uniform inflow in an infinite space, the near-wall particles withstand a greater aerodynamic drag (enhancement factor) due to non-uniform velocity distribution, offset pressure distribution, and asymmetrical flow vortices. As particles get closer to the wall, the effect of aerodynamic drag enhancement becomes more pronounced. Moreover, the enhancement effect of aerodynamic drag on the near-wall particles becomes more evident as the non-spherical particles elongate and the flow-facing area (angle of attack) increases. Finally, considering the shape of non-spherical rod-shaped particles and the drag enhancement due to near-wall shear flows, the least squares method was applied to fit the expression using an exponential format for the enhancement factor of near-wall aerodynamic drag for different particles. It shows that the difference of drag enhancement factors at the same δ (dimensionless particle-wall distance) among different particles in the near-wall region usually does not exceed 10%. Thus, in most cases, the enhancement factor of spherical particles can be used to estimate non-spherical particles, roughly. This study provides a basis for investigating particle motion characteristics in the near-wall region of advanced reactors.

The aerodynamic configuration design of wide-range hypersonic vehicle has become one of the research hotspots. The new aerodynamic configuration of high-pressure capturing wing (HCW) can meet the requirements of high volume ra-tio, high lift and high lift-to-drag ratio at the same time. The preliminary research of this configuration is mainly aimed at the hypersonic state. Based on this background, this paper took the wide-range hypersonic vehicle as the main target and developed a new bi-wing configuration according to the basic design principle of HCW. The research results show that the lift coefficient of the vehicle can be increased by about 16.6% when the capturing wing is added in the subsonic range. Furthermore, the capturing wing can suppress the jump of the aerodynamic focus of the vehicle in the transonic range, and the vehicle is statically stable in the wide-speed range.

Copyright of Journal of Harbin University of Science & Technology is the property of Journal of Harbin University of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The dense medium cyclone is widely used in coal separation process. The experimental study on internal flow field and particle motion characteristics of dense medium cyclone is difficult and time-consuming with high cost, due to the complicated separation process. With the development of numerical calculation technology, the numerical simulation method was widely used to study the multiphase flow field inside the cyclone. In this paper, the computational fluid dynamics (CFD) and discrete analysis (DEM) coupling techniques were used to numerically simulate the separation process of dense medium cyclones, which provided a new way to optimize the structural parameters and operating parameters of dense medium cyclones. The Fluent software was used to study the velocity field, density field, pressure gradient field and viscosity field of the internal suspension of the cyclone. The EDEM software was used to study the coal particle movement behavior and the evaluation of separation efficiency during the cyclone separation process. The results showed that the pressure distribution and the pressure gradient of suspension were basically symmetrical, and the pressures at the overflow and underflow outlet were the lowest. The pressure gradient was formed along the radial direction, the difference gradually increased, and the largest pressure gradient was at the boundary of the air column. The coal particles in different sizes had different residence time inside the cyclone. For the coal particles of same density, the smaller the particle size, the longer the residence time. The residence time of the discharged coal particles in the overflow in the cyclone was significantly longer than that from the underflow outlet. For coal particles discharged from the overflow outlet, the higher the density, the longer the residence time. While for coal particles discharged from the underflow outlet, the higher the density, the shorter the residence time. The structural parameters of different cyclones had different effects on separation process, and the influence of the diameter of the overflow pipe was the most significant. When the diameter of the overflow pipe exceeded 500 mm, a complete air column cannot be formed, resulting in failure to separation. When the diameter of the overflow pipe was 300 mm, the separation efficiency was better. In addition, the insertion depth of the over-flow pipe significantly affected the separation efficiency. When the insertion depth was 160 mm, the separation density increased, and the fine high-density coal particles would misplace into the overflow. When the insertion depth of the overflow was 320-800 mm, the separation density was close to the suspension density, Ep value was 0. 084-0. 100, and the separation efficiency was better. The diameter of the underflow outlet had a great influence on the separation precision of the cyclone. When the diameter was 272 mm and 306 mm, the separation density was close to the density of the suspension, and the Ep value was less than 0. 1, which had a better separation efficiency. The length of the cylindrical section had little effect on the separation density. [ABSTRACT FROM AUTHOR]

Noninvasive coronary fractional flow reserve derived from CT angiography (FFRCT) is a major advance within cardiovascular imaging in recent years. It can identify pathology-specific ischemia and provide information for clinical decisions on revascularization, serving as a gatekeeper for invasive coronary angiography.This paper reviews the research progress of FFRCT and briefly discusses its limitations.

