100 results about "Mechanics of fluids" patented technology

A collection system and method for various uses including the efficient collection of leaves. The system includes a specially designed chute element and an attachable draw-string type of plastic bag. The bag unit has plural perforations formed therein to provide for an equalization of air pressure and resultant ease of placement of collected items into the bag. The invention incorporates fluid mechanics principles related to air flow and air pressure equalization.

The invention provides a parameter calculation method, a system, a readable storage medium and a computer device. The method comprises: processing blood vessel images to obtain pixel-based preliminarysegmentation of an aorta and a coronary artery respectively; The centerline of aorta is extracted from the pixel segmentation of aorta, and the smooth contour curve of aorta is calculated along the centerline of aorta. The centerline of coronary artery is extracted from the pixel segmentation of coronary artery, and the smooth contour curve of coronary artery is calculated along the centerline ofcoronary artery. According to the centerline and contour curve, the three-dimensional models of aorta and coronary artery were established and combined to obtain the three-dimensional model of bloodvessel. The three-dimensional model of blood vessel is gridded to obtain the model grid information. According to the grid information of the model, the hydrodynamic equations are solved to obtain thehemodynamic parameters. The parameter calculation method of the invention has a complete blood vessel modeling system and a parameter calculation system with wide applicability, and the precision andthe universality are improved.

The invention discloses a multifunctional fluid mechanics experimental device. The multifunctional fluid mechanics experimental device comprises a water source, a reynolds experiment pipe, a Bernoulli experiment pipe, an on-way resistance pipe, a local resistance pipe, a valve local resistance measuring pipe, a pitot pipe, a Venturi meter, an orifice plate flowmeter, a piezometer pipe, a measuring groove, selection valves and adjusting valves; the reynolds experiment pipe, the Bernoulli experiment pipe, the on-way resistance pipe, the local resistance pipe, the valve local resistance measuring pipe, the Bernoulli experiment pipe, the venture meter and the orifice plate flowmeter form into six testing pipe sections in a parallel mode; the selection valves are installed at inlet sections of the experiment pipe sections; the inlet sections of the experiment pipe sections are connected with a water source through the selection valves; the adjusting valves are installed at outlet sections of the experiment pipes; the outlet sections of the experiment pipes are connected with the measuring groove through the adjusting valves. According to the multifunctional fluid mechanics experimental device, the separated experiment pipelines are integrated in one experiment device, frequent assembling and disassembling is avoided, leakage is reduced, the experiment pipelines are clear at a glance and not easy to mix, and user understanding of the experimental principle is facilitated.

The invention relates to a hemodynamic parameter calculation method and system and an electronic device. The method comprises the following steps of A carrying out preliminary blood vessel segmentation on an original medical image; B extracting a blood vessel center line according to the preliminary blood vessel segmentation result; C calculating a blood vessel contour on a vertical plane along the blood vessel center line; D generating a three-dimensional model of the blood vessel at the intermediate difference value of the blood vessel contour; E gridding the three-dimensional model of the blood vessel to obtain model grid information; F quantifying fluid simulation parameters; and G solving a fluid mechanics equation according to the model grid information and the fluid simulation parameters to obtain the hemodynamic parameters. Compared with the prior art, the application has a complete blood vessel modeling system and a parameter calculation system, by which errors can be greatlyreduced compared with the prior art, and the precision and universality of blood vessel dynamics parameter calculation are integrally improved.

The invention relates to the field of non-contact flow field measurement in experimental fluid mechanics, in particular to a method and device for synchronous testing of fluid flowing and solid motioninformation based on PIV and PTV technologies. On the basis of coupling of the particle image velocimetry (PIV) technology and particle tracking velocimetry (PTV) technology, a tracer particle with the minimum scale is used for replacing and marking a fluid mass point in a liquid flow field; a boundary of solid and liquid intersection is marked by a rhodamine reagent; a high-speed camera is usedfor recording a motion track of the marked fluid mass point and a motion track of a marked object boundary under irradiation of laser with the wavelength of 532nm, so that the flowing information of aflow field and motion information of an object are obtained simultaneously in one test. Therefore, a data measuring error between repeated testing is avoided; and the test workload and cost are reduced.

