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40 results about "Incompressible flow" patented technology

In fluid mechanics or more generally continuum mechanics, incompressible flow (isochoric flow) refers to a flow in which the material density is constant within a fluid parcel—an infinitesimal volume that moves with the flow velocity. An equivalent statement that implies incompressibility is that the divergence of the flow velocity is zero (see the derivation below, which illustrates why these conditions are equivalent).

Cooling element of precision worm wheel gear grinding machine and its multi-objective thermal-fluid topology design optimization method

The present invention discloses a multi-objective thermal-fluid topological design optimization method for the cooling element of a precision gear grinding machine tool, comprising the following steps: Step 1: Define the design domain: Expand the cooling element into a plane, define a two-dimensional design domain representing the cooling element's geometric structure, and discretize it using the finite element method; Step 2: Numerical modeling: Model the cooling element as a porous medium; Under the conditions of laminar incompressible flow, the fluid dynamics are governed by the dimensionless forms of the continuity equation and the momentum equation; The fluid-solid coupled heat transfer model is governed by the dimensionless energy conservation equation; Step 3: Construct an objective function: The optimization objective is defined as a weighted function of heat transfer and fluid dissipated power, and a fluid-solid heat transfer topological optimization model is constructed; Step 4: Solve the objective function; Step 5: Restore the shape and structure of the cooling element. The present invention also discloses a precision gear grinding machine tool and a cooling element.
Owner:CHONGQING UNIV

Valve assembly with air release and sensor

The present invention discloses a valve assembly comprising a seat ring, a valve plate assembly movable between a sealed position within the seat ring and an open position outside the seat ring. A fitting can pass through the valve plate, and / or a sensor assembly can extend through the fitting with a sensor mounted below the valve plate assembly. The sensor assembly provides enhanced monitoring capabilities by being positioned in the incompressible fluid column below the valve plate assembly, ensuring accurate sensing of relevant parameters. This configuration allows for efficient and reliable operation of the valve assembly, enhancing its performance and functionality in various applications.
Owner:MUELLER INT LLC

A method for constructing a ship pressure field model in shallow water waves and a target determination method

The present invention provides a method for constructing a ship pressure field model in shallow water waves and a target determination method. The method uses ideal incompressible fluid theory to establish the continuity equation and momentum equation satisfied by the ship in the geodetic coordinate system. Based on the shallow water assumption, a depth-averaged perturbation velocity potential is introduced. Combined with the bottom boundary conditions and the free surface boundary conditions, a flow field control equation expressed by the depth-averaged perturbation velocity potential is constructed. The wave source term within the domain is set according to the wave environment, and the moving pressure term is set according to the ship type. The wave source term within the domain and the moving pressure term are substituted into the flow field control equation to simulate the effect of the surface ship disturbance in the wave environment, thereby obtaining the ship pressure field control equation. Based on the ship pressure field control equation, the ship pressure field model is constructed in combination with the initial and boundary conditions of the flow field, as well as the relationship between the flow field pressure and velocity potential. The model is adapted to rapidly calculate the pressure field under different environments, thereby improving the prediction efficiency of the ship pressure field signal.
Owner:NAVAL UNIV OF ENG PLA

Incompressible fluid flow numerical solution method based on deep learning and spectral differential

The invention discloses an incompressible fluid flow numerical solution method based on deep learning and spectral differentiation, and belongs to the technical field of fluid mechanics. The problems that when a neural network is used for solving high Reynolds number flow, calculation burden of a high-order derivative is too heavy, long-time simulation precision of unsteady flow such as vortex shedding is attenuated, adaptability of complex boundaries such as a channel wall face and a periodic boundary group is poor, and a hardware video memory is limited in solving of large-scale flow such as three-dimensional turbulent flow are solved. The method specifically comprises the steps of adopting a solution of a memory-saving reversible neural network approximation equation; deducing a space-time Chebyshev differential matrix to quickly and accurately calculate a space-time partial derivative; a unified spectral discrete format is adopted in the space-time dimension, global space-time information is integrated, and the non-local effect of the flow field is considered. Through fusion of spectral differential and a reversible neural network, a loss function composed of a residual error of a Navier-Stokes equation and an initial boundary condition matching error is optimized, incompressible fluid flow can be efficiently solved on equipment with a limited memory, and complex boundary conditions are adapted.
Owner:HARBIN ENG UNIV

