4052results about "Sustainable transportation" patented technology

The invention discloses an interior noise analysis and prediction method of a high speed train. The method comprises the following steps: establishing a train reconditioning train body model, a statistical energy analysis model of a body in white structure and an interior and exterior vocal cavity statistical energy analysis model, and carrying out simplification and subsystem division; obtaining the statistical energy analysis parameters of the train body structure and an interior vocal cavity model, and loading the statistical energy analysis parameters onto a train body structure model plate subsystem and a vocal cavity model subsystem; and obtaining exterior vocal excitation source energy borne on the train body, applying the exterior vocal excitation source energy onto the exterior vocal cavity statistical energy analysis model, causing the exterior vocal excitation source energy to reach an interior vocal cavity after the exterior vocal excitation source energy is attenuated by the sound insulation property of a structural plate in a body in white structure model so as to obtain structural noise energy radiated into the train by the reconditioning train body under the function of the two-line suspension force of a compartment, and then, carrying out interior noise analysis and prediction. The problem that the interior noise of the train is difficult in prediction and the problems of the upper limit boundedness of a frequency domain, complex calculation flow, incomplete motivation consideration in the traditional method are overcome, calculation efficiency and prediction accuracy are improved, and development and test cost is lowered.

A method for designing an engine case static structure of a gas turbine engine includes creating signals representing an engine case static structure knowledge base of information. The knowledge base has a plurality of design rule signals with respect to a corresponding plurality of parameter signals of associated elements of an engine case static structure, wherein the knowledge base comprises at least one data value signal for each of the plurality of design rule signals. A desired data value signal is entered for a selected one of the plurality of parameter signals of an associated element of the engine case static structure and compared to the corresponding data value signal in the knowledge base for the corresponding one of the plurality of design rule signals. Signals representative of a geometric representation of the selected parameter signal may be created.

The invention relates to a pneumatic elastic analytical method, and provides a pneumatic elastic mechanical characteristic analytical method of a hypersonic speed aircraft in thermal environment. According to the method, the piston theory is used for carrying out frequency domain nonsteady aerodynamic calculation on a full-aircraft finite element model of the hypersonic speed aircraft; on the basis, the pneumatic thermal effect on the model in the hypersonic speed thermal environment is considered; the weak coupling effect of pneumatic thermal input in aerodynamic input and elastic force input is ignored; only the structure temperature steady-state characteristics under the pneumatic thermal load effect are considered; after the steady aerodynamic calculation, the thermal flux density on the surface of the aircraft is obtained by adopting a reference enthalpy method; further, the steady temperature distribution on the surface of the aircraft is calculated; the practical equivalent rigidity matrix of the structure at the moment is obtained; and the critical flutter speed is calculated by an engineering method. The pneumatic elastic mechanical characteristic analytical method has the advantages that the pneumatic elastic analytical problem of the hypersonic speed aircraft in the pneumatic thermal environment is solved, and the pneumatic elastic performance of the hypersonic speed aircraft is improved through flutter speed analysis.

A PoF based method for calculating mission reliability of an electronic product comprises steps as follows: step one, information of all mission profiles of the product is collected, and an environment profile of each mission is determined; step two, thermal simulation and vibration simulation of environmental stress of each mission are performed, and a local response of the product to an environmental load is obtained; step three, a product simulation model is established; step four, simulation calculation of the product in all the mission profiles is completed, and the mean time to failure and a main failure mechanism of the product are obtained; and step five, the mission reliability of the product is calculated according to the mean time to failure. According to the PoF based method for calculating the mission reliability of the electronic product, all missions of the product during lifetime use are considered, the environmental stress of each mission is simulated, and the mean time to failure and the mission reliability of the product are comprehensively calculated. By means of a PoF model, the direction relation between parameters of a product material, structure, process and the like and the reliability can be obtained, and a design improvement direction is clearly and directly provided for the product.

