115 results about "Thermal boundary conditions" patented technology

The invention discloses a high-temperature mechanical properties testing system of tunnel lining structure, comprising fire thermal environment simulation subsystem; heat insulation subsystem; base and lining structure mechanical border simulation subsystem; loading subsystem, measurement subsystem; data acquisition subsystem; lining structure thermal border simulation subsystem. This tested system can better simulate characteristics of the tunnel fire (quick heating-up, high maximum temperature reached) and a variety of tunnel fire scenes; can simulate the thermal border condition of tunnel lining structure system and effect of surrounding soil, groundwater to components; can simulate the effect of formation resistance force to lining structure system; can impose a variety of loads- temperature conditions to lining structure system; can impose different displacement border conditions to lining structure system. The invention is safe, reliable, easy to use, with low failure rate, can meet the requirements of mechanical performance test of tunnel lining structure at high temperature (after high temperature).

The invention provides a test and analysis method for overall fire resistance of a high-rise steel frame structure. The method includes: establishing a temperature field finite element model and a mechanical field finite element model for a high-rise steel frame structure system; designing corresponding fire condition parameters according to standard fire conditions, establishing a fire dynamics model by a spatial air temperature rise model or by a fluid dynamics calculation procedure FDS to calculate spatial temperature fields under various fire conditions, and using an obtained time-varying spatial temperature field as a thermal boundary condition for the temperature field finite element model of the whole structure; calculating the finite element model by finite element software; calculating the temperature field finite element model by software, substituting the obtained finite element temperature field to the mechanical field finite element model, and calculating to obtain a mechanical field; estimating whether the structure system collapses or not or exceeds the design limits or not according to calculation results; performing quantitative analysis on fire loss economy, and judging the economy of a fire protection design scheme.

The invention discloses a method for reconstructing a nonuniform temperature field inside structure and based on transient-state thermal boundary inversion. The method includes that on the basis of transition time of ultrasonic pulse echo, transient-state thermal boundary conditions causing temperature change of the structure is inverted; on this basis, non-steady-state temperature distribution inside the structure is reconstructed by solving a thermal conduction equation. Compared with existing ultrasonic temperature measuring methods, the method has the advantages that ultrasonically-detected inside temperature is not acquired directly through transition time and is acquired through inverted transient-state thermal boundary conditions, so that temperature in the method is not a single average value on a transmission path any more but specific temperature distribution, and the method is higher in temperature resolution and higher in stability and can realize realtime and high-accuracy reconstruction of temperature distribution inside solid structure at different moments.

The invention discloses a high-temperature mechanical properties testing system of lining structure system of circular tunnel, which includes the following seven parts: fire thermal environment simulation subsystem; heat insulation subsystem; base and lining structure mechanical border simulation subsystem; loading subsystem, measurement subsystem; data acquisition subsystem; lining structure thermal border simulation subsystem. This tested system can better simulate characteristics of the tunnel fire (quick heating-up, high maximum temperature reached) and a variety of tunnel fire scenes; can simulate the thermal border condition of tunnel lining structure system and effect of surrounding soil, groundwater to components; can simulate the effect of formation resistance force to lining structure system; can impose a variety of loads- temperature conditions to lining structure system; can impose different displacement border conditions to lining structure system. The invention is safe, reliable, easy to use, with low failure rate, can meet the requirements of mechanical performance test of tunnel lining structure at high temperature (after high temperature).

The invention discloses a uniaxial creep testing device and a uniaxial creep testing method for frozen earth with a temperature gradient. The device consists of a pressure cover, a height adjusting cushion block, a convex pedestal, an upper refrigerating plate, a lower refrigerating plate and heat insulation plates, wherein a piston and a vacuumizing channel are arranged at the upper part of the pressure cover in a sliding way, and refrigerating fluid circulating channels and a test lead wire channel are formed in the convex pedestal. In the testing process, the heat insulation plate, the lower refrigerating plate, a sample, the upper refrigerating plate, the heat insulation plate and the pressure cover are sequentially mounted on the convex pedestal, and the space between the convex pedestal and the pressure cover is sealed by an O-shaped seal ring; an adiabatic boundary condition required by the sample is realized by vacuumizing in the pressure cover; the vertical temperature gradient of the sample is realized by regulating cold medium temperatures in the upper refrigerating plate and the lower refrigerating plate; and a creep load required by the sample is realized by regulating the forced direction and size of the piston. According to the uniaxial creep testing device and the uniaxial creep testing method, a unidirectional stress state and the stable adiabatic boundary condition can be provided, and the device and the method are suitable for research of uniaxial creep characteristics of the frozen earth under the conditions of different temperature gradients and scales.