Landing gear assemblies, rotorcraft and rotorcraft methods

A landing gear assembly for rotorcraft includes a shock absorber, a ground support assembly and an airframe linkage assembly. The shock absorber includes a force sensor to detect a pressure of an incompressible fluid within the shock absorber and a temperature sensor to detect a temperature of the fluid. The ground support assembly is linked to the shock absorber and includes an axle and a ground contact element movable in relation to the axle. The linkage assembly is linked to the shock absorber and / or the ground support assembly and includes a position sensor to detect movement of the axle between compressed and uncompressed conditions of the shock absorber. Various rotorcraft include one, two, three or more landing gear assemblies and an attitude control system. Various rotorcraft methods process sensor signals from one, two, three or more landing gear assemblies at the attitude control system to provide various rotorcraft functions.
Owner:THE BOEING CO

A method for analyzing dynamic mode and flow stability of double-box-girder flow field

ActiveCN120874179BAccurate numerical simulationSimulation results are reliableGeometric CADSustainable transportationBridge engineeringComputational model
The application discloses a kind of double box girder flow field dynamics modal and flow stability analysis method and system, belong to bridge engineering field.This method first establishes double box girder flow field model by computational fluid dynamics, solves the momentum equation and continuity equation of two-dimensional incompressible flow;Dynamic modal decomposition is carried out again, and eigenvalue, characteristic mode and other information are obtained;Finally, based on linear stability theory, the flow field component is expressed as the sum of steady-state solution and disturbance term, and the global linear flow stability equation is obtained by substituting into the equation, and the flow stability is analyzed by discrete.This method can accurately extract the modal characteristics of each order, providing a scientific basis for wind-induced vibration analysis of double box girder, and has important application value.The method of the application occupies less computing resources, has high numerical accuracy, and can be further expanded to higher precision calculation model according to computing resources, and is suitable for application in actual bridge engineering.
Owner:HARBIN INST OF TECH

Computer system for digitally simulating pseudo-incompressible fluid flow in a computer aided design model

Systems and methods for digitally simulating a fluid flow in a three-dimensional computer-aided design (CAD) model of a simulation space include digitally simulating movement of one or more digital particles representing the fluid from one or more first voxels in a mesh to one or more second voxels in the mesh, performing one or more interaction operations on the one or more digital particles at the one or more second voxels to determine a distribution of the one or more digital particles. A first quantity represented by the distribution of the one or more digital particles is based on a temperature and a pressure at the one or more second voxels and a reference fluid density. A second quantity represented by the distribution of the one or more digital particles is based on the reference fluid density, velocities of the one or more digital particles, and a mean fluid velocity.
Owner:DASSAULT SYSTEMS AMERICAS CORP

Generating downhole motor torque and RPM of a downhole motor with a drilling fluid having a compressible portion

ActiveUS12680401B2Control systemMotor control
A downhole motor control system may identify a downhole compressible density of a drilling fluid using a downhole temperature and a downhole pressure of the drilling fluid, the drilling fluid including an incompressible portion and a compressible portion, the drilling fluid flowing downhole with a downhole compressible flow component and an incompressible flow component. A downhole motor control system may determine the downhole compressible flow component using the downhole compressible density, a surface compressible density of the compressible portion at a surface location, and a surface compressible flow component of the compressible portion at the surface location. A downhole motor control system may identify a downhole compressible fraction of the drilling fluid based on the downhole compressible flow component and the incompressible flow component. A downhole motor control system may generate a composite flow rate of the drilling fluid based on the incompressible flow component and the downhole compressible fraction.
Owner:SCHLUMBERGER TECH CORP