【Objective】 Weir is a device to measure water flow in open channels. Its accuracy and robustness depend on many factors. In this paper, we studied the performance of the triangular crested weir as impacted by sediment deposition in open channels. 【Method】 The study was based on computational fluid dynamic modelling. We simulated water flow under nine conditions ranging from no sediment deposition to full sediment deposition using the software FLUENT 19.0. The simulated results were verified against experimental measurements. 【Result】 ①The simulation results were reliable and robust as comparison with experimental data showed that the simulated water flow rate and velocity distribution in the channels agreed well with those experimentally measured. ②When the theoretical flow rate was 0.221 0 L/s, the simulated and measured flow rates fluctuated erratically as the thickness of the sediment deposition increased, and the simulated flow water differed from the theoretical one with the difference varying from -0.45% to 8.60%. ③When the theoretical flow water was 0.221 0 L/s, comparison of the free-surface profiles with and without sediment deposition showed that the simulated and measured profiles occurred at different degrees of water level accumulation near the weir plate; the height of water level increased erratically with the increase in sediment deposition. 【Conclusion】 Comparison with experimental data showed that the simulation results are accurate and reliable. The water level in front of the weir rises because of the sediment deposition, and the flow capacity of the weir increases as a result. However, as the wire traditional formula does not have a correction term to account for sediment deposition, the flow rate estimated is smaller than the real ones.

Chemical vapor deposition (CVD) technique is widely used in industrial production, but the products of CVD technique are influenced by many parameters. To determine how the changes of the parameters influence the deposition quality, repeated experiments are needed to be carried out. By introducing computational fluid dynamics (CFD) method into CVD realm for the numerical simulation of the CVD process, the overall research costs can be reduced and the efficiency of deposition can be improved effectively. In this paper, the conception of computational fluid dynamics was briefly introduced, and then the analysis methods of CFD simulation were described with the instance of ANSYS Fluent software. Finally, the applications of CFD method in the establishment of research models of CVD reactions, structural improvement of CVD reactors and optimization of CVD technique were reviewed respectively.

Copyright of Journal of Drainage & Irrigation Machinery Engineering / Paiguan Jixie Gongcheng Xuebao is the property of Editorial Department of Drainage & Irrigation Machinery Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

ObjectiveIn this paper, the hydrostatic resistance of a planing craft is studied using the high-precision numerical simulation method to improve the numerical prediction accuracy. MethodsThe three-dimensional viscous flow field of a planing craft in calm water is numerically simulated using the computational fluid dynamics (CFD) method combined with the Savitsky method and overset grid technique, and the flow field characteristics of the craft under different load coefficients and speeds are analyzed. ResultsThe calculated results of the resistance, sinkage and trim angle of the planing craft are in good agreement with the experimental results, and the spray phenomenon and distribution of water and air on the bottom of the craft are simulated normally, which shows that this method can accurately and effectively predict the resistance performance of planing craft. With the increase in the load coefficient, the peak value of the pressure coefficient on the keel increases, and the position of the pressure center moves forward. With the increase in speed, the peak value of the pressure coefficient on the keel decreases, the position of the pressure center gradually moves towards the stern, the angle between the stagnation line and the longitudinal section in the center plane decreases, the depth of the cavity behind the transom decreases, and the length of the cavity increases. ConclusionsThis study provides an accurate and effective numerical calculation method for the resistance prediction of planing craft, and can provide technical support for the numerical study of the hydrodynamic performance of such craft.

Copyright of Journal of Drainage & Irrigation Machinery Engineering / Paiguan Jixie Gongcheng Xuebao is the property of Editorial Department of Drainage & Irrigation Machinery Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Grid generation is an important step of computational fluid dynamics.In the process of large-scale numerical simulation,the time consumption of grid generation increases with the number of grids which often increases with the simulation accuracy.Based on the grid generation algorithm in an open-source software called OpenFoam,this paper proposes a hybrid parallel me-thod of OpenMP and MPI for polyhedral grid generation.By theoretical analysis,we show that when the hybrid parallel method is used to generate the same quality grids,increasing the number of threads and grid cells will reduce the time consumption of grid generation.Three numerical simulations using different solvers show that the grids generated by the hybrid parallel method and the original method have close qualifications,and the simulation results are almost indistinguishable from those of the original method.Furthermore,the time consumption of this method to generate the same quality and quantity grids can be reduced to less than a quarter of the time consumption without using OpenMP parallel method.

