114 results about "Boiling heat transfer" patented technology

The invention discloses a micro-channel flow boiling enhanced heat transfer device based on a bionic structure. The device comprises a micro-channel structure base body, a channel inner surface wettability regulation and control layer, a working medium inlet and a working medium outlet. A bionic structure microchannel is arranged in the microchannel structure base body, the inner wall of the microchannel structure base body is provided with a micron-scale or nanometer-scale texture structure, the bionic structure microchannel is composed of a main channel and branch channels of at least three levels of fractal hierarchical structures, the width ratio of the branch channels is 1: 0.2-0.5, and the length range of the branch channels is 2-10 mm. And the contact angle gradient of the wettability regulation and control layer on the inner surface of the channel is 5-120 degrees. The tail end of each branch channel is provided with a bubble capturing groove with the diameter of 5-10 mm and the depth of 5 mm. The device can improve the boiling heat transfer coefficient, reduce the flow resistance and improve the bubble generation and desorption process, and is suitable for the fields of heat dissipation of high-heat-flux electronic equipment, aerospace heat management, chemical reaction and the like.

The invention belongs to the technical field of enhanced boiling heat exchange, and designs a non-uniform fractal micro-pit structure and super-hydrophilic composite surface, which comprises a micro-pit structure, a micro-pit structure area and a super-hydrophilic channel, the micro-pit structure and the micro-pit structure area can be obtained through a nanosecond laser micromachining technology, a non-uniform fractal micro-pit structure is formed on the surface of the copper base, and the super-hydrophilic channel can be obtained in a chemical oxidation mode. According to the non-uniform fractal micro-pit structure and super-hydrophilic composite surface, the number of vaporization cores can be increased under the low heat flux, the directional bubble convergence process can be achieved under the medium heat flux, liquid backflow can be enhanced under the high heat flux, bubble film forming can be delayed, and the critical heat flux can be increased; therefore, the enhanced boiling heat exchange effect under different heat flux densities is achieved.

The invention discloses a supercooled boiling and boiling critical numerical simulation method and device, a medium and equipment, and relates to the technical field of heat transfer science. The method comprises the following steps: establishing a mixture model, and adding inertial acceleration volume force generated in a non-inertial system into a momentum conservation equation of the mixture model to obtain a non-inertial system mixture model; establishing a bubble dynamic model according to the various acting forces acting on the wall bubbles and the inertial acceleration volume force, and obtaining a plurality of bubble characteristic parameters according to the bubble dynamic model; establishing a wall surface heat flow distribution model, and substituting the bubble characteristic parameters into the wall surface heat flow distribution model to obtain a wall surface heat flow density model; and coupling the wall surface heat flux density model and the non-inertial system mixture model to obtain a two-phase boiling heat transfer and boiling critical calculation model which is used for simulating a boiling heat transfer working condition under a motion condition. The numerical simulation method is few in computing resources, wide in application range, good in convergence and high in prediction precision.

The invention relates to the technical field of phase change heat transfer, and particularly discloses a multi-field coupling enhanced phase change heat transfer visualization experiment research device which comprises a vacuum cavity provided with a heat exchange block mounting hole, an auxiliary cooling device mounting hole, first to fifth thermocouple mounting holes, a wire mounting hole, an electric field, a magnetic field mounting position and an electromagnetic wave incident port. The heat exchange block is mounted in the heat preservation sleeve; the auxiliary cooling device is mounted in the auxiliary cooling device mounting hole; a heating rod mounting hole is formed in the bottom of the end cover; the heating rod is mounted in the heating rod mounting hole; the heat preservation sleeve is installed in the heat exchange block installation hole and provided with an ultrasonic oscillation generating device installation position. The electric field-magnetic field generating device is provided with an electric field generating device and a magnetic field generating device. The influence of the superheat degree and the supercooling degree on enhanced thin liquid film boiling heat transfer and enhanced condensation heat transfer can be researched by changing the heating rod and the heat exchange fluid flow.