Metal hose gas pressure loss test method and system

The invention relates to the technical field of metal hose inspection and detection, in particular to a metal hose gas pressure loss test method and system, and the method comprises the steps: S101, carrying out drying treatment on gas, S102, carrying out dynamic pressure adjustment on the gas, S103, carrying out data acquisition and analysis, and S104, outputting a dynamic pressure loss coefficient and an error analysis result. Step S105, adjusting a preset pressure gradient or a flow set value according to an error analysis result until the error analysis result accords with a simulation verification threshold value, and step S106, closing gas supply, releasing residual pressure of the pipeline, and checking the sealing performance of the pipeline and the reset state of the valve; according to the invention, the problems of gas compressible flow characteristic simulation distortion, inconvenient storage tank fixation and condensation interference caused by insufficient drying treatment due to adoption of incompressible fluid in a traditional metal hose pressure loss test are solved; and the problems of poor test stability and simulation analysis errors caused by incomplete data of a single-side metering mode and lack of dynamic cooperative regulation and control are solved.
Owner:AEROSUN CORP

Supply chain goods flow transfer method and system based on multi-agent cooperation

PendingCN122653295AIncrease effective throughputGuaranteed uptimeLogistics managementControl engineering
The present application relates to the field of supply chain logistics scheduling, and provides a supply chain cargo transfer method and system based on multi-agent cooperation, which comprises the following steps: a center node constructs an incompressible fluid continuity equation with a diffusion term, obtains a continuous global navigation field by solving, and distributes the field to edge agents; the edge agents analyze the field gradient vector based on the field, convert the field gradient vector into a speed control instruction, and use the speed control instruction to drive continuous movement; the edge agents detect local physical disturbances, convert the local physical disturbances into field correction parameters, and upload the field correction parameters; the center node takes the field correction parameters as a field update source, substitutes the field correction parameters into a solving process, updates the continuous global navigation field, and distributes the field to form a closed-loop regulation and control. Thus, the instruction confrontation and oscillation between the center discrete path and the edge continuous potential field are eliminated, macro flow control is realized in a flexible and smooth manner, and the system robustness is greatly improved.
Owner:安徽云易智能技术有限公司

Displacement generating device for hydraulic direct-push drilling machine

The displacement generating device comprises a tetragonal machine body, a motor device, a hydraulic valve and an electric cabinet, and an oil outlet of a hydraulic pump is connected with a port P of the hydraulic valve; a cylindrical bulge, a central blind hole and a radial blind hole are respectively arranged on the lower surface of the machine body, radial, vertical and circumferential oil ducts are arranged in the machine body, a horizontal oil duct is connected with an air filter and a liquid level meter, and a communicating oil duct is arranged in the concave structure; the top cylinder body is connected with the cavity III; the bottom cylinder body is connected with the central blind hole to form a cavity II; the radial oil duct is communicated with the upper and lower blind holes to form a sealing cavity I filled with incompressible fluid; the radial blind holes in the bottom and the circumferential oil duct form a cavity IV which is communicated with a port B of the hydraulic valve; the hydraulic valve A port drives the cavity III to push the top piston rod, fluid is transferred to the bottom piston rod through the cavity I, and hydraulic oil in the cavity IV flows back to the cavity II through the T port. High-precision displacement synchronization is achieved through the incompressible fluid medium, and the positioning and sampling performance of the drilling machine is remarkably improved.
Owner:TIANJIN ENG MACHINERY INST

Generating downhole motor torque and RPM of a downhole motor with a drilling fluid having a compressible portion

A downhole motor control system may identify a downhole compressible density of a drilling fluid using a downhole temperature and a downhole pressure of the drilling fluid, the drilling fluid including an incompressible portion and a compressible portion, the drilling fluid flowing downhole with a downhole compressible flow component and an incompressible flow component. A downhole motor control system may determine the downhole compressible flow component using the downhole compressible density, a surface compressible density of the compressible portion at a surface location, and a surface compressible flow component of the compressible portion at the surface location. A downhole motor control system may identify a downhole compressible fraction of the drilling fluid based on the downhole compressible flow component and the incompressible flow component. A downhole motor control system may generate a composite flow rate of the drilling fluid based on the incompressible flow component and the downhole compressible fraction.
Owner:SCHLUMBERGER TECH CORP

