CN111561830A - Small-channel parallel pipeline heat exchanger with fins and calculation method - Google Patents

Small-channel parallel pipeline heat exchanger with fins and calculation method Download PDF

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CN111561830A
CN111561830A CN202010313876.7A CN202010313876A CN111561830A CN 111561830 A CN111561830 A CN 111561830A CN 202010313876 A CN202010313876 A CN 202010313876A CN 111561830 A CN111561830 A CN 111561830A
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heat exchanger
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parallel
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tube
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CN111561830B (en
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郑时红
赵云鹏
茅新波
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Zhejiang Yifei Technology Co ltd
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D1/00—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators
    • F28D1/02—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid
    • F28D1/04—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with tubular conduits
    • F28D1/053—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with tubular conduits the conduits being straight
    • F28D1/05316—Assemblies of conduits connected to common headers, e.g. core type radiators
    • F28D1/05333—Assemblies of conduits connected to common headers, e.g. core type radiators with multiple rows of conduits or with multi-channel conduits
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B39/00—Evaporators; Condensers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F1/00—Tubular elements; Assemblies of tubular elements
    • F28F1/10—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses
    • F28F1/12—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element
    • F28F1/24—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element and extending transversely
    • F28F1/32—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element and extending transversely the means having portions engaging further tubular elements
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
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Abstract

The small-channel parallel pipeline heat exchanger with the fins comprises an inlet pipe, parallel pipelines and a discharge pipe, wherein the parallel pipelines are respectively communicated with the inlet pipe and the discharge pipe, the parallel pipelines are provided with the fins and are arranged into at least one row, and the outer diameter d of each parallel pipeline is the same as the outer diameter d of each parallel pipelineoThe value range of (d) is more than 1mmoAnd when the diameter is less than or equal to 3.95mm, a calculation formula between the heat exchange quantity of the heat exchanger and the structure of the heat exchanger is provided. The technical scheme of the invention has the following beneficial effects: the heat exchanger has high heat exchange efficiency, low noise and energy saving.

Description

Small-channel parallel pipeline heat exchanger with fins and calculation method
Technical Field
The invention relates to the field of heat exchangers, in particular to a small-channel parallel pipeline heat exchanger with fins and a calculation method.
Background
The heat exchanger is an energy-saving device which can realize heat transfer between two or more media with different temperatures according to Carnot cycle or reverse Carnot cycle, so the heat exchanger can be used as a condenser or an evaporator. The condenser is used for cooling a medium in the heat exchanger by using a medium outside the heat exchanger, so that the medium outside the heat exchanger absorbs heat of the medium in the heat exchanger to increase the temperature, and if the medium is a phase-change substance, energy storage is realized under the condition that the temperature is unchanged; the evaporator is characterized in that a medium outside the heat exchanger is used for heating the medium in the heat exchanger, so that the medium outside the heat exchanger absorbs the cold energy of the medium in the heat exchanger to reduce the temperature, and if the medium is a phase change material, the energy storage is realized under the condition that the temperature is not changed.
At present, the most common heat exchanger is that a medium (such as gas like air or liquid like water) outside a heat exchanger tube exchanges heat with a refrigerant (which may be liquid or gas) inside the heat exchanger tube through natural convection or forced convection. For example, in a heat exchange system comprising a fan, an air channel and a heat exchanger, the fan is over against the windward side of the heat exchanger main body to force air to convect, the air speed in the middle of the air channel is the largest, the heat exchange effect is the best, but the air speed at the edge of the air channel is the smallest or almost 0, the heat exchange effect is obviously poor, and the whole heat exchange effect of the heat exchanger is influenced. In addition, according to different application scenes of the heat exchanger, the use of the medium in the heat exchanger pipeline also has specificity, and the specificity also often limits the overall heat exchange effect of the heat exchanger.
Disclosure of Invention
This application is to the poor technical problem of whole heat transfer effect that above-mentioned defect arouses, and the angle of conversion solution problem through improving heat exchanger self structure, has compensatied because of the not good consequence of heat exchange efficiency that above-mentioned defect arouses. The heat exchanger after improvement, its heat exchange efficiency, heat transfer performance all present jump grade formula promotion.
