13 results about "Flow resistivity" patented technology

The invention relates to the technical field of reactor safety analysis, and provides a pressurized water reactor pressure vessel lower chamber flow distribution analysis method. The method comprises the following steps: establishing a fluid domain three-dimensional geometric model; performing unstructured grid division on the fluid domain three-dimensional geometric model to generate a three-dimensional calculation grid; selecting a turbulence model; setting inlet boundary conditions and physical property parameters of the coolant; the reactor core area is equivalent to a porous medium area, and flow resistance parameters of the porous medium area are set; based on the three-dimensional calculation grid, adopting a selected turbulence model, loading flow resistance parameters of a porous medium area and inlet boundary conditions and physical property parameters of a coolant, and carrying out three-dimensional flow simulation to obtain coolant flow distribution at the section of a reactor core inlet; and evaluating the flow distribution uniformity of the reactor core inlet according to a preset flow distribution evaluation criterion. The method is used for simulating three-dimensional flow of a coolant in a lower cavity of a reactor pressure vessel, acquiring a flow field structure and flow distribution data of the coolant, and performing quantitative evaluation.

The invention discloses a superstructure device optimization method and equipment giving consideration to ventilation and noise reduction and a storage medium, and relates to the field of acoustics. According to the superstructure device optimization method and equipment giving consideration to ventilation and noise reduction and the storage medium, a superstructure device giving consideration to ventilation and noise reduction performance is designed, an agent model reflecting the relation between structure parameters of the superstructure device and flow resistance and noise reduction performance is constructed, and a sequence optimization strategy is established; the superstructure device considering ventilation and noise reduction performance is designed according to the proxy model and the sequential optimization strategy, and the structure parameters of the superstructure device can be optimized to reduce the flow resistance on the basis of improving the noise reduction performance so as to optimize the ventilation performance.

The application discloses a kind of multistage distributed cold traps based on lunar surface environment, including arch shell, the inner surface of arch shell is pasted with sealing film, several cold trap units are installed in the inner surface of arch shell and are distributed in array;The cold trap unit includes framework, the outer side of framework is attached with sealing film, the inner side of framework is cold trap entrance and is pasted with selective permeation membrane with molecular sieve effect, the bottom surface of framework is fixedly provided with microcapsule phase change layer, and porous medium made of high thermal conductivity material is embedded in the inside of framework;The porous medium is arranged in the inside of framework with gradual porosity or with gradient porosity.The application not only reduces vapor flow resistance and enhances surface desublimation active site density, but also realizes space matching of heat flow density and vapor flux, improves energy quality transfer synergistic efficiency, and can also buffer external radiation fluctuation, so as to maintain long-term stability of temperature inside cold trap.

The invention belongs to the related technical field of heat sinks, and discloses a fixed wall temperature design method for a porous heat sink, which comprises the following steps: S1, constructing a physical model of the heat sink, determining related parameters of the heat sink, a coolant and a porous medium, and setting a designed wall temperature according to a maximum allowable temperature or an expected temperature; s2, ideal local Nusselt number distribution in the flowing direction of the coolant is solved and obtained; s3, establishing the correlation between the local Nusselt number of the heat sink in the coolant flowing direction under the designed wall temperature condition and a to-be-designed structure parameter, and obtaining a corresponding function relationship; and S4, solving to obtain continuous function distribution of the to-be-designed structure parameters along the flowing direction. According to the method, under the constraint of the given wall surface maximum temperature, the porosity or the function distribution of the filling porous cross-sectional area in the flowing direction can be obtained, so that the flowing resistance is remarkably reduced, the wall surface temperature uniformity is improved, and the power and the thermal stress of the pump are effectively reduced.

In some embodiments according to the present disclosure, methods for mitigating particle retention are provided including the use of frequency sweep excitation to eject particle in the sweep. In some embodiments according to the present disclosure, the acoustically driven fluid ejector can be capable of being switched between multiple modes of operation. In other embodiments according to the present disclosure, the acoustically driven fluid ejector can be altered such that it includes the capability to be filled with a biocompatible material to aid in the mitigation of particle aggregation in the acoustically driven fluid ejector. In some embodiments according to the present disclosure, the solid structure and number of nozzles of the acoustically driven fluid ejector can be adjusted such that the ejector of the acoustically driven fluid ejector can be self-pumping, i.e. no external pumping mechanism other than acoustics driven flow drag is used.

This invention discloses a perforated plate sound-absorbing structure with adjustable equivalent surface acoustic impedance (ESI). It includes a perforated panel, a cavity on the back of the panel, and a flexible sound-absorbing layer within the cavity. The flexible sound-absorbing layer is parallel to and always covers the back of the perforated panel. The flexible sound-absorbing layer has different flow resistivity distributions in different regions along its length. The flexible sound-absorbing layer is connected to a roller assembly to drive it to translate along its length. By aligning the different flow resistivity regions of the flexible sound-absorbing layer with the back of the perforated panel, the equivalent surface acoustic impedance of the perforated plate sound-absorbing structure can be adjusted. This solution achieves continuous and precise adjustment of the equivalent surface acoustic impedance by translating the flexible sound-absorbing layer, which always covers the back of the perforated panel and has a gradient or segmented flow resistivity distribution, thereby changing the corresponding positions of different flow resistivity regions on the back of the perforated panel. The adjustment accuracy is high, and it can meet the impedance matching requirements at different frequencies.