A porous layer is arranged on the surface of the inner wall of a micro-channel in the micro-channel heat exchanger, and the porous layer is filled with a lubricating agent; and anodizing the inner wall of the micro-channel to obtain a porous layer. The invention further provides a preparation method of the ultra-smooth micro-channel heat exchanger, which comprises the following steps: taking the micro-channel heat exchanger as an anode, performing anodic oxidation treatment on the inner wall of the micro-channel, and preparing the porous layer on the surface of the inner wall of the micro-channel; and then the porous layer is filled with a lubricating agent, and the ultra-smooth micro-channel heat exchanger is obtained. The invention further provides application of the ultra-smooth micro-channel heat exchanger in electronic devices. The ultra-smooth micro-channel heat exchanger has good corrosion resistance and high boiling heat exchange efficiency.

The invention provides a steam generator heat transfer pipe dirt growth simulation and boiling heat transfer test device. The device comprises a simulation heat transfer pipe system, a reaction kettle system and a sliding thermocouple system, dirt growth speed regulation and control of a compact layer and a sparse layer of the heat transfer tube are realized through direct electric heating and increase of Fe ion concentration, and the problems of slow growth and large difference between dirt pore distribution and a power station in a traditional dirt experiment are solved; measurement of data at multiple positions in the circumferential direction of multiple heights is achieved through fine control of the sliding thermocouple, the reliability and repeatability of the data are verified through mutual verification of the data, and the repeatability and reliability of the data can be analyzed under the same working condition in combination with dirt observation and sampling analysis after an experiment. And a reliable coupling relationship between dirt growth and boiling heat transfer characteristics is obtained.

The invention discloses a large-temperature-difference high-temperature fused salt and water heat exchange steam production system and a control method. The system comprises a fused salt storage tank, a high-pressure hot water storage tank, a fused salt-water / steam heat exchanger and a steam pocket, the fused salt-water / steam heat exchanger is of a multi-shell-pass spiral coil pipe type heat exchanger structure. A plurality of limiting inner barrels are arranged in a shell barrel to form annular cavities of different levels, a plurality of heat transfer pipes are connected in parallel and wound around a central pipe or the wall of an upper-level fiber inner barrel to form spiral coil pipes, and a plurality of sets of spiral coil pipes are arranged in the annular cavities respectively. A shell side fused salt liquid inlet, a shell side fused salt liquid outlet, a pipe side water inlet and a pipe side steam outlet are formed in the shell cylinder body; the fused salt-water / steam heat exchanger is connected with an outlet and an inlet of the fused salt storage tank and further connected with a water outlet and an inlet of the high-pressure hot water storage tank. High-temperature thermal shock damage of the heat exchanger and pipeline blockage caused by fused salt solidification can be effectively eliminated, membrane boiling of water is inhibited, the heat transfer efficiency is high, and system operation is safe and reliable.

The invention discloses a subtractive etching micro-nano multistage rough structure copper surface for strengthening boiling heat transfer and a preparation method thereof, and relates to the technical field of micro-nano composite structure strengthening phase change heat transfer. The etched micro-nano multistage coarse structure completely covers the surface of the copper substrate, the micro-nano multistage coarse structure comprises micron-scale concave cavities, nano-scale concave cavities / holes and nano-scale granular bulges, and the micron-scale concave cavities, the nano-scale concave cavities / holes and the nano-scale granular bulges jointly form a multistage structure; performing ultrasonic cleaning on the target metal substrate by using a cleaning solution; and a mixed aqueous solution of ammonium persulfate and chlorate is used as an etching solution, and the cleaned target metal substrate is left to stand in the etching solution for etching. And after the etching is finished, cleaning to obtain the etched micro-nano composite rough structure surface. Ammonium persulfate and chlorate are used as solutes, and the mass ratio of the solutes to the solvent is 1: 3. The mass ratio of the ammonium persulfate to the chlorate in the solute is (1: 9)-(3: 7). The method has high production efficiency, shows good thermal stability in a boiling test, and is beneficial to industrial large-scale application and production.