The invention discloses a method for quickly calculating the influence of high-temperature ablation of a high-speed aircraft cover body on the electrical property of an antenna. The method comprises the steps that material attributes and thermal boundary conditions of a high-speed aircraft antenna cover are determined; the simulated antenna cover body ablation process undergoes transient thermal analysis; overall temperature distribution and outer surface ablation morphology of the antenna cover are extracted at a certain moment; dielectric constants and loss tangent under the temperature distribution at the moment are calculated; the thickness after antenna ablation is calculated; transmission coefficients after change of the dielectric constants, the loss tangent and thickness are calculated; the transmission coefficients of the ablated antenna cover are calculated; the electrical property functions of an ideal antenna cover-antenna system are determined; a model is established, andthe electric property of the antenna after the high-speed aircraft antenna cover is ablated is calculated. By adopting the method, the influence of high-temperature ablation of the high-speed aircraftcover body on the electrical property of the antenna in the process of flying in a near space can be quickly and effectively calculated, a theoretical guidance is provided for design, real-time compensation and the like, and thus reliable work of a high-speed aircraft guiding system is ensured.

The invention discloses a correction method of the distribution of a quenching stress field of an aluminum alloy thick plate. In the method, on the combination of X-ray surface stress calibration and finite element modeling and simulation, sample deformation deviation produced by the traditional layer cutting method during a stress test process is obtained, and the traditional computation model is corrected by a layered deformation compensation polynomial fitting function, thus, computation accuracy of the stress field in the layer cutting method is drastically improved, and the result comparison deviation is controlled to be +/-20MPa. The method comprises the steps of: obtaining and correcting a quenching heat transfer boundary condition, analyzing layer cutting deviation and correcting layer cutting computation model mathematically. The method has the advantages that by using the characteristics of multi test methods, the stress is accurately designed in a multi-layer complementary way, and the correction method based on multi test methods is provided; the defect that the traditional single test method has bad accuracy is overcome; and the deformation compensation function is introduced to correct the test deviation, so that higher test accuracy is achieved. The method is reliable, rational in analysis, notable in effect and environmental-protection, and can effectively improve the innerstress computation accuracy of the aluminum alloy thick plate and the like, thereby being suitable for industrialization and scientific research.

The invention relates to a supercritical water-oil displacement simulator and method. The supercritical water-oil displacement simulator comprises a high-pressure metering pump, an outlet of the high-pressure metering pump is connected with the pure water side of a crude oil middle piston container, the pure water side of a formation water middle piston container and the inlet end of a supercritical water generator at the same time, the oil side of the crude oil middle piston container, the formation water side of the formation water middle piston container and the outlet end of the supercritical water generator are connected with the inlet end of a core simulating device at the same time, the outlet end of the core simulating device is sequentially connected with a heat exchange system, a back-pressure adjusting device and a gas-liquid separating device, and the core simulating device is arranged in a temperature tracking and monitoring system which is used for adjusting temperature of the wall surface of the core simulating device so that a constant wall temperature boundary or adiabatic boundary can be formed on the wall surface. Constant temperature of a core can be achieved in the oil saturating process, adiabatic boundary conditions are formed in the oil displacement stage, energy loss of injected hot fluid can be avoided, the influence on test results by external heating is eliminated, and the simulator is suitable for researching the displacement rule of supercritical water-oil displacement.

The present invention discloses a welding residual stress measurement method based on the ABAQUS. The method comprises: according to the geometry of the test piece, establishing a 3D geometric model of the welded test piece; performing global mesh generation on the model; loading material data and thermal boundary conditions to simulate the welding process; and finally solving the temperature field and the stress field. The numerical simulation results of the method disclosed by the present invention have high accuracy and can be used as an effective tool for welding process design and parameter optimization.

A method of reducing distortion in a spray formed rapid tool includes the steps of making a model of a desired tool and constructing a ceramic pattern as the inverse of the model. The method also includes the steps of building a thermal model of the desired tool from a solid model of the ceramic pattern and applying thermal boundary conditions to the thermal model based on known conditions. The method also includes the steps of running the thermal model to produce a temperature distribution of the desired tool and determining any temperature deviations in the temperature distribution above a predetermined value. The method further includes thermally spraying a metal material against the ceramic pattern to form the desired tool if there are no temperature deviations in the temperature distribution above the predetermined value.

