31 results about "Flow oscillation" patented technology

The present invention discloses an Ethernet network fault recovery method. The present invention comprises that when the elimination of the ring network fault is detected, a master node forwards out a unicast data packet of which the access is from a port, and the other nodes recover the packet forwarding; according to the forwarding path of the data packet after a sub part is blocked, the forwarding table information of the node is synchronized; and sub part is blocked by the master node. The present invention realizes the uninterrupted forwarding of the unicast data packet in the process of recovering the ring network fault, and avoids the possible broadcasting turmoil; meanwhile, the synchronization mechanism of a forwarding table avoids the flow oscillation caused by the ring network because of the refreshing and forwarding of all the nodes, thereby the fault recovery process is smoother.

An apparatus for attenuating acoustic resonance generated by flow over a cavity in a surface comprises a plurality of flat flaps proximate to an upstream edge of the cavity. The flaps are disposed in an array spaced in a width direction of the cavity edge, and are oscillated by the flow in two degrees of freedom solely by the flow, independent of an actuation mechanism. Each flap includes a first hinge generally coextensive with the surface for enabling oscillation in a first degree of freedom and a second hinge orthogonal to the first hinge and forming a tab for enabling oscillation in a second degree of freedom. The hinges are constructed with torsional spring constants that provide predetermined oscillation frequencies and magnitudes. The apparatus can include a deployment mechanism for moving each flap between a stowed position wherein it is generally flush with the surface and a deployed position wherein the flap can be oscillated by the flow.

A new method for stabilizing the regional mode power/flow oscillations in a boiling water reactor core is introduced in this invention. The method depends on introducing flow resistance or partitions in the common flow plena (upper core plenum and/or lower plenum). The said resistance or partitions function to reduce or prevent the flow communication between any two groups of fuel assemblies through the common plena, thus preventing the excitation of the neutron flux first azimuthal harmonic mode. The partition devices of this invention, which provide the flow resistance, must divide the flow area in a common core plenum into three or more flow paths, as dividing the plenum in two flow paths only would not prevent the instability but would simply result in re-orienting the instability neutral line dividing the core assemblies into two sides oscillating out-of-phase. Alternative embodiments of this invention are Mercedes sign three section dividers, or Cruciform four section dividers, which are placed inside the upper and/or lower plenum of a boiling water reactor core.

The invention discloses a squirrel-cage flow regulating valve with a regulating window. The squirrel-cage flow regulating valve comprises an outer shell, a power assembly, a valve rod, a valve elementand a valve seat, wherein the outer shell is provided with a hollow valve cavity; the outer shell is provided with a valve rod opening used for installing the valve rod, an inlet used for allowing fluid to flow in and an outlet used for allowing the fluid to flow out; the power assembly is used for driving the valve rod to move in the axial direction; the valve element is installed at the other end of the valve rod and provided with a through hole used for communicating a rod cavity with a rodless cavity; the valve seat is packaged in the valve cavity and positioned through the outer shell; the valve seat is provided with the regulating window; the power assembly drives the valve element to move up and down along the valve seat through the valve rod; and the opening degree of the window of the valve seat is determined by displacement of the valve element. According to the squirrel-cage flow regulating valve, the through hole is formed to balance the force, acting on the valve element,of the fluid, the medium flowing oscillation situation can be weakened, and therefore the working stability is better; and the power assembly is used for driving the valve element to move linearly, and the precision is high. The squirrel-cage flow regulating valve can be applied to a liquid oxygen methane variable thrust engine, and the requirement for the flow regulating precision is met.

The invention discloses a visual analysis method for flow oscillation after gas is injected into lead bismuth fluid. The method comprises the steps that (1), a lead bismuth alloy is injected into a double-pipe circulation device, the different amounts of helium or argon is injected into the lead bismuth alloy, and then a measuring device is used for calculating thermophysical parameters at different temperatures; (2), grid dividing is carried out on the double-pipe circulating device, the solution sequence of a CFD calculation model is set, and a convergence control criterion is set; (3), a solution equation is listed according to the set solution sequence, calculation models of the parameters of heat transfer coefficient are selected according to the natural convection feature of the lead bismuth alloy, and load data are calculated and transferred by means of an iterative loop mode; (4), CFD software is utilized for converting data information into image information and displaying the image information visually.