The invention discloses a low-resistance acoustic lining panel with elliptical holes and a design method thereof, the low-resistance acoustic lining panel comprises a perforated plate, a plurality of uniformly distributed through holes are formed in the perforated plate, the hole opening direction of the through holes is perpendicular to a fixed wall, and the through holes are elliptical holes; the short axis direction of the elliptical hole is the same as the airflow direction; the short axis length of the elliptical hole is greater than the thickness of the acoustic viscosity boundary layer corresponding to the target sound wave frequency; the elliptical holes are uniformly distributed in rows and columns on the fixed wall, and the elliptical holes in adjacent rows are distributed in a staggered manner, so that the elliptical holes in the middle row and the center connecting lines of the left and right adjacent elliptical holes in the front and back rows can form an equilateral triangle. According to the acoustic liner perforated plate, the hole shape of an existing acoustic liner perforated plate is changed into the oval shape from the original round shape, the size of the oval hole is designed, the flow resistance coefficient of the acoustic liner can be reduced on the premise that the overall acoustic performance of the acoustic liner is not changed, the considerable resistance reduction effect is achieved, and therefore oil consumption of an airplane can be reduced.

The invention relates to a method for continuously determining the particle size distribution of solid particles having different particle sizes, which are transported in a transport direction in a transport stream and during which impact with an impinging body provided as a waveguide and generate an acoustic signal, which propagates in the impinging body as a solid-state acoustic wave, and detecting the acoustic signal with a vibration sensor. The invention further relates to a measuring device for carrying out the method. In order to obtain a more accurate result when determining the particle size distribution while taking into account a change in the flow energy of the transport flow, it is proposed to reduce the piezoresistive component of the flow resistance of the striking part of the striking body in the direction of incident flow.

The invention discloses a low-resistance acoustic lining panel based on crescent inclined open pores and a design method thereof, the structure adopts a perforated plate with crescent inclined open pores to replace a circular perforated plate of an original acoustic lining, the crescent opening direction is consistent with the airflow direction, and by reducing the size of the open pores in the flow direction and reducing the airflow entering a cavity, the low-resistance acoustic lining panel is formed. Therefore, the flow resistance of the acoustic liner is reduced, the sectional area of the opening is kept unchanged, and the acoustic performance of the acoustic liner is ensured to be unchanged.

Acoustic articles and related methods are provided. Specifically, the present invention provides an acoustic article having a porous layer (102, 104, 106) placed in contact with a heterogeneous filler comprising porous carbon and having an average surface area of 0.1 m2 / g to 10,000 m2 / g. The acoustic article may have a flow resistance of from 10 MKS Rayls to 5000 MKS Rayls. Optionally, the porous layer comprises a non-woven fibrous layer or a perforated film having a plurality of open pores having an average narrowest diameter of from 30 microns to 5000 microns. The heterogeneous filler may enhance low frequency performance without significantly compromising high frequency performance, thickness, or weight.

The present application belongs to the technical field of micro-interface dynamics research, and relates to a method and system for realizing prediction of micro two-phase interface imbibition behavior of porous media, comprising: obtaining a pore network composed of pores and throats according to a target porous medium; calculating the flow rate of injected two-phase fluid at the throat; calculating the fluid flow rate under the main interface displacement mode and the wetting mode displacement mode respectively according to the flow rate of injected two-phase fluid at the throat; determining the displacement mode of the two-phase fluid interface according to the fluid flow rate ratio under the two displacement modes; calculating the corresponding flow resistance at the throat according to the displacement mode of the two-phase fluid interface; updating the motion control equation of the two-phase fluid according to the flow resistance, thereby completing the prediction of the micro two-phase interface imbibition behavior of the porous medium. The present application clearly defines the preferential flow path and dynamic evolution mode of different types of interfaces in the displacement process in the complex pore structure of the porous medium, and realizes accurate discrimination of the fluid interface type under transient conditions.

The application provides a coalescence flow guide module and equipment for strengthening multiphase quick separation, which is composed of "eight" shaped coalescence units formed by first coalescence plates and second coalescence plates respectively inwardly inclined at an angle, and the coalescence flow guide module is formed by horizontal and vertical translation and superposition of the coalescence units; gaps are left between adjacent first coalescence plates and second coalescence plates in the vertical direction; the gaps in the coalescence units form ascending channels in the vertical direction, and the gaps between adjacent coalescence units form descending channels in the vertical direction. The application utilizes the shallow pool principle to reduce the time required for liquid droplets to float or sink, and utilizes the hydrophilicity and hydrophobicity of the material surface of the coalescence plate to improve the liquid droplet coalescence efficiency; the inclined coalescence plate forms completely separated and non-interfering ascending channels and descending channels, so that the multiphase quick separation can be realized, and the application has the advantages of small flow resistance, good coalescence effect and difficult back mixing.

An automotive sound-insulating trim component having spring-mass characteristics comprising a porous fibrous spring layer and a mass layer laminated together, wherein the porous fibrous spring layer has an Air Flow Resistivity lower than 7500Ns / m4 and a Damping Loss Factor equal to or higher than 0.15.