CN110309591A - It exchanges heat under a kind of flat finned heat exchanger air side laminar condition and drag computation method - Google Patents
It exchanges heat under a kind of flat finned heat exchanger air side laminar condition and drag computation method Download PDFInfo
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- CN110309591A CN110309591A CN201910583038.9A CN201910583038A CN110309591A CN 110309591 A CN110309591 A CN 110309591A CN 201910583038 A CN201910583038 A CN 201910583038A CN 110309591 A CN110309591 A CN 110309591A
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- 238000004364 calculation method Methods 0.000 claims abstract description 8
- 238000012546 transfer Methods 0.000 claims description 9
- 238000004088 simulation Methods 0.000 claims description 6
- 238000010206 sensitivity analysis Methods 0.000 claims description 5
- 230000001419 dependent effect Effects 0.000 abstract 1
- 238000012821 model calculation Methods 0.000 abstract 1
- 238000012512 characterization method Methods 0.000 description 4
- 238000013461 design Methods 0.000 description 3
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- 238000004378 air conditioning Methods 0.000 description 1
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- 238000004134 energy conservation Methods 0.000 description 1
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/20—Design optimisation, verification or simulation
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
- G06F2119/08—Thermal analysis or thermal optimisation
Abstract
The invention discloses the heat exchange and resistance calculation formulae under a kind of flat finned heat exchanger air side laminar condition, the following steps are included: step 1: establishing fin tube model, and using the spacing of fin, thickness, tube spacing, pipe number of rows and inlet velocity, tube wall temperature as Variable Factors, orthogonal test operating condition is designed.The numerical value that different operating conditions are flowed and conducted heat calculates, and obtains the changing rule of heat exchange amount and flow resistance.Step 2: providing about Reynolds number, Prandtl number and spacing of fin and characteristic length ratio is independent variable on the basis of verifying to the model calculation, expressed using the nusselt number of heat exchange amount and the resistance factor of flow resistance as the power function of dependent variable；Step 3: fitting each coefficient value in functional relation using least square method.It can be used for calculating heat exchange and resistance of the flat finned heat exchanger under laminar condition by this set calculation formula, and determine that spacing of fin influences the performance of flat finned heat exchanger.
Description
Technical field
The present invention relates to Thermal Power Engineering Fields, specifically, being under a kind of flat finned heat exchanger air side laminar condition
Heat exchange and drag computation method.
Background technique
Current flat finned heat exchanger is widely used to the various necks of air-conditioning, heat pump since structure is simple, easy to process
Domain.For its heat transfer and flow resistance characteristics, also there is miscellaneous Heat transfer corelation, existing Heat transfer corelation is all Nu Sai
The relationship of your number and Reynolds number, Prandtl number；The relationship of resistance factor and Reynolds number.Since application is mostly outdoor or empty
Under the occasion of turbulent flow, these formula are suitable for air side flow velocity and are in the calculating under turbulent condition air-flow state.
Now with the development of electronics industry, various electronic equipments show highly integrated and miniaturization trend, as
The radiator of the electronic equipments such as high integration computer, mostly indoors, air side flow speed is decreased obviously applicable situation；Together
When influence of the spacing of fin to heat transmitter it is especially prominent.
There is presently no the calculation formula that spacing of fin heat exchanging device performance influences under laminar condition.Based on this, this hair
Bright patent proposes the calculation formula of heat exchange and resistance under a kind of flat finned heat exchanger air side laminar condition, gives nusselt number
The scope of application of heat exchange, Correlations and formula with resistance factor characterization.Pass through the formula, it may be determined that different fins
Heat exchanger heat exchange and resistance performance under spacing.
Summary of the invention
It is the flat finned heat exchanger performance of laminar flow that the purpose of the present invention is to provide a kind of suitable for air side flow state
Determination method.This method can substitute traditional experimental method.In view of lamina air flow state is difficult to realize in laboratory
The case where, by numerical computation method, the variation characteristic of this heat exchanger performance is analyzed, by data preparation, provides this kind of change
The coefficient of heat transfer of hot device and the calculation formula of the flow resistance factor are used for practical Selection and Design.
To achieve the above object, the present invention the following steps are included:
1, heat exchanger structure parameter (spacing of fin, fin thickness, tube spacing, pipe number of rows) is determined, in the base that structural parameters determine
It on plinth, is tested by numerical simulation, establishes numerical simulator；
2, the number of debugging flowing and three big conservation equations (mass-conservation equation, momentum conservation equation, energy conservation equation) of heat transfer
It is worth calculation procedure, simulates flowing and heat compensator conducting property of the heat exchanger under various operating parameters (inlet velocity, tube wall temperature)；
3, influence sensitivity analysis is done to the parameter for influencing above-mentioned Numerical Simulation Results, finding out influences heat exchanger heat transfer and mobility
Can most important structural parameters be spacing of fin, most important operating parameter is inlet velocity, and by heat exchange amount and flow resistance
It is expressed as dimensionless expression-form (see formula 1 and formula 2):
(1)
(2)
- nusselt number；
- constant coefficient:Constant coefficient in-formula (1),Constant coefficient in-formula (2)；
—Reynolds number；
- Prandtl number；
- spacing of fin；
- characteristic length；
,—Index coefficient:
,—Index coefficient.