The present invention relates to boiling water reactors (BWR) disclosing a new method and device for preventing the flow and power oscillations from growing to severely large amplitudes thus protecting the reactor from the consequences of instabilities associated with the so-called anticipated transients without scram (ATWS). This invention introduces a new method for preventing boiling water reactor fuel damage due to the growth of unstable density wave oscillations to severely large magnitudes. The method limits the growth of the density waves by limiting the magnitude of the oscillation of the coolant mass flow rate at the inlet of the fuel bundle such that only upward flow is permitted. Further growth of the density wave beyond inlet flow reversal is thus prevented which limits the severity of the coolant flow conditions at the fuel clad surface in the entire fuel assembly such that dryout either does not occur or rewetting of the clad surface occurs every oscillation cycle such that excessive high clad temperatures that may cause its failure do not occur. A device realizing this method is comprised of a screen structure placed inside the lower tie plate of the fuel assembly. The said screen is free to move between two plates with aligned holes. The said screen is lifted upward such that the flow holes are not obstructed allowing upward flow of the coolant as required for normal operation. In the case the flow direction is reversed the hydraulic lifting force vanishes and the screen structure moves to a lower position blocking flow holes and obstructing flow in the reverse (downward) direction. This invention is particularly useful for limiting the consequences of unstable oscillation should the ability of the reactor operator to shut down the reactor power with control rod scram be lost as part of the hypothetical scenario known as anticipated transient without scram (ATWS). It is also useful to mitigate the consequences from a loss-of-coolant accident. This invention additionally functions as a debris filter to protect the cladding of the fuel rods.

The invention provides a system and method that applies novel algorithms and compositions for efficiently adjusting compression, unit turn down, pressure and flows of a pressure swing adsorption unit. The present invention also reduces overall horsepower, increases unit's product gas recovery, maximizes product gas quality and allows for non-disturbance of upstream and downstream equipment in regard to pressure and flow oscillations. Raw gas streams addressed include methane (CH4), nitrogen (N2), oxygen (O2), carbon dioxide (CO2), water (H2O), Hydrogen Sulfide (H2S) and non-methane organic compounds (NMOC) gases/vapors. The invention incorporates a CO2 and H2O trim units and provides a VPSA N2 and O2 rejection section.

The invention relates to the technical field of water vapor external reforming solid oxide fuel cells, in particular to a method for controlling and optimizing SOFC system oscillation caused by water vapor flow oscillation. Comprising the following steps: modeling a steam external reforming SOFC system; the condition of water vapor flow oscillation is simulated and analyzed; introducing an oscillation control algorithm based on fuzzy control, and proposing a control and optimization strategy; and analyzing and applying an optimization effect according to a simulation experiment result. According to the design of the invention, the water vapor oscillation model is constructed, so that frequent discharge experiments on the SOFC system are not needed, and system faults are avoided; respectively designing a single/double input fuzzy controller, and controlling the temperature and voltage in the SOFC system within a reasonable range through simulation to realize control of system oscillation; a fuzzy control rule and a control strategy are designed, real-time tracking of a set value is achieved, oscillation is prevented from spreading in the SOFC system, and therefore the performance of the system is optimized.

The invention discloses an oscillatory flow filtering method for an electronic meter at a zero flow point. The method comprises the following steps: carrying out the collection of the flow of the meter at an initial sampling time interval t1, and obtaining the real-time flow Qs; judging whether the flow Qs is less than the starting flow of the meter or not, if yes, determining that the current instantaneous flow Q of the meter is equal to 0, and if not, determining that the current instantaneous flow Q of the meter is equal to Qs; recording the current instantaneous flow Q of the meter and thedirections of flow Q1, Q2,..., QN obtained by N times of sampling before Q, wherein N is an integer greater than or equal to 2; and judging whether the absolute value of the current instantaneous flow Q is less than a preset flow threshold value or not, and if the absolute value of the current instantaneous flow Q is less than the preset flow threshold value, performing zero-flow oscillation flowfiltering. The oscillation flow near the zero flow can be effectively filtered, the economic loss of the user caused by the zero flow oscillation flow is reduced, and the normal flow and the functions of the meter are not influenced.

