122 results about "Critical heat flux" patented technology

An apparatus for cooling single and multiple high-flux and ultra-high-flux heat dissipating devices, comprising a liquid coolant module having a base plate and a cover plate defining therebetween a liquid coolant chamber with a liquid coolant inlet port and a liquid coolant outlet port in fluid communication with the liquid coolant chamber; at least one heat dissipating device mounted to the liquid coolant module; a multi-level-cooling-enhancement stud mounted upon each heat dissipating device and disposed within the liquid coolant module; and apparatus for inducing phase change nucleate boiling of a subcooled liquid coolant within the liquid coolant module to enhance its cooling performance.

The phase change heat-accumulating heat pump water heater includes mainly compressor, evaporator, fan, throttle, filtering drier, cold water inlet pipe, hot water outlet pipe, thermal circulating pipe and phase change heat accumulator. The phase change heat accumulator consists of mainly temperature sensor, casing, insulating material, inner container, phase change heat-accumulating material and hext exchanging pipe. In the said water heater, the evaporator absorb heat from the air source, the compressor produce power by means of electric energy, and the phase change material stores heat and heats water. Some electric heater may be also set inside the phase change heat accumulator optionally as auxiliary heater. The present invention has small size, light weight, convenient use and flexible installation.

The invention relates to a coupling analysis method of a rod cluster subchannel and a critical heat flux mechanism model. The coupling analysis method comprises the following steps: firstly, setting the average heat flux qo of rod cluster channels, and calculating thermo-hydraulic parameters in the channels by adopting a subchannel analysis method; secondly, when the thermo-hydraulic parameters obtained through calculation in the step 1 reach a stable state, correcting and converting the obtained subchannel thermo-hydraulic parameters into a control volume of the critical heat flux mechanism model, judging a critical heat flux occurrence type, calling a departure nucleate boiling type or dry type critical heat flux mechanism model, and solving critical heat flux qCHF; and thirdly, judgingwhether critical heat flux can occur in the hottest channel, if conditions are not met, returning to the step 1 and modifying the preset average heat flux qo of the channels, and repeating the step 1and the step 2 until the conditions are met. The coupling analysis method provided by the invention has the advantages that the critical heat flux in the rod cluster subchannel can be effectively predicted, data dependency is reduced, application range is widened, and the coupling analysis method provided by the invention is significant on design and safety analysis of a reactor.

The invention discloses a resistance distribution-based method for analyzing a sub-channel with a grid mixing effect. The method comprises the steps of collecting experimental data of multiple mixing grids including a mixing grid of a to-be-analyzed reactor core in different working conditions, fitting a momentum source term relational expression capable of reflecting mixing performance of key parts of the mixing grids, and adding the momentum source term relational expression to a corresponding momentum conservation equation; and by solving a mass conservation equation, the momentum conservation equation and an energy conservation equation, obtaining more accurate local thermo-hydraulic parameters in the reactor core, thereby enabling prediction of a critical heat flux (CHF) value and a CHF position to be more accurate. The method is not limited by a structure and a solving method of a sub-channel program, and can be widely applied to the calculation of various types of sub-channel programs including a sub-channel program of a uniform flow model, a drift flow model or a two-fluid model.

The invention relates to a high heat flux density boiling enhanced heat exchange technology, in particular to amicroelectronic chip high efficiency cooling technology with a high heat flux density, particularly the boiling enhanced heat exchange structure of chips and the fabrication method thereof, which is characterized in that a plurality of lug bosses with a column structure are corroded on the surface of a chip; a SiO2 layer is splashed on the surface of the chip with the lug bosses; and the SiO2 layer is corroded to form a porous structure. The boiling enhanced heat exchange structure of chips can provide sufficient bubble nucleation number and a larger effective heat exchange area under the circumstance of a lower wall surface superheat degree, thereby solving the problem that the thermal shock of the chip exists from incipient boiling to nucleate boiling, and meanwhile, improving critical heat flux density remarkably to ensure the effective heat exchange of a high heat flux density electronic device.

The invention provides a microchannel cooling device. The microchannel cooling device comprises a cooling device body and a plurality of microchannels; the cooling device body is made of a shape memory alloy material; a heat-emitting device is attached on the outer surface of the cooling device body; the plurality of microchannels are formed inside the cooling device body; one end of each of the plurality of microchannels is connected with the inlet of a cooling working medium, the other end of each of the plurality of microchannels is connected with the outlet of the cooling working medium; and the shape memory alloy material of the cooling device body is trained, such that the hydraulic diameter of the microchannels above a preset temperature is greater than the hydraulic diameter of the microchannels below the preset temperature. According to the microchannel cooling device of the invention, under high heat flux density, the hydraulic diameter of the microchannels in the trained nickel titanium shape memory alloy is expanded by 1% to 20%, such that, the mass flow rate of the working medium in the microchannels can be increased, and therefore, the numerical value of critical heat flux density can be increased.