The invention mainly adopts the following technical scheme:
beltThe finned small-channel parallel pipeline heat exchanger comprises an inlet pipe, parallel pipelines and a discharge pipe, wherein the parallel pipelines are respectively communicated with the inlet pipe and the discharge pipe, the parallel pipelines are provided with fins and are arranged into at least one row, and when the outer diameter d of the parallel pipelines is larger than the outer diameter d of the parallel pipelinesoThe value range of (d) is more than 1mmoWhen the diameter is less than or equal to 3.95mm, the heat exchange quantity of the heat exchanger and the structure of the heat exchanger accord with the following formula:
Figure BDA0002458835770000021
wherein Q is heat exchange quantity and the unit is W; c0The value of the error coefficient is 0.8-1.2; c1The value is constant and is between 0.023 and 0.027; c2Is a constant and takes a value of 1.2-1.4; lambda is the coefficient of thermal conductivity of the medium outside the pipe, and the unit is W/(m.k); rho is the density of the medium outside the pipe and has the unit of kg/m3(ii) a Mu is dynamic viscosity of medium outside the pipe, and the unit is Pa.s; cp is the constant-pressure specific heat capacity of the medium outside the pipe, and the unit is J/(kg. K); s is the flow of medium circulating outside the pipe and is m3S; delta t is the heat exchange temperature difference and has the unit of K; m is the number of the heat exchanger tube rows; ζ is the tube spacing factor; h is the height of the heat exchanger and the unit is m; doIs parallel pipeline external diameter in m, B is heat exchanger thickness in m, is fin factor, η is tube row factor, psi is tube layer factor, and tube spacing between adjacent parallel pipelines is BtThe tube spacing factor ζ ═ bt/do(ii) a The distance between the adjacent fins is bfThe fin factor bf/doThe distance between the centers of the corresponding pipeline pipes between two adjacent parallel pipelines is t, and the pipe row factor η is t/do(ii) a The pipe layer factor psi is the number of layers set according to the reasonable state of the distribution of the medium in the pipe in the parallel pipeline.
Wherein the parallel pipelines are arranged in at least two rows.
Wherein, the parallel pipeline is made of metal materials.
Wherein the parallel pipelinesWall thickness (d) of the tubeo-di) The value range of/2 is 0 < do-di) A/2 is less than or equal to 0.4mm, wherein diIs the parallel pipeline inner diameter.
Wherein a distance b between adjacent finsfThe value range of (b) is more than or equal to 1mmf≤4mm。
Wherein the fins are arranged perpendicular to the extending direction of the parallel pipes.
A method for calculating the heat exchange quantity of a small-channel parallel pipeline heat exchanger with fins is disclosed, wherein the heat exchange quantity of the heat exchanger is calculated by adopting the following formula:
Figure BDA0002458835770000031
wherein Q is heat exchange quantity and the unit is W; c0The value of the error coefficient is 0.8-1.2; c1The value is constant and is between 0.023 and 0.027; c2Is a constant and takes a value of 1.2-1.4; lambda is the coefficient of thermal conductivity of the medium outside the pipe, and the unit is W/(m.k); rho is the density of the medium outside the pipe and has the unit of kg/m3(ii) a Mu is dynamic viscosity of medium outside the pipe, and the unit is Pa.s; c. CpThe constant pressure specific heat capacity of the medium outside the pipe is expressed in J/(kg.K); s is the flow of medium circulating outside the pipe and is m3S; delta t is the heat exchange temperature difference and has the unit of K; m is the number of the heat exchanger tube rows; ζ is the tube spacing factor; h is the height of the heat exchanger and the unit is m; doIs parallel pipeline external diameter in m, B is heat exchanger thickness in m, is fin factor, η is tube row factor, psi is tube layer factor, and tube spacing between adjacent parallel pipelines is BtThe tube spacing factor ζ ═ bt/do(ii) a The distance between the adjacent fins is bfThe fin factor bf/doThe distance between the centers of the corresponding pipeline pipes between two adjacent parallel pipelines is t, and the pipe row factor η is t/do(ii) a The pipe layer factor psi is the number of layers set according to the reasonable state of the distribution of the medium in the pipe in the parallel pipeline.
By adopting the technical scheme of the invention, the invention has the following beneficial effects: according to the technical scheme, the corresponding optimal structure (the structure with the best heat exchange effect) of the heat exchanger can be obtained by setting the numerical value of the required heat exchange quantity, so that the labor and time costs consumed by various data tests during the research and development of the structure of the heat exchanger are effectively reduced; vice versa, whether the product meets the scene requirements can be quickly judged by calling the structural features of the product, and an active guiding effect is played in the aspect of researching and developing the heat exchange performance of the product; through improving the structure of heat exchanger, adopt the design of small pipe diameter and matched with tube pitch, fin interval etc. with it, cut into very little polylith passageway with outside of tubes fluid, make the heat exchanger form "little channel effect", can obviously improve the heat exchange effect outside the parallel pipeline of heat exchanger, changed the angle of solving the problem, and then compensatied other factors and to the harmful effects of heat exchanger heat transfer effect, the heat exchanger performance is compared and is presented the promotion of stepping type in current product.