The utility model provides a novel vertical multi-stage evaporation reboiler which comprises a reboiler shell, a plurality of liquid collecting tanks are mounted in the reboiler shell, a gas channel is arranged between one end of each liquid collecting tank and the inner side of the reboiler shell, and a heat exchange tube is mounted in each liquid collecting tank; a feed liquid distributor is correspondingly arranged at the upper part of the uppermost liquid collecting tank or a feed liquid distributor is correspondingly arranged at the upper part of each liquid collecting tank; the feed liquid distributors are connected with the bottom of the reboiler shell through feed liquid pipelines; the lower part of the reboiler shell is connected with a liquid inlet pipeline, and the upper part of the reboiler shell is connected with a gas outlet pipeline; a plurality of liquid collecting tanks are designed, so that step-by-step heating of fluid can be realized; therefore, the reboiler has higher boiling heat transfer efficiency under a lower heat transfer temperature difference, the energy utilization rate is improved, and the application range of the reboiler is expanded; in addition, when the cold fluid can flow step by step, the uniform heat transfer effect is achieved.

The invention discloses a large-density-ratio two-phase boiling heat transfer simulation method based on a lattice Boltzmann algorithm. The method comprises the following steps: solving a corresponding pseudo potential according to density and a corresponding non-ideal state equation, calculating various forces in a multiphase system, and calculating a source item in a gas-liquid phase change model; calculating relaxation factors corresponding to different moments in the multiphase flow field and the temperature field according to entropy stability conditions and specific attributes of fluid, and executing collision and migration according to an evolution equation obtained by calculation and substituted into the multiphase flow field and the temperature field; and calculating macroscopic physical quantities such as density, speed and temperature at each grid point according to the density and temperature distribution function, and judging whether iteration is ended or not. The two-phase density ratio in simulation of the gas-liquid boiling problem can be effectively improved, simulation of the phase change conversion process of water and water vapor under the real condition is achieved, and the simulation problem of complex multi-phase flow heat transfer is solved.

The invention provides a multi-physics-field coupled core particle microchannel boiling heat exchange experiment testing device and testing method, and belongs to the field of boiling heat exchange experiment testing devices. According to the invention, a laser thermal control module, a reflection temperature measurement module, a particle velocity measurement module, a three-dimensional micro-control module, a stress test module, a sound field test module and an electric field test module are creatively integrated, and flexible combination and active control of each physical field are realized through standardized interfaces. Local point heating is achieved through pulse laser, non-contact transient surface temperature analysis is achieved through a heat reflection method, a micro-nano scale phase change flow field is analyzed through a PIV system, local thermal stress is measured through an embedded film strain gauge set, and automatic alignment and cooperative measurement of all modules are achieved in combination with a high-precision piezoelectric displacement table. Through modular design and system integration, accurate coupling and cooperative measurement of multiple physical fields of light, sound, heat, force and flow on the core particle scale are realized.

The present invention discloses a composite microstructure surface that utilizes microtubes and micropores to synergistically enhance boiling heat transfer, comprising a microcolumn matrix and a plurality of microcolumn units distributed in an array on the microcolumn matrix. The microcolumn unit is composed of a plurality of microcolumns distributed in an array, and each microcolumn has microtubes symmetrically arranged on each side wall and micropores symmetrically arranged on the top. By adding micropores on the top surface of the microcolumn, the number of vaporization cores on the microstructure surface is effectively increased, the superheat of the surface is reduced, and thus the boiling heat transfer coefficient of the surface is improved; secondly, microtubes are provided on each side wall of the microcolumn, and by utilizing the interaction between microcolumns, micropores and microtubes in regulating the gas-liquid behavior during the boiling process, a multi-directional rehydration system is established from the rehydration channel to the microcolumn unit groove and the microtube rehydration, thereby enhancing the rehydration capacity of the surface, increasing the critical heat flux density of the surface, delaying the occurrence of boiling crisis, and achieving synergistic enhancement of the boiling heat transfer performance of the microstructure surface.