The invention provides a noninvasive portal vein hemodynamic parameter measuring method which includes the steps of firstly, using a thin-section CT image to build a three-dimensional geometric model of a liver portal vein; secondly, using the finite element analyzing method of hydromechanics calculating software ANSYS to perform meshing on the geometric model and build a three-dimensional mathematic model; thirdly, calculating the hemodynamic parameter of the portal vein in an analog manner to obtain a speed and pressure distribution effect picture. The method is safe, noninvasive, simple to operate, visualized, quantized and high in accuracy, and the effective model is built for scientific researches and clinic services.

The invention discloses a Gobi integrated environment wind tunnel simulation device applied to the field of environment wind tunnel simulation equipment. The Gobi integrated environment wind tunnel simulation device comprises a power segment, a snow segment and a test segment arranged in sequence; a fan is arranged in the power segment; a snow generator is arranged in the snow segment; a sand generator is arranged at an entry of the test segment; the lower wall of the test segment is provided with a rotary table that bears an experimental model; the upper wall of the test segment is provided with a rainfall device and a plurality of solar radiation lamps. Much of current environment wind tunnel experimental devices refer to fluid mechanics researches in the aircraft or aerospace field, andthere are scarcely no simulation devices for Gobi integrated environment wind tunnels. As Gobi is a terrain of certain converge in the territory of China, simulation researches on Gobi integrated environments are of significant practical guidance on running and flight of automobiles and unmanned aerial vehicles in Gobi. The Gobi integrated environment wind tunnel simulation device can function tosimulate Gobi experiencing sandstorm, blizzard, windstorm and high-solar-irradiation environments.

The invention discloses a small-flow ultrasonic flowmeter error estimation method based on flow lines, and belongs to the technical field of ultrasonic flowmeter design and error analysis. The method comprises the steps that a three-dimensional model of a flowmeter is built according to the actual structure of the low-speed micro-flow flowmeter; the flow field distribution of a flow channel is obtained through CFD software, the fluid backflow state and flow line distribution considering the influence of a transducer are generated, and a backflow length is calculated; the metering error of the flowmeter is analyzed according to revised speed difference method power correction factors and a matching expression. The error estimation method for the low-speed micro-flow flowmeter, especially a small-diameter single-track ultrasonic flowmeter, is built on the basis of the fluid mechanics theory and the CFD technology, the expression of the power correction factors is matched, and the foundation is laid for further improving the measuring accuracy of the flowmeter and expanding engineering application.

The invention relates to a method for inverting the mass concentration of atmospheric particulates based on the flight time of the particulates. The mass concentration of the particulates can be inverted according to the flight speed and the sampling flow on the basis of an aerodynamic particulate spectrometer. According to the work principle of the aerodynamic particulate spectrometer, the particulates with different particle sizes have only speed up at any one point on an airflow track after the particulates pass through an accelerating nozzle, so the flight speed of particles can be obtained through the flight time. The relationship between the flight speed and the mass of the particles can be obtained according to a momentum conservation theorem and aerodynamic and hydromechanical principles, so the mass concentration of the particulates can be inverted through the flight speed and the sampling flow. The method provided by the invention can be used for inverting the mass concentration of the atmospheric particulates according to the dynamic feature of the particulates and provides an inversion algorithm capable of measuring the mass concentration of the atmospheric particulates accurately, in real time and on line.

The application discloses a blood vessel blood flow simulation method based on a mechanics equation, a blood flow simulation device, and a computer readable storage medium. The method comprises: acquiring feature data of a blood vessel; constructing a three-dimensional model of the blood vessel according to the feature data and carrying out three-dimensional model definition of a calculation area;carrying out discretization processing on the calculation area to generate a grid depicting the calculation area; constructing a physical mathematical model including a fully coupled fluid mechanicsgoverning equation and a solid mechanics governing equation, of the calculation area; on the basis of the grid, calculating the physical mathematical model and acquiring blood flow parameters and blood vessel parameters of the calculation area; and calculating change parameters of the grid based on the blood vessel parameters and thus updating the calculation area. Therefore, accurate and efficient simulation of the blood flow in a blood vessel is realized.

The invention relates to a method for simulating a high-speed rail subgrade grouting microscopic mechanism based on fluid particle coupling, which comprises the following steps: step S10, establishinga simplified model of a subgrade, dividing grids, and establishing a fluid phase control equation; S20, acting the fluid on the particles, and carrying out stress calculation; Step S30, acting on theparticles, and updating information such as speed and position of the particles according to the Newton's second law: the soil particles are solved by applying the Newton's second law according to the relationship between force and displacement; and S40, inputting the updated particle speed, position and other information into the CFD, and continuing the next step of calculation. According to theinvention, a computational fluid mechanics and particle mechanics coupling calculation mode is introduced into grouting research; in previous studies, a single particle is generally adopted to simulate a soil body, a function is applied to simulate grout, the whole grouting process cannot be accurately simulated, and the method overcomes the defect that the function is used to simulate the grout,and improves the accuracy of numerical simulation grouting.

The invention discloses a three-dimensional flow thermal coupling modeling method for a cement grate cooler. The modeling method takes a cement clinker layer in the grate cooler as a porous medium, applies a mechanics of fluid through porous media theory for modeling, and comprises the following steps: building a three-dimensional flow thermal coupling physical model of the cement grate cooler according to the cooling condition of the clinker in the grate cooler; building a three-dimensional flow thermal coupling mathematical model of the grate cooler according to the physical model, the law of mass conservation, the law of conservation of momentum and the law of conservation of energy. The modeling method has the benefits that the factors of grate speed, supplied wind velocity, side wall heat dissipation, feeding temperature, clinker particle diameter, and the like are considered; the three-dimensional temperature distribution of the clinker can be calculated conveniently and accurately; different cooling strategies are simulated by adjusting the working condition parameters, so as to obtain an optimal strategy enabling the grate cooler to work efficiently and reasonably, improve the heat recovery efficiency of the grate cooler, and achieve the purposes of energy conservation and emission reduction; the modeling method is the optimal clinker cooling strategy applied to confirm that the discharging temperature of the grate cooler is relatively low, and the recovery wind warm is relatively high.

The invention discloses a nonlinear unsteady aerodynamic force order reduction method based on computational fluid mechanics. The nonlinear unsteady aerodynamic force order reduction method is used for solving the technical problem that an existing linear unsteady aerodynamic force order reduction method based on computational fluid mechanics is poor in precision. According to the technical scheme, a linear part of a nonlinear reduced-order model is obtained based on a Volterra series theory and a system minimum feature implementation algorithm; obtaining a nonlinear part of the nonlinear reduced-order model through an output error minimization process. Compared with the linear reduction model based on Volterra series in the background technology, the method has the advantages that the more accurate aeroelastic response can be predicted and obtained, and the second-order Volterra kernel function does not need to be identified, so that the calculation cost is reduced, and the calculation precision is improved. In addition, the model keeps a simple form, and can be conveniently applied to engineering practice.

The invention relates to a sensor, the device and use for sewage flux detection. It is used for the water flux auto-detection, control and management in the city environment protection, mine, metallurgy, constructing material, electric power and chemical industry. The device is made up of the open-channel flux slot and the board intelligent sensor. The open-channel flux slot is designed according to the open-channel hydrodynamics Bernoulli's theory. The board intelligent sensor is divided into two parts: one part is signal detection part; the other is intelligent data processing part and the wireless data transforming part. The detection signal is not been influence by the temperature and pressure. It is convenience to be installed, used and maintained. It is proper for the flux meter of the wild open-channel and the cloacae out.