The invention discloses an aviation aircraft undercarriage cabin flow oscillation control method, which comprises the following steps: establishing a numerical model of an undercarriage cabin, and setting the cabin bottom of the undercarriage cabin to be a porous material in the numerical model; determining boundary conditions; substituting the boundary conditions into a numerical model, and solving porous wall surface flow of the cabin bottom; calculating a radiation noise amplitude based on the porous wall surface flow data of the cabin bottom; evaluating the noise level, and regulating and controlling the porous wall surface parameters based on the noise level. The invention provides a flow oscillation control method for an aviation aircraft landing gear cabin, and aims to solve the problems of configuration change, aerodynamic performance damage, huge energy consumption, incapability of responding to dynamic characteristics and the like in a noise control technology for the landing gear cabin in the prior art and realize the purpose of controlling the flow oscillation of the landing gear cabin on the premise of keeping the configuration of the landing gear cabin unchanged. The flow environment in the cavity is improved as simply as possible, and radiation noise is suppressed.

The invention discloses a method for identifying an initial point of density wave oscillation of a parallel channel. The method comprises the following steps: A, power disturbance is performed on the channel on the basis of initial thermal hydraulic parameters and heating power; B, the divergence condition of a flow oscillation curve after implementation of power disturbance is confirmed; C, if the flow oscillation curve diverges, the heating power is reduced; if the flow oscillation curve does not diverge, the heating power is increased and then the divergence condition of the flow oscillation curve is confirmed again until the flow oscillation curve diverges; D, the steps B and C are cycled to identify the initial point of density wave oscillation, enhancement of previous cycle is higher than that of later cycle in the multiple cycles, and the decrement of each cycle is the enhancement of the cycle. According to the method, the heating power is increased or reduced on the basis of the initial thermal hydraulic parameters and heating power, the initial point of density wave oscillation is found out finally, the identification precision is high, identification can be realized through a program, and the efficiency is high.

The invention provides a treatment device for rural domestic refuse leachate. Medicament mixing equipment is internally provided with a honeycomb-shaped reactor and a steam spraying pipe, wherein heating pipes are arranged in a plurality of vertical pipes in the honeycomb-shaped reactor; the medicament mixing equipment and the upper part of a turbulence-state processor are connected through a pipeline; a mud discharging and liquid discharging pipeline is arranged at the lower end of a turbulence shell body of the turbulence-state processor; an inner cavity is internally provided with a spraying pipe net, a turbulence-state adsorption mechanism and an aeration pipe; the spraying pipe net is connected with an external water pump through a pipeline; the turbulence-state adsorption mechanism is internally provided with a reaction ball and is provided with an active resonance device and a pressurizing impeller; the active resonance device is internally provided with a resonance head and a vibration rod; the resonance head is internally provided with a high-frequency vibrator; an aeration hole is formed in the upper part of the aeration pipe; a dispersion unit in the turbulence shell body is composed of two polyaluminum chloride dispersion pipes; a stable flow buffering unit is composed of a plurality of macromolecular stable flow screen meshes; and a stable flow oscillation unit iscomposed of a plurality of stable flow oscillation bodies. The device can be used for effectively treating the rural domestic refuse leachate.

The invention relates to the technical field of two-phase flow coupling, in particular to a two-phase flow coupling method based on a signal filtering nuclear power system program, and the method comprises the steps: S1, building a thermal model of a simulation object; s2, splitting the thermal model according to a flow boundary, and taking parameters such as pressure and gas phase internal energy as coupling input parameters of the flow boundary; s3, a nuclear power plant operation simulation platform NURES is utilized to couple the split thermal model, and the coupling mode is two-phase fluid coupling; and S4, performing first-order lagging filtering on the pressure value in the two-phase fluid coupling output interface transmission parameters, and taking the obtained new pressure value as a coupling input parameter. According to the method, during thermal program parallel calculation of a nuclear power plant simulation platform, the flow oscillation phenomenon occurring when two-phase flow exists in a coupling interface is eliminated through first-order lagging filtering processing, and the problems that simulation operation and operation data are unstable and unreasonable due to the fact that two-phase flow oscillation exists in a simulation model are solved.