CN204330647U - A kind of system for measuring tube bank heat transfer characteristic - Google Patents
A kind of system for measuring tube bank heat transfer characteristic Download PDFInfo
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- CN204330647U CN204330647U CN201420813513.XU CN201420813513U CN204330647U CN 204330647 U CN204330647 U CN 204330647U CN 201420813513 U CN201420813513 U CN 201420813513U CN 204330647 U CN204330647 U CN 204330647U
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- heat
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- tube bundle
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Abstract
The utility model discloses a kind of system for measuring tube bank heat transfer characteristic, comprise intake stack, it is air inlet on the left of intake stack, intake stack inside is provided with axial flow blower from left to right successively, air channel gate and venturi section, the first straight length is connected on the right side of venturi section, first straight length inside is provided with pitot tube, pitot tube is connected with microbarograph, removable heat-exchanging tube bundle test section is connected with on the right side of first straight length, the second straight length is connected on the right side of heat-exchanging tube bundle test section, it is exhaust outlet on the right side of second straight length, the left and right sides of heat-exchanging tube bundle test section is equipped with temperature sensor I, temperature sensor I is connected with data acquisition unit I.Native system only needs the test section changing design heat-exchanging tube bundle, and supporting air channel and water side ducts need not be changed, and system has versatility; System measuring point chooses the use needs meeting measurement mechanism, measures accurately; Ensure thermal equilibrium, test findings error is less.
Description
Technical field
The utility model relates to a kind of system for measuring tube bank heat transfer characteristic.
Background technology
In engineering practice, heat interchanger is all widely used in industries such as power, chemical industry, metallurgy, space flight, air-conditioning, refrigeration, machinery, light textile, buildings, heat interchanger has multi-form accordingly according to different purposes and heat exchange environment, and wherein heat-exchanging tube bundle is widely used in the indirect Convective Heat Transfer of two media.In order to strengthen convection heat transfer' heat-transfer by convection effect, on the basis of traditional heat exchange pipe, reprocess, mainly contain swirl element, the spiral pipes etc. such as the extended surfaces such as the treatment surface such as coating or porous surface, rough surface, fin, turbulent element, twisted straps or helical blade.
In the indirect heat exchanger of two media, temperature difference and the heat interchanging area of the heat exchange amount in the unit interval and cold fluid and hot fluid are directly proportional, i.e. Q=KA Δ t, and in formula, K---the coefficient of heat transfer is the index of reflection heat exchanger heat transfer effect power.The overall coefficient of heat transfer K's restrained is relevant to the convection transfer rate of the heat conduction restrained, two media, and different tube banks is due to its external heat-exchanging face structure difference, and its overall coefficient of heat transfer is also different with convection transfer rate.Therefore, restrain for different augmentation of heat transfer, measure the overall coefficient of heat transfer of experimental section under different wind speed, the convection transfer rate of wind side verifies, to instructing, the design ap-plication of various heat exchange tube bank in Practical Project is very important.
Not having at present can accurately to the system that the coefficient of heat transfer of various heat exchange tube bank is measured.Main Problems existing has: for different designs operating mode, needs to arrange supporting air channel and water side ducts, and experiment porch does not have versatility; Experiment porch is built position limitation, measures out of true; Heat exchange influence factor is more, and test thermal equilibrium is difficult to ensure, test findings error is larger.
Utility model content
The purpose of this utility model is for overcoming above-mentioned the deficiencies in the prior art, provides a kind of system for measuring tube bank heat transfer characteristic, and this system only needs the test section changing design heat-exchanging tube bundle, and supporting air channel and water side ducts need not be changed, and have versatility.