The invention discloses a thermal analysis method of an aero-engine component, which comprises the following steps: a model is established by comprehensively considering the structure of the aero-engine component, the radiation heat transfer in the flow form, the convection heat transfer and the heat conduction factors; according to the model, the boundary conditions of heat transfer, geometricaldimensions, physical parameters and flow parameters are obtained; according to the boundary conditions, geometrical dimensions, physical parameters and flow parameters, the wall temperature of hot end, wall temperature of cold end, surface temperature of sandwich material, outlet temperature of sandwich chamber, average temperature of sandwich chamber and heat flux are calculated. The invention comprehensively considers the influence of radiation heat transfer, convection heat transfer and heat conduction of high-temperature components, and provides and verifies the calculation method and program realization considering radiation heat transfer, thereby solving the thermal analysis problem of engine components considering radiation effect under high-temperature environment.

The invention discloses a temperature analyzing method for a lockup clutch friction plate of a hydraulic torque converter. The temperature analyzing method comprises the following steps of: 1, obtaining controlling oil pressure and friction rotation speed of a lockup clutch of the hydraulic torque converter through a CAN (controller area network) line; 2, calculating heat-flow density of the lockup clutch friction plate: the heat-flow density q is obtained through a formula: q= mu Rp delta omega, wherein mu is a friction factor of the friction plate, R is the semidiameter of the friction plate, the unit of the R is millimeter, p is the controlling oil pressure of the lockup clutch, the unit of the p is Pa, the delta omega is the sliding friction speed difference of the lockup clutch, and the unit of the delta omega is rpm; 3; establishing a two-dimensional simplified model of the lockup clutch of the hydraulic torque converter; 4, establishing a three-dimensional flow fixed coupled model of the lockup clutch of the hydraulic torque converter, generating a grid and setting a boundary condition, wherein the boundary condition comprises a material characteristic, a boundary convective heat transfer coefficient, a periodicity boundary, an operation oil inlet parameter, an operation oil outlet parameter and a friction plate heat boundary condition; and 5, simulating and calculating the temperature of the converter lockup clutch friction plate of the hydraulic torque converter.

The invention discloses an Invar steel PMIG weaving welding temperature field and a deformation simulation method.A thermal-mechanical coupling model used for analyzing an Invar steel thick plate temperature field and a stress strain field; through reasonably setting welding technology parameters, a swinging route and pre-deformation, the established coupling model is solved and calculated by the utilization of related finite element analysis software, the Invar steel temperature field and strain field distribution and deformation conditions under the corresponding welding technology parameters are obtained through loading and solving thermal boundary conditions and mechanical boundary conditions, and then the welding technology is instructed and optimized.

The invention relates to the technical field of simulation methods of a temperature field, and discloses a simulation method of a temperature field of a cylinder head of a low-speed diesel engine. The method comprises following steps: establishing the geometric model of a cylinder head; defining material properties according to the physical property parameters of the materials of the cylinder head; carrying out mesh generation according to the defined material properties; defining boundary conditions which comprise the definitions of a displacement boundary condition and a thermal boundary condition; loading heat source and solving the temperature field with a Newton iteration method; and analyzing and evaluating the result of the temperature field. The simulation method of the temperature field of the cylinder head of the low-speed diesel engine has the advantages of being low in cost and short in period through the method of computer simulation, reduces the manufacturing quantity of a testing cylinder, and therefore can effectively save resources.

A thermal control system having an initial bore condition and a thermal boundary condition for an MRI includes a thermal controller adapted to set at least one dynamic limit on power input into an MRI gradient coil. The dynamic limit is determined for a first commanded prescription as a function of the initial bore condition and the thermal boundary condition.

The invention provides a method for predicting deformation of an additive manufacturing part. According to the method, a three-dimensional solid model of a preprinted part is established according tocharacteristics and technological characteristics of additive manufacturing and is subjected to heat transfer analysis according to actual printing paths, then corresponding distribution functions ofthe temperature in time and space are constructed by an additive manufacturing temperature field when a moving heat source activates each layer of metal units in the heat transfer analysis by data fitting software, and the corresponding distribution functions in mechanical analysis are used as thermal boundary conditions for activating each layer of metal units. Thus, not only can the calculationprocess of mechanical analysis be simplified, but also accuracy of mechanical analysis results can be effectively ensured, and efficiency of deformation prediction of the additive manufacturing part is greatly improved. Compared with a traditional finite element numerical simulation method, the method has the advantages that calculation time is shortened by 90% or higher and calculation efficiencyis improved by 10 times, and the method is suitable for large-scale calculation of large parts in additive manufacturing.