Computer system for digitally simulating pseudo-incompressible fluid flow in a computer aided design model

Systems and methods for digitally simulating a fluid flow in a three-dimensional computer-aided design (CAD) model of a simulation space include digitally simulating movement of one or more digital particles representing the fluid from one or more first voxels in a mesh to one or more second voxels in the mesh, performing one or more interaction operations on the one or more digital particles at the one or more second voxels to determine a distribution of the one or more digital particles. A first quantity represented by the distribution of the one or more digital particles is based on a temperature and a pressure at the one or more second voxels and a reference fluid density. A second quantity represented by the distribution of the one or more digital particles is based on the reference fluid density, velocities of the one or more digital particles, and a mean fluid velocity.
Owner:DASSAULT SYSTEMS AMERICAS CORP

Actuating device for actuating vehicle function

The invention relates to an actuation device for actuating a vehicle function, comprising: a support device; a fluid pad assembly having at least one fluid pad protruding from the carrier device, the fluid pad including at least one resilient enclosure and a first volume having an incompressible fluid at least partially surrounded by the resilient enclosure; and at least one hydropneumatic accumulator fluidly connected to the first volume, the at least one elastic enclosure absorbing an actuation force of the driver's foot in multiple directions such that a deformation of the at least one elastic enclosure caused by the actuation force results in a reduction in the enclosed first volume and an increase in the internal pressure, the at least one sensor unit detects a deformation of the at least one elastic enclosure caused by the actuating force and forwards it to the at least one evaluation and control unit electrically coupled to the at least one sensor unit, and at least one control unit which generates at least one control signal for controlling the vehicle function as a function of a deformation of the elastic enclosure detected by the at least one sensor unit and caused by the actuating force.
Owner:ROBERT BOSCH GMBH

Asynchronous GMRES precondition method for AI acceleration of pressure Poisson equation in incompressible flow numerical calculation

The invention discloses an asynchronous GMRES precondition method for AI acceleration of a pressure Poisson equation in incompressible flow numerical calculation, and belongs to the field of computational fluid mechanics. Aiming at the calculation bottleneck of a traditional GMRES method when a pressure Poisson equation is solved, the method adopts an asynchronous parallel AI precondition framework, neural network training and flow field solving are decoupled, and concurrent execution is achieved. The solver thread performs real-time inference by using the current model, and provides high-quality initial guess; the weight is optimized in the background of the trainer thread, and the lagging is tolerated by using the flow field time coherence. Experimental results show that the method shortens the solving time by 67%-82% on the premise of ensuring convergence precision, and is suitable for large-scale fluid simulation.
Owner:SOUTHWEAT UNIV OF SCI & TECH

Method for analyzing dynamic modality and flow stability of flow field around double box girders

The invention discloses a method and a system for analyzing dynamic modality and flow stability of a flow field around a double-box girder, and belongs to the field of bridge engineering. The method comprises the following steps: firstly, establishing a double-box girder surrounding flow field model through computational fluid dynamics, and solving a momentum equation and a continuity equation of a two-dimensional incompressible flow; performing dynamic mode decomposition to obtain information such as characteristic values and characteristic modes; and finally, based on a linear stability theory, representing a flow field component as a sum of a steady-state solution and a disturbance term, substituting the sum into the equation to obtain a global linear flow stability equation, and analyzing the flow stability through discretization. The method can accurately extract modal features of each order, provides a scientific basis for double-box girder wind-induced vibration analysis, and has important application value. The method occupies few computing resources, is high in numerical precision, can be further expanded to a computing model with higher precision according to the computing resources, and is suitable for being applied to actual bridge engineering.
Owner:HARBIN INST OF TECH

A Temperature Field Simulation Method for the Roller Continuous Quenching Process Based on FLUENT

The present invention discloses a method for simulating the temperature field in the roll continuous quenching process based on FLUENT, which includes the following steps: clarify the process machine equipment parameters in the roll quenching process according to the roll speed of the quenching machine and the relevant parameters of each cooling section of the quenching machine; use FLUENT to perform finite element analysis on the jet impingement cooling process of the steel plate in each cooling section and the flow cooling process of the retained water on the upper surface of the steel plate, and analyze the internal surface heat transfer situation of the steel plate in this cooling section based on the basic principle of incompressible fluid flow and the fluid-thermal-solid coupling finite element method to obtain the heat transfer boundary conditions of the steel plate in this cooling section; conduct quenching experiments according to the quenching process parameters in each cooling section, verify the heat transfer boundary conditions obtained by FLUENT, and make corrections; write the surface heat transfer load of the steel plate according to the corrected surface heat transfer conditions to obtain the temperature field in the actual roll continuous quenching process. The present invention can effectively reduce the experimental cost on the premise of ensuring the simulation accuracy and can obtain more accurate temperature field data in the roll continuous quenching process.
Owner:NANJING IRON & STEEL CO LTD

Computer system for digital simulation of pseudo-incompressible fluid flow in computer-aided design model

A computer system for digital simulation of pseudo-incompressible fluid flow in a computer-aided design model is disclosed. Systems and methods for digital simulation of fluid flow in a three-dimensional computer-aided design (CAD) model of a simulation space include: digitally simulating movement of one or more digital particles representing a fluid from one or more first voxels in a grid to one or more second voxels in the grid; one or more interaction operations are performed on the one or more digital particles at the one or more second voxels to determine a distribution of the one or more digital particles. The first quantity represented by the distribution of the one or more digital particles is based on the temperature and pressure at the one or more second voxels and the reference fluid density. The second quantity represented by the distribution of the one or more digital particles is based on the reference fluid density, the velocity of the one or more digital particles, and the average fluid velocity.
Owner:DASSAULT SYSTEMS AMERICAS CORP

Shallow water wave ship pressure field model construction method and target judgment method

The invention provides a ship pressure field model construction method and a target judgment method in shallow water waves, which adopt an ideal incompressible fluid theory, establish a continuity equation and a momentum equation satisfied by ship navigation under a geodetic coordinate system, and introduce a disturbance velocity potential averaged along the depth based on shallow water assumption. Constructing a flow field control equation expressed by the disturbance velocity potential averaged along the depth by combining a water bottom boundary condition and a free surface boundary condition; setting intra-domain wave source making items according to the wave environment; setting a moving pressure item according to the ship type; substituting the intra-domain wave generation source item and the moving pressure item into the flow field control equation to simulate the water surface hull disturbance influence in the wave environment to obtain a ship pressure field control equation; and constructing a ship pressure field model based on the ship pressure field control equation in combination with the initial condition and the boundary condition of the flow field and the relational expression between the flow field pressure and the velocity potential. The method is suitable for rapid calculation of pressure fields in different environments, and the forecasting efficiency of ship pressure field signals is improved.
Owner:NAVAL UNIV OF ENG PLA

Method and system for using quantum incompressible fluid to achieve fusion from cavitation

Disclosed herein is a system for generating neutrons with thermal fusion, composition for use in the same, and method of using the same. The system comprises a crucible, the crucible having a quantum incompressible fluid and a gas bubble therein, a piston having an end submerged within the quantum incompressible fluid, and a controller coupled to the piston configured to drive the piston to generate an acoustic resonance in the quantum incompressible fluid.
Owner:RGT UNIV OF CALIFORNIA

Downhole power generation system

PendingAU2025222114A1MechanicsElectric generator
A downhole power generation system (10) comprising a pressure chamber assembly (12) having a first movable element (14, 48, 49) which at least partially encloses a first variable volume chamber (V1A) and a second movable element (16, 48', 49') which at least partially encloses a second variable volume chamber (V1B), each movable element (14, 48, 49, 16, 48', 49') having an exterior surface and an interior surface, and the first and second variable volume chambers (V1A, V1B) being connected by a conduit (18) so that they together enclose a closed volume (V1) containing an incompressible fluid, the conduit (18) providing a path for flow of the incompressible fluid between the first variable volume chamber (V1A) and the second variable volume chamber (V1B) when the first and second movable elements (14, 48, 49, 16, 48', 49') move so that one of the first or second variable volume chamber (V1A, V1B) contracts and the other expands, the system further comprising a generator device (20) which is located in the conduit (18), and which is configured to use the flow of incompressible fluid along the conduit (18) to generate power.
Owner:INTERWELL NORWAY AS