Drawings
Fig. 1 is a schematic view of the overall structure of the heat exchanger of the present application.
FIG. 2 is a schematic diagram of the structure of the inner diameter, the outer diameter and the space between pipes of the parallel pipeline.
Fig. 3 is a schematic view of a parallel tube fin structure.
FIG. 4 is a schematic diagram of a structure in which a plurality of parallel rows of pipes are arranged in parallel.
FIG. 5 is a schematic view of a structure of a multi-row parallel pipeline in a staggered arrangement.
Fig. 6 is a diagram of a heat exchanger structure parameter iterative program.
Fig. 7 is a heat exchanger of the present application compared to a conventional evaporator tested.
1 inlet pipe, 2 parallel pipelines, 3 discharge pipes, 4 fins and 5 layering devices.
Detailed Description
The invention will be further elucidated with reference to the drawings in which:
referring to fig. 1 to 5, a finned small channel parallel pipe heat exchanger includes an inlet pipe 1, a parallel pipe 2, and an outlet pipeThe pipe 3 and the parallel pipeline 2 are respectively communicated with the inlet pipe 1 and the outlet pipe 3, the parallel pipeline 2 is provided with fins 4, the parallel pipeline 2 is arranged into at least one row, and when the external diameter d of the parallel pipeline 2 is larger than the external diameter d of the parallel pipelineoThe value range of (d) is more than 1mmoWhen the diameter is less than or equal to 3.95mm, the heat exchange quantity of the heat exchanger and the structure of the heat exchanger accord with the following formula:
Figure BDA0002458835770000041
wherein Q is heat exchange quantity and the unit is W; c0The value of the error coefficient is 0.8-1.2; c1The value is constant and is between 0.023 and 0.027; c2Is a constant and takes a value of 1.2-1.4; lambda is the coefficient of thermal conductivity of the medium outside the pipe, and the unit is W/(m.k); rho is the density of the medium outside the pipe and has the unit of kg/m3(ii) a Mu is dynamic viscosity of medium outside the pipe, and the unit is Pa.s; c. CpThe constant pressure specific heat capacity of the medium outside the pipe is expressed in J/(kg.K); s is the flow of medium circulating outside the pipe and is m3S; delta t is the heat exchange temperature difference and has the unit of K; m is the number of the heat exchanger tube rows; ζ is the tube spacing factor; h is the height of the heat exchanger and the unit is m; doIs parallel pipeline outer diameter in m, B is heat exchanger thickness in m, is fin factor, η is tube row factor, psi is tube layer factor, and tube spacing between adjacent parallel pipelines 2 is BtThe tube spacing factor ζ ═ bt/do(ii) a The distance between adjacent fins 4 is bfFin factor bf/doThe distance between the centers of the corresponding pipeline pipes between two adjacent rows of parallel pipelines 2 is t, and the pipe row factor η is t/do(ii) a The pipe layer factor psi is the number of layers set according to the reasonable state of the distribution of the medium in the pipe in the parallel pipeline. Psi is an integer greater than 0 and the parallel conduit 2 is divided into at least one layer. Preferably, as shown in fig. 1, the parallel circuit 2 is provided with at least one stratification means 5, the parallel circuit 2 being divided into at least two layers. When the parallel pipelines have only one row, the distance t between the centers of the corresponding pipelines between two adjacent rows of parallel pipelines 2 can be understood as infinite. Preferably, each row of parallel pipelines 2 is provided with at least one pipe, when each row of parallel pipesIt is a special case of the present application when the circuit 2 is provided with only one tube, for example by using serpentine tubes in a "parallel" relationship by a serpentine, increasing the overall length of the tubes, more preferably with at least two tubes per parallel line 2, for example a coiled heat exchanger or a straight heat exchanger using two or more "parallel" tubes per line. Preferably, the parallel pipe external diameter doThe value range of (d) is more than 0.46mmoLess than or equal to 6.6mm, more preferably, the external diameter d of the parallel pipelineoThe value range of (d) is more than 1mmoLess than or equal to 5mm, most preferably, the outside diameter d of the parallel pipesoThe value range of (d) is more than 1mmoLess than or equal to 3.95 mm. Because the parallel pipeline adopts the design of small pipe diameter, compared with the conventional pipe diameter, the pipe wall of the parallel pipeline does not need to bear the larger pressure of a medium in the pipe, so the requirements on the thickness and the mechanical strength of the pipe wall are reduced, and according to a heat exchange quantity formula Q ═ a ×. delta.t, wherein Q is the heat exchange quantity, A is the heat exchange area, a is the heat exchange coefficient, delta t is the heat transfer temperature