Embodiments of the invention disclose an efficient numerical simulation method and device for an urban scale geothermal field group well system. The method comprises the steps of obtaining geologicaldata of a geothermal field to determine a range of a model calculation area, and building a three-dimensional geological numerical model of a research area according to a geological section map; determining water-heat initial conditions of the model; partitioning heat storage parameters, and distinguishing a heat storage layer and a heat coverage layer; determining water-heat boundary conditions of the whole simulated heat storage system; simplifying geothermal wells into one-dimensional linear geometry, and adding the geothermal well linear geometry into the model according to a distributiondiagram and coordinates of the geothermal wells; setting inflow and outflow boundary conditions of temperatures and fluids for the geothermal wells, and considering a heat exchange process of the fluids in the geothermal wells and surrounding rock masses by adopting an equivalent heat exchange coefficient, wherein the influence of a sleeve pipe and a mortar layer is also contained in the equivalent heat exchange coefficient; and setting a time period function for the model and discretizing each year into two time periods including a heating season and a non-heating season. The difficult problems of grid division and calculation speed of three-dimensional simulation of urban scale geothermal fields can be solved.

The invention relates to a bionic principle-based structure cooling channel layout optimization design method. The method comprises the steps of firstly building a geometric model for design according to the shape size of a design object, then applying a heat source and heat boundary conditions to a structure according to actual working conditions, and performing finite element heat analysis to obtain heat dissipation of each unit; and by adopting a cooling channel layout optimization design mathematic model, repeatedly updating a section area of a cooling channel according to a growth mechanism of a natural branch system, namely, a branch always grows according to a direction and a speed of enabling the whole system function to be optimal, until the total volume of the grown cooling channel reaches a predetermined total volume upper limit qV0. Through the optimization design method, the cooling channel layout is reasonable and the cooling efficiency can be improved; and compared with empirical design and analogical design adopted by a conventional cooling channel layout, an optimal layout under complex heat boundary conditions can be realized.

The invention provides a diamond anvil cell sample temperature measuring method, and belongs to the technical field of temperature measurement under high temperature and high pressure. Firstly diamondanvil cells are assembled; thermocouples are arranged on the designated positions of the bottom surface and the side edges of two diamond anvil cells to read the temperature of the corresponding points; and then fitting calculation of the temperature gradient is performed: a finite element model is established according to the real experimental size, the bottom surface temperature of the diamondanvil cells measured by the experiment acts as the thermal boundary condition to be inputted to the finite element model, the anvil face input temperature of the two diamond anvil cells is changed until the simulation temperature of the temperature measuring points of the side edges if fit with the temperature read by the experiment, and then the anvil face input temperature of the diamond anvil cells is the real experimental temperature and is also the sample surface temperature. The method is simple, easy to implement and great in experimental repetition so that the problem that the thermocouples cannot be conveniently arranged because of the small size of the sample chamber can be solved; and the experimental error caused by substituting the sample temperature by the side edge temperature of the diamond anvil cells can be compensated.

The invention discloses a bridge structure temperature field monitoring method. The method comprises the following steps: S1, respectively calculating convective heat transfer and radiant heat transfer by utilizing an actually measured air temperature and a real-time air speed; S2, calculating solar radiation by utilizing the daily ordinal number and the solar radiation on the horizontal plane; S3, calculating a thermal boundary condition of the bridge according to the convective heat transfer, the radiant heat transfer and the solar radiation; S4, determining a heat exchange model of the bridge according to the thermal boundary condition of the bridge; and S5, solving the heat exchange model of the bridge by utilizing finite element numerical simulation to obtain a temperature field of the bridge, and completing monitoring of the temperature field of the bridge structure. The method does not need to depend too much on actually measured temperature data, only needs to install meteorological stations including temperature sensors, wind speed sensors and a total radiometer at a bridge site, and suggests that a few temperature sensors are installed on a bridge and model parameters areadjusted during initial use; cost is low and installation and usage are convenient; the monitoring range is wide, and full-bridge temperature monitoring can be realized.

