149 results about "Energy equation" patented technology

The invention discloses a method and a system for simulating bubble motion in transformer oil by considering multi-physics field coupling, and the method comprises the steps: fusing an energy equation into a mass conservation and momentum conservation equation, and constructing a multi-physics field model which considers the coupling of an electric field, a thermal field and a flow field; introducing a k-epsilon turbulence model into the multi-physics field model to obtain a first optimized multi-physics field model; the k-epsilon turbulence model is an oil flow model in a large transformer; introducing a phase field method into the first optimized multi-physics field model to obtain a second optimized multi-physics field model; various forces of bubble motion are introduced into the second optimized multi-physics field model, and a third optimized multi-physics field model is obtained; and performing parameter solving on the third optimized multi-physical field model to obtain the movement process of the bubbles in the transformer oil. According to the invention, a multi-physical field model considering coupling of an electric field, a thermal field and a flow field is constructed, and comprehensive and accurate simulation of bubble motion in transformer oil is realized.

The invention discloses a heat transfer calculation method for an interval capillary core pulsating heat pipe, which comprises the following steps of: constructing a relational expression of steam bomb temperature and pressure, and calculating the steam bomb pressure; constructing a liquid bomb energy equation, and calculating a liquid bomb temperature initial value; constructing an interval capillary core pulsating heat pipe liquid elastic momentum equation, and calculating liquid elastic displacement; constructing different pipe section liquid film length calculation formulas, and calculating different pipe section liquid film lengths; the heat transfer amount of liquid film evaporation and condensation is obtained, and the corresponding mass variation of the steam bomb is calculated; obtaining a relational expression of mass flow and pressure of the steam bomb, and calculating to obtain a new pressure value of the steam bomb; constructing a relational expression between the temperature and the pressure of the steam bomb, and obtaining a new value of the temperature of the steam bomb; constructing a liquid bomb energy equation, obtaining a new liquid bomb temperature value, and carrying out comparison iteration; obtaining sensible heat transferred in and out of the liquid bomb, and calculating the thermal resistance of the pulsating heat pipe; and outputting the calculation result to complete the calculation of the heat transfer model. The method provides guidance for design and development of the pulsating heat pipe covering the capillary cores at intervals.

The invention discloses a supercritical carbon dioxide pipeline transportation simulation method and device. The method comprises the following steps: acquiring physical property data of the supercritical carbon dioxide pipeline; correcting the unit of the physical property data; obtaining a preset steady-state calculation formula; correcting a partial derivative formula in the preset steady-state calculation formula to obtain a corrected steady-state calculation formula; and inputting the physical property data after unit correction into the corrected steady-state calculation formula, and carrying out steady-state calculation so as to realize static simulation of supercritical carbon dioxide pipeline transportation. According to the scheme provided by the invention, by correcting the physical property unit in the steady-state calculation formula and correcting the partial derivative formula of the unit mass flow rate of the energy equation part in the steady-state calculation formula on the fixed distance, the correctness of steady-state data of supercritical carbon dioxide during pipeline transportation is ensured.

The invention discloses a construction method of an underground heat exchange model of a U-shaped middle-deep layer buried pipe. The construction method comprises the steps of collecting monitoring data of underground heat exchange of a preset buried pipe, preprocessing the monitoring data, and constructing a physical model of the underground heat exchange of the U-shaped middle-deep layer buried pipe based on the monitoring data; soil temperature distribution and wall temperature are obtained based on the physical model according to the heat transfer process outside the drill hole, and the water temperature at the next moment is obtained based on an energy equation of circulating fluid according to the heat transfer process inside the drill hole; performing underground temperature field evolution simulation analysis on the basis of the mathematical model of the soil temperature distribution, the wall temperature and the water temperature at the next moment to obtain simulation data, and constructing a U-shaped medium-deep buried pipe underground heat exchange model on the basis of underground temperature field evolution simulation; time sequence deviation analysis is conducted on the simulation data and the monitoring data to obtain time deviation data, the U-shaped middle-deep layer buried pipe underground heat exchange model is optimized according to the time deviation data, and a target model is output.