4, data are programmed processing, carry out data fitting, determine that the constant coefficient C and power in formula 1 and formula 2 refer to
Number system numberWith.Result after fitting is shown in formula 3 and formula 4:
(3)
(4)
The scope of application of formula 3 and formula 4 are as follows: 444≤Re≤ 3405；Prandtl numberPrAbout 0.701.
5, according to the calculating correlation, heat exchanger heat exchange and the resistance performance under different spacings of fin can be analyzed, is such
The Selection and Design of heat exchanger provides foundation.
Detailed description of the invention
The present invention will be further described with reference to the accompanying drawing.
Fig. 1 is a kind of heat exchange of flat finned heat exchanger air side of the present invention and the implementation steps of drag computation method.
Fig. 2 is model structure of the invention.
Fig. 3 is change curve of the inlet velocity of the invention simulated to nusselt number.
Fig. 4 is change curve of the inlet velocity of the invention simulated to resistance factor.
Fig. 5 is change curve of the spacing of fin of the invention simulated to nusselt number.
Fig. 6 is change curve of the spacing of fin of the invention simulated to resistance factor.
Fig. 7 is the variation characteristic that the present invention provides the heat exchanger heat-transfer performance.
Fig. 8 is the variation characteristic that the present invention provides the heat exchanger flow resistance performance.
Specific embodiment
The invention proposes heat exchange and drag computation methods under a kind of flat finned heat exchanger air side laminar condition, in order to make
Advantages of the present invention, technical solution are clearer, clear, elaborate combined with specific embodiments below to the present invention.
1, model structure parameter.
As shown in Figure 1, heat exchange and drag evaluation side under a kind of flat finned heat exchanger air side laminar condition of the present invention
Method, design first finned heat exchanger structural parameters (with specified heat exchange amount for 5.0 kW explanation), mainly spacing of fin,
The determination of the parameters such as thickness, tube spacing, pipe number of rows, structural parameters are shown in Table 1:
Table 1
| Structural parameters | Numerical values recited | Unit |
| Outer tube diameter | 12.5 | mm |
| Interior caliber | 10 | mm |
| Wall thickness | 2.5 | mm |
| Spacing of fin | 2 | mm |
| Fin thickness | 1 | mm |
| Pipe longitudinal pitch | 12.5(1 times of outer tube diameter) | mm |
| Pipe number of rows | 1 | Row |
| Pipe horizontal spacing | 32.476(1.5Times outer tube diameter, when pipe number of rows > 1) | mm |
2, operating parameter and related thermodynamic data.
According to Numerical Simulations, thermodynamics transitivity data are set, are shown in Table 2:
Table 2
| Inlet velocity (m/s) | 1 |
| Inlet pressure (Pa) | 6.79 |
| Outlet pressure (Pa) | -1.2 |
| Inlet temperature (K) | 303 |
| Outlet temperature (K) | 320.65 |
| Mass flowrate (kg/s) | 0.0003786 |
| Air specific heat (kJ/ (kg*K)) | 1.005 |
| Smallest cross-sectional speed (m/s) | 3.48 |
| Characteristic length (m) | 0.00476 |
| Kinematic viscosity (m2/ s) | 0.000016 |
| Atmospheric density (kg/m3) | 1.165 |
| Zone length (m) | 0.05 |
3. correlated results.
It is tested according to numerical simulation, obtains correlation calculation result, be shown in Table 3:
Table 3
| Pressure drop △ P(Pa) | 7.99 |
| Heat exchange amount Q(W) | 6.7157 |
| Reynolds number Re | 1035.3 |
| Nusselt number Nu | 6.612 |
| Resistance factor f | 0.1078 |
Change the structural parameters and operating parameter of flat finned heat exchanger, simulate the flowing under different condition and heat transfer variation characteristic,
The relation curves such as pressure drop, heat exchange amount, nusselt number, resistance factor etc. and inlet velocity, spacing of fin, fin thickness are obtained, are seen
Fig. 3, Fig. 4, Fig. 5, Fig. 6.
4, model verifying and sensitivity analysis.
Simulation the data obtained is compared with relevant experimental data, in the base that the correctness to analog result is verified
On plinth, the sensitivity analysis of affecting parameters is carried out to calculated result.
Determined according to sensitivity analysis, obtaining influences fin heat exchange and the most important structural parameters of resistance performance between fin
Away from most important operating parameter is inlet velocity.
5, correlation form is determined.
Select the influence characterization of spacing of fin at characteristic length ratio group become dimensionless (), it selects into one's intention as revealed in what one says
Speed characterization parameter be.Determine that correlation form is as follows:
(1)
(2)
- nusselt number；
- constant coefficient:Constant coefficient in-formula (1),Constant coefficient in-formula (2)；
—Reynolds number；
- Prandtl number；
- spacing of fin；
- characteristic length；
,—Index coefficient:
,—Index coefficient.
6, fitting formula.
When handling formula (1), (2), using double-log form.I.e. both members take logarithm simultaneously, and power function is converted
For linear function (see formula 3 and formula 4).Wherein when being fitted nusselt number, Prandtl number air be not higher than at 30 DEG C when,
It can be identified as 0.701, index takes the empirical value to be,Logarithm be -0.1184, formula each so only there are three
Numerical value undetermined.
(3)
(4).
Data fitting procedure is write, determines each coefficient in formula 3 and formula 4.Obtain 5 He of formula of characterization heat exchange amount
Characterize the formula 6 of flow resistance.
(5)
(6).
7, use scope explanation.
According to Nu, Re,Evaluation, provide the scope of application of formula 5 and formula 6 are as follows: the range of Reynolds number are as follows:
444 ≤ Re≤ 3405；Prandtl numberPrNumerical value when for air-side temperature not higher than 30 DEG C, can be taken as 0.701.
According to the formula scope of application, Fig. 7 and Fig. 8 are set forth nusselt number and resistance factor under applicable elements and become
Change feature.
Claims (4)
1. heat exchange and drag computation method under a kind of flat finned heat exchanger air side laminar condition, it is characterised in that successively include
Following steps:
(1) flat finned heat exchanger structural parameters are determined, such as inlet velocity, tube wall temperature, spacing of fin, fin thickness, Guan Jian
Away from, pipe number of rows, and establish physical model；
(2) debugging flowing and Calculation of Heat Transfer simulated program, and the resulting data of analogue simulation are subjected to sensitivity analysis, obtain shadow
Ring the biggest impact factor of fin heat exchange and resistance factor are as follows: inlet velocity and spacing of fin；
(3) data fitting is carried out, obtains the Nu Sai about the expression of Reynolds number, Prandtl number, spacing of fin and characteristic length ratio
The calculating correlation of your number and resistance factor；
(4) according to gained correlation, the heat exchange of heat exchanger and resistance performance under different spacings of fin are analyzed.
2. a kind of heat exchange of flat finned heat exchanger air side according to claim 1 and drag computation method, feature exist
In heat exchange and resistance correlation are as follows:,。
3. a kind of heat exchange of flat finned heat exchanger air side according to claim 2 and drag prediction method, feature exist
There are equation coefficients, Reynolds number in correlationRe, Prandtl numberPr, spacing of finWith characteristic lengthDRatio。
4. heat exchange and the drag computation method of a kind of flat fin air side according to claim 2, it is characterised in that provide
Calculate the computer capacity of correlation: Reynolds numberRange are as follows: 444≤Re≤ 3405；Prandtl numberPrValue be about
0.701。
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110738011A (en) * | 2019-10-11 | 2020-01-31 | 中国航发沈阳发动机研究所 | Temperature evaluation method and system for structural components in engines |
| CN113901591A (en) * | 2021-12-08 | 2022-01-07 | 中国空气动力研究与发展中心低速空气动力研究所 | Hot wire unit dry power calculation method and liquid water content calculation method based on same |
| CN115587505A (en) * | 2022-12-08 | 2023-01-10 | 中国核动力研究设计院 | Flow heat transfer model construction method and device based on dimensionless characteristic parameters |
| CN117434111A (en) * | 2023-12-19 | 2024-01-23 | 北京蓝威技术有限公司 | Thermal resistance testing method for fin radiator under natural convection |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107391807A (en) * | 2017-06-28 | 2017-11-24 | 西安交通大学 | Plate-fin heat exchanger heat transfer flow performance value analogy method based on transient technology |
-
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Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107391807A (en) * | 2017-06-28 | 2017-11-24 | 西安交通大学 | Plate-fin heat exchanger heat transfer flow performance value analogy method based on transient technology |
Non-Patent Citations (2)
| Title |
|---|
| 康海军等: "平直翅片管换热器传热与阻力特性的实验研究", 《西安交通大学学报》, pages 2 * |
| 王巧丽: "余热回收翅片管换热器传热与流体力学特性研究", 《中国优秀硕士学位论文全文数据库》, pages 19 * |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110738011A (en) * | 2019-10-11 | 2020-01-31 | 中国航发沈阳发动机研究所 | Temperature evaluation method and system for structural components in engines |
| CN113901591A (en) * | 2021-12-08 | 2022-01-07 | 中国空气动力研究与发展中心低速空气动力研究所 | Hot wire unit dry power calculation method and liquid water content calculation method based on same |
| CN115587505A (en) * | 2022-12-08 | 2023-01-10 | 中国核动力研究设计院 | Flow heat transfer model construction method and device based on dimensionless characteristic parameters |
| CN117434111A (en) * | 2023-12-19 | 2024-01-23 | 北京蓝威技术有限公司 | Thermal resistance testing method for fin radiator under natural convection |
| CN117434111B (en) * | 2023-12-19 | 2024-03-15 | 北京蓝威技术有限公司 | Thermal resistance testing method for fin radiator under natural convection |
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