The invention discloses an optimization design method of fibre enhanced composite material marine propeller blades, which relates to an optimization design method of propeller blades and aims at solving the problem of imperfect design method of the fibre enhanced composite material marine propeller blades. On the basis of offsets data of the original high-speed metal propeller blades, the method is calculated by using a fluid-solid coupling method combining with the implementation of predeformation strategy, a blade structure is composed by mixed fibre composite materials, the surface of a blade adopts fibre glass enhanced composite material, the interior of the blade adopts the mixture of carbon fiber and Kelvar fiber enhanced composite material, and the specific mixed paving mode and the mixing ratio are determined according to the hydro elastic design result of a fibre enhanced composite material marine propeller. The optimization design method is used for designing the propeller blades.

The invention provides a digital ship model plane motion organization experimental method based on computation fluid dynamics CFD software FLUENT. The method includes applying a FLUENT pre-process software GAMBIT to establish a research object model and a control domain; arranging a triangle grid on the model surface, then arranging a unstructured grid in the control domain; setting the boundary condition, joining an user-defined function UDF document, introducing dynamic grid technology, using a finite volume method based on the complete unstructured grid, realizing a pure swaying movement, a pure rising and falling movement, a pure oscillatory movement, a pure pitching movement and a pure rolling movement carried on by a plane motion organization experiment; applying a science computation software MATLAB to do Fourier expansion of a force and a moment coefficient obtained by the FLUENT, being fitted by EXCEL least squares method, obtaining a hydrodynamic force coefficient of a vertical plane and a horizontal plane as well as the related hydrodynamics analysis by dimensionless. The invention carries on the digit plane motion organization experiment using the CFD software, can satisfy the request of hydrodynamic force data in the design initial period of a submersible.

The present invention discloses a helicopter aerodynamic layout optimization method capable of reducing the adverse effect of aerodynamic interference. According to the method, aiming at the defects of a wind tunnel test and a CFD method and based on a discrete vortex method and a surface element method, a coupled aerodynamic interference high-precision analysis model for a helicopter is set up, so that the influence of aerodynamic interference on the helicopter can be considered only by simulating calculation without carrying out the wind tunnel test; compared with the CFD method, the method has the advantages of greatly reducing the requirements of a simulation model for computing resources and shortening computing time. In order to further reduce calculated amount and a optimization region, a helicopter fuselage shape parameter model is set up by a parametric method and a combined optimization method based on an agent model is adopted, so that the optimal helicopter aerodynamic outline and layout are obtained and the purpose of reducing aerodynamic interference to improve the flight characteristics of the helicopter is achieved. The helicopter aerodynamic layout optimization method can be applied to the conceptual design phase of the helicopter so as to improve the flight characteristics, the balancing characteristic, stability and manoeuvrability of the helicopter.

The invention relates to the field of modeling of aerocrafts in the aerospace field, in particular to a pneumatic modeling method which is suitable for a hypersonic aerocraft and based on CFD, a feasible thought is provided for pneumatic modeling with high experiment costs, the analysis and design progresses of the hypersonic aerocraft are promoted, a comprehensive and reliable modeling method is provided for development of a novel hypersonic aerocraft model, the development cost is reduced, and great application prospects and economic value are realized. According to the technical scheme, the CFD pneumatic modeling method for the hypersonic aerocraft is composed of three parts, namely the pre-treatment part of carrying out numerical modeling and mesh division, the solver part for calculation and solution and the after-treatment part for carrying out result analysis, wherein the pre-treatment part includes the two sub-parts of building a geometric model and dividing calculation meshes. The CFD pneumatic modeling method for the hypersonic aerocraft is mainly applied to design and manufacturing of aerospace aerocrafts.