The invention discloses a visual description method for a plane streamline of a heart flow field. The method comprises the following steps: extracting blood flow velocity component within a two-dimensional observing plane in an acoustic beam direction on the basis of two-dimensional color Doppler ultrasound image information; through calculating a Doppler flow function and a Doppler flow distance function of a two-dimensional detection plane flow field, representing three-dimensional flowing by using a point source and a point sink; quantizing the Doppler flow distance function by using unit flow q; determining positions of the point source and the point sink according to a quantizing result and a Doppler blood flow velocity distribution situation; respectively using the point source and the point sink as a starting point and an end point of a plane streamline; and connecting the corresponding starting point and the end point according to a principle that flow function values of plane flows are equal to each other, so as to draw the plane streamline. Through the adoption of the visual description method disclosed by the invention, the motion state of the heart flow field within the detection plane can be effectively described in a visual way and solid basis is laid for effective visual observation and accurate quantitative evaluation of fluid kinetic status of the heart flow field.

The invention relates to the technical field of fluid mechanics, and provides a new method for analyzing a pipeline water hammer, a water hammer equation under a moving coordinate system is solved, and simulation of a water hammer phenomenon in a pipeline is achieved. Meanwhile, the pipeline water hammer problem can be more conveniently simulated on the premise that the numerical precision is met.Therefore, the technical scheme adopted by the invention is as follows: the method comprises the following steps: step 1, initialization: initializing related variables, particles and upstream and downstream virtual particle information; step 2, listing a solving equation and performing iterative computation; and step 3, outputting a result. The method is mainly applied to fluid mechanics engineering design occasions.

The invention discloses a valve body structure optimization method based on eddy current distribution, which comprises the following steps of: firstly, performing three-dimensional modeling according to a design file of a valve, establishing a complete valve entity model, and establishing a valve internal flow channel model by extracting a flow channel of the valve; calculating a flow field in the valve by utilizing computational fluid mechanics software through mesh generation and a numerical simulation method; through post-processing of a calculation result, visualizing of a valve body flow field to determine eddy current distribution in the valve; through quantitative definition of characteristic parameters of a valve body flow channel and optimization of structural parameters, achieving the effects of eliminating vortexes and improving the flow capacity. The eddy current in the valve can be optimized and eliminated, the flow capacity of the valve is improved, tedious and complex theoretical calculation and experimental correction are avoided, the design process of the valve body is greatly simplified, and a new thought is provided for eliminating the eddy current in the valve and improving the flow capacity of the valve.

The invention relates to the field of fluid mechanics. A method for reducing the water hammer effect comprises the steps that bypass water channels (1-1) of a Tesla valve are integrated to two sides of a main channel (1), and the fluid direction of a fluid channel is the high-resistance direction of a Tesla valve structure; a bypass valve (2-1) is designed on the bypass water channel (1-1), and amain valve (3) is designed on the main channel (1); when the main channel (1) works, the main valve (3) is opened and the bypass valve (2-1) is closed; and when the main channel (1) needs to be closed, the bypass valve (2-1) is closed firstly, the flow speed of the fluid channel is reduced, and then the main valve (3) is closed. A liquid flow shutoff system comprises the main channel (1), the bypass water channel (1-1), the main valve (3) and the bypass valve (2-1). In a water conservancy project, the method for reducing the water hammer effect is adopted to reduce the water hammer effect. According to the method, the system and the water conservancy project, the structure is simple, the cost is low, the time can be saved, the loss is reduced, the service lifetime is long, the promotion iseasy, and a new technical thought is provided.

The invention discloses a volute molded line generation method of a centrifugal fan. The method comprises the following steps that 1, a basic molded line is obtained according to a logarithm spiral line equation, wherein Q is the design flow of a volute, R2 is the radius of a volute base circle, c '< 2 > u is the tangential component velocity of a limited blade under the actual condition, and theta is the polar angle; the method is characterized by further comprising the following steps that (2) a basic molded line R = R2emtheta is obtained; and 3) increasing the radius of the base circle and/or changing m so as to increase the volute tongue gap of the volute to obtain the volute molded line. Compared with the prior art, the method has the advantages that by increasing the radius of the base circle of the volute molded line or changing m, the overall width can be kept unchanged to guarantee flow while the volute tongue gap is increased and noise is reduced, a section of smooth transition curve is generated on the basis of an original spiral line by combining fluid mechanics knowledge and a volute design theory and tightly combining with reality, and a flow field is smooth.