Propeller hydrodynamic force rapid estimation method, device, equipment and medium

The invention provides a propeller hydrodynamic force rapid estimation method, device, equipment and medium, and the method comprises the steps: adopting a plurality of curved surfaces which are coaxial with a propeller and have different radiuses, cutting a single blade profile of a three-dimensional geometric model of the propeller, and forming blade sections with different radiuses, obtaining a group of quasi two-dimensional curved surface calculation models; performing rapid grid division on each quasi-two-dimensional curved surface calculation area containing the propeller tangent plane, and setting a flow field boundary condition and a flow field initial condition for the divided calculation area; on the basis of set conditions, an incompressible flow pressure correction method is adopted for unsteady numerical calculation, and axial force and circumferential force borne by the curved surface airfoil profile in each divided calculation area under different working conditions are obtained through solving; based on different cross section positions and axial force and circumferential force on each cross section, total thrust and total torque borne by blades of the propeller thruster are calculated through radial integral approximation, so that the problems that mutual influence of flow fields in complex thruster design is difficult to evaluate, and efficiency and precision of a traditional method are unbalanced are solved.
Owner:CHINA ACAD OF AEROSPACE AERODYNAMICS

Fluid-structure interaction method for simulating autonomous swimming of flexible organisms based on improved immersed boundary method

The application discloses a flow-solid coupling method for simulating autonomous swimming of flexible organisms based on an improved immersed boundary method, and the method comprises the following steps: A, initial parameters are specified at each interface; B, a distribution technique is used to divide the control equation of the immersed boundary-lattice Boltzmann flux solver into a prediction step and a correction step; C, in the prediction step, the intermediate flow field velocity is solved by using the lattice Boltzmann flux solver; D, in the correction step, the intermediate flow field velocity is corrected by using the improved boundary condition forced immersed boundary method to obtain a new flow field velocity; E, if the simulation time is reached, the whole simulation process is ended, and if the simulation time is not reached, the step B is returned to. The flow-solid coupling method can meet the non-slip boundary condition, does not cause the non-physical flow line penetration phenomenon, and eliminates the complicated matrix solving process, so that a large amount of calculation cost can be saved, and the method is suitable for three-dimensional incompressible flow simulation of immersed objects.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS

Power support unit for a movable flap

The invention relates to a power support unit (100) for a movable flap (110), in particular for a vehicle flap, with at least one pivotally connected adjusting element (120), wherein the adjusting element (120) has a working chamber (130) filled with a fluid and at least one piston rod (140) which partially penetrates the working chamber (130) as well as a guide and sealing package (160) arranged at a first end (122) of the adjusting element (120) and sealing the adjusting element (120). According to the invention, the working chamber (130) is completely filled with an incompressible fluid and a spring chamber (180) is provided, which is sealed and separated from the working chamber (130) by means of a separating element (200) which is movable in the adjusting element (120), in which a spring element (190) is arranged to pressurize the separating element (200) in such a way that the piston rod (140) can be extended, wherein the spring element (190) is provided as a mechanical spring element and / or as a pressurized gas filling. The invention further relates to an adjustment device for a movable flap (110), in particular for a vehicle flap, with a power support unit (100) and a further adjustment element (330).
Owner:STABILUS GMBH

Electronically adjustable sway bar link

This invention pertains to sway bar systems, and a method of controlling their operation. Specifically, the present invention relates to provide a way of adjusting the response characteristics of a sway bar system by changing the structure of the typical sway bar links and regulating the modified structure by utilizing an electronically adjustable sway bar link. Said electronically adjustable sway bar link comprises a twin tube cylinder filled with mixed incompressible fluid and pressurized gas and forms a determined volume in order to host pressurized gas higher than fluid flow regulation functions, permitting a directional control valve to always remain fully submerged in incompressible fluid and to modify the fluid path between each tube of said twin tube cylinder, allowing closed or opened fluid flow operation, determined by a controlling device receiving an electronic input and piloting said directional control valve.
Owner:SUSPENSION DIRECT INC

