53 results about "Transient heat transfer" patented technology

A novel procedure is disclosed, that can be incorporated into Finite Element Analysis (FEA) or other similar analysis techniques, to obtain the steady state temperature distribution in a coupled transient heat transfer analysis rapidly as well as accurately. A scale factor is used to reduce the thermal inertia per unit volume (specific heat capacity) in regions of steady state temperature distribution, thereby hastening the achievement of steady state. An application of this procedure to estimate steady state temperature distributions within cutting tools, and the estimation of cutting tool wear based on the obtained steady state temperature distributions is shown as an example.

The invention provides a phase-field method-based microstructure evolution simulation method in a welding process in a transient state. The phase-field method-based microstructure evolution simulation method in the welding process in the transient state comprises the following steps of simplifying conditions and initializing a model, building the model according to parameters of a solidification process of a welding pool; building a macro transient heat transfer and growth rate model, wherein the welding pool is regarded to be formed by combining two semi-elliptical spheres, one semi-elliptical sphere is in a molten state and the other semi-elliptical sphere is in a solidified state in the welding process; building the macro transient heat transfer and growth rate model on the basis of hypotheses; building a microstructure evolution model and building a phase-field model of simulating microstructure evolution of the welding pool on the basis of the Ginzburg-Landau theory; and carrying out macro-micro coupling calculation, introducing a transient temperature gradient and a dendrite growth rate into the model, calculating a macro-micro coupled phase-field model and obtaining a microstructure evolution simulation result of the welding pool.

The invention provides a loose coupling modeling method for fluid-solid coupling heat transfer. The loose coupling modeling method is characterized in that the transient change process of a flow filed is ignored, and the global transient heat transfer process is assumed to be performed in a quasi-stable-state flow field. The method comprises the specific calculation procedures that 1, the flow field is updated, wherein only fluid is taken as a solving object, the fluid-solid coupling wall surface is set as a fixed temperature boundary of the fluid, and the flow field is solved through a stable-state CFD algorithm; 2, transient heat transfer is calculated, wherein the fluid and solid are both taken as the solving object, the fluid-solid coupling wall surface is set as a heat transfer coupling boundary, a momentum equation and a turbulent flow equation of the fluid are closed, and transient heat transfer is calculated until the flow field is updated for the next time and/or calculation stops; 3, the first step and the second step are repeated, wherein flow field updating and transient heat transfer calculating are alternately performed until the time arrives at the transient heat transfer termination moment. For the forced-convection heat transfer process of air in a pipe, by comparing the modeling method with a tight coupling calculation result of Fluent commercial software, the absolute error is 1 K or below, the calculation efficiency is improved by one order of magnitude, and the engineering calculation requirement is met.

The propensity for turbocharger turbine divider wall to crack in the turbine housing is minimized by matching the mass of the divider wall more closely to the transient heat transfer between said divider wall and the exhaust gas flowing past it. This is achieved by providing said divider wall having a cross-sectional shape defined substantially by a Log₂ curve.

The invention relates to a method for estimating heat transfer during water quench of an aluminum part. The method includes:

• • estimating the heat transfer of the aluminum part when a temperature of the part is greater than 500° C. using

q=α(ΔT)   (1);

• • estimating the heat transfer of the aluminum part when the temperature of the part is greater than T₂ and less than 500° C. using

q=k₁ΔT^{k<sub2>2 </sub2>}  (4);

• • estimating the heat transfer of the aluminum part when the temperature of the part is greater than T₁ and less than T₂ using a critical point function equation selected from:

q=c₁ΔT^{c<sub2>2 </sub2>}  (5).

Systems, methods, and articles to predict transient heat transfer, or temperature distribution, or both of a quenched aluminum casting are also described.

The invention discloses a method and an apparatus for obtaining a cyclic temperature field. The method comprises the steps of dividing a shaft into two or more component parts in a radial direction of a pipe column; according to well drilling state parameters, obtaining a heat transfer differential equation for calculating transient heat transfer information of the component parts in drilling and non-drilling processes; and performing discrete and numerical iteration processing on the heat transfer differential equation to obtain transient temperature distribution of the shaft. According to the method and the apparatus, the cyclic temperature field is calculated according to the well drilling state parameters, so that the cyclic temperature field can be obtained in the drilling and non-drilling processes, and the working efficiency of obtaining the cyclic temperature field is improved.

A heat exchange component includes a part configured for exchanging thermal energy, the part is formed of at least one solid state Martensitic transformation phase change material which is configured to readily undergo a solid-solid martensitic transformation from one crystalline structure to another different crystalline structure during a change in temperature in the normal and/or anticipated operating temperatures of the heat exchange component. In some embodiments, the system further includes a temporally-evolving external temperature/heat source which changes the temperature and resultant phase of the solid-state phase change material. The temporally-evolving external temperature/heat source may involve a solid conducting material or electronic/photonic component, a fluid, a plasma, and/or a radiation source. The heat exchange component may be configured as a flat plate, tube, finned structure, porous structure, graded structure, cold plate, heat exchanger, condenser, evaporator, or any component generally regarded as a thermal energy storage or heat transfer structure in various embodiments.