For achieving the above object, the utility model adopts following technical proposals:
A kind of system for measuring tube bank heat transfer characteristic, comprise intake stack, it is air inlet on the left of described intake stack, described intake stack inside is provided with axial flow blower from left to right successively, air channel gate and venturi section, the first straight length meeting the certain length of the measurement instrument precision such as pitot tube is connected on the right side of described venturi section, described first straight length inside is provided with pitot tube, pitot tube is connected with microbarograph, removable heat-exchanging tube bundle test section (can change according to different operating mode) is connected with on the right side of described first straight length, the second straight length of certain length is connected on the right side of described heat-exchanging tube bundle test section, be exhaust outlet on the right side of described second straight length, the left and right sides of described heat-exchanging tube bundle test section is equipped with temperature sensor I, described temperature sensor I is connected with data acquisition unit I, data acquisition unit I by time measure the wind-warm syndrome of heat-exchanging tube bundle test section air inlet and exhaust outlet.The lower end of described heat-exchanging tube bundle test section connects water inlet pipe, and the upper end of described heat-exchanging tube bundle test section connects rising pipe, and described water inlet pipe is connected with water bath with thermostatic control by spinner-type flowmeter and centrifugal water pump.Described rising pipe is connected with water bath with thermostatic control.
The water inlet pipe of described heat-exchanging tube bundle test section and rising pipe are equipped with temperature sensor II, and described temperature sensor II is connected with data acquisition unit II, data acquisition unit II by time measure water inlet and the water delivering orifice water temperature of heat-exchanging tube bundle test section.
Described water inlet pipe end is connected with air release, and air release is connected with heat-exchanging tube bundle test section.
Described water bath with thermostatic control is can set temperature and the electrical heating water bath with thermostatic control of record heat time.Water bath with thermostatic control adopts electrically heated mode, has the function of heating pipe built-in Shu Yunhang timing, accurately can calculate electrical heating power, for heat Balance Calculation; Can regulating thermostatic coolant-temperature gage voluntarily, precision can reach ± and 0.5 DEG C.
Water bath with thermostatic control, water inlet pipe, heat-exchanging tube bundle test section and rising pipe form water loops, are wherein the water side of flowing in heat-exchanging tube bundle test section; Outside air inlet, axial flow blower, venturi section, the first straight length, heat-exchanging tube bundle, air channel, the second straight length form air circuit, and wherein outside heat-exchanging tube bundle, air channel is air side.
The beneficial effects of the utility model are: native system only needs the test section changing design heat-exchanging tube bundle, and supporting air channel and water side ducts need not be changed, and system has versatility; System measuring point chooses the use needs meeting measurement mechanism, measures accurately; System ensures thermal equilibrium, and test findings error is less.
Accompanying drawing explanation
Fig. 1 is the structural representation that the utility model measures tube bank heat transfer characteristic system;
Fig. 2 is that overall heat exchange coefficient and air side convection transfer rate are with wind speed changing trend diagram;
In figure, 1 is air inlet, and 2 is axial flow blower, 3 is air channel gate, and 4 is venturi section, and 5 is pitot tube, 6 is microbarograph, and 7 is change of current tube bank test section, and 8 is data acquisition unit, 9 is temperature sensor, and 10 is exhaust outlet, and 11 is spinner-type flowmeter, 12 is centrifugal water pump, 13 is water bath with thermostatic control, and 14 is the first straight length, and 15 is the second straight length.
Embodiment
Below in conjunction with drawings and Examples, the utility model is further illustrated.
As shown in Figure 1, for measuring the system of tube bank heat transfer characteristic, comprise intake stack, it is air inlet 1 on the left of described intake stack, intake stack 1 inside is provided with axial flow blower 2 from left to right successively, air channel gate 3 and venturi section 4, the first straight length 14 meeting the certain length of the measurement instrument precision such as pitot tube is connected on the right side of venturi section 4, first straight length 14 inside is provided with pitot tube 5, pitot tube 5 is connected with microbarograph 6, removable heat-exchanging tube bundle test section 7 (can change according to different operating mode) is connected with on the right side of first straight length 14, the second straight length 15 of certain length is connected on the right side of heat-exchanging tube bundle test section 7, be exhaust outlet 10 on the right side of second straight length 15, the left and right sides of heat-exchanging tube bundle test section 7 is equipped with temperature sensor 9, temperature sensor 9 is connected with data acquisition unit 8, data acquisition unit 8 by time measure the wind-warm syndrome of heat-exchanging tube bundle test section 7 air inlet 1 and exhaust outlet 10.The lower end of heat-exchanging tube bundle test section 7 connects water inlet pipe, and the upper end of heat-exchanging tube bundle test section 7 connects rising pipe, water inlet pipe by spinner-type flowmeter 11 and centrifugal water pump 12 with can set temperature with record the electrical heating water bath with thermostatic control 13 of heat time and connect.The rising pipe of heat-exchanging tube bundle test section 7 is connected with water bath with thermostatic control 13.
The water inlet pipe of heat-exchanging tube bundle test section 7 and rising pipe are equipped with temperature sensor, and temperature sensor is connected with data acquisition unit, data acquisition unit by time measure water inlet and the water delivering orifice water temperature of heat-exchanging tube bundle test section.
Water inlet pipe end is connected with air release, and air release is connected with heat-exchanging tube bundle test section 7.Water bath with thermostatic control 13, water inlet pipe, heat-exchanging tube bundle test section 7 and rising pipe form water loops, are wherein the water side of flowing in heat-exchanging tube bundle test section 7; Outside air inlet 1, axial flow blower 2, venturi section 4, first straight length 14, heat-exchanging tube bundle, air channel, the second straight length 15 form air circuit, and wherein outside heat-exchanging tube bundle, air channel is air side.
Flange joint is carried out in removable heat-exchanging tube bundle test section and air channel, " nine grids " method of employing, the mean wind speed obtaining current stabilization xsect is obtained with pitot tube and microbarograph measurement, and at heat-exchanging tube bundle test section successively both sides set temperature sensor, with data acquisition unit by time determination test section import and export wind-warm syndrome.
" nine grids " method, namely carries out 16 deciles to the rectangular duct xsect of current stabilization before and after tested tube bank, respectively in the horizontal quartern, longitudinal quartern fixed point, carries out the measurement of 9 fixed points.Wind speed on rectangular duct xsect is uneven, and the measuring error of single-point is comparatively large, and in order to reduce measuring error, " nine grids " method of employing is measured, and obtains the mean wind speed of xsect.
Can to be connected with heat-exchanging tube bundle with the self-control electrical heating water bath with thermostatic control of record heat time and to supply water to described heat-exchanging tube bundle through centrifugal water pump, spinner-type flowmeter by set temperature, the connection water inlet pipe and water outlet pipe of water bath with thermostatic control between heat-exchanging tube bundle installs water inlet, leaving water temperature sensors, with data acquisition unit by time determination test section import and export water temperature.
Water bath with thermostatic control adopts electrically heated mode, has the function of heating pipe built-in Shu Yunhang timing, accurately can calculate electrical heating power, for heat Balance Calculation; Can regulating thermostatic coolant-temperature gage voluntarily, precision can reach ± and 0.5 DEG C.
Embodiment 1:
Direct measurement comprises the wind speed that 8 rows 8 arrange the cooling water flow of rectangle elliptical fin tube bank in parallel, inflow temperature, leaving water temperature, temperature of inlet air, outlet temperature, rectangular duct.
The basic size of rectangle elliptical fin tube bank is as shown in table 1.
In actual measurement, measure in accordance with the following steps:
(1) water bath with thermostatic control water-filling, and be heated to design temperature;
(2) open water pump, slow running, until the intrafascicular air of developmental tube is emptying, water is overflowed at air release place, high-speed cruising water pump, until stable conditions (it is identical that pipeline section thermometric is imported and exported in water side);
(3) blower fan is opened, and standard-sized sheet flashboard, maximum wind velocity runs half an hour, treats stable conditions, and the time period that the heating arrangement reading water bath with thermostatic control is frequently opened, for checking water side draught heat and the thermal equilibrium adding heat; Add heat be water bath with thermostatic control add heat; Caloric receptivity formulae discovery, i.e. cm (t
1-t
2mass rate × (inlet water temperature-outlet water temperature) of)=4.187 × water;
(4) read number and adopt the water side of instrument and the out temperature of air side, and adopt " nine grids " method, obtain with pitot tube and microbarograph measurement the mean wind speed obtaining xsect;
(5) aperture of flashboard is regulated, after stable conditions (30min), under repetition (4) step obtains different wind speed, the out temperature of water side and air side, and the mean wind speed of xsect;
(6) process experimental data, remove test bad point (thermal equilibrium error is more than 10%), calculate the coefficient of heat transfer of heat-exchanging tube bundle.