Methods, apparatus, media, and systems for computing locally compressible flow in low-speed flow fields

The application discloses a kind of method, equipment, medium and system for calculating local compressible flow in low-speed flow field, belong to the field of computational fluid dynamics, comprising the following steps: in the process of calculating local compressible flow in low-speed flow field, different algorithms are used to process by grid velocity determination;When the speed in the grid is less than the set value one, the incompressible pressure correction equation is solved;When the speed is between the set value one and the set value two, the compressible pressure correction equation is solved, and the interface density correction calculation result is calculated by linear interpolation method;When the grid speed is greater than the set value two, the compressible pressure correction equation is solved.The present application can obtain more accurate low-speed flow field and local compressible flow field, and is suitable for calculating local incompressible flow field.
Owner:CALCULATION AERODYNAMICS INST CHINA AERODYNAMICS RES & DEV CENT

Flexible coating for suppressing underwater bubble jet load and method of manufacture

The application discloses a flexible cover layer for inhibiting underwater bubble jet load and a manufacturing method thereof, and comprises a flexible cover layer, a rubber outer layer and a closed-cell foam sandwich layer; the rubber outer layer and the closed-cell foam sandwich layer are pasted to form the flexible cover layer; the other side of the closed-cell foam sandwich layer is pasted to a cabin wall or a side plate of an underwater vehicle; the rubber outer layer supports and protects the closed-cell foam sandwich layer, and prevents the closed-cell foam sandwich layer from being torn under the action of explosion impact due to the thin single foam wall; the manufacturing method comprises the following steps: obtaining material parameters through experiments, obtaining explosion load information through a scaled-down experiment; presetting the thickness of each layer, coupling numerical solutions of compressible fluid models and incompressible fluid models with a finite element structure model, performing finite element numerical calculation, optimizing the structure thickness according to the finite element calculation result, and manufacturing the flexible cover layer according to the thickness. The application has the advantages of better absorbing shock wave energy generated by underwater explosion and inhibiting and blocking the impact of high-speed bubble jet load.
Owner:BEIJING INST OF TECH

Apparatus constrainable to a diver for buoyancy control

An apparatus constrainable to a diver, including a buoyancy control system for a diver including: —a rigid means which identifies an operating zone; the operating zone being intended to receive a gas and an incompressible liquid; the zone being defined by a first chamber or by the sum of at least a first and a second chamber; —a first means for introducing the incompressible fluid into the operating zone; —a first means for introducing the gas into the operating zone; —a pressurised tank of the gas, the first means for introducing the gas being operatively interposed between the tank and the operating zone; —a means for evacuating a fluid from the operating zone, the fluid being the gas and / or the incompressible liquid.
Owner:HEAD WATERSPORTS SPA

A method for predicting grouting slurry diffusion range in coal seam floor area

The application provides a method for predicting the grouting slurry diffusion range of a coal seam floor area, comprising: obtaining a slurry water displacement model containing minefield stratum parameters and grouting borehole parameters of the coal seam floor area; obtaining a Brinkman equation for describing the incompressible fluid flow caused by reinforcing materials in a porous medium based on the Navier-Stokes equation and the Darcy law; wherein the Brinkman equation contains a viscosity term and a pressure gradient term; taking the grouting pressure, slurry density, dynamic viscosity, porous medium permeability, and porous medium porosity as the influencing factors of slurry diffusion, and obtaining various parameter combinations of each influencing factor and level; using the various parameter combinations, simulating the slurry diffusion process based on the slurry water displacement model by using the Brinkman equation, to obtain the optimal parameter combination and the corresponding slurry diffusion range. The method can scientifically and accurately predict the slurry diffusion range, and improve the consistency and reliability of the grouting treatment effect.
Owner:HEBEI UNIV OF ENG