The invention discloses a material high-temperature thermophysical parameter rapid measurement method which comprises the following steps of according to the material thermophysical parameter-medium temperature-ultrasonic propagation characteristic, adopting an ultrasonic pulse-echo method to acquire an ultrasonic propagation time under the condition of transient heat transfer, inversing materialparameters in a heat transfer equation through the ultrasonic propagation characteristic, and rapidly measuring the thermophysical parameter of a material along with temperature change without loss and contact. By measuring for one time only, the method is capable of acquiring various material thermophysical parameters such as thermal conductivity, specific heat capacity or thermal diffusivity atdifferent temperatures from the room temperature to 400 DEG C, for example, when the temperature of the heating surface of a tested piece is raised to a preset temperature such as 400 DEG C, and has the outstanding advantages of rapid measurement speed, low cost, good universality, large measurement range and the like.

The invention discloses a method and a device for acquiring well cementation circulating temperature. The method comprises the steps that a shaft is divided into two or more components in the radial direction; a heat transfer differential equation for calculating transient heat transfer information of all the components is obtained in combination with radial and/or axial heat conduction information; and the heat transfer differential equation is subjected to dispersion and numerical iteration processing to obtain transient temperature distribution of the shaft. According to the embodiment, the well cementation circulating temperature is calculated in combination with the radial and/or axial heat conduction information, and the calculation precision of the well cementation circulating temperature is improved.

The invention discloses a method for measuring the inner wall temperature of a nuclear power station pipeline. The method comprises steps of establishing a unit transient heat transfer model; deriving a numerical computation method using the unit transient heat transfer model; measuring the outer wall temperature of a pipeline; and taking the measured outer wall temperature of the pipeline as a known quantity, and using the numerical computation method to obtain the inner wall temperature of the pipeline. Compared with the prior art, the invention has no requirement of drilling a hole in a tested pipeline, accurately masters temperature distribution information of the inner wall of the pipeline under a precondition that the structure of the primary loop pipeline (containing a radiative fluid) of a nuclear power station is not destroyed, achieves radioactivity containment more effectively, and improves operation security of the nuclear power station. Meanwhile, the outer wall temperature of the pipeline is directly measured instead of the temperature of a fluid in the pipeline, and thus computation of a heat transfer coefficient is omitted, and the computation accuracy of the pipe wall temperature field is obviously improved. In addition, the invention also discloses a device for measuring the inner wall temperature of the nuclear power station pipeline.

The invention provides a thermal response testing method for rock-soil thermal conductivity distribution. The method is used for testing the thermal conductivity of rock soil in different underground depth layers. The method comprises the following steps: firstly, establishing a multi-dimensional transient heat transfer model of a buried pipe heat exchanger by considering heat transfer in the depth direction of rock soil, simulating a longitudinal temperature distribution curve of fluid in the heat exchanger, then testing temperature distribution data of the fluid at different depths in the heat exchanger through experiments, and finally using a multi-objective optimization algorithm and directly adopting fluid temperature distribution data to predict rock soil thermal conductivity distribution data in multiple spatial layers at the same time. The rock soil thermal conductivity distribution tested by the method has high precision, the problem of poor convergence during layered testing of a traditional method can also be solved, meanwhile, the testing precision is not affected by depth, and the method is wide in applicability and high in testing efficiency.

The invention discloses a fluid temperature field analysis method for a double-pipe buried pipe heat exchanger, and belongs to the technical field of ground source heat pumps. The method comprises thesteps: establishing transient heat transfer equations of an inner pipe fluid and an outer pipe fluid, analyzing radial one-dimensional heat transfer in backfill soil and soil by adopting a compositemedium column heat source model, and respectively establishing a heat transfer model of the double-pipe buried pipe heat exchanger in two flowing directions (inner-in and outer-out: the fluid flows infrom the inner pipe and flows out from the outer pipe; wherein a fluid flows in from the outer pipe and flows out from the inner pipe); based on the established heat transfer model, setting a time step length, equally dividing an inner pipe fluid and an outer pipe fluid into a plurality of nodes along the axial direction respectively, dispersing a heat transfer equation, establishing an algebraicequation of each node, and calculating the temperatures of all nodes at each moment by adopting an iterative method, thereby completing the calculation of fluid temperature fields changing along withdepth and time in two flowing directions. The method has the characteristics of small calculation amount, high precision, wide applicability and the like.