The invention discloses a multi-objective optimization design method for a wheel, relates to the technical field of vehicle engineering and aims at solving the problems that the optimization space is limited and automatic optimization design is not carried out through joint transferring of calculation software with various properties due to the fact that only limited performance of the vehicle is analyzed and optimized and parametric modeling is lost at present. The method comprises the steps of topological optimization of a wheel fatigue test, combined topological optimization modeling, fatigue performance analysis, impact performance analysis, aerodynamic performance analysis and multi-objective optimization. Five working conditions of a dynamic bending fatigue test of the wheel, a dynamic radial fatigue test, an impact test of an impact hammer opposite to a spoke, an impact test of the impact hammer opposite to a window and air dynamics analysis of the wheel are set; the properties, such as the strength, the rigidity, the vibration characteristic, the fatigue life, the fatigue life security coefficient, the impact performance, the air dynamic property and the lightweight performance of the wheel are comprehensively considered; various performance parameters are calculated through finite element software emulation; and optimization design is carried out on the wheel by setting the performance parameters to be constraint conditions or objective functions.

The invention discloses a full-firing-direction autonomous reentry guidance method based on a three-dimensional reentry trajectory analytical solution. The full-firing-direction autonomous reentry guidance method comprises the following steps of 1, building of a kinematical equation and a dynamical equation, 2, summarizing of the reentry guidance method, 3, descent stage guidance strategies, 4, steady gliding stage guidance strategies and 5 height-adjustment stage guidance strategies. The full-firing-direction autonomous reentry guidance method has the advantages that reentry guidance of an aircraft with the large lift-drag ratio can be guided effectively, low-damping and long-period trajectory oscillation caused by the high lift-drag ratio can be restrained effectively, the peak value ofthe heat flux density is reduced, and tracking of a reference track is facilitated; inertia force caused by earth rotation and actual aerodynamic force are combined into equivalent aerodynamic force,an equivalent aerodynamic section is planned through the analytical solution, and thus the aircraft has the omni-directional reentry task processing capability; and an equivalent aerodynamic section fitting formula based on the inverse proportional function is put forward, the reentry trajectory analytical solution based on the complex equivalent aerodynamic section form is further deduced, and thus high precision, all-dimensional applicability and high robustness are achieved.

The invention discloses an aeroengine remaining service life prediction method based on an LSTM network and an ARIMA model. The method comprises the following steps: n engine health index (LSTM-HI) models based on an LSTM depth neural network are established according to engine historical degradation data; According to the engine sensor data, the ARIMA model is trained and the engine sensor parameters are predicted backward in many steps. By predicting the sensor parameters, according to LSTM-HI index is used to evaluate whether the engine is degraded to failure, and the remaining service lifeand its probability distribution are obtained. The invention provides a novel method for predicting the remaining service life of an aeroengine, which has high accuracy and feasibility, and plays anactive role in promoting the real-time health management of the aeroengine and reducing the maintenance cost.

The invention discloses a method for designing a water-spraying boost pump hydraulic model for an efficient and large-power-density ship. The method comprises the following steps that type selection design of water-spraying boost pump hydraulic parameters is conducted, two-dimensional axial face projective geometry is determined, three-dimensional geometrical shapes of an impeller and guide blades are obtained according to a parameterized ternary reversal design method, a three-dimensional geometrical shape of a shrinkage nozzle is obtained through circumferential rotation, the three-dimensional geometrical shapes of the impeller, the guide blades and the shrinkage nozzle are combined to obtain the water-spraying boost pump hydraulic model. The method has the outstanding advantages that the design period is short, the design quality is high, and the water-spraying boost pump hydraulic model which has the advantages of being high in efficiency, compact and large in power density can be rapidly and reliably designed. The geometrical shapes of the impeller and the blades are obtained according to the parameterized ternary reversal design method, so that on the condition that the water-spraying boost pump hydraulic model is kept compact, the efficiency is improved, cavitation is restrained, and the power density is increased in the researching and developing process of a high-speed ship water-spraying boost pump.