According to system heat balance, the overall coefficient of heat transfer of test section, the convection transfer rate of air side can be calculated.
Heat balance: Q=Q
1=Q
2=Q
3,
Heat transfer in water side: Q
1=c
1m (t'
1-t "
1),
Air side heat exchange amount: Q
2=c
2m'(t'
2-t "
2),
Electrical heating amount: Q
3=PT (for checking thermal equilibrium, the test bad point more than 10% should be rejected), wherein, c
1represent the specific heat capacity of water side, c
2represent the specific heat capacity of air side; M represents the mass rate of water side, and m' represents the mass rate of air side; T '
1represent the water inlet water temperature of water side, t "
1represent the water delivering orifice water temperature of water side; T '
2represent the air inlet wind-warm syndrome of air side, t "
2represent the exhaust outlet wind-warm syndrome of air side; P is water bath with thermostatic control heating tube power, and T is the heat time.
1) the overall coefficient of heat transfer
According to overall heat exchange amount: Q=KA Δ t,
Obtain the overall coefficient of heat transfer:
Wherein, area A is the experiment pipeline section total area:
The A=A1+A2=fin total area+naked pipe total area.
Log-mean temperature difference Δ t will revise adverse current log-mean temperature difference according to distributary, tries to achieve:
Adverse current log-mean temperature difference:
wherein Δ t
maxbe the maximum temperature difference of the import and export of two kinds of fluids, Δ t
minbe the minimum temperature difference of the import and export of two kinds of fluids,
According to dimensionless group:
And look into " distributary, when a kind of fluid chemical field, one other fluid do not mix " temperature difference correction factor figure and obtain revising ψ value, obtain the log-mean temperature difference of distributary:
Δt＝ψ·Δt
m。
2) air side convection transfer rate
First calculate the applicable elements that water effluent state meets Seider-Tate correlation, Nu-number Nu can be calculated
f, physical significance represents the temperature of zero dimension gradient of the fluid of near wall, and it represents that fluid is to the power of convection heat transfer.And according to
wherein d is caliber, h
ffor fluid side convection transfer rate, λ is coefficient of heat conductivity, can calculate the convection transfer rate of water side
Wherein h
1for the convection transfer rate of water side, λ is coefficient of heat conductivity, Nu
1for water side Nu-number, d is caliber, Re
1for heat exchanger tube water side Reynolds number, Pr
1for Prandtl number, d is caliber, and L is pipe range, η
1for the coefficient of kinetic viscosity under fluid temperature (F.T.), η
wfor the coefficient of kinetic viscosity under wall surface temperature;
The material of rectangle elliptical finned tube is steel pipe, gets its coefficient of heat conductivity λ=45W/ (m ﹒ K), according to
Wherein K is the overall coefficient of heat transfer, h
1for the convection transfer rate of water side, δ is heat-exchanging tube bundle wall thickness, and λ is coefficient of heat conductivity, h
2for the convection transfer rate of air side, the convection transfer rate of air side can be tried to achieve:
According to the method described above, the main calculation results obtained in the present embodiment is as shown in table 2.
Table 2 test section experimental data summary sheet
| Sequence number | Mean wind speed | Overall heat exchange coefficient | Air side convection transfer rate |
| m/s | W/(m 2﹒K) | W/(m 2﹒K) | |
| 1 | 11.24 | 25.41 | 29.09 |
| 2 | 10.67 | 24.25 | 27.63 |
| 3 | 9.68 | 23.37 | 26.43 |
| 4 | 9.06 | 23.23 | 26.23 |
| 5 | 8.69 | 22.86 | 25.75 |
| 6 | 8.39 | 22.22 | 25 |
| 7 | 7.63 | 21.86 | 24.55 |
| 8 | 7.21 | 21.65 | 24.27 |
| 9 | 6.19 | 18.88 | 20.82 |
| 10 | 5.41 | 17.85 | 19.59 |
Fig. 2 overall heat exchange coefficient and air side convection transfer rate is obtained with wind speed changing trend diagram, the situation that the heat exchange property that this figure reflects heat interchanger intuitively changes with wind speed according to the curve map that the Plotting data in table 2 becomes.As shown in Figure 2, under different wind speed, overall heat exchange coefficient and air side convection transfer rate present identical Changing Pattern, overall trend is strengthen along with wind speed raises heat transfer effect, this and wind side flow-disturbing increase, air side convection heat transfer strengthens relevant, and the flow-disturbing that also show increases low temperature side can augmentation of heat transfer effect.