The invention belongs to the technical field of battery energy storage, and discloses a simulation analysis method for heat dissipation of a battery energy storage system, which comprises the following steps of: establishing a three-dimensional model and a three-dimensional simulation model of a heat dissipation module of the energy storage system; establishing finite element simulation models of the liquid cooling plate and the battery module; establishing a two-fluid heat dissipation finite element simulation model comprising an air flow field and a liquid flow field; setting boundary conditions, and performing grid division in fluid simulation software; starting an energy equation in fluid simulation software, and calculating and extracting an air flow field of the energy storage system and a battery module temperature distribution cloud picture by adopting a turbulence model; three-dimensional simulation updating is conducted on the heat dissipation module of the energy storage system, and the arrangement structure of a cooling liquid inlet and a cooling liquid outlet and the structure of an air outlet are changed; and re-extracting the calculation result. According to the method, an electrochemical energy storage system finite element model combining an air cooling heat dissipation system and a liquid cooling heat dissipation system is constructed, so that the diversified requirements of energy storage devices of different scales in practical application are better met.

The invention discloses a phase change sweating cooling non-equilibrium flow heat transfer numerical simulation method which comprises the following steps: after initialization assignment, obtaining physical property parameters of a liquid phase and a gas phase according to a fluid temperature, and calculating a mixing density, a hybrid viscosity, a mixing enthalpy, a convection term coefficient and a diffusion term coefficient; boundary conditions are given to the cooling fluid continuity equation, the cooling fluid momentum equation, the cooling fluid energy equation and the porous framework energy equation; solving a cooling fluid continuity equation and a cooling fluid momentum equation; various items in a cooling fluid energy equation and a porous skeleton energy equation are divided into an unsteady state item, a convection item, a diffusion item and a source item, the four items are expressed by compiling a UDF function and then loaded into a UDS equation in FLUENT, new mixing speed, new mixing pressure intensity, new mixing enthalpy and new solid phase temperature are solved, and the optimal mixing speed, the optimal mixing enthalpy and the optimal solid phase temperature are obtained. The difference value between the initial value and the corresponding initial value in the iteration is judged, if the requirement is met, calculation can be ended, and if not, iteration is conducted again after the solid phase temperature and the fluid saturation are updated.

The invention relates to the technical field of computational fluid mechanics and combustion science, in particular to a flame surface simulation method and device for supersonic combustion, and the method comprises the steps: solving a continuity equation, a momentum equation, a mixing fraction equation and an energy equation in a supersonic cold state mixing process; obtaining a mixing fraction distribution, a pressure distribution and a mixture total internal energy distribution; calculating a one-dimensional flame to construct a four-dimensional table of at least one mixing fraction-progress variable-oxidant side total internal energy-pressure based on the one-dimensional flame; and acquiring progress variable information of the supersonic combustion based on the four-dimensional table to obtain a flame surface simulation result of the supersonic combustion. According to the method, two control variables of pressure and oxidant side total internal energy can be introduced on the basis of a traditional small flame model according to the characteristics of supersonic combustion, and an Euler random field method is introduced to describe a joint probability density distribution function between the control variables, so that the influence of a preset probability density function is reduced, and the calculation precision is improved.

The invention discloses a method for designing a high-uniformity Fresnel lens with equal-width receiving areas, which comprises the following steps of: dividing a receiving surface of the Fresnel lens into a plurality of receiving areas with equal width, and establishing an energy equation of each receiving area and the Fresnel lens; based on the energy equation and a preset condensation ratio, determining the number of ring teeth of the Fresnel lens corresponding to each receiving area; determining a critical value of the ring tooth inclination angle of the Fresnel lens, and determining the focal length of the Fresnel lens according to the critical value of the ring tooth inclination angle; and designing a lens generatrix, and obtaining a size parameter of each ring tooth in the Fresnel lens corresponding to each receiving area. According to the invention, equal energy density distribution on the receiving surface is taken as a design idea, and the receiving surface is divided into a plurality of receiving areas with the same width so as to design parameters of each ring tooth of the Fresnel lens, so that high-uniformity distribution of energy density is realized, and the problem of non-uniform energy distribution on the receiving surface after condensation of the Fresnel lens is solved.

The invention discloses a three-dimensional fire modeling method based on a lattice Boltzmann method, and the method comprises the following steps: building a fire model which comprises a calculation module and a self-adaptive mesh refinement module, the calculation module comprises a lattice Boltzmann flow module, a buoyancy driving module, a combustion module based on gradient dynamic triggering, an energy equation module, a flue gas transportation module containing particle sedimentation and visibility calculation, and a multi-component transportation module. According to the fire modeling method based on the lattice Boltzmann method, LBM flow field data serves as core drive and is transmitted to the combustion module, the flue gas transportation module and the multi-component transportation module in real time, accurate convection and diffusion information is provided, meanwhile, the self-adaptive grid refining module dynamically adjusts the grid resolution according to the gradient of key physical quantities, and therefore the fire modeling accuracy is improved. The accuracy can be ensured, the calculation amount is reduced, and the calculation speed is increased. And the prediction precision, robustness and real fire complexity capturing capability of the model are obviously improved.

The invention discloses a heavy gas signal verification method based on double-floating-ball gas relay baffle stress. The heavy gas signal verification method comprises the following steps that a double-floating-ball gas relay heavy gas signal response platform is built; establishing a simulation model according to the structural parameters and material data of the gas relay in the step 2; compiling a stress analysis model of the double-floating-ball gas relay by using UDF, importing FLUENT software, and simulating the motion characteristics of the baffle by using a dynamic grid method; starting an energy equation and an SST k-omega turbulence model in sequence; setting numerical calculation parameters including physical parameters of the insulating oil, boundary conditions, a solving method and solving precision; simulating and calculating the stress corresponding to the baffle plate at the heavy gas action moment of the gas relay according to the action of different excitation pressure intensities, and judging whether the stress corresponding to the baffle plate at the heavy gas action moment measured by the test and simulation accords with each other or not; the invention provides a powerful tool for optimizing the design of the gas relay and improving the safe operation of the transformer.

The invention relates to a mountain river flood dynamic rehearsal method, device and equipment based on big data fusion and a medium. The method comprises the following steps: acquiring a multi-source fusion data set of a target mountain river; based on the multi-source fusion data set, recognizing the flood type of the target mountain river in combination with a preset threshold rule to obtain the flood type and cause parameters; according to the flood type and the cause parameter, calculating a design flood peak flow value of each node in the target mountain river; according to each design flood peak flow value, performing section-by-section trial calculation through an energy equation to obtain a design flood surface line; and performing dynamic simulation processing on the flood routing process of the target mountain river based on the designed flood water surface line, and generating a flood routing dynamic simulation report of the target mountain river. The method can accurately adapt to the characteristics of diverse causes and complex propagation process of flood in a mountain river, and remarkably improves the refinement degree and reliability of flood rehearsal.

The invention provides a high-filling particle viscous fluid mixed heat generation and transfer multi-scale simulation method and system, and belongs to the technical field of multiphase flow numerical simulation and heat transfer and friction heat generation coupling calculation. A uniform flow-heat generation-heat transfer coupling solution is constructed under a double-fluid model and a KTGF framework; a drag force model more suitable for a dense particle system is introduced in an interphase momentum exchange link; a BVK drag force model is adopted, and dynamic calculation of an interphase exchange coefficient is realized in a solver through a user-defined function; therefore, the prediction consistency of the solid-phase volume fraction distribution and the relative slip velocity under the high filling condition is improved; particle phase dissipation heat generation, solid-liquid interface friction heat generation and particle-wall surface friction heat generation are introduced as controllable heat source items, and are coupled to a liquid phase and particle phase energy equation according to a set heat distribution coefficient, so that the problem that friction related heat sources are difficult to accurately characterize when only software built-in options are relied on is solved.

The invention discloses an efficiency evaluation method and system based on unsteady flow heat exchange numerical simulation, and the method comprises the steps: a), carrying out the discretization solving of an incompressible Navier-Stokes equation through a single-step time marching algorithm STA, and obtaining an instantaneous flow field; b) on the basis of the instantaneous flow field obtained in the step a), a turbulence model is adopted, turbulence energy k and a turbulence dissipation rate epsilon are updated through single iteration of an STA algorithm, and turbulence viscosity is obtained through calculation; c) utilizing the instantaneous flow field in the step a) and the turbulence viscosity in the step b) to solve an energy equation through single iteration of an STA algorithm, and simulating heat conduction and convective heat transfer phenomena in the fluid to obtain a temperature field; and d) based on the instantaneous flow field, the turbulence viscosity and the temperature field in the steps a) to c), numerical simulation is carried out by controlling the time step delta t and the grid error to meet CFL conditions, and an efficiency evaluation result is obtained. According to the method, the calculation efficiency is greatly improved, and the calculation process of transient flow can be optimized on the premise of ensuring high precision.