The invention discloses an optimization method of a smooth and steady gliding trajectory of a hypersonic flight vehicle. The optimization method specifically comprises the steps that 1, a reentry dynamics equation and a trajectory process constraint are established; 2, a trajectory damping control technology is extended; 3, the trajectory damping control technology is utilized to improve the dynamics equation; 4, a hp self-adaptive Radau pseudo-spectral method is utilized to solve an optimal control problem. The optimization method effectively inhibits trajectory jumping by changing the dynamic characteristics of a reentry trajectory and establishes the optimal control problem having smooth and steady state characteristics by changing the dynamic characteristics of the reentry trajectory, the difficulty of numerical solution is greatly reduced, the high-precision smooth and steady gliding trajectory meeting multiple constraint requirements can be obtained within short time, the optimization efficiency of the smooth and steady gliding trajectory is improved, and the regularity of the trajectory optimization is greatly strengthened.

A computer-aided method suitable for assisting in the design of an aircraft by providing relevant dimensioning values corresponding to an aircraft component in transonic conditions inside a predefined parameter space by means of a reconstruction of the CFD computations for an initial group of points in the parameter space using a POD reduced-order model, comprising the following steps: a) Decomposing for each flow variable the complete flow field into a smooth field and a shock wave field in each of said computations; b) Obtaining the POD modes associated with the smooth field and the shock wave field considering all said computations; c) Obtaining the POD coefficients using a genetic algorithm (GA) that minimizes a fitness function; d) Calculating said dimensioning values for whatever combination of values of said parameters using the reduced-order model. The invention also refers to a system able to perform the method.

The invention provides a hypersonic speed guided missile multi-field coupling dynamics integrated simulation analysis method, which comprises the following steps of: establishing a coupled structural motion equation; improving an aerodynamic heating calculation method; improving an unsteady aerodynamics calculation method; establishing an integrated simulation analysis technique process; designing a relationship between an integrated simulation analysis operation model and data; and realizing an integrated simulation analysis system. Compared with the prior art, the aerodynamic heating calculation method and the unsteady aerodynamics calculation method are improved; various techniques of flutter analysis, thermal flutter analysis, pneumatic servo elastic analysis and thermal pneumatic servo elastic analysis are integrated; and an effective integration method for integrally solving and optimally designing a high-speed winged missile all-missile combination body coupling dynamics problem is provided.

The invention discloses a method for analyzing the fatigue life of a steering knuckle, comprising the following steps: 1) obtaining the fatigue load of the steering knuckle; 2) carrying out uniaxial tensile material test on the use material; 3) if the fatigue load is under the static load condition, the elastic-plastic finite element analysis method is adopted to solve the problem; or, if it is the actual pavement load spectrum, the elastic-plastic finite element analysis is carried out on the points exceeding the yield strength by elastic finite element method and linear superposition method,and the modified stress-strain results are obtained. 4) analyzing the biaxiality of the obtained stress response in time domain to determine the load state of the steering knuckle; 5) calculating thedamage accumulation and life of steering knuckle. The present invention solves the problem of time-consuming finite element solution under the input of actual pavement load spectrum, at the same time, the stress and strain of the material entering the plastic phase are considered, so that the result is more accurate, and fatigue analysis is carried out by combining the static load condition or the single channel static load condition, and more references are provided in the design phase.

The invention relates to a method of computer simulation of the aerodynamic behaviour of an aircraft (10) in flight close to the ground. This method is used to identify the slope effect relative to the ground effect.

To achieve this, a uniform boundary condition comprising a predetermined speed (U_P) with a non-zero tangential component and a non-zero normal component is imposed on a plane (21) modelling the ground; and a discrete numerical model of the Navier-Stokes equations is solved by computer on a volume mesh with said boundary condition imposed on said plane (21), so as to obtain a numerical solution for a fluid flow inside a computational domain defined by said mesh.

The invention discloses a design method of a hydraulic model of a shaftless drive type integrated motor pump jet. By means of the method, the propeller which is equal to a seven-blade highly skewed propeller in open water efficiency and lower in radiation noise can be designed, wherein a motor and the pump jet are completely integrated. The method comprises the steps of a pump fluid channel hydraulic parameter type selection design, a parametric three-dimension reversal design of pre-positioned stator and post-positioned impeller blades, non-air-gap pump jet open water performance checking, and propelling, cavitation and noise performance and strength checking of the integrated motor pump jet. The pump jet which is composed of a thick guide pipe of an embedded motor stator, a motor annular rotor, an air gap, a pre-positioned stator and a post-positioned impeller is designed. The propelling efficiency is 0.589, the power is 3.7 MW and the pump jet can propel submersible vehicles with the navigational speed being 16 knots. The number of the stator blades is 13, the number of the impeller blades is 9, an NACA 16 wing type thickness distribution method is adopted for the stator blades and the impeller blades, and the impeller is highly skewed. The design method can be directly used for realizing shaftless electric propelling of unverwater vehicles, and is also suitable for shaft type pump jets and torpedo post-positioned stator type integrated motor pump jets.

The invention relates to a method for designing a Terminal sliding mode controller of a hypersonic vehicle. The Terminal sliding mode control has an advantage that a system on a sliding mode surface can be converged within limited time. In order to keep the nonlinearity of a model and to facilitate the design of a control system, an input-output linearization method is used for processing the model in the paper, after that, state variables are reselected according to the design requirements of the Terminal sliding mode control, and a nonlinear sliding mode surface is designed; a sliding mode control law is designed for the designed Terminal nonlinear sliding mode surface, to ensure that the system can reach the sliding mode surface, and to prove the stability of the system; finally, the given control law is subjected to simulation verification, and the results show that the designed sliding mode controller can realize the effective control of the hypersonic vehicle.

The invention discloses a method for forecasting the noise value of a propeller noise value in uneven inflow. The method for forecasting the noise value of the propeller in the uneven inflow comprises the steps that firstly, a CFD computation grid is divided, steady iterative computation is conducted so that the water flowing performance parameter and the water speed of an inflow opening can be worked out and the accuracy of a model is verified; secondly, CFD unsteady computation is conducted, the period state of blade cavitation and the blade cavitation area change of the propeller are recoded; thirdly, through CFD flow field data, acoustic boundary element value computation is conducted, and load noise of the propeller is worked out; finally, the noise of the propeller is worked out through the blade cavitation monopole radiation noise of the propeller and the load noise of the propeller.

The invention relates to a modal synthesis dynamic modeling and analysis method for an automobile driving axle system. The method is characterized by comprising the steps that 1, a finite element model of all components of a driving axle is established, boundary nodes are defined according to the connecting relation between the components, a modal synthesis model of all the components is established, and a modal synthesis rigidity matrix and a mass matrix of all the components are obtained; 2, a connecting relation model of all the components is established; 3, the modal synthesis rigidity matrix and the mass matrix of all the components are assembled according to the connecting relation, a complete modal synthesis dynamic model of the driving axle system is established, and a rigidity matrix and a mass matrix of the driving axle system are obtained; 4, natural vibration frequency and a regular vibration mode of the dynamic model of the driving axle system are calculated, and a mode superposition method is adopted to calculate the dynamic response of the driving axle system under excitation of dynamic engaging force of gears of a main reducing gear. In the whole modeling process, high universality and calculating efficiency are achieved, and the method can be widely applied to dynamic analysis of a gear transmission system.

The invention discloses a nonlinear modeling method and a linear trimming method for a composite rotor aircraft, and belongs to the technical field of control of composite rotor aircrafts. According to the method, the aerodynamic characteristics of all parts are analyzed, and a split modeling method is adopted to carry out dynamic modeling; on the basis of the model, combined with a quasi-Newton iteration method and a sequence quadratic programming method, a quasi-Newton-sequence quadratic programming method is proposed to dynamically balance the dynamic model of the composite rotor aircraft and make small disturbance linearity at the equilibrium point, so that an approximate linearized kinetic equation for the equilibrium point can be obtained. The dynamic model established by using the modeling method disclosed by the invention is high in confidence coefficient and simple in calculation, in addition, the new trimming method provided by the invention can avoid solving the inverse matrix of the objective function Hessian matrix, the calculation is simplified, the relatively high convergence speed is ensured, and the method can be used for researching the control method of the composite rotor aircraft.

The invention discloses an electric vehicle pedestrian warning sound design method. For people's different reactions to sounds of different frequency bands, a lot of sound samples are designed, a BP neural network prediction model optimized through a genetic algorithm is established by using sound quality objective psychoacoustic parameters and subjective evaluation results, the model can provide guidance for screening subsequent sound samples, the screening process of the sounds is simplified, and the cost is saved. According to the actual operation condition of a vehicle, a multi-condition intelligent control system is established, thus electric vehicle/hybrid electric vehicle can intelligently select suitable sounds and emit the sounds in different operation conditions, the magnification times of a gain circuit is intelligently selected according to the background noise volumes, and thus the emitted warning sound can reasonably warn pedestrians and do not cause the noise pollution of an environment. The invention also discloses an electric vehicle or hybrid electric vehicle pedestrian warning sound design method and a warning sound control system and a control method thereof.

The invention discloses a hypersonic velocity aircraft wing spar structural reliability analysis method based on a stress-strength interference theory. The method comprises the steps that according to a geometric structure, proposed by NASA, of a six-degree-of-freedom hypersonic velocity aircraft universal model and an aerodynamic derivative equation, a stress analysis model of a wing spar root is built; flight constraint conditions of different flight phases are determined according to a flight envelope, the structural strength of the wing spar root is analyzed by combining material strength characteristic parameters at different temperatures; a stress-strength interference model is built according to a random load capacity and strength analysis data, and under the situation that the structural strength degrades along with increasing of flight frequency, the structural reliability of the model is calculated. According to the hypersonic velocity aircraft wing spar structural reliability analysis method based on the stress-strength interference theory, the frequency of the random load action on wing spars of an aircraft in the flight course is organically combined with wing spar structural strength degradation, and the accuracy of the reliability analysis is improved.

The present invention belongs to the field of vehicle passive suspension vibration isolation, and relates to a positive synthesis and passive implementation method of a vehicle ISD suspension electromechanical network system. The method comprises: Step 1: determining a dynamic model of vehicle suspension vibration and a performance evaluation index thereof; Step 2: establishing a vehicle ISD suspension electromechanical network system; Step 3: according to the performance optimization target, under the positive real inequality constraints, using the improved multi-PSO algorithm to optimize thesolution of the vehicle ISD suspension electromechanical network system to obtain the corresponding impedance transfer function coefficients; Step 4: carrying out positive real synthesis on the impedance transfer function obtained from the vehicle ISD suspension electromechanical network system; and Step 5: carrying out passive implementation on the vehicle ISD suspension electromechanical network system based on the electromechanical inertia. According to the method disclosed by the present invention, the limitation of the ISD suspension structure type design method and the difficult problemthat the impedance type design method cannot implement can be effectively solved, and a new method is provided for the structure design and implementation of the suspension.

The invention discloses a low noise forward design method for a rail vehicle. The low noise forward design method comprises the following steps of S1, determining a complete vehicle noise design target of the rail vehicle; S2, decomposing acoustic indexes of each component of the rail vehicle according to the complete vehicle noise design target; S3, conducting acoustic simulation according to thedecomposed acoustic indexes; S4, performing an acoustic test on each component of the rail vehicle, and comparing acoustic simulation results to obtain optimal parameters of each component of the rail vehicle; S5, according to the optimal parameters of each component of the rail vehicle, performing simulation analysis on the complete vehicle noise; S6, according to complete vehicle noise simulation analysis results, updating the acoustic indexes of each component of the rail vehicle to achieve the low noise forward design for the rail vehicle. The method solves the noise problem in the production process of the rail vehicle and achieves the predictability of the final noise result, avoids the reverse treatment for the noise problem, improves the effects of vibration reduction and noise reduction, and saves manpower and material resources.

Disclosed is an aerodynamic stability predicting and estimating method of an aerial engine under a counter thrust state. The method comprises the following steps of, firstly, performing aeroplane/engine integrated counter thrust air turbulence field fully-three-dimensional numerical simulation under the counter thrust state and obtaining the distortion maps and the distortion indexes of the inlet flow field of the engine under the counter thrust state; under the premise of obtaining the distortion indexes of the inlet flow field of the engine under different skating speeds of the aeroplane in the counter thrust state, performing integral stability computing analysis on influence of inlet flow field distortion on the aerodynamic stability of the engine in the counter thrust state; thirdly, taking the engine inlet flow field distortion maps obtained through three-dimensional flow field computing as the target to design an inlet flow field distortion generator used for aerial engine bench tests; fourthly, performing engine bench tests through the engine inlet flow field distortion generator, during the tests, starting a counter thrust device to measure the working state of the engine in real time and further to estimate the engine aerodynamic stability in the counter thrust state when inlet flow field distortion exists.

The invention provides a large-scale intelligent group independent collaborative modeling method for imitation of starling group flight. The method comprises the steps of initializing a population andparameters thereof, setting as follows: in the initial state, all Agents use initial positions as optimal positions, and all Agents use optimal values of six or seven most closest neighbors as localoptimal values; calculating a fitness function, and setting distribution anisotropy of neighbors around each Agent, wherein six or seven most closest neighbors are isotropic, and interaction between the Agents depends on a topological distance; selecting an updating company, comprising the step of selecting one of the six or seven most closest neighbors as an updating company for a certain Agent;defining an interaction relationship of Agents; and updating Agent speed and position. The method has a broad application prospect in military, emergency, industrial and medical care fields like dronecluster intensive formation, group emergency evacuation in a large collection place, large-scale robot group collaborative operation, and disease spread control.

The invention discloses a simulation calculation method for an aerodynamic performance of an automobile wind protecting cover. The simulation calculation method for the aerodynamic performance of the automobile wind protecting cover comprises a first step of building a physical model of the fan wind protecting cover; a second step of carrying out calculation region setting and grid division; a third step of setting border conditions; a fourth step of carrying out simulation calculation on the aerodynamic performance of the wind protecting cover in the presence of a given rotating speed of the fan by utilizing CFD simulation software Fluent; and a fifth step of optimizing a wind protecting ring structure based on a vortex dynamic theory and characteristics of a flow field around vanes, and benchmarking with experimental data to verify accuracy of the model. By post-processing a simulation calculation result and utilizing the vortex dynamic theory and the characteristics of flow lines around the fan, the structure of the wind protecting cover is optimized, and the performance of the fan wind protecting cover is accordingly improved.

The invention provides a numerical inversion method for obtaining Weibull distribution parameters of roadway surrounding rock, which relates to the technical field of mining rock mechanics and solvesthe technical problem of determining parameters of roadway heterogeneous distribution fractured rock mass in the numerical simulation process. The method comprises the following steps: (1) monitoringroadway deformation; (2) interval estimation of geological strength index of surrounding rock of roadway; (3) Establishing three-dimensional numerical model by using finite element simulation software; (4) parameter setting of probability distribution of heterogeneous rock mass; (5) assigning the material parameters of the numerical model; (6) Setting boundary conditions and excavation calculationof the model; (7) extracting monitoring data to monitor roadway deformation; (8) Calculate the correlation coefficient and check the heterogeneity parameter of rock mass. This method also has the advantages of high precision of parameter inversion, conformation to the actual engineering conditions on the spot, high reliability and the like.