difference, the reciprocal of the heat exchange coefficient a, namely 1/a is the heat exchanger heat resistance R, the parallel pipeline comprises three parts: riHeat exchanger in-tube thermal resistance; rwThermal resistance of the heat exchanger pipe wall; roExternal heat resistance of heat exchanger tube, i.e. a 1/(R)i+Rw+RO) The thermal resistance R outside the heat exchanger tube is reduced by adjusting the tube spacing factor, the fin factor, the tube row factor and the likeoThe value of (d); by adjusting the diameter of the pipe, the thermal resistance R in the heat exchanger pipe is reducediThe heat exchange coefficient a is influenced, and the heat exchange efficiency of the product is further improved; compared with the diameter of the micro-pipe, the production process difficulty of the parallel pipeline with the small inner diameter is correspondingly reduced, and the production efficiency and the yield are improved. Preferably, C0The value of (a) is between 0.9 and 1.1.
Referring to fig. 3, 4 and 5, the parallel pipes 2 are arranged in at least two rows. Preferably, the parallel pipes 2 may be arranged in parallel or staggered. Preferably, the distance t between the corresponding pipe centers between two adjacent rows of parallel pipes 2 refers to the distance between the pipe centers of the sequentially corresponding pipes between each row of parallel pipes. Because the density of the medium passing through the cross section of the pipeline is different when the medium in the pipeline is in a gas phase state, a vapor-liquid coexisting state and a liquid phase state, and the space required by the gas phase state is far larger than that required by the liquid phase state in the required theoretical space, the parallel pipeline needs to be layered (whether the layering is reasonable or not is mainly determined by the property of the medium and the distribution state of the medium) according to the property of the medium and the distribution state of the medium in the parallel pipeline. Generally, when the heat exchanger is used as a condenser, the number of parallel pipelines at the position where the refrigerant flows into the heat exchanger is far greater than that of parallel pipelines at the position where the refrigerant flows out of the heat exchanger; when the heat exchanger is used as an evaporator, the number of parallel pipelines at the position where the refrigerant flows out of the heat exchanger is far larger than that of parallel pipelines at the position where the refrigerant flows in the heat exchanger, so that the uniform distribution of the refrigerant in the heat exchanger can be ensured. Meanwhile, after the parallel pipelines are divided into a plurality of equal parts, the flow rate of the medium is greatly increased compared with that of the parallel pipelines. The flow velocity of the medium (refrigerant) in the pipe is increased, and the heat transfer effect of the medium and the inner wall of the pipe is also positively influenced.
Further, the parallel pipeline 2 is made of a metal material. The parallel pipelines are made of metal materials, so that the thermal resistance R of the walls of the parallel pipelines can be effectively reducedwThe numerical value of (2) plays a positive role in improving the heat exchange efficiency of the heat exchanger. Preferably, the parallel pipeline 2 is made of aluminum, and compared with the parallel pipeline made of copper and other materials in the prior art, the parallel pipeline has absolute advantages in material cost and processing difficulty. When the parallel pipelines of the heat exchanger are made of metal materials, RwIs much smaller than RiAnd RoTherefore, the formula of the heat exchange coefficient a in an ideal state is as follows:
Figure BDA0002458835770000061
by the theorem of extreme values, when ai＝aoWhen a isi*aoObtain the maximum value, ai+aoAchieving a minimum value, and thus α maximum value, is also a goal of the heat exchanger industry in pursuit of heat exchange efficiency, and therefore, in designing heat exchangers, it is preferable to try to maximize aiAnd aoTend to be consistent, or the heat exchangers need to be externally arranged to parallel pipelines in order to obtain the maximum heat exchange effectThe heat exchange performance is matched with the heat exchange performance in the pipe.
Referring to FIG. 2, the wall thickness (d) of the parallel pipeline 2o-di) The value range of/2 is 0 < do- di) A/2 is less than or equal to 0.4mm, wherein diIs the parallel pipeline inner diameter. Preferably, the wall thickness (d) of the parallel pipeline 2 is taken into consideration in combination with strength, thermal resistance, production cost, and the likeo-di) The value range of the/2 is less than or equal to 0.2mm (d)o-di) The/2 is less than or equal to 0.4 mm. The inner diameter d of the parallel pipeline is very thiniThe numerical range of (A) also falls substantially within the numerical range of 1mm to 3.95 mm.
Referring to fig. 1 and 3, the interval b between adjacent fins 4fThe value range of (b) is more than or equal to 1mmfLess than or equal to 4 mm. Preferably, the spacing b between adjacent fins 4fThe value range of (b) is more than or equal to 2mmfLess than or equal to 4 mm. This kind of structural design cuts heat exchanger main part windward side into very little polylith passageway, has enlarged heat exchange area after fin and the parallel pipeline tight fit on the one hand, and on the other hand is on the microstructure, and there is the cutting action in the flowing medium of existence of fin outside the tubes of the heat exchanger, reaches the purpose of accurate distribution for the heat exchange aggravation between the flowing medium of outside of tubes and the parallel pipeline, can form "little channel effect", can obviously produce positive influence to the heat exchange effect outside the parallel pipeline of heat exchanger outside the tubes.
As shown in fig. 3, the fins 4 are arranged perpendicular to the extending direction of the parallel tubes 2.
A method for calculating the heat exchange quantity of a small-channel parallel pipeline heat exchanger with fins adopts the following formula to calculate the heat exchange quantity of the heat exchanger:
Figure BDA0002458835770000071
wherein Q is heat exchange quantity and the unit is W; c0The value of the error coefficient is 0.8-1.2; c1The value is constant and is between 0.023 and 0.027; c2Is a constant and takes a value of 1.2-1.4; lambda is the coefficient of thermal conductivity of the medium outside the pipe, and the unit is W/(m.k); rho is outside of the pipeDensity of the medium in kg/m3(ii) a Mu is dynamic viscosity of medium outside the pipe, and the unit is Pa.s; c. CpThe constant pressure specific heat capacity of the medium outside the pipe is expressed in J/(kg.K); s is the flow of medium circulating outside the pipe and is m3S; delta t is the heat exchange temperature difference and has the unit of K; m is the number of the heat exchanger tube rows; ζ is the tube spacing factor; h is the height of the heat exchanger and the unit is m; doIs parallel pipeline external diameter in m, B is heat exchanger thickness in m, is fin factor, η is tube row factor, psi is tube layer factor, and tube spacing between adjacent parallel pipelines is BtThe tube spacing factor ζ ═ bt/do(ii) a The distance between adjacent fins is bfFin factor bf/doThe distance between the centers of the corresponding pipeline pipes between two adjacent parallel pipelines is t, and the pipe row factor η is t/do(ii) a The pipe layer factor psi is the number of layers set according to the reasonable state of the distribution of the medium in the pipe in the parallel pipeline. Referring to fig. 6, in the operation process, the heat exchange amount task to be completed by the heat exchanger (in the heat exchanger structure design process, the heat exchange amount is used as a design parameter), the medium (fluid) parameters corresponding to a specific scene, and the like can be input into the computer, the computer calculates reasonable structure parameters of some heat exchangers in an iterative manner, and repeatedly compares product test data corresponding to the reasonable structure parameters with the heat exchange amount task to be completed by the heat exchanger to select the optimal heat exchanger structure parameters. An error coefficient C exists between the heat exchange quantity task needing to be finished by the heat exchanger and the heat exchange quantity obtained by actual measurement0Preferably, C0The value of (a) is between 0.9 and 1.1, and specifically, the actually measured heat exchange quantity Q of the heat exchangerMeasured in factThe following relationship exists between the heat exchange quantity Q calculated by the formula: qMeasured in factQ + Δ Q, where Δ Q is the error value. When the heat exchanger is detected through a laboratory, because the laboratory cannot realize complete heat insulation, the deviation delta Q exists between the heat exchange quantity measured by the laboratory and the heat exchange quantity Q generated by the heat exchanger1The larger the heat exchange quantity of the heat exchanger is, the larger the existing deviation is, and the deviation value delta Q is1± (5-10)%) Q; when the theoretical simulation is carried out, a calculation method of uniformly distributing the wind volume on the windward side is adoptedThe condition that air quantity is unevenly distributed exists during actual test, and deviation delta Q exists between heat exchange quantity measured in a laboratory and heat exchange quantity Q generated by a heat exchanger2The larger the heat exchange quantity of the heat exchanger is (the wind speed on the windward side is also large at the moment), the larger the existing deviation is, and the deviation value delta Q is2+ - (2-5)%) Q: when the method based on least square infinite approximation is adopted, the deviation delta Q exists between the numerical value calculated by the formula and the heat exchange quantity Q generated by the heat exchanger3(+/- (1-3)%) Q. Proved by verification, the technical scheme of the application is that the outer diameter d of the parallel pipelineoThe value range of (d) is more than 1mmoWhen the diameter is less than or equal to 3.95mm, the result is most accurate; in parallel pipeline outside diameter doThe value range of (d) is more than 1mmoLess than or equal to 5mm, and the accuracy is inferior; in parallel pipeline outside diameter doThe value range of (d) is more than 0.46mmoLess than or equal to 6.6mm, and the accuracy is repeated. The heat exchanger structure and the calculation method obtained by adopting the thermodynamic principle and a large number of experimental fits have positive significance on heat exchange quantity calculation and heat exchanger structure design, and can be suitable for the occasions of industry (such as chemical industry, papermaking, electric power, pharmacy, petroleum, reclaimed water treatment and the like), light industry (such as heating ventilation, air conditioners, refrigerators, commercial refrigerators, air energy heat pumps and the like) and transportation (such as automobiles, ships and high-speed rails).
Further, through doing the complete machine experiment on the household electrical appliances product of using above-mentioned heat exchanger, can further verify that this application technical scheme has a great deal of advantage compared with prior art:
test one:
a. application as evaporator on a domestic frost-free refrigerator: the comparison was performed on a household refrigerator model BCD-208W product, the parameters of which are listed in table one.
TABLE-technical parameters of BCD-208W
Figure BDA0002458835770000081
Figure BDA0002458835770000091
The product uses a special-shaped tube heat exchanger as an evaporator to carry out a power consumption comparison operation test, the traditional heat exchanger adopts a snakelike aluminum evaporator (with fins) with the outer diameter of 8mm, and the filling quantity R600a is 42 g; the heat exchanger of the application adopts an aluminum finned small-channel evaporator (the product thickness is reduced to about 1/3), and as shown in fig. 7, the filling amount R600a of the refrigeration system is 31 g.
b. Comparison of test data (see Table two)
Comparison of experimental data of heat exchangers of Table II as evaporators
Figure BDA0002458835770000092
c. And (3) data analysis:
adopt the overall dimension of this application heat exchanger, under width I and the unchangeable condition of height h, the thickness B of heat exchanger has nearly reduced 1/3 (traditional heat exchanger thickness is about 60mm, this application heat exchanger thickness is 40mm), can effectively practice thrift the space, and the product is suitable for the place more extensively.
And secondly, from experimental data results, the power consumption is saved by about 7% (═ 1-0.625/0.682), the product energy efficiency index is improved by 2.85 percentage points, and the heat exchanger is more energy-saving than the traditional heat exchanger.
From experimental data results, the defrosting duration is shortened by nearly 3.4 minutes (the average defrosting time of a common heat exchanger is 23 minutes, and the average defrosting time of the heat exchanger is 19.6 minutes).
In addition, for further improving the heat exchange efficiency of this application heat exchanger, can also follow the aspect of heat transfer medium and fan overall arrangement and begin:
1. when the fluid medium outside the pipe is set to be air or water, the physical property parameters of the fluid medium are basically determined as shown in the following table III:
table three physical parameters of air and water
Figure BDA0002458835770000101
The same structure of the heat exchanger, the heat exchange amount when the fluid medium is set to air is QAir conditionerAnd the heat exchange quantity Q of the fluid being waterWater (W)Selecting proper flow of air or water in the heat exchange industry, substituting the physical parameters of the air or water into the formula to obtain the following relational expression:
Qwater (W)/QAir conditioner≈3.5
It can be concluded that under the same heat exchanger size and with proper flow of fluid, the heat exchange amount obtained when the fluid is water in the heat exchanger is more than 3 times of the heat exchange amount obtained when the fluid is air in the heat exchanger. Therefore, the small-channel heat exchanger can exchange heat by taking air as fluid in an air conditioner, a refrigerator and the like, and is more suitable for exchanging heat with the heat exchanger by taking water as fluid in an air energy heat pump, so that the air energy is converted into energy of water temperature rise.