The application belongs to the technical field of hydrogen liquefaction, and provides a test platform and method for falling film boiling heat transfer characteristics of non-azeotropic refrigerant for liquid hydrogen, which comprises a gas filling system, a pre-cooling circulation system, a cryogenic circulation system and a falling film boiling test platform; the outlet and the inlet of the gas filling system are connected with the inlet and the outlet of the falling film boiling test platform through pipelines; the pipeline between the outlet of the gas filling system and the inlet of the falling film boiling test platform passes through the pre-cooling circulation system and the cryogenic circulation system; the pre-cooling circulation system and the cryogenic circulation system provide temperature conditions for hydrogen liquefaction; the real situation under the pre-cooling and cryogenic circulation systems is comprehensively considered; accurate measurement of temperature and pressure is realized; reliable data basis is provided for evaluation and optimization of the flow and heat transfer characteristics of the non-azeotropic refrigerant for liquid hydrogen; and the falling film boiling heat transfer characteristics of the non-azeotropic refrigerant for liquid hydrogen can be fully understood.

The present application relates to a kind of slab continuous casting high temperature casting blank surface temperature on-line detection method, belong to slab continuous casting technical field, comprising the following steps: S1: based on film temperature sensor production detection piece and measuring disc, and according to process requirement in corresponding two cooling zone sector segment clamp roll installation;S2: local transient heat conservation analysis is carried out to temperature measurement node, obtains the heat balance equation of considering conduction, convection and radiation heat transfer mode;S3: based on single node temperature time series discrete algorithm and according to temperature detection value, the heat balance equation is carried out numerical calculation, to reconstruct the actual temperature of the side above water film on slab surface is determined;S4: boiling heat transfer mechanism theory analysis is carried out, determines its corresponding critical characteristic temperature and the heat transfer mode where it is;S5: under stable film boiling heat transfer mechanism, according to classic flat plate temperature analytical theory, combined with the temperature of the side above water film on slab surface obtained again reconstruction calculation, to finally obtain the real temperature value of slab surface.

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 single-sintering porous metal mold with different pore diameters for boiling heat exchange, and relates to the field of preparation equipment of porous metal for boiling heat exchange. The die comprises an outer die sleeve, a lower die base and three functional pressure heads, specifically, basic metal powder is compacted through a basic pressure head with a flat end face, then pore channels are pressed out through a pore-forming pressure head with thin cylindrical protrusions, finally, the pore channels are filled with powder with different particle sizes through a filling pressure head with matched through holes, and finally porous metal structures with different pore diameters are obtained through single-time sintering. The preparation process of porous metal with different pore diameters is simplified, the cost is reduced, pore collapse caused by secondary hole machining is avoided, and meanwhile the nucleation efficiency and the heat exchange performance of boiling heat exchange can be remarkably improved through the porous structures with different pore diameters.

This invention discloses a modular low-voltage switchgear suitable for smart grids, belonging to the field of low-voltage switchgear technology. It includes a cabinet with multiple module slots inside, each containing multiple auxiliary heat transfer components. Drawer units are installed within the module slots, and each drawer unit is equipped with a breathing heat dissipation unit. This invention replaces the rigid sealing structure with a multi-layer corrugated metal diaphragm assembly. It utilizes the corrugated elastic compression to absorb impact energy, automatically quenching flames through interlayer slits, and leverages the evaporation and condensation cycle of the phase change working fluid to achieve efficient heat conduction without occupying the internal installation space of the drawer unit. This solves the problem of limited heat dissipation capacity in explosion-proof switchgear. Furthermore, by mixing magnetic particles into the liquid phase change working fluid, the boundary layer is disturbed under the drive of the auxiliary heat transfer components, promoting bubble generation and detachment, significantly enhancing the nucleation boiling heat transfer coefficient.