The invention relates to the technical field of mold temperature optimization design, and discloses a mold temperature optimization design method for a VARI process mold filling stage. The method comprises the following steps: establishing a mathematical model containing resin viscosity, curing reaction and an energy equation; establishing a finite element model based on the geometric dimension of the part; setting the initial temperature of the mold to be the room temperature of 25 DEG C, and tracking the viscosity and curing degree change; obtaining low viscosity time and gelation time of the resin; calculating the mold filling time and comparing the mold filling time with the former two; and judging whether the current temperature meets the condition that the mold filling time is less than two key times, and if not, adjusting the temperature and repeatedly calculating. According to the method, the mathematical model comprehensively considering the dynamic factors is established, and the numerical simulation and optimization algorithm is combined, so that rapid optimization design of the mold temperature of workpieces with different shapes and sizes is realized, and the success rate of the VARI process and the quality of the workpieces are improved.

The present disclosure relates to a method and system for optimizing aerodynamic characteristics of a flow equalization air ring structure in a medium-speed coal mill based on Fluent simulation. The method comprises establishing and optimizing a model of the flow equalization air ring structure, meshing the model using Ansys ICEM, importing meshes, arranging an MRF rotating region on a dynamic ring structure, selecting an energy equation model, setting a DPM and a boundary condition, and adopting a modified mixture gas model based on empirical formulas for boundary conditions at an inlet and outlet, initializing computation information of a mesh node, setting a solver and performing iterative solving, after a computation result converges, performing post-processing on the computation result, storing the computation result, modifying structural parameters, and repeating the above steps to obtain a plurality of simulation results to obtain parameters of an optimal flow equalization air ring structure.

The present application discloses a phase field analysis method based on the influence of oxygen vacancies on hafnium oxide-based ferroelectric films, including: considering the influence of oxygen vacancy concentration on hafnium oxide-based ferroelectric films, determining the total energy equation; establishing the constitutive equations of various physical fields based on the influence of oxygen vacancies through the energy equation; determining the control equations of various physical fields; solving through the finite element method, deriving the weak form of the control equations of various physical fields based on the influence of oxygen vacancies, and establishing a phase field calculation model based on the influence of oxygen vacancies for hafnium oxide-based ferroelectric films according to the weak form of the equations, so as to simulate the domain structure cloud diagram and its phase transition law of polymorphic coexistence of hafnium oxide-based ferroelectric films under different oxygen vacancy concentrations. The present application can provide theoretical guidance on the influence of oxygen vacancies for experimenters during the experiment through the establishment of a calculation model, thereby effectively reducing the experimental cost, and having a preset range control value for the oxygen vacancy concentration used in the experiment.

The invention discloses a method for accelerating the iterative convergence speed of a highly nonlinear surface-to-surface radiation problem, and the method comprises the steps: S1, building a geometric model of a to-be-analyzed structure, and carrying out the mesh generation, and obtaining a temperature field finite element model; s2, setting properties, grid control parameters, boundary conditions, initial conditions and solving information of the temperature field finite element model; s3, information of the temperature field finite element model is obtained, and initialization is carried out; s4, establishing a heat transfer overall matrix; S5, selecting a radiation facet, and calculating to obtain a radiation angle coefficient matrix; s6, establishing a cavity radiation energy equation; s7, obtaining a final temperature iterative calculation equation based on the cavity radiation energy equation and the heat transfer overall matrix, and solving the final temperature iterative calculation equation; and S8, iteratively solving until the set calculation ending time, and obtaining the temperature field. According to the method, the cavity radiation energy equation and the heat transfer overall matrix are processed through the semi-implicit separation Newton method, so that the final temperature field iteration equation is obtained, iteration calculation is carried out, and the convergence efficiency can be remarkably improved.

The invention discloses a design method of a uniform condensing lens with wide angular domain receiving performance, which relates to the technical field of space solar power stations and comprises the following steps: constructing energy equations of each receiving area and a plurality of lens ring teeth corresponding to the receiving area by taking uniform energy distribution on each receiving area as a constraint; wherein the lens ring teeth are located on the emergent surface of the lens, and light enters from the incident surface of the lens and reaches each receiving area after being refracted; determining a lens ring tooth number corresponding to each receiving area according to a preset condensation ratio and an energy equation; analyzing the influence of the inclination angle of the lens ring tooth on the optical characteristics of the lens ring tooth, and obtaining the critical value of the inclination angle of the lens ring tooth and the optimal focal length of the lens; and designing a generatrix of the lens, and constructing a uniform condensing lens function with wide-angle-domain receiving performance so as to realize parameter design of the lens. The problem that the condensation efficiency and the light spot uniformity are suddenly reduced during non-vertical incidence of light can be effectively solved.

The invention discloses a battery pole piece baking parameter prediction method, electronic equipment and a storage medium, and relates to the technical field of lithium ion battery manufacturing. The method comprises the following steps: S1, acquiring wind field data based on oven CFD simulation and processing the wind field data into convective heat transfer and mass transfer boundary conditions; s2, calculating a pole piece temperature field and residual solvent content by using a heat and mass transfer resistance model and an energy equation; s3, judging the fluidity of the slurry according to the solvent content: solving a momentum equation considering gravity, wind shear force and surface tension when the content is high, and calculating capillary seepage of the porous medium when the content is low; and S4, explicit iterative calculation is carried out until a pole piece parameter estimated value is output. According to the method, the problem of macroscopic and microscopic scale coupling calculation is avoided through step-by-step decoupling, and the dynamic drying process of the slurry can be accurately reflected.

The invention discloses a heat transfer calculation method for pulsating heat pipes with adjustable inclination angles and liquid filling rates. The heat transfer performance of the pulsating heat pipes with different inclination angles and liquid filling rates is researched by adopting a numerical method; calculating the heat transfer process by solving the energy equation of the steam bomb and the energy and momentum equation of the liquid bomb, so as to predict the pulsation phenomenon of the working medium in the pulsating heat pipe; on the basis of a momentum heat mass transfer model, calculating the phase change heat transfer capacity through film condensation and a down-flow film boiling heat transfer coefficient, investigating the influence of different inclination angles on the liquid film thickness and the down-flow film speed, and increasing the influence of the down-flow film on the liquid elastic length; and the liquid bomb pulsation condition of the pulsating heat pipe under different inclination angles and different liquid filling rates is researched, and then the heat transfer performance of the pulsating heat pipe is calculated. The working heat transfer performance of the pulsating heat pipes with different inclination angles and liquid filling rates and the motion state of the working medium are analyzed and calculated, and guidance is provided for parameter development and engineering application of the pulsating heat pipes.

The invention discloses a fracture-vug type gas reservoir well testing model with a shaft connected with a large karst cave and an establishing method and application of the fracture-vug type gas reservoir well testing model. The method comprises the following steps: selecting proper gas reservoir parameters to establish a fracture-vug type gas reservoir well testing model for connecting a shaft with a large karst cave according to a physical model for connecting the shaft with the large karst cave; according to the gas reservoir characteristics, an energy equation between the shaft and the large karst cave is established, the energy equation considers pressure loss at the joint of the large karst cave and the shaft, and the actual geological condition is better met. The novel fracture-vuggy gas reservoir well test interpretation method using the fracture-vuggy gas reservoir well test model comprises the following steps: performing solution and numerical inversion according to the fracture-vuggy gas reservoir well test model to obtain a real space bottom hole pressure solution; a real space bottom hole pressure value is obtained by utilizing the real space bottom hole pressure solution and combining the gas reservoir parameter actual value; and fitting the real space bottom hole pressure value with the actually measured bottom hole pressure data to obtain parameters such as the volume of the large karst cave. The karst cave volume of the gas reservoir can be explained more accurately by using the gas reservoir type well testing model.

The present invention provides a method for calculating the temperature distribution during the roasting process of a self-baking electrode in a DC electric arc furnace, comprising determining the structural parameters of the self-baking electrode and the operating parameters of the electric arc furnace; determining the material and physical property parameters of each component of the self-baking electrode; establishing an electric-thermal conversion relationship between each component of the self-baking electrode and the electrode paste based on the coupling principle of the electromagnetic field and the temperature field during the roasting process of the self-baking electrode, solving the energy equation and the Maxwell equations, and calculating the temperature distribution of the self-baking electrode during the roasting process. By calculating the temperature distribution of the self-baking electrode, the matching degree between the operating parameters of the electric arc furnace, the structural parameters of the self-baking electrode and the components of the electrode paste can be predicted, so that the roasting effect of the self-baking electrode is optimized. This method can significantly reduce the cost of temperature measurement, save resources, and provide a scientific basis for the roasting scheme of the self-baking electrode, thereby improving the production efficiency of the electric arc furnace, ensuring the quality of the self-baking electrode, and reducing the potential safety hazards that may occur during the roasting process of the self-baking electrode.

The invention discloses a method and device for simulating the freezing process of a salt water film on the surface of a typical component of a polar ship, belongs to the technical field of salt water freezing process simulation, and particularly relates to simulation of the freezing process of the salt water film on the surface of the typical component of the polar ship. The problems that research on the existing brine freezing process is too simplified, and factors such as dynamic influence of salt migration (precipitation) on the freezing process and dynamic change of a contact angle caused by a hysteresis effect are not considered, so that simulation of the seawater droplet freezing process is not accurate enough are solved. The method comprises a solving step used for solving a momentum equation, an energy equation and a concentration equation according to input parameters of a saline film freezing numerical model to obtain output parameters of the saline film freezing numerical model. The method and the device for simulating the freezing process of the saline water film on the surface of the typical component of the polar ship are suitable for simulating the freezing process of the saline water film on the surface of the typical component of the polar ship.

The present disclosure provides a method, apparatus, electronic device, and storage medium for estimating point cloud motion. The method includes: obtaining a point cloud frame to be estimated and a reference point cloud frame; sampling motion center points in the reference point cloud frame to construct a point cloud motion deformation map; determining a first matching relationship between the reference point cloud frame and the point cloud frame to be estimated; constructing a point cloud motion energy equation according to the first matching relationship and the point cloud motion deformation map; solving the point cloud motion energy equation to determine a sparse non-rigid motion field corresponding to the motion center points; performing interpolation on the sparse non-rigid motion field to determine a fine non-rigid motion field; compensating the reference point cloud frame based on the fine non-rigid motion field to obtain a reference motion compensation frame; determining a second matching relationship between the point cloud frame to be estimated and the reference motion compensation frame; constructing an inter-frame rate distortion function between the point cloud frame to be estimated and the reference motion compensation frame based on the second matching relationship; and iteratively estimating the inter-frame rate distortion function to determine the point cloud motion. The estimation accuracy of the point cloud motion can be improved.

The invention discloses a method for establishing a mathematical model of a self-temperature-regulating building envelope based on a phase change energy storage material. The method comprises the steps of constructing a three-dimensional physical model, and describing solid-liquid two-phase energy exchange, natural convection and phase interface dynamic change during phase change; assumed conditions such as shell thickness neglecting are set; establishing a continuity equation, a momentum equation and an energy equation in sequence, and respectively describing heat exchange fluid mass conservation, fluid flowing behaviors and phase change material temperature changes; initial and boundary conditions of solidification and melting processes are determined, temperature gradient driven phase change is ensured, and heat exchange is carried out through a coupling surface. The mathematical model constructed by the invention can effectively simulate the self-temperature-regulating capability of the phase change energy storage material under different conditions, provides a theoretical basis for designing a more efficient self-temperature-regulating building envelope, and promotes the development of passive energy-saving buildings.

The invention discloses a method for predicting unfrozen water content in a soil thawing process based on a pre-thawing theory. The method comprises the following specific steps: step 1, deducing an association relationship between an ice-water two-phase chemical potential difference and a temperature difference; 2, establishing an interface energy equation, and deducing a quantitative expression of the thickness and temperature difference of the pre-melting layer; 3, calculating the residual moisture content; 4, a Van Genuchten moisture feature model is introduced to describe the relation between the residual saturation and the temperature; the model prediction precision is excellent, the physical significance is clear, dynamic changes of unfrozen water of different soil textures can be accurately described, and theoretical support and a practical method are provided for cold region infrastructure anti-freezing design and soil moisture prediction.