2. The surface formed by the height h and the width I of the heat exchanger is used as the main windward surface of the heat exchanger, and the obtained heat exchange quantity is QI*hThe surface formed by the height h and the thickness B of the heat exchanger is used as the main windward surface of the heat exchanger, and the obtained heat exchange quantity is Qh*BWhen the sizes of the heat exchanger structures are consistent and the types and the flow rates of the fluids are consistent, the heat exchange quantity ratio obtained by different windward sides of the main body is as follows:
Figure BDA0002458835770000111
the height h of the heat exchanger is much larger than the thickness B, so that the formula shows that Q is obtainedI*hMuch less than Qh*BIf the height h is much greater than the thickness B, then QI*hWill be much smaller than Qh*BThrough calculation of the formula, the heat exchanger can obtain better heat exchange effect of the heat exchanger only by changing the windward side of the main body of the heat exchanger under the external conditions of the same size, the same fluid type, the same flow speed and the like. In the application environment of using heat exchanger in air conditioner and refrigerator, the original face formed from height h and width I of axial fan to heat exchanger can be used as main windward face of heat exchanger, and the face formed from height h and thickness B of heat exchanger can be used as main windward face of heat exchanger, so that it can be used for air conditioning, refrigerator and other placesAnd the better heat exchange performance is obtained, and the miniaturization of the overall dimension of the unit consisting of the heat exchanger, the fan or other refrigeration parts (such as a compressor, a throttle valve and the like) is also obtained.
The technical scheme of the application has the following advantages in the practical application process:
(a) two positive effects on heat exchange mechanism that improve heat exchange efficiency are brought: the windward side and the heat exchange area of the main body, the heat exchange area in the pipe and the medium flowing state greatly improve the heat exchange efficiency:
(b) the flow velocity of fluid outside the pipe (wind speed of a fan) can be further reduced by improving the structure of the heat exchanger, so that the fluid noise during heat exchange is reduced (for example, the wind noise is reduced by 2-3 db (A));
(c) the heat exchanger can be further reduced in physical size to fit onto space constrained refrigeration heat exchange equipment or to miniaturize the equipment, with physical size ratios smaller 1/3;
(d) the material for the heat exchanger can be further reduced, so that cost benefit is generated for refrigeration and heat exchange equipment, 1/3 can be saved under the condition of the same material, and the weight is light by 10-15%;
(e) the filling amount of the refrigerant is controlled, and compared with the traditional heat exchanger, the inner volume of a pipeline through which the refrigerant flows is much smaller, and the filling amount of the refrigerant can be reduced by 1/4; the defrosting mechanism of the product is changed, when the pipe diameter size of the heat exchanger pipeline is adopted, the defrosting time can be effectively improved, when convection or radiation conduction heat is adopted to defrost the heat exchanger, the defrosting time (the time from defrosting to defrosting is finished) can be increased by 10% -35%, when a refrigerant in the parallel pipeline flows (for example, when an air conditioner refrigeration cycle is reversed) or when a solid heat transfer mode that an electric heating wire is pasted on the surface of the heat exchanger is adopted to defrost the heat exchanger, the defrosting time can be increased by 55% -65%.
Although particular embodiments of the present invention have been described above, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims (7)

1. The utility model provides a parallel pipeline heat exchanger of little passageway of taking fin, includes admission pipe, parallel pipeline and discharge pipe, parallel pipeline respectively with the admission pipe with the discharge pipe is linked together its characterized in that: the parallel pipelines are provided with fins and are arranged into at least one row, and the outer diameter d of the parallel pipelines isoThe value range of (d) is more than 1mmoWhen the diameter is less than or equal to 3.95mm, the heat exchange quantity of the heat exchanger and the structure of the heat exchanger accord with the following formula:
Figure FDA0002458835760000011
wherein Q is heat exchange quantity and the unit is W; c0The value of the error coefficient is 0.8-1.2; c1The value is constant and is between 0.023 and 0.027; c2Is a constant and takes a value of 1.2-1.4; lambda is the coefficient of thermal conductivity of the medium outside the pipe, and the unit is W/(m.k); rho is the density of the medium outside the pipe and has the unit of kg/m3(ii) a Mu is dynamic viscosity of medium outside the pipe, and the unit is Pa.s; c. CpThe constant pressure specific heat capacity of the medium outside the pipe is expressed in J/(kg.K); s is the flow of medium circulating outside the pipe and is m3S; delta t is the heat exchange temperature difference and has the unit of K; m is the number of the heat exchanger tube rows; ζ is the tube spacing factor; h is the height of the heat exchanger and the unit is m; doIs parallel pipeline external diameter in m, B is heat exchanger thickness in m, is fin factor, η is tube row factor, psi is tube layer factor, and tube spacing between adjacent parallel pipelines is BtThe tube spacing factor ζ ═ bt/do(ii) a The distance between the adjacent fins is bfThe fin factor bf/doThe distance between the centers of the corresponding pipeline pipes between two adjacent parallel pipelines is t, and the pipe row factor η is t/do(ii) a The pipe layer factor psi is the number of layers set according to the reasonable state of the distribution of the medium in the pipe in the parallel pipeline.