The application discloses a high-flux heat exchange device based on a thermo-chemical reaction auxiliary, which comprises a heat exchange chamber and a chemical phase change working medium. The chemical phase change working medium comprises a liquid cooling base fluid and a reversible thermal decomposition solute. The thermal decomposition temperature threshold of the reversible thermal decomposition solute is lower than the physical boiling point of the liquid cooling base fluid under the current environment. When the temperature or pressure of the heat exchange surface reaches the thermal decomposition temperature threshold, the reversible thermal decomposition solute undergoes an endothermic decomposition reaction on the heat exchange surface, rapidly generates a large number of non-condensable bubbles and high-frequency separates, thereby triggering strong local micro-convection disturbance of the fluid and absorbing a large amount of chemical decomposition heat, and finally achieving heat dissipation of the heating element. The application accelerates the transfer of wall heat by using a thermo-chemical reaction, and improves the separation rate of bubbles at the solid-liquid interface, breaks the engineering resistance that bubbles are difficult to nucleate and efficiently separate in traditional boiling heat transfer, and realizes rapid and large absorption and transfer of the combined chemical reaction heat of the solute and the latent heat of vaporization of the base fluid.

The invention discloses a structured surface based on bionics and an optimization method thereof, and belongs to the technical field of thermal management, and according to the structured surface based on bionics and the optimization method thereof, through the multistage microstructure design of bionic ruellia grass blades, hexagonal columnar infinitesimal elements and conical mastoids are creatively fused, and collaborative optimization of wettability and boiling heat transfer performance is achieved. The I-level infinitesimal structure forms uniform fluid infusion microgrooves through a hexagonal columnar array, the surface roughness is remarkably improved, on the basis, the II-level infinitesimal structure adds a conical mastoid of a plane structure to the top of a columnar infinitesimal, the pinning effect is weakened through 5-micron round corner treatment, the apparent contact angle is further reduced, and the spreading diameter is further increased. According to the multi-stage structural design, vertical transportation of liquid is promoted through the capillary action and the Laplace pressure difference, the motion resistance of liquid drops is reduced through the smooth edge, the spreading limitation of a traditional structured surface is broken through, and a better wetting condition is provided for boiling heat transfer.

The invention discloses a high-pressure lower pool boiling experiment device and experiment system to meet the requirements of high-pressure lower pool boiling heat transfer performance test and visual shooting. The experimental device comprises a boiling container main body arranged between an upper cover plate and a lower cover plate, a heat conductor and a heat insulator, a boiling pool is arranged in the boiling container main body, an auxiliary electric heater is arranged in the boiling pool, and a visual window is arranged on the side face of the boiling container main body; the upper end of the boiling container body is hermetically connected with the upper cover plate, a heat conductor is arranged at the lower end of the boiling container body corresponding to the boiling pool, the heat insulator is hermetically arranged between the heat conductor and the boiling container body, and a pool boiling electric heater is mounted in the heat conductor; and a test piece connected with the heat conductor and used for reflecting heat transfer performance and bubble behavior is arranged at the joint of the upper end of the heat conductor and the boiling pool. The experimental device is resistant to high pressure, good in sealing performance and safety, and capable of achieving boiling heat transfer performance testing and visual shooting of pure refrigerants and refrigerant-lubricating oil mixture pools.

The present invention discloses a microelectronic device temperature control and heat dissipation system based on vapor-liquid phase change nanoemulsion boiling heat transfer, which relates to the field of thermal management technology of microelectronic devices, including a fan radiator, a circulating water pump, a controllable ultrasonic emulsification module and a heat exchanger connected in sequence. The water-cooled heat dissipation system adopts a vapor-liquid phase change nanoemulsion with phase change function (ultrapure water as a continuous phase and a low-boiling organic fluoride as a dispersed phase) as a heat exchange medium, and the configured emulsion is pre-filled into the pipeline of the water-cooled heat dissipation system. The controllable ultrasonic emulsification module is used to perform real-time online regulation of the emulsion parameters to match the heat dissipation requirements of the microelectronic device. By replacing the heat exchange medium of the water-cooled heat dissipation system, the heat dissipation performance is significantly improved compared with single-phase flow heat exchange under the same pump work and the same flow conditions, and the efficient temperature control and heat dissipation requirements of microelectronic devices with a junction temperature not exceeding 85°C are met, and the safe and stable operation of the microelectronic devices under the trend of miniaturization and high integration is guaranteed.