The invention discloses a multi-stage pipe network leakage positioning method and system based on a hydraulic model sensitivity matrix and sparse inversion, and relates to the field of monitoring and leakage detection of an urban water supply pipe network, and the method comprises the steps: S1, linearizing a pipe network continuity equation and an energy equation at a normal operation point of a baseline working condition, obtaining a sensitivity matrix of the leakage rate and the demand disturbance to the pressure residual error, and establishing a linear approximation relation; s2, constructing an optimization problem with L1 regularization based on the relationship; eliminating a demand disturbance item, converting into a non-negative LASSO problem, and completing suspicious node positioning; s3, convex combination approximation of sensitivity of nodes at the two ends is introduced for the suspicious pipe section, an optimization target is constructed, and the internal leakage continuous position and the leakage amount of the pipe section are estimated; and S4, a joint optimization problem is constructed based on the pressure residual data of the multiple time periods, consistent selection of leakage positions of the multiple time periods is kept, and final leakage positioning is realized. According to the method, pipe network leakage positioning is accurately and efficiently completed through multi-stage progressive positioning.

The invention discloses a suspension cable type crossing frame bearing cable optimization type selection method based on the law of conservation of energy. The method comprises the following steps: S1, carrying out related setting on a dynamic impact process when a suspension cable type crossing frame generates line displacement and line breakage accidents, and simplifying problems; s2, calculating a gravitational potential energy formula of the wire and the bearing cable before an accident working condition, namely a safe paying-off working condition; s3, analyzing the energy change rule of the wire and the bearing cable after the accident condition occurs and when the net falling wire is in contact with the bearing cable and jointly moves to the lowest point, and calculating the elastic potential energy variable of the bearing cable; s4, based on the law of conservation of energy, combining the energy equations before and after the accident to obtain a calculation formula of the impact coefficient and the comprehensive safety coefficient; according to the method, the energy change rule of the impact of the drop wire on the bearing cable is analyzed, a dynamic motion equation and a mechanical calculation model of the suspension cable type crossing frame in the accident state are formed, and the problem that the selection precision of the bearing cable is low due to the fact that an existing calculation method is rough when the impact coefficient is selected is solved.

The invention discloses a method and a system for quickly calculating the inherent frequency of a stator core. The method comprises the following steps: constructing a five-degree-of-freedom cylindrical shell theoretical model, and converting five degrees of freedom of a cylindrical shell into a single-variable function through a variable separation method; calculating strain energy and kinetic energy of the orthotropic cylindrical shell without the reinforcing ribs and the reinforcing ribs; in combination with a Lagrange interpolation function and a GLL integral point, axially segmenting the stator, and performing matrix expression on energy equations of the cylindrical shell and the stator teeth to obtain a stiffness matrix and a mass matrix corresponding to the discrete cylindrical shell and stator teeth; and respectively adding the stiffness matrixes and the mass matrixes corresponding to the cylindrical shell and the stator teeth to obtain a total stiffness matrix and a total mass matrix, carrying out eigenvalue solution on the total stiffness matrix and the total mass matrix to obtain the square of the inherent angular frequency of the stator core and a displacement fitting function in each direction, and converting to generate the inherent frequency of the stator core. According to the method, the inherent frequency of the stator core under each boundary condition can be quickly calculated.

The application discloses a pulsating heat pipe heat transfer model and a calculation method based on oscillating flow characteristic number, and belongs to the technical field of heat exchange equipment, and comprises the following steps: establishing a pulsating heat pipe model, determining working medium and evaporation section and condensation section temperature; taking initial amplitude, initial frequency, initial liquid film thickness and initial bullet temperature as assumed parameters, solving liquid bullet temperature distribution through a liquid bullet energy equation; constructing a liquid bullet motion equation based on the initial amplitude and the initial frequency, calculating liquid bullet displacement and combining the initial bullet temperature to calculate bullet pressure; calculating bullet temperature according to bullet pressure and performing iterative correction; updating liquid bullet temperature distribution according to the corrected bullet temperature and calculating liquid film theoretical thickness, and performing iterative correction; based on the oscillating flow Nusselt correlation, the initial amplitude and the initial frequency are iteratively corrected, and the sensible heat and the flow thermal resistance are calculated according to the iteratively converged parameters. The application discloses the correlation between the oscillating flow characteristic number and the heat transfer performance, and provides reliable data support for heat pipe design.