In order to investigate the fluid structure interaction problems occurring in tube bundles, a numerical model is presented. The unsteady three-dimensional Navier-Stokes equation and LES turbulence model are computed w...
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In order to investigate the fluid structure interaction problems occurring in tube bundles, a numerical model is presented. The unsteady three-dimensional Navier-Stokes equation and LES turbulence model are computed with finite volume approach on structured grids combined with the technique of dynamic mesh. The model presents a three dimensional fully coupled approach with solving the fluid flow and the structure vibration simultaneously, for the tube bundles in cross flows. The results show that, the presented model is validated with experimental data and compared with existing models in the literature. Trajectory of single tube is "8" shape at "locked in". The two parallel tubes oscillate in opposite phase and both have the same amplitude. For pitch higher than 1.5D, there is no mutual influence of the tubes and response is close to the case of single tube. The lift force and amplitude of downstream tube of two inline tubes are increasing as the pitch increases. The upstream tube is almost not influenced by the downstream one when the pitch is larger than 2D. The fluid force and response are close to the case of single tube.
Self-Powered Neutron Detectors (SPNDs), which are widely used in nuclear reactors to obtain core neutron flux distribution, are accurate at steady state but responds slowly to changes in neutron flux. Dynamic compensa...
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During the process of preliminary and conceptual design of hypersonic vehicles, predicting surface friction as well as heat flux is crucial to the design of the thermal protection system (TPS) and optimization of aero...
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ISBN:
(数字)9781624102561
ISBN:
(纸本)9781624102561
During the process of preliminary and conceptual design of hypersonic vehicles, predicting surface friction as well as heat flux is crucial to the design of the thermal protection system (TPS) and optimization of aero-thermodynamics. This paper primarily focuses on two aspects. Firstly, an engineering code has been successfully developed to compute the approximate heating rates of general three-dimensional hypersonic vehicles at angles of attack using unstructured grids for perfect gas. A three-dimensional linear description of surface and flowfield is proposed, based on which an improved axisymmetric analog method is developed, which calculates inviscid surface streamlines and metric coefficients over the body. An implicit surface fitting method is introduced to fit the primary curvatures at stagnation point and a robust marching scheme for calculating heating rates downstream of stagnation region is developed. The proposed engineering approach is verified through a spherically blunted cone and a double ellipsoid, satisfactory agreement between calculation results and wind tunnel experimental results is found. Secondly, a quasi-waverider wing-body model is constructed, the sharp leading-edge of the wing is blunted using circular tips with distinct values of radius, the bluntness effect on the aerodynamic performance is investigated, which would be of vital importance for future work in designing and optimizing the shape of the blunt leading-edge on hypersonic vehicles.
In order to change the poor adaptability and low efficiency of the message router in enterprise service bus, this paper proposed a natural language processing based semantic-level message routing algorithm and design ...
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In china,the development and application goals of Small Modular reactor(SMR) aim at electricity generation area,heat supply area,and seawater desalination area,*** main technical features of the SMR areas follows:inte...
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In china,the development and application goals of Small Modular reactor(SMR) aim at electricity generation area,heat supply area,and seawater desalination area,*** main technical features of the SMR areas follows:integrated pressurized water reactor,reactor coolant pump and reactor pressure vessel connected by short pipe,steam generator sets in reactor pressure vessel,control rod drive mechanism(CRDM),pressure vessel,reactor internals,Once-Through Steam Generator(OTSG),and canned motor pump are all mature *** on the characteristic of the reactor and OTSG,the automatic control design of the SMR is discussed in this paper,and the simulation results are presented to illustrate the control scheme.
A heavy-load positioner with series-parallel mechanism was put forward according to the heavy-load positioner’s task demand. Two rotational DOFs were realized by the spherical 3-DOF mechanism with a restricted embran...
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This paper presents a reasoning method based on the combination of Textual CBR and RBR to deal with the case described by the natural language with the intention of resolving the information retrieval in the flight-te...
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Subset Simulation provides an efficient and robust method to estimate the failure probabilities at small probability levels for a single failure mode defined by the system response concerned. However, estimating failu...
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Magneto-rheological elastomers (MREs) are a new kind of Magneto-rheological materials mainly composed of polymer rubber and micro-sized magnetizable iron particles. In this technical note, a shear-mode semi-active dyn...
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ISBN:
(纸本)9781634392389
Magneto-rheological elastomers (MREs) are a new kind of Magneto-rheological materials mainly composed of polymer rubber and micro-sized magnetizable iron particles. In this technical note, a shear-mode semi-active dynamic vibration absorber (SDVA) based on MREs is proposed and the dynamic design principle of an axial SDVA attached to ship shafting is studied. The material preparation of MREs and their properties under different magnetic fields are introduced. The structure of a single SDVA is designed. Furthermore, the natural frequencies of the single SDVA under different magnetic fields and temperatures are experimentally evaluated. It is found that the natural frequency of SDVA has a decreasing trend with the temperature increasing. However, it has an increasing trend with the excitation current increasing in the same temperature situation. The effect of temperature is more obvious than the excitation current.
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