The invention discloses a visual pool type boiling and critical heat flux density test system and a test method. The visual pool type boiling and critical heat flux density test system comprises a transparent water tank, electric heating rods, a test section and winches. The transparent water tank is used for loading heat exchange working media, the electric heating rods are arranged at the bottomof the water tank, the test section is suspended in the water tank, and the winches are connected with the test section by steel wire ropes and are used for adjusting inclination angles of the test section. The visual pool type boiling and critical heat flux density test system and the test method have the advantages that pool type boiling and CHF (critical heat flux) tests can be carried out, accordingly, data of CHF on the outer surfaces of lower seal heads of pressure vessels under the conditions of severe reactor accidents can be obtained, and safety design can be carried out.

Disclosed herein is an that includes a substrate; and a nanoporous coating disposed thereon; the nanoporous coating having a thickness of about 5 nanometers to about 10 micrometers; where an interface between the substrate and the nanoporous coating is disposed at an angle of about 60 degrees to about 120 degrees to a horizontal; the nanoporous coating being in contact with a liquid; the nanoporous coating being operative to improve the critical heat flux by an amount of about 20% to about 100% over a surface that does not have a nanoporous coating.

The invention discloses a rod bundle channel local area gas-liquid two-phase annular flow liquid film thickness instantaneous conductivity measurement system. The instantaneous conductivity measurement system mainly comprises a rod electrode unit, a plurality of electrode pairs, a signal generation module, a signal acquisition module, a data processing module and a liquid film calibration device.The thickness of the annular flow liquid film in the local area of the rod bundle channel can be accurately measured; and the Dryout type critical heat flux density triggering condition can be accurately predicted by determining the uneven distribution characteristic of the rod wall circumferential liquid film thickness and the liquid film circumferential cooperative propagation mechanism, so thatthe normal use of related elements of a nuclear reactor system and the safety of a reactor under accident working conditions are guaranteed.

The invention discloses a non-uniform electric heating nuclear fuel simulation rod and a test method thereof, and belongs to the field of reactor experimental research. The nuclear fuel simulation rodprovided by the invention is applied to critical heat flux density experimental research of nuclear fuel assemblies, and relates to the experimental research of thermal hydraulic performance of the fuel assemblies. The nuclear fuel simulation rod provided by the invention takes the situation that a current flows through a conductor to generate heat as the principle, and uses non-uniform heat generated along the axial direction of an electric heating rod to simulate non-uniform heat release along the axial direction of a nuclear fuel rod, so as to perform the critical heat flux density experimental research of the nuclear fuel assemblies.

The invention discloses a nuclear fuel assembly based structural grillwork with a flow hybrid coordinating effect. The structural grillwork comprises a grillwork formed by mutually perpendicularly interweaving a plurality of stripes, a pair of mixing wings are respectively arranged on the two sides of the top of the intersection position of the stripes, and each stripe is recessed to form a half-buckled-shaped rigid protruding structure. With the adoption of the half-buckled-shaped rigid protruding structure, the coordination between a clamping system and a mixing system is achieved, the hybrid performance of the structural grillwork is enhanced, thereby improving the critical heat flux density of a nuclear fuel assembly; and with the oblique channel type paired half-buckled-shaped rigid protruding structure, the internal flow of the structural grillwork is effectively rectified, so that the pressure loss is reduced to some extent.

The invention discloses a simulation apparatus and a simulation method for heat flux density of the lower head of a pressure vessel. The simulation apparatus comprises an arc simulator which is a cuboid as a whole; the arc simulator bends towards one of the side surfaces of the arc simulator to form a quarter circular ring with a rectangular cross section, the external diameter of the arc simulator is R, the internal diameter of the arc simulator is R-B, B is the thickness of the arc simulator, and the width of the arc simulator is Am. The simulation apparatus provided by the invention can simulate heat power of core melts under different accident conditions and cooling flow of the lower head at the same time; the apparatus can also simulate heating of the core melts under severe accident conditions; the apparatus cooperates with other structures to form a cooling channel together; and the apparatus is applicable to experiments on flow and heat transfer characteristics and critical heat flux density of the external surface of the lower head of the pressure vessel under severe accident conditions in a laboratory, can acquire the limit value of the critical heat flux density of the external surface of the lower head and provides a basis for designing and validity evaluation of a severe accident mitigation system.