By reference to the accompanying drawings embodiment of the present utility model is described although above-mentioned; but the restriction not to the utility model protection domain; one of ordinary skill in the art should be understood that; on the basis of the technical solution of the utility model, those skilled in the art do not need to pay various amendment or distortion that creative work can make still within protection domain of the present utility model.
Claims (9)
1. one kind for measure tube bank heat transfer characteristic system, it is characterized in that, comprise intake stack, it is air inlet on the left of described intake stack, described intake stack inside is provided with axial flow blower, air channel gate and venturi section from left to right successively, the first straight length is connected on the right side of described venturi section, described first straight length inside is provided with pitot tube, pitot tube is connected with microbarograph, removable heat-exchanging tube bundle test section is connected with on the right side of described first straight length, being connected to the second straight length on the right side of described heat-exchanging tube bundle test section, is exhaust outlet on the right side of described second straight length.
2. the system measuring tube bank heat transfer characteristic as claimed in claim 1, it is characterized in that, the left and right sides of described heat-exchanging tube bundle test section is equipped with temperature sensor I.
3. the as claimed in claim 2 system measuring tube bank heat transfer characteristic, it is characterized in that, described temperature sensor I is connected with data acquisition unit I, data acquisition unit I by time mensuration heat-exchanging tube bundle test section air inlet and the wind-warm syndrome of exhaust outlet.
4. the system measuring tube bank heat transfer characteristic as claimed in claim 1, is characterized in that, the lower end of described heat-exchanging tube bundle test section connects water inlet pipe, and the upper end of described heat-exchanging tube bundle test section connects rising pipe.
5. the system measuring tube bank heat transfer characteristic as claimed in claim 4, it is characterized in that, described water inlet pipe is connected with water bath with thermostatic control by spinner-type flowmeter and centrifugal water pump, and described rising pipe is connected with water bath with thermostatic control.
6. the system measuring tube bank heat transfer characteristic as claimed in claim 4, is characterized in that, the water inlet pipe of described heat-exchanging tube bundle test section and rising pipe are equipped with temperature sensor II.
7. the as claimed in claim 6 system measuring tube bank heat transfer characteristic, it is characterized in that, described temperature sensor II is connected with data acquisition unit II, data acquisition unit II by time the water inlet of mensuration heat-exchanging tube bundle test section and water delivering orifice water temperature.
8. the system measuring tube bank heat transfer characteristic as claimed in claim 4, it is characterized in that, described water inlet pipe end is connected with air release, and air release is connected with heat-exchanging tube bundle test section.
9. the system measuring tube bank heat transfer characteristic as claimed in claim 5, is characterized in that, described water bath with thermostatic control is can set temperature and the electrical heating water bath with thermostatic control of record heat time.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420813513.XU CN204330647U (en) | 2014-12-19 | 2014-12-19 | A kind of system for measuring tube bank heat transfer characteristic |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420813513.XU CN204330647U (en) | 2014-12-19 | 2014-12-19 | A kind of system for measuring tube bank heat transfer characteristic |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104483349A (en) * | 2014-12-19 | 2015-04-01 | 山东大学 | System and method for measuring heat exchange characteristics of tube bundle |
| CN111289214A (en) * | 2020-03-13 | 2020-06-16 | 浙江银轮机械股份有限公司 | Wind tunnel experimental device and temperature measuring method |
-
2014
- 2014-12-19 CN CN201420813513.XU patent/CN204330647U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104483349A (en) * | 2014-12-19 | 2015-04-01 | 山东大学 | System and method for measuring heat exchange characteristics of tube bundle |
| CN111289214A (en) * | 2020-03-13 | 2020-06-16 | 浙江银轮机械股份有限公司 | Wind tunnel experimental device and temperature measuring method |
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|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20150513 Termination date: 20161219 |
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| CF01 | Termination of patent right due to non-payment of annual fee |