The invention discloses a damage-free quick measurement method of a high temperature contact thermal resistance. According to the medium temperature-ultrasonic propagation characters, ultrasonic propagation time under a transient heat transfer condition is acquired by means of an ultrasonic-echo method, and further the inverse problem of thermo-conduction is subjected to optimization solution, sothat the interface contact thermal resistance parameters, changing with temperature, are measured in a quick, damage-free and non-contact manner. The method only needs simple measurement devices and short measurement period, is free of contact between a sensor and a to-be-tested test piece, so that interference due to the contact between the sensor and the to-be-tested test piece and limitation onmeasurement range due to high temperature resistance of the sensor are avoided.

The invention provides a device and a method for measuring temperature of a high temperature quartz fusing furnace based on a transient heat transfer theory. Three K type thermocouples are arranged in a quartz fusing furnace, wherein the quartz fusing furnace comprises a circular graphite sleeve; a boron nitride layer is wrapped on the graphite sleeve; a magnesium oxide layer is coated on the boron nitride layer; the three K type thermocouples are located in a same plane of the quartz fusing furnace and are distributed along the radial direction of the quartz fusing furnace on the basis of the axis of the graphite sleeve; the three K type thermocouples are connected with a computer through a wire and a signal processing device; the computer is used for calculating the temperature of the quartz fusing furnace according to the temperature measured by the three K type thermocouples. According to the invention, a plurality of K type thermocouples with temperature resistance limit of about 1200 DEG C are adopted for indirectly measuring the high temperature in the quartz fusing furnace, the measuring precision is high and the cost is low.

The invention discloses a thin-wall pipe material heat conductivity coefficient calculating method adopting a transient heat transfer calculation model and belongs to the field of solid-material thermophysical property measurement. The thin-wall pipe material heat conductivity coefficient calculating method includes: putting forward a new thin-wall pipe heat conductivity coefficient calculating model-a Hot Spring model and giving out a concrete formula; measuring to-be-measured temperature points in the model by applying a temperature sensor, and performing fitting on response data of the measured temperature time to acquire a time parameter sigma; determining the formula of the final Hot Spring model and calculating out heat conductivity coefficient of a thin-wall pipe material according to the slope of the formula. Compared with the prior art, the thin-wall pipe material heat conductivity coefficient calculating method has the advantages that reprocessing of the to-be-measured sample is not needed, experiment procedure is simplified, and precision in measuring the heat conductivity coefficient of the to-be-measured sample of the kind is improved.

The invention discloses a combined heat and power generation system day-ahead scheduling method based on heat supply network partial differential equation constraint. The technical scheme comprises: establishing a partial differential equation model capable of reflecting the transient heat transfer characteristic of a heat supply network based on the first law of thermodynamics; Secondly, carryingout difference processing on the heat supply network partial differential equation, taking an algebraic equation set obtained by difference as a partial constraint condition, and taking the minimum daily operation cost as an objective function to establish a day-ahead optimization scheduling model of the combined heat and power generation system; And finally, according to the heat supply networkpartial differential equation constraint-based combined heat and power generation system day-ahead scheduling model, determining a scheduling plan of each device in the system, a planned power of a connection line and an operation state of the heat supply network. The optimal scheduling method provided by the invention can reflect the real operation state of the heat supply network and improve theoperation economy of the combined heat and power generation system.

The invention provides a method for determining the transient temperature of air pre-cooled and pre-heated concrete aggregates. In the process of pre-cooling and pre-heating the aggregates through air, the aggregates are naturally stacked in a storage bin and form a mutual coexistence combination with gaps; therefore, the aggregates in the storage bin and the gaps form a kind of porous medium; a convective heat transfer process of air at the positions of the aggregates in the storage bin and the gaps can be regarded as an unstable-state heat conduction process generated under the action of convective heat transfer at the position of an air inlet section of the porous medium of the aggregates and the gaps; and the unstable-state heat conduction process of the porous medium of the aggregates in the storage bin and the gaps is equivalent to the unstable-state heat conduction process of a three-dimensional cube under the third boundary condition. Because four sides of the storage bin are insulated and only the air inlet section is in the heat transfer process under the third boundary condition, the transient temperature solution of the storage bin, namely the three-dimensional cylinder, can be simplified to the transient heat transfer problem of a one-dimensional infinite plate.

The invention discloses a generative design method for a special-shaped fuel structure of a fast neutron reactor core. A particle discretization method is combined with a transient heat transfer theory to construct a fast neutron reactor core temperature field simulation solving tool; physical parameters of the control particles are changed by means of isogeometric mapping to push the shape and size of the fuel structure to change, and an optimal structure is found through loop iteration; according to the method, the isogeometric analysis method is adopted to design the special-shaped fuel structure, the complicated grid division process is avoided, and the calculation time is saved; self-adaptive mesh refinement can be realized to obtain an optimal heat transfer structure; the design boundary is described by a function, the structure contour is clearer, and the design precision is higher.