Provided is a sub-channel analysis method combining resistance and energy distribution and containing a grillwork mixing effect. The method comprises the steps of fitting a momentum source term relational expression and an energy source term relational expression which can reflect mixing performance of mixing grillwork key components by collecting experimental data of multiple mixing grillworks including a nuclear reactor core mixing grillwork to be analyzed under different working conditions, adding the momentum source term relational expression to a corresponding momentum conservation equation, and adding the energy source term relational expression to a corresponding energy conservation equation; obtaining more precise local thermal hydraulic parameters in a nuclear reactor core by solving a mass conservation equation, the momentum conservation equation and the energy conservation equation, and accordingly making the prediction of a critical heat flux(CHF) value and a CHF position more accurate. The sub-channel analysis method combining resistance and energy distribution and containing the grillwork mixing effect is not limited by a sub-channel program structure and solving method, can be widely applied to various types of sub-channel program calculation, and is mainly applied to a sub-channel program of a two-fluid model.

The invention discloses a visual measurement experiment device of critical heat flux density of an integrally sintered rectangular narrow slit channel. The visual measurement experiment device comprises a conductive circuit formed by an inlet end copper row, a heating plate, and an outlet end copper row, a fluid flow channel composed of an inlet channel, an inlet buffer cavity, a rectangular narrow slit channel, an outlet buffer cavity, and an outlet channel, a rectangular narrow slit channel formed by a heating plate embedded in a groove of an integrally sintered ceramic substrate and a stainless steel plate embedded with a quartz glass and withstanding the impact of gas-liquid two-phase fluids with high temperature and high pressure, a pressure measuring assembly embedded in the integrally sintered ceramic substrate for measuring relevant experimental parameters, and a thermocouple assembly. The fluid passes the inlet channel and the inlet buffer cavity, and then enters the rectangular narrow slit channel. A boiling critical phenomenon occurs after the fluid is heated in the rectangular narrow slit channel. The movement behavior of vapor phase can be effectively observed throughthe quartz glass when boiling critical occurs in the channel. the occurrence of the critical boiling phenomenon is judged through the vapor phase movement behavior and the temperature information of the thermocouple. An experiment guarantee condition is provided for the mechanism of deeply researching the critical boiling phenomenon in the rectangular narrow slit channel.

The invention discloses a micro-nano structure array heat dissipation surface and a preparation method thereof. The heat dissipation surface comprises a heat dissipation substrate and an array structure which is constructed on the surface of the heat dissipation substrate and formed by cones composed of a fluorine-containing polymer and heat conducting particles. The heat dissipation surface can greatly increase the effective heat exchange area, the surface roughness and the heat conducting coefficient, facilitates the transfer of heat to a fluorine-containing working medium, facilitates nucleate boiling of the fluorine-containing working medium, can strengthens a wetting ability of the fluorine-containing working medium for the heat dissipation surface, improves the critical heat flux density and plays a role of strengthening phase change heat transfer. The preparation method comprises the steps of uniformly stirring and mixing a fluorine-containing polymer emulsion, the heat conducting particles, a solvent, an auxiliary and the like to obtain slurry, printing the slurry on the surface of the heat dissipation substrate through a silk-screen printing process, drying to remove the solvent, then performing thermal treatment in the protective atmosphere, enabling the fluorine-containing polymer resin to be solidified on the surface of the heat dissipation substrate, and obtaininga heat dissipation surface with a micro-nano structure array. The preparation steps are easy and easy to implement, and scale production is easy to be realized.

The invention discloses a Gaussian process regression-based critical heat flux density prediction method, which is specifically implemented according to the following steps of: 1, dividing a collecteddata set into two parts, namely 70% of data as a training set and the balance of 30% of data as a test set, and recording D * = [(X *, y *)}; 2, preprocessing the training set data and the test set data by adopting a standard normal variable method to enable the mean value of the training set D and the test set D * to be 0 and the standard deviation to be 1; 3, inferring the relation between thetraining input variable and the training target output by using Gaussian process regression to obtain a critical heat flux prediction model; And 4, predicting the critical heat flux density through the system pressure P, the mass flow rate G and the balanced steam content Xe by using the obtained critical heat flux density prediction model. The method can accurately and effectively predict the critical heat flux density.

The invention discloses a nonuniform wet silicon-based micro-channel phase change heat exchanger with a communicated top, and belongs to the technical field of electronic cooling. Upper glass and bottom silicon are in anodic bonding to form the micro-channel phase change heat exchanger, a liquid inlet and a liquid outlet are formed in the upper glass, a liquid inlet tank, a liquid outlet tank andnucleated hole arrays are arranged on the front of the bottom silicon, the nucleated hole arrays are parallelly connected with micro-channels, the opened micro-channels are communicated at the top each other, hydrophilic silicon dioxide thin films are arranged on the side surfaces and the bottom surfaces of the micro-channels and the top surface of the rib wall between the micro-channels, the nucleated hole arrays are positioned at the bottoms of the micro-channels, hydrophobic silicon is arranged on the inner surfaces of the nucleated hole arrays, and an electric heating film is processed onthe back of the bottom silicon and used for simulating an external heat source. The phase change heat exchanger has the advantages that the heat exchanger has low starting temperature, a high heat exchange coefficient and critical heat flux density, high heat transfer stability and a wide application prospect.

The invention discloses an electrostatic atomizing and cooling capacity evaluation device with an adjustable nozzle space angle, belonging to the technical fields of heat exchange and cooling. The electrostatic atomizing and cooling capacity evaluation device comprises an electrostatic atomizing and cooling system and a critical heat flux and heat transfer coefficient measurement system, wherein the electrostatic atomizing and cooling system comprises a big fan-shaped disc, a small fan-shaped disc, an adjustable handle, a guide rail, a first sliding block, an injection pump, a silicone rubber tube and a bracket; the critical heat flux and heat transfer coefficient measurement system comprises a purple copper bar, a K-shaped thermocouple wire, a heat insulation sleeve, a box cover, a purple copper block, an electric heating bar, a graphite felt heat insulation tray, a second sliding block, a base, a supporting block, a graphite felt heat insulation supporting block, a guide block, a voltage meter, a variable resistor and a K-shaped thermocouple. According to the electrostatic atomizing and cooling capacity evaluation device, electrostatic atomization transient-state and steady-state heat transfer experiments can be carried out on the same device at different nozzle space angles, in different target distances and with different output voltages, heating powers and cooling medium fluxes of a high voltage static generator, and the critical heat flux and the heat transfer coefficient can be measured.

The invention discloses an immersion cooling heat dissipation structure, a radiator, a heat dissipation system and a manufacturing method of the immersion cooling heat dissipation structure. The immersion cooling heat dissipation structure comprises a boiling heat exchange unit, and the boiling heat exchange unit comprises a first surface and a second surface which are arranged back to back; a microstructure composed of a plurality of opposite convex parts and/or a plurality of opposite concave parts is distributed on the first surface, and the first surface is at least used for making contactwith an electrically insulating immersion cooling medium; the second surface is a smooth face and used for being attached to a heating element, or the second surface and the heating element are integrally arranged. The immersion cooling heat dissipation structure provided by the invention has the advantages of higher heat exchange area, more nucleation sites, stronger capillary fluid infusion capability, excellent boiling heat exchange performance, high heat transfer coefficient and critical heat flux density, low superheat degree of a nucleation boiling starting point and great advantages ina small-space high-heat-flux heat dissipation application scene; meanwhile, the manufacturing process is relatively flexible and controllable, the cost is low, industrial large-scale application canbe achieved, and the market competitiveness is high.

An enhanced immersion cooling device with a diversion function comprises a sealed casing, a deflector and an insulating working medium arranged in the casing, wherein the air deflector is vertically arranged in the shell, the air deflector is an ascending channel of the insulating working substance and a return channel of the insulating working substance is formed between the adjacent air deflector, the cold source and the heat source are respectively located above and below the shell, and the insulating working substance flows through the ascending channel and the return channel in the shellto form a directional circulation of an enclosed space. The directional cycle of the invention can enhance the liquid supply flow of the heat source, enhance heat exchange, and delay the appearance ofthe critical heat flux. The upward gas column or liquid column and downward liquid in different channels can effectively avoid gas-liquid retrogression, that is, the phenomenon of ascending bubbles entrapping downward liquid in the process of violent boiling does not occur, which reduces most of the flow resistance and is also conducive to the heat transfer of the device.

The invention discloses a temperature measuring device for the wall temperature of a fine rod narrow gap under a motion condition. The temperature measuring device comprises heating element pipes andone or more sheathed thermocouples. One or more temperature measuring holes are formed in the outer circumferential walls of the heating element pipes in the circumferential direction of the heating element pipes. Compensating conductors of the sheathed thermocouples penetrate through the heating element pipes and then extend outwards. The outer walls of the compensating conductors of all the sheathed thermocouples are sequentially wrapped with high-temperature isolating coatings and high-temperature isolating adhesive tapes. The heating element pipes are filled with high-temperature isolatingsilicone. Through the technical scheme, wall surface temperatures of different positions of all the heating element pipes of a high-temperature fine rod bundle narrow gap fuel assembly can be accurately measured under the motion condition, the sheathed thermocouples do not shed or are not subjected to an insulation failure, temperature measuring parts conduct temperature measuring in the rod bundle heating element pipes, thus flow fields and temperature fields beside the heating element pipes cannot be interfered, and thermo-technical performance parameters such as the heat transfer coefficient and the critical heat flux density of the fuel assembly can be accurately obtained by carrying out heat transfer experiments of the fuel assembly under the motion condition.