Jet flow cold plate with gradually-reduced outlet type micro channel
Technical Field
The invention belongs to the technical field of heat exchange of power electronic components, and particularly relates to a jet flow cold plate with a tapered outlet and a small channel.
Background
Electronic device, micro-electromechanical system and high-power laser with high integration levelThe rapid development of the electronic chip is moving to the direction of small size and high power, the heat dissipation degree in the unit body is higher and higher, the heat productivity and the temperature are increased sharply, and the heat flux is up to 106-107W/m2The temperature of the local hot spot exceeds the safety warning value within a very short time, thereby causing serious problems of reliability and safety of machinery, chemistry, electricity and the like. Research shows that 30% of failures of power electronic devices can be caused by thermal failure and thermal stress of the devices, and the higher the working temperature of the devices, the smaller the safe operation margin is; the greater the temperature fluctuation, the shorter the thermal cycle life;
in order to solve the heat dissipation problem of high heat flux density chips, a batch of high efficiency heat sinks have been developed in recent years, wherein the spray cooling technology has gained wide attention with its remarkable heat dissipation performance. The jet cooling technology is characterized in that a high-speed jet fluid impacts a heat transfer surface in a normal direction, a very thin speed and temperature boundary layer is formed near a stagnation point, and high turbulence intensity generated by high-speed jet flow is used for obtaining high heat exchange efficiency, so that the jet cooling technology has a remarkable cooling effect on local high-temperature hot spots of a high-heat-flow-density heat source;
the patent application with the publication number of CN109654932B discloses an 'impact jet cooling system with a thread cone heat sink', which comprises a jet nozzle, a heat sink and a heat source, wherein the heat sink comprises a cone and a base, the bottom surface of the cone is connected with the upper surface of the base, the jet nozzle is positioned right above the vertex of the cone, and the heat source is tightly attached to the lower surface of the base. The local heat transfer coefficient of the stagnation point region in the impact jet flow cooling system provided by the invention is higher, and the thickness of a temperature boundary layer formed by the wall surface jet flow region is reduced by the secondary impact jet flow of the turning region, so that the effects of enhancing the heat exchange capacity and improving the cooling efficiency are achieved. However, in the wall surface jet flow region outside the stagnation point region and the turning region, the flow boundary layer is significantly increased, which results in a significant reduction of the heat exchange coefficient of the region, so that the temperature of the heat sink part of the region is greatly increased, i.e. the temperature of the central region of the heat sink is lower, the peripheral temperature of the heat sink is higher, and the temperature of the whole heat sink is uneven. If the temperature unevenness is too high, on one hand, the whole area of the cooled object cannot be controlled within an allowable range, and on the other hand, the cooled object may generate large temperature difference thermal stress, so that the cooled object is damaged.
Disclosure of Invention
The invention aims to solve the problems and provide a jet flow cold plate with a gradually-reduced outlet type micro channel, which has a simple structure and is reasonably designed.
The invention realizes the purpose through the following technical scheme:
the utility model provides a little passageway's of export gradual shrinkage efflux cold plate, includes the upper cover plate, runs through the jet nozzle who sets up in upper cover plate center department, cold drawing chamber and with the heat source of laminating mutually in the bottom in cold drawing chamber, with the efflux in cold drawing chamber strikes the stagnation district and is the center, follows the wall efflux district in cold drawing chamber outwards is equipped with the little passageway of export gradual shrinkage type that supplies efflux working medium to circulate.
As a further optimization scheme of the invention, the outlet tapered micro channel comprises a plurality of layers of arc-shaped fins with the same height and number, which are arranged along the circumferences of different radiuses of the cold plate cavity, the arc lengths of the arc-shaped fins on each layer are the same, the arc-shaped fins on the circumferences with adjacent radiuses are arranged in a staggered mode, and an arc-shaped outlet is reserved between every two adjacent arc-shaped fins on each layer.
As a further optimization scheme of the invention, the radius of the arc-shaped fins of each layer from the center of the cold plate cavity is in an increasing relationship of gradually reducing the difference, the arc length of the arc-shaped fins is gradually increased along with the increase of the radius of the arc-shaped fins of each layer, and the arc length of the corresponding arc-shaped outlet is gradually reduced.
As a further optimization scheme of the invention, the upper cover plate is arranged at the upper part of the cold plate cavity, and the inner side wall of the upper cover plate is tightly contacted with the upper end surface of each section of arc-shaped fin.
As a further optimization scheme of the invention, the number of layers of the arc-shaped fins is 4-20, and the number of the arc-shaped fins corresponding to each layer is 4-10.