The invention relates to a method for predicting a small-angle welding temperature field of rotating arc low-alloy structural steel. The method comprises the steps that according to the welding conditions of the small-angle welding temperature field of the rotating arc low-alloy structural steel, an experiment board is selected, and welding thermal cycle parameters are measured through a thermocouple; a model is built and a mesh is divided for specific conditions; a model thermal boundary condition is determined; a rotating arc heat source model is calculated, the cross section state of the rotating arc heat source model is extracted and compared with the actually measured cross section, the error of the cross section state and the actually measured cross section is decreased through fine adjustment, the boundary conditions and the heat source model are applied to rotating arc low-alloy structural steel welding simulation analysis, the temperature field is calculated, the welding thermal cycle parameters are extracted, and prediction of the small-angle welding temperature field of the rotating arc low-alloy structural steel is completed. The numerical simulation technology based on a small number of process tests is adopted, quantitative analysis and simulation of the small-angle welding temperature field of the rotating arc low-alloy structural steel are achieved, the experiment cost and workloads are reduced, and a guiding significance is provided for development and application of rotating arc welding.

The invention discloses a simulation method and device for multi-physical-field coupling of an electric reactor and a storage medium. The method comprises the steps of acquiring geometrical parameters, material data and working condition information of an electric reactor; establishing a geometric model of the reactor according to the geometric parameters, and performing mesh generation on the geometric model to obtain a plurality of geometric components; setting a material attribute corresponding to each geometric component according to the material data; setting boundary conditions of the reactor according to the working condition information; wherein the boundary conditions comprise an electromagnetic field boundary condition, a thermal boundary condition and a flow field boundary condition; according to preset solving settings, electromagnetic field analysis, making thermal and flow field analysis one by one to obtain analysis result data; and carrying out post-processing on the analysis result data to judge whether the design of the reactor is reasonable or not. According to the invention, electric-magnetic-thermal-fluid coupling field analysis of the electric reactor can be realized, and the design of the electric reactor is optimized, so that the electric reactor can operate more stably.

The invention relates to a controllable coolant pump. The aim of the invention is to develop a controllable coolant pump (having a gate valve) driven by a belt pulley, allowing significant reduction in both pollutant emissions and frictional losses and fuel consumption over the entire working range of the engine, and allowing reliable actuation of the gate valve with very low drive power, even under unfavorable thermal boundary conditions, such as in proximity of the turbocharger, as well as under very limited installation space, and ensuring continued functioning of the coolant pump (fail-safe) even if the controller fails, and characterized by a very simple, low-cost production and assembly design ''standardized'' for different pump sizes, thereby ensuring continuously high operational reliability at a high volumetric efficiency, and requiring no air-free charging in the factory, and that can be simply and inexpensively integrated in the engine management system. The controllable coolant pump according to the invention, having a gate valve and driven by a belt pulley (3) and having a hydraulically actuated gate valve connected to a ring piston (29) is characterized in that an axial piston pump (61) disposed in the pump housing (1) is driven and ''operated'' by means of a swashplate (32) having a suction groove (33) and disposed on the back side of the flywheel (5), the ''pumped volume flow'' thereof being controlled in a defined manner by means of a solenoid valve (13) such that precise displacement of the hydraulically actuated gate valve is ensured.

The invention discloses a method for measuring a nonuniform temperature field in a wall and the wall thickness, and the method comprises the steps: phase differences separately measured by using an ultrasonic longitudinal wave method and an ultrasonic transversal wave method are obtained, the phase differences are used as the input quantity, the equivalent thermal boundary condition and wall thickness are obtained based on a multiparameter inversion method of the inverse heat conduction problem, and the temperature field distribution states of the furnace wall or tube wall in different times are obtained according to the direct heat conduction problem. The method can be used for measuring the nonuniform temperature field in structures such as a blast furnace wall, a high-temperature steam pipeline wall and the like under a wall thickness unknown condition.

The invention discloses a projection objective structural optimization method for reducing deformation of an extreme ultra-violet lithography system, which adopts finite element simulation software to build a finite element model of a reflector to be optimized with the center thickness and the border width of the reflector as parameters. Then thermal boundary conditions and structural boundary conditions of the reflector are loaded, the finite element simulation software is used for obtaining structural distortion of each panel point of the reflector, and therefore, a two-dimensional (2D) structural distortion root mean square (RMS) value of a clear aperture area of the reflector is calculated. The center thickness and the border width of the reflector are set to be design variables in the finite element simulation software, the 2D structural distortion RMS value of the clear aperture of the reflector is set to be a target function, the center thickness and the border width of the reflector are changed, and the target function is approximately smallest. The center thickness and the border width of the reflector corresponding to the minimum value of the target function are considered to be optimizing results. The projection objective structural optimization method can reduce deformation of each face of the reflector and reduce influences of deformation of the reflector on photoetching performance of an exposure system without introducing additional-adding devices.