2. The finned mini-channel parallel tube heat exchanger of claim 1 wherein: the parallel pipelines are arranged into at least two rows.
3. The finned mini-channel parallel tube heat exchanger of claim 1 wherein: the parallel pipelines are made of metal materials.
4. The finned mini-channel parallel tube heat exchanger of claim 1 wherein: wall thickness (d) of the parallel lineso-di) The value range of/2 is 0 < do-di) A/2 is less than or equal to 0.4mm, wherein diIs the parallel pipeline inner diameter.
5. The finned mini-channel parallel tube heat exchanger of any one of claims 1 to 4, wherein: the distance b between the adjacent finsfThe value range of (b) is more than or equal to 1mmf≤4mm。
6. The finned mini-channel parallel tube heat exchanger of claim 5 wherein: the fins are arranged perpendicular to the extending direction of the parallel pipelines.
7. A method for calculating the heat exchange capacity of a small-channel parallel pipeline heat exchanger with fins is characterized by comprising the following steps: the heat exchange quantity of the heat exchanger is calculated by adopting the following formula:
Figure FDA0002458835760000021
wherein Q is heat exchange quantity and the unit is W; c0The value of the error coefficient is 0.8-1.2; c1The value is constant and is between 0.023 and 0.027; c2Is a constant and takes a value of 1.2-1.4; lambda is the coefficient of thermal conductivity of the medium outside the pipe, and the unit is W/(m.k); rho is the density of the medium outside the pipe and has the unit of kg/m3(ii) a Mu is dynamic viscosity of medium outside the pipe, and the unit is Pa.s; c. CpIs outside of a tubeThe specific heat capacity at constant pressure of the medium is J/(kg. K); s is the flow of medium circulating outside the pipe and is m3S; delta t is the heat exchange temperature difference and has the unit of K; m is the number of the heat exchanger tube rows; ζ is the tube spacing factor; h is the height of the heat exchanger and the unit is m; doIs parallel pipeline external diameter in m, B is heat exchanger thickness in m, is fin factor, η is tube row factor, psi is tube layer factor, and tube spacing between adjacent parallel pipelines is BtThe tube spacing factor ζ ═ bt/do(ii) a The distance between the adjacent fins is bfThe fin factor bf/doThe distance between the centers of the corresponding pipeline pipes between two adjacent parallel pipelines is t, and the pipe row factor η is t/do(ii) a The pipe layer factor psi is the number of layers set according to the reasonable state of the distribution of the medium in the pipe in the parallel pipeline.
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH09273967A (en) * 1996-04-03 1997-10-21 Hitachi Ltd Calculator for flow passing through heat sink
CN102508958A (en) * 2011-10-28 2012-06-20 北京航空航天大学 Optimal parameter determination method for plate-fin evaporator
CN103150439A (en) * 2013-03-14 2013-06-12 西安交通大学 Plate-fin heat exchanger oriented forecasting method for flow and heat exchange performances of fin
CN110008579A (en) * 2019-03-29 2019-07-12 中国原子能科学研究院 The design method of vertical fins tubing heat exchanger
CN110598322A (en) * 2019-09-12 2019-12-20 揭阳市美度实业有限公司 Simulation evaluation and optimization design method for integrated downward-convex pressure-stabilizing flow-distributing automobile condenser

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH09273967A (en) * 1996-04-03 1997-10-21 Hitachi Ltd Calculator for flow passing through heat sink
CN102508958A (en) * 2011-10-28 2012-06-20 北京航空航天大学 Optimal parameter determination method for plate-fin evaporator
CN103150439A (en) * 2013-03-14 2013-06-12 西安交通大学 Plate-fin heat exchanger oriented forecasting method for flow and heat exchange performances of fin
CN110008579A (en) * 2019-03-29 2019-07-12 中国原子能科学研究院 The design method of vertical fins tubing heat exchanger
CN110598322A (en) * 2019-09-12 2019-12-20 揭阳市美度实业有限公司 Simulation evaluation and optimization design method for integrated downward-convex pressure-stabilizing flow-distributing automobile condenser

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