As a further optimization scheme of the present invention, the value range of the main structural parameters of the jet flow cold plate is as follows: the inner diameter of the cross section of the jet nozzle is D, and the value range is 1mm-4 mm;
the heights H of the arc-shaped fins are equal and take the values of 2D-4D, the thicknesses W of the arc-shaped fins are also equal and take the values of 1D-2D;
the radius R1 corresponding to the arc-shaped rib on the innermost layer ranges from 2D to 4D;
the radius Rn corresponding to the arc-shaped fins on the outermost layer does not exceed 25 mm;
the ratio of the difference values of the corresponding radiuses of the two adjacent layers of arc-shaped fins is 0.8-0.99;
the range of the convergent radian angle alpha of the arc-shaped outlet at the interval layer is 5-30 degrees.
A high-efficiency radiator of a jet flow cold plate containing the outlet tapered micro-channel as described in any one of the above.
The application of the high-efficiency radiator in the technical field of high-heat-flux-density chip radiating is disclosed.
The invention has the beneficial effects that:
1. according to the invention, the arc-shaped fins are arranged in a staggered manner in the wall surface jet area outside the jet impact stagnation area to form a tapered arc-shaped outlet, and the radial distance between two adjacent layers of arc-shaped fins is gradually reduced, so that the jet working medium flows to the outer layer area, the cross section area of a flow channel between the arc-shaped fins is smaller, and the arc-shaped outlet is smaller, therefore, the flow velocity of the jet working medium is increased, the heat exchange of the outer layer area is enhanced, the temperature level of the jet area on the wall surface of the jet cold plate is reduced, the problems of lower temperature and higher peripheral temperature of the heat sink central area in the conventional jet impact are solved, the heat source contacted with the bottom of the whole jet cold plate can be effectively cooled in the whole area, the temperature of a cooled object can be controlled at a lower level in an all-round manner, and the jet cooling effectiveness is enhanced; meanwhile, the temperature of the cooled surface is uniform, the phenomenon that the temperature difference thermal stress generated by uneven temperature distribution caused by conventional jet flow impact is overlarge is avoided, namely, the cooled object is prevented from being damaged due to overlarge temperature difference thermal stress, and the reliability of jet flow cooling is enhanced.
Drawings
FIG. 1 is an exploded view of a fluidic cold plate with tapered exit microchannels according to the present invention;
FIG. 2 is a top view of a cold plate chamber of the present invention;
FIG. 3 is a schematic flow diagram (quarter circle) of the jet working medium in the cold plate cavity according to the present invention;
FIG. 4 is a diagram of the horizontal sectional temperature of a cold plate (quarter circle, unit:. degree. C.) of a conventional jet impact plate heat sink;
FIG. 5 is a temperature diagram of the horizontal section of the cold plate of the gradually tapered micro channel of the jet impact outlet according to the present invention (quarter circle, unit:. degree. C.);
in the figure: 1. a jet nozzle; 2. an upper cover plate; 3. a cold plate chamber; 31. arc-shaped ribs; 32. an arc-shaped outlet; 4. a heat source.
Detailed Description
The present application will now be described in further detail with reference to the drawings, it should be noted that the following detailed description is given for illustrative purposes only and is not to be construed as limiting the scope of the present application, as those skilled in the art will be able to make numerous insubstantial modifications and adaptations to the present application based on the above disclosure.
Example 1
As shown in fig. 1, a little passageway's of export gradual shrinkage efflux cold drawing, includes upper cover plate 2, runs through the fluidic nozzle 1 that sets up in upper cover plate 2 center department, cold drawing chamber 3 and with the heat source 4 of the laminating of the bottom in cold drawing chamber 3, upper cover plate 2 sets up in cold drawing chamber 3 upper portion, and 2 inside walls of upper cover plate and the up end in close contact with of each section arc fin 31, with the jet impact stagnation district of cold drawing chamber 3 is the center, follows the wall efflux district in cold drawing chamber 3 outwards is equipped with the little passageway of export gradual shrinkage type that supplies the circulation of efflux working medium.