Aerodynamic noise level has become an important performance index of civil aircraft, and it is drawing more and more attention. Most airframe noise research based on CFD method is aimed at aircraft individual parts at present, while lack of noise prediction for the complex high fidelity full aircraft model. Due to the interaction between aircraft parts, noise prediction between single part and the actual configuration are very different in the aspect of calculation conditions, noise generation and propagation. Only by using more realistic model can the noise be accurately predicted. In this paper, high-resolution mesh and high-precision hybrid RANS/LES method, combined with the FW-H acoustic analogy method, are employed to predict the noise of a turboprop's high-fidelity 1/6 scale model of landing configure. The improved delayed detached eddy simulation (IDDES) method was used to simulate the flow in the near-field sound source region, and the sound source characteristics of the whole turboprop are obtained. In addition to the two important noise sources-flap side edge and wing tip, numerical simulation also found other two important noise sources resulting from the interaction between parts-interaction between nacelle wake and flap, and the complex flow between flap inner side and fuselage. Results of far-field noise show that in the longitudinal symmetry plane of the fuselage, the noise mainly propagates to the lower front and over back direction, and the dipole characteristics are very obvious. In the plane perpendicular to the incoming flow, the noise in the transverse direction is weaker.

Lead-cooled fast reactor (LFR) is known as a typical reliable new type reactor by the US Department of Energy (DOE), and the potential accidents of LFR are necessary to assess. Steam generator tube rupture (SGTR) accident can cause high-pressure hyperbaric steam-water jetting into liquid lead bismuth eutectic (LBE) pool, and leads to a rapid pressure rising in the reactor primary system together with a potential pressure wave crashing the structures. This paper focuses on the computational fluid dynamics (CFD) analyses of SGTR experimental research on the LIFUS5/MOD2 experiment facility. A two-dimensional symmetrical slice with 1 million 570 thousand structured mesh was established for the experimental reaction vessel, and each side except the injection nozzle were set as adiabatic no slip boundary in order to achieve the non-decompression process. In the aspect of multiphase model settings, the Eulerian-Eulerian two-phase flow model was adopted to track the steam-LBE interface in the transient simulation, and the CSF surface tension polynomial together with Lee substituted evaporation model were considered. In addition, the injection of high-pressure water in each time step was separated to two parts: latent heat and injected steam, so as to calculate both endothermic and jet of flash evaporation simultaneously. Among them, the latent heat was realized by user-defined functions (UDF), and the injected steam was adopted as compressible real gas with R-K gas state equation. Based on the above settings, three established thermal-hydraulics phenomena including pressure rising of LBE environment together with pressure wave spreading, level fluctuation of liquid environment with argon entrainment and level rising of liquid environment and diffusion of injected steam were analyzed. From the results a conclusion can be reached that CFD numerical simulation has little error on calculating pressure rising with pressure wave spreading. In addition, the peak value of pressure wave rises with back pressure of water increasing, and the pressure of partial steam cavity is lower than that of LBE pool around it, in turn inhibits the occurrence of its explosion. Meanwhile, LBE in the middle firstly washes up and impacts the structures, and then entrains the argon when it falls back, in turn causes the combination of argon and steam cavity, or the secondary segmentation to small argon bubbles. Moreover, the diffusion of the steam cavity along the radial direction becomes more intense with the increase of the axial height, accompanies by the steam cavity divided from the center to the edge along the radius.

Drawing inspiration from the morphological characteristics of the creatures in nature, imitating and learning from the excellent aerodynamic shape to obtain better flight performance is the basic idea of the design of morphological bionic aircraft.This paper introduces the development background of morphological bionic aircraft, and analyzes two research process of morphological bionic aircraft "top-down" and "bottom-up";According to the categories of bird-like aircraft, fish-like aircraft and other bionic aircraft, the current development status is introduced respectively.The key technologies such as the extraction method of shape features, the method of solving problems in aircraft design process referring to the excellent biological characteristics, identification of aerodynamic parameters of bionic aircraft and other key technologies, and the inspection method of morphological bionic result are explored, and the future development trend of the morphological bionic aircraft is summarized.The content of this article is of certain reference significance for the design of morphological bionic aircraft.

Two-phase flow (Gas-liquid) in pipelines is widely present in many fields, such as nuclear industry, chemical industry, and petroleum transportation. Compared with single-phase flow, the density, pressure, and momentum flux in two-phase flow change greatly in the flow. When flowing through a valve, elbows, tees, and other components, a pulsating force is induced, which is termed as the “flow-induced force.” Flow-induced force causes pipeline vibration. If the vibration frequency is close to the natural frequency of the pipeline, a resonance phenomenon occurs that can further increase the vibration amplitude of the pipeline and consequently cause fatigue damage to the pipeline system. Therefore, research on flow-induced force is of great significance for the safe design and operation of pipelines. In this paper, the research progress on the mechanism, influencing factors, and calculation models of flow-induced force was reviewed. The results show that the change of momentum flux is the dominant factor in causing flow-induced force. The pressure fluctuations, pulsation of the liquid slug, and the volatile liquid wave also contribute to force fluctuation. This study aims to establish a complete theoretical system of flow-induced force mechanism that shows varying wave characteristics with different flow patterns. Most of the current studies focus on single horizontal pipe or riser pipe. With the development of deep-sea oil and gas, demand on gathering and transportation-riser pipeline systems is increased, making it a great engineering significance to study the flow-induced force in a variety of pipeline-riser systems. The empirical and theoretical models are gradually established. The ability of CFD software to simulate flow field and excitation force offers numerous advantages. Therefore, research on the accuracy of CFD software calculation results and the comparison and optimization of effective CFD calculation simulation methods will have important scientific research value for development in the future. This article comprehensively summarized the current research status of gas-liquid two-phase internal flow excitation, which can provide guidance for further related research.

In this paper, the flow control system consists of some small microflaps located between the rear fins of the projectile. These microflaps can alter the flow field in the finned region of the projectile resulting in asymmetric pressure distribution and thus producing control forces and moments, furthermore to provide directional control for a supersonic projectile. Due to the small size and high speed characteristics of projectile, which is with fast and valid response characteristics, this flow control system has initially shown excellent potential in terms of supersonic flow control. The CFD simulation used here solves steady-state Reynolds-averaged Navier-Stokes equation with two-equation turbulence model k-ε. Firstly, we investigate the flow mechanism around microflap in supersonic flow, the flow fields around the microflap are complex, involving three-dimensional shock-shock, shock-boundary layer interactions. Secondly, for the microflap and the fin of Basic Finner configuration, the influence of microflap geometric parameters, microflap locations on aerodynamics is obtained and the interference mechanism is explored. Finally, several typical roll and pitch control layouts are described. According to the simulation results and their analysis, some preliminary conclusions can be drawn: by analyzing the flow interference mechanism between microflap and the fin, we find that the separated shocks ahead of the microflap, the bow shocks around microflap, and the trailing-edge wake, have influences on fin's surface pressure; among these factors, the bow shocks are stronger than separated shocks, furthermore it can generate larger high pressure region. Then we find out the aerodynamic characteristics of several typical control layouts at a supersonic speed, Ma=2.5, furthermore, hence nearly 4.8% drag is increase compared with the condition without microflap. As the number of microflaps increasing, the control aerodynamic forces and moments increases almost linearly. With a proper layout of the microflap's location, quick change in the surface pressure distribution can be achieved for rear fins of the projectile, the microflap should be mounted that can increase the high pressure zone, meanwhile, reduce the low pressure zone on the surface of fins, thus modulating the projectile's attitude can be realized.

A wind tunnel of high temperature and long operation time requires the use of cooling techniques,so we need design cooling channels on the nozzle. In this paper,rectangular cooling channels of high cooling efficiency were used to study the factors affecting nozzle cooling. First of all,a three-dimensional model of nozzle cooling structure was established. Secondly,the type of heat transfer of the nozzle was detailedly analyzed and at the same time radiation heat transfer was taken into account. Then based on the principle of simplicity and accuracy,a series of assumptions were made for the calculation model. Finally CFD techniques were used to carry out the numerical simulation. By analyzing the results of study,we obtained the rules how the aspect ratio of cooling channels influenced nozzle cooling,the difference whether or not considering radiation heat transfer,and the impact of gas flow total temperature on nozzle cooling.