As shown in fig. 2, the outlet tapered micro channel includes a plurality of layers of arc fins 31 with the same height and number, which are arranged along the circumferences of different radii of the cold plate cavity 3, the same radius circumference is one layer, the arc length of the arc fin 31 on each layer is the same, an arc outlet 32 is left between two adjacent arc fins 31 on each layer, the number of the layers of the arc fins 31 is 4-20, and in this embodiment, the number of the arc fins 31 is 6;
the number of the arc-shaped fins 31 on each layer of the circumference with different radiuses is equal, the number of the corresponding arc-shaped outlets 32 is also equal, the number of the arc-shaped fins 31 in each layer is 4-10, in the embodiment, the number of the arc-shaped fins 31 on each layer of the circumference with different radiuses is 6, and the number of the corresponding arc-shaped outlets 32 is also 6;
the arc-shaped fins 31 on the adjacent radius circumferences are arranged in a staggered manner, so that after a jet flow working medium impacts a jet flow impact stagnation area of the cold plate cavity 3 through the jet flow nozzle 1, the jet flow working medium enters along an arc-shaped outlet 32 between the two arc-shaped fins 31 on the innermost layer, the flow direction can be changed, and zigzag bending and streaming are performed between the arc-shaped fins 31 on each layer, a heat source 4 contacted with the bottom of the whole jet flow cold plate can be effectively cooled in the whole area, and the flow curve of the jet flow working medium in the cold plate cavity is shown in figure 3;
in order to further enhance the flowing and heat exchanging effect of the bending flow-around area, the radius of the arc-shaped fin 31 at each layer from the center of the cold plate cavity 3 is in an increasing relationship of gradually decreasing difference, that is, the distance between two adjacent layers of arc-shaped fins 31 is gradually decreased with the increase of the radius of each layer of arc-shaped fin 31, and the arc length of the arc-shaped fin 31 is gradually increased and the arc length corresponding to the arc outlet 32 is gradually decreased, so that the flowing cross-sectional area of the jet flow working medium is gradually decreased as the jet flow working medium flows towards the outer layer of arc-shaped fin 31, the flow velocity of the jet flow working medium is increased, the heat exchange of the corresponding outer layer area is enhanced, the temperature level of the jet flow area on the wall surface of the jet flow cold plate is reduced, the problems of lower temperature and higher peripheral temperature of the central area of the heat sink in the conventional jet flow impact are solved, and the heat source 4 contacted with the bottom of the whole jet flow cold plate can be effectively cooled in the whole area, the temperature of the cooled object can be controlled at a lower level in an all-round way, and the effectiveness of jet cooling is enhanced; meanwhile, the temperature of the cooled surface is uniform, the phenomenon that the temperature difference thermal stress generated by uneven temperature distribution caused by conventional jet flow impact is overlarge is avoided, namely, the cooled object is prevented from being damaged due to overlarge temperature difference thermal stress, and the reliability of jet flow cooling is enhanced.
The utility model provides a contain as above arbitrary the high-efficient radiator of efflux cold plate of the little passageway of export gradual shrinkage type compares traditional high-efficient radiator to high-speed efflux fluid normal direction strikes cold plate chamber 3, guarantees that 3 efflux in cold plate chamber strike the stay point district along the outside temperature distribution of wall efflux district more even, increases the refrigerated validity of efflux and reliability.
The application of the high-efficiency radiator in the technical field of high-heat-flux-density chip radiating is disclosed.
Meanwhile, in order to obtain the optimal temperature uniformity effect of the jet flow cold plate, the value range of main structural parameters in the jet flow cold plate is correspondingly limited:
the inner diameter of the cross section of the jet nozzle 1 is D, and the value range is 1mm-4 mm;
the heights H of the arc-shaped ribs 31 are equal and take the value of 2D-4D, and the thicknesses W of the arc-shaped ribs are also equal and take the value range of 1D-2D;
the radius R1 corresponding to the arc-shaped rib 31 at the innermost layer ranges from 2D to 4D;
the radius Rn corresponding to the arc-shaped rib 31 on the outermost layer does not exceed 25 mm;
the ratio of the difference of the corresponding radiuses of the arc-shaped ribs 31 of the two adjacent layers is 0.8-0.99;
the range of the convergent radian angle alpha of the arc outlet 32 at one layer interval is 5-30 degrees.
Through the limitation, the problems of lower temperature of the central area of the heat sink and higher peripheral temperature in the conventional jet flow impact are solved, so that the heat source contacted with the bottom of the whole jet flow cold plate can be effectively cooled in the whole area, and the temperature of the cooled object can be controlled at a lower level in an all-round way.
As shown in fig. 4, a horizontal cross-sectional temperature diagram of a quarter-circle cold plate of a conventional jet impact plate type heat sink is shown, where data unit is "c", it can be seen that the temperature difference of the cold plate reaches 45 ℃, which results in a large temperature difference, on one hand, all parts of an object to be cooled are not effectively cooled to a low temperature level, and on the other hand, the object to be cooled by the cold plate is also subjected to a large temperature difference stress, which easily causes damage to the object to be cooled.
Fig. 5 shows a horizontal cross-sectional temperature diagram of a quarter circle cold plate of a tapered micro channel of a jet impact outlet, similarly, the temperature difference of the jet impact cold plate is only 6 ℃, compared with the cooling effect of conventional jet impact, the temperature uniformity is remarkably improved, the temperature level of a cooled object is integrally reduced, the temperature uniformity is high, and the temperature difference stress borne by the cooled object is small, so that the operation reliability of the cooled object is ensured.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention.