CN108956687A - digital heat transfer comprehensive experiment device and method - Google Patents
digital heat transfer comprehensive experiment device and method Download PDFInfo
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Abstract
The invention relates to a digital heat transfer comprehensive experiment device and a method, which are characterized by consisting of a steam system, a cold medium system, a heat exchange system and a data acquisition control system; wherein the heat exchange system consists of a reinforced tube heat exchanger, a smooth tube heat exchanger, an air cooling fin heat exchanger (5) and a condensate tank (6): the reinforced pipe heat exchanger is parallel to the smooth pipe heat exchanger; the reinforced inner tube heat exchange tube (11) in the reinforced tube heat exchanger and the inner tube of the smooth tube heat exchange tube (12) in the smooth tube heat exchanger are respectively connected with a cold medium system through pipelines; the steam system is connected with a reinforced inner tube heat exchange tube (11) and a smooth tube heat exchange tube (12) in parallel on the shell side; the data acquisition control system consists of a temperature sensor, a pressure sensor, a flowmeter sensor and a control panel. The invention is used for measuring the heat transfer coefficient in the chemical principle teaching experiment; carrying out experimental comparison on heat transfer parameters of different heat transfer media and different heat exchangers; and collecting and summarizing experimental data and uploading the experimental data to a data terminal server or a cloud platform.
Description
The technical field is as follows:
the invention relates to a digital chemical principle experiment teaching device and a method, which are used for measuring a convection heat transfer coefficient.
Technical background:
the measurement of the convective heat transfer coefficient generally refers to the convective heat transfer coefficient when a fluid is forced to be turbulent in a round smooth tube, for example, water vapor heats a cold medium (such as cold water, air, etc.). The enhanced heat transfer is called as a second generation heat transfer technology by the academic community, and the heat transfer area of the design can be reduced so as to reduce the volume and the weight of the heat exchanger; the heat exchange capacity of the existing heat exchanger is improved; the heat exchanger can work under a lower temperature difference; and the resistance of the heat exchanger can be reduced to reduce the power consumption of the heat exchanger, and energy and funds are more effectively utilized. The existing heat transfer coefficient measuring device has the following common problems: 1) the heat exchanger component is single, if one of a single-tube heat exchanger, a shell-and-tube heat exchanger, a finned heat exchanger and the like is adopted usually, in the student experiment process, the heat supply coefficient of the single heat exchanger can be obtained only, and the heat transfer performance of the single heat exchanger component cannot be compared with that of other heat exchanger components; 2) how to improve the heat exchange capacity of the heat exchanger at present, reduce the energy loss of the heat exchanger in order to reduce the power consumption of the heat exchanger, utilize the energy more effectively, it is a problem to be solved; 3) to how all to take manual record with traditional experimental data, for example temperature, pressure, pipe diameter, heat transfer area etc. the papery data is unfavorable for preserving, inconvenient big data centralized analysis and integrated management, to the stability evaluation of experimental apparatus and the record of using of equipment, can't carry out scientific management.
The invention content is as follows:
in view of the problems, the invention aims to provide a digital heat transfer comprehensive experiment device, and the invention also aims to provide a method for conducting heat transfer teaching experiments by using the digital heat transfer comprehensive experiment device.
The technical scheme of the invention is as follows: the digital heat transfer comprehensive experimental device is characterized in that: the system consists of a steam system, a cold medium system, a heat exchange system and a data acquisition control system; wherein: the heat exchange system consists of a reinforced tube heat exchanger, a smooth tube heat exchanger, an air cooling fin heat exchanger 5 and a condensate tank 6: the reinforced tube heat exchanger consists of a reinforced tube observation sleeve 9, a reinforced tube external pressure-resistant glass sleeve 10 and a reinforced inner tube heat exchange tube 11; the smooth tube heat exchanger consists of a smooth tube heat exchange tube 12, a smooth tube external pressure-resistant glass sleeve 13 and a smooth tube observation sleeve 14; the reinforced pipe heat exchanger is parallel to the smooth pipe heat exchanger and is positioned below the smooth pipe heat exchanger; the heat exchange tube 11 with the strengthened inner tube and the inner tube of the heat exchange tube 12 with the smooth tube are respectively connected with a cold medium system through pipelines; the outside of the heat exchange tube 11 of the strengthening inner tube is sleeved and connected with a pressure-resistant glass sleeve 10 outside the strengthening tube, and the pressure-resistant glass sleeve 10 outside the strengthening tube is sleeved and connected with an observation sleeve 9 of the strengthening tube; the outside of the smooth tube heat exchange tube 12 is sleeved with a smooth tube external pressure-resistant glass sleeve 13, and the outside of the smooth tube external pressure-resistant glass sleeve 13 is sleeved with a smooth tube observation sleeve 14; a steam pipeline of a self generator 3 of the steam system is respectively connected with a reinforced inner pipe heat exchange tube 11 and a smooth pipe heat exchange tube 12 in parallel; the tail parts of the shell sides of the enhanced inner tube heat exchange tube 11 and the smooth tube heat exchange tube 12 are connected with the air-cooled fin heat exchanger 5 and the condensate tank 6 through pipelines; the heat exchange tube 11 with the strengthened inner tube and the heat exchange tube 12 with the smooth tube are connected with an outdoor sewer through a pipeline at a tube pass emptying port; the cold medium system consists of material conveying equipment, a frequency converter 2 and a turbine flowmeter 4: wherein the material conveying equipment is connected with the turbine flowmeter 4 and the inner pipe of the reinforced inner pipe heat exchange pipe 11 of the reinforced pipe heat exchanger in the heat exchange system by pipelines; the inner pipes of the smooth pipe heat exchange pipes 12 of the smooth pipe heat exchanger in the heat exchange system are communicated in parallel; the data acquisition control system consists of a temperature sensor, a pressure sensor, a flowmeter sensor and a control panel; the inlet and outlet walls of the heat exchange tube 11 of the strengthening inner tube are respectively provided with a first temperature sensor 8a and a fourth temperature sensor 8 d; the inlet and outlet walls of the smooth-tube heat exchange tube 12 are respectively provided with a second temperature sensor 8b and a third temperature sensor 8 c; the inlet and outlet sections of the heat exchange tube 11 of the reinforced inner tube and the heat exchange tube 12 of the smooth tube are provided with a differential pressure sensor 15 and a pressure sensor 16; wherein the first temperature sensor 8a, the second temperature sensor 8b, the third temperature sensor 8c, the fourth temperature sensor 8d and the turbine flowmeter 4 are all connected with the control panel.
The heat exchange tube 11 with the reinforced inner tube is preferably any one of a finned tube, a threaded tube, a corrugated tube or a circular straight tube with a spiral coil inserted inside; the reinforced tube observation sleeve 9 and the smooth tube observation sleeve 14 are both transparent PVC tubes, PP tubes and stainless steel sleeves, and are provided with a section of open slot in which organic glass is embedded; condensation phenomena can be observed.
The digital heat transfer comprehensive experimental device can be used for an air-water vapor system and a water-saturated water vapor system; for an air-water vapor system, the material conveying equipment adopts a fan 1 a; for the water-saturated vapor system, the material conveying equipment adopts the pump equipment 1b to pump water into the inner pipe of the double-pipe heat exchanger.
The method for conducting the heat transfer teaching experiment by using the digital heat transfer comprehensive experiment device comprises the following specific steps: starting a power supply of a self-generator 3 of the steam system, and heating to generate saturated water vapor; opening an inlet valve and an outlet valve of a heat exchange tube 12 of the smooth tube heat exchanger, starting cold medium conveying equipment, and adjusting a turbine flowmeter 4 to measure the temperature of a second temperature sensor 8b and the temperature of a third temperature sensor 8c under a certain flow; simultaneously measuring the pressure difference data between the 12 inlet and the 12 outlet of the smooth pipe heat exchanger pipe; (III) heat exchange data measurement of the reinforced pipe: switching branches, automatically filling water vapor into a heat exchange tube 11 of the enhanced tube heat exchanger, and adjusting a turbine flowmeter 4 to measure the temperature of a first temperature sensor 8a and the temperature of a fourth temperature sensor 8 d; simultaneously measuring the pressure difference data between the inlet and the outlet of the heat exchange tube 11 with the reinforced inner tube; after the experiment is finished, the steam self-generator 3 is closed, the cold medium conveying equipment is closed, the bypass valve is fully opened, and the water and the non-condensable gas in the pipeline are discharged; (V) processing experimental data: and uploading the original data to a server or a cloud platform, analyzing and processing the experimental data, and generating an experimental report.
For air-water vapor systems: preferably selected from the steam pressure range of the generator: 0 to 1.2 kPa; the measuring range of the measured air turbine flowmeter 4 is 0-30 m3H; uniformly taking 6 pieces of measured flow data; measuring the pressure drop range within the tube: 6 groups of data are measured within the range of 0-10 kPa.
More preferably the steam pressure range: 0 to 1.1 kPa; the measuring range of the measured air turbine flowmeter 4 is 10-20 m3H; the pressure drop range in the measuring tube is 1.4-5.5 kPa.
For water-steam systems: preferably selected from the steam pressure range of the generator 3: 0 to 1.4 kPa; 4 measuring ranges of the turbine flowmeter are 0-3 m3H; uniformly taking 6 pieces of measured flow data; the pressure drop measuring range of the round smooth tube heat exchanger 10 is 1-10 kPa; high strengthThe pressure drop measuring range of the chemical tube 9 is 1-100 kPa.
More preferably from the steam pressure range of the generator 3: 0 to 1.2 kPa; the measuring range of the turbine flowmeter 4 is 0.4-1 m3H; the pressure drop measuring range of the round smooth tube heat exchanger 10 is 2.8-10 kPa; the pressure drop measuring range of the reinforced pipe 9 is 7.5-55 kPa.
The invention comprises the following steps: 1. two sets of heat exchange assemblies are connected in parallel to compare the transverse heat supply coefficients; 2. a turbulent flow device is added to strengthen the heat transfer effect; 3. the device is provided with a digital instrument and an instrument system, automatically acquires data in the experimental process, uploads the data to a terminal server or a cloud platform, centralizes and collects the data, and analyzes big data; meanwhile, the experimental result of the experimental device is evaluated, and the performance stability of the experimental device is investigated.
The two sets of heat exchange assemblies are connected in parallel, wherein the first set of heat exchanger is a visible single sleeve pipe and is internally provided with a red copper pipe; the condensation condition of water vapor in the double-pipe heat exchanger on the outer wall of the horizontal pipe can be observed, the influence factors on the heat coefficient are known through experiments, and the associated Nu (A is multiplied by Re) under the forced turbulence in the circular straight pipe is determinedm×Pr0.4The value of the medium constant A, m, 6 data points were measured; the relation between the pressure drop delta P in the tube of the double-tube heat exchanger and Nu can be measured, and 6 groups of data points are measured; the total heat transfer coefficient of the sleeve heat exchanger can be measured; the wall surfaces at the two ends of the heat exchange tube are respectively provided with 3 temperature measuring points, so that the experimental data can be acquired in real time on line and the process can be automatically controlled.
the parallel heat exchange assembly selects finned tubes, screwed tubes, corrugated tubes or circular straight tubes with inserted spiral coils as reinforced tubes to measure the heat coefficient of forced convection, and measures the heat coefficient of forced convection of water or air in the reinforced tubes with the reinforcing ratio alphaReinforcement of/α>1.1。
The digital heat transfer comprehensive experiment device is matched with a touch screen embedded control system or a computer control system on a control cabinet, and MCGS industrial control configuration software is adopted as software; the online monitoring experiment software is provided, so that remote centralized data acquisition and control can be realized; the system has a data remote transmission function, and data can be uploaded to a cloud platform and a server.
Has the advantages that:
the invention connects two sets of heat exchange components in parallel to compare the transverse heat supply coefficients; a turbulent flow device is added to strengthen the heat transfer effect; the device is provided with a digital instrument and an instrument system, automatically acquires data in the experimental process, uploads the data to a terminal server or a cloud platform, centralizes and collects the data, and analyzes big data; the experimental result of the experimental device can be evaluated at the same time, and the performance stability of the experimental device can be inspected.
Description of the drawings:
FIG. 1 is a flow chart of a digital heat transfer integrated experimental apparatus (air-water vapor); wherein 1a, a fan; 2. a frequency converter; 3, a steam self-generator; 4. a turbine flow meter; 5. an air-cooled finned heat exchanger; 6. a condensate tank; 7. a rotameter; 8a first temperature sensor; a second temperature sensor 8 b; a third thermometer sensor 8 c; a fourth thermometer sensor 8 d; 9. a reinforced tube observation sleeve; 10. a pressure-resistant glass sleeve outside the strengthening pipe; 11. strengthening the inner pipe heat exchange pipe; 12, smooth pipe heat exchange pipes; 13. a pressure-resistant glass sleeve outside the smooth pipe; 14. a smooth tube viewing sleeve; 15. a differential pressure sensor; 16. a pressure sensor;
FIG. 2 is a flow chart of a digital heat transfer integrated experimental apparatus (water-steam); wherein 1b, a water pump; 2. a water tank; 3. a steam self-generator; 4. a turbine flow meter; 5. an air-cooled finned heat exchanger; 6. a condensate tank; 7. a rotameter; 8a first temperature sensor; a second temperature sensor 8 b; a third thermometer sensor 8 c; a fourth thermometer sensor 8 d; 9. a reinforced tube observation sleeve; 10. a pressure-resistant glass sleeve outside the strengthening pipe; 11. strengthening the inner pipe heat exchange pipe; 12, smooth pipe heat exchange pipes; 13. a pressure-resistant glass sleeve outside the smooth pipe; 14. a smooth tube viewing sleeve; 15. a differential pressure sensor; 16. a pressure sensor;
FIG. 3 is a graph showing relationship between the number of slip tubes lg (Nu/Pr ^0.4) -lg (Re) in the air-water vapor system;
FIG. 4 is a graph showing the relationship between the reinforcement tubes lg (Nu/Pr ^0.4) -lg (Re) in the air-steam system;
FIG. 5 is a graph comparing Δ P-Nu for enhanced tubes and smooth tubes in an air-water vapor system;
FIG. 6 is a graph showing relationship between the number of slip tubes lg (Nu) and lg (Re) in the water-steam system;
FIG. 7 is a graph showing the relationship between the reinforcement pipes lg (Nu) and lg (Re) in the water-steam system;
FIG. 8 is a graph comparing Δ P-Nu for enhanced and smooth tubes in a water-steam system.
The specific implementation mode is as follows:
example 1 digital Heat transfer Integrated experiment device (air-steam) teaching experiment strengthen description of experimental device performance (experimental device as figure 1)
The experimental method and the steps are as follows: the experimental method and the steps are as follows: and (I) switching on a power supply main brake, setting heating voltage, starting a switch of an electric heater of the steam self-generator 3, and starting heating. And secondly, after the experiment begins for a period of time, water is boiled, water vapor automatically fills the heat exchange tubes 12 of the smooth tube heat exchanger, and constant amount of vapor is discharged from the vapor discharge port by observation, which marks that the experiment can begin. After heating for about 10min, starting the air blower 1, ensuring that the temperature sensor is stable for 8min to start measurement when the experiment starts, and reading the air flow rate V by the turbine flowmeter 4; reading the air inlet temperature t1And air outlet temperature t2(ii) a Three measured temperatures t of a second temperature sensor 8b at the wall of the smooth-tube heat exchange tube 12 at the air inlet endw11，tw12，tw13(ii) a Three measured temperatures t of a third temperature sensor 8c on the wall of the air outlet smooth pipe heat exchange pipe 12w21，tw22，tw23(ii) temperature; measuring temperature T at steam inlet end in smooth pipe external pressure-resistant glass sleeve 13 pipe1Temperature T at the outlet of the steam2(ii) a Measuringmeasuring the pressure difference between two ends of the pressure-resistant glass sleeve 13 outside the smooth pipe, reading the pressure △ P of the differential pressure sensor 15, and reading the air flow velocity V by rotating the turbine flowmeter 4iAnd repeatedly measuring the average value of the temperatures of the second temperature sensor 8b and the third temperature sensor 8c to obtain 8 groups of air flow values. The heating voltage can be kept constant during the whole experiment process, and can be properly adjusted along with the change of the air flow. And thirdly, switching the branch, automatically filling the water vapor into the heat exchange tube 11 of the heat exchanger with the reinforced inner tube, and observing that the constant amount of the vapor is discharged from the vapor outlet, which marks that the experiment can be started. Measuring after the temperature is stabilized for 8min, and reading the air flow rate V by reading the turbine flowmeter 4; reading the air inlet temperature t1And air outlet temperature t2(ii) a Three measured temperatures t of a first temperature sensor 8a on the wall of a heat exchange tube 11 of an air inlet end reinforced tubew11，tw12，tw13(ii) a Three measured temperatures t of the fourth temperature sensor 8d on the wall of the air outlet reinforced pipe heat exchange pipe 11w21，tw22，tw23(ii) temperature; measuring the temperature T at the steam inlet end in the pressure-resistant glass sleeve 10 outside the strengthening tube1Temperature T at the outlet of the steam2measuring the pressure difference between two ends of a pressure-resistant glass sleeve 10 outside the reinforced pipe, reading the pressure △ P of a differential pressure sensor 15, and reading the air flow velocity V by rotating a turbine flowmeter 4iAnd repeatedly measuring the average value of the temperatures of the first temperature sensor 8a and the fourth temperature sensor 8d to obtain 8 groups of air flow values. The heating voltage can be kept constant during the whole experiment process, and can be properly adjusted along with the change of the air flow. And (5) repeating the experimental steps of the step (II). 6 sets of experimental data were determined. And (IV) after the experiment is finished, closing the steam self-generator 3, closing the air blower 1a after 5min, fully opening the bypass valve, and completely discharging the water and the non-condensable gas in the pipeline. (V) processing experimental data: and uploading the original data to a server or a cloud platform, analyzing and processing the experimental data, and generating an experimental report. Specific experimental data are summarized in tables-1 and 2 below.
for experimental data processing, the heat coefficient of convection heating alphaiMean temperature difference Δ tmAverage temperature t of inner tube temperature measuring pointw1Heat exchange area in tube AiHeat transfer quantity QiMass flow rate WiCalculated from the following formula:
wherein,
Ai＝π×di×L；Qi＝Wi×Cpi×(t2-t1)；
the average of the three temperatures is likewise taken as the outlet wall temperature Tw2The inner pipe of the double-pipe heat exchanger is a red copper pipe, the pipe wall is thin, the heat conductivity coefficient is large, the thermal resistance of the pipe wall can be ignored, and the inner temperature and the outer temperature of the pipe wall can be approximately considered to be equal, namely tw1＝Tw1，tw2＝Tw2。
The Nu, Re and Pr of the Nu-Seal quasi-number are respectively solved by the following formulas:
Nu＝A×Rem×Pr0.4。
re and Nu at different flow rates are determined by experiment, then plotted according to the relationship of lg (Nu/Pr ^0.4) -lg (Re), and then the values of A and m are determined by a linear regression method.
due to αReinforcement of/α＝Nu/Nu0For the convenience of studying the strengthening effect of the strengthening means, the strengthening ratio Nu/Nu can be used0As a criterion, Nu is the Nusselqin number of the enhanced double-pipe heat exchanger, Nu0The ratio of the NusselLo number to the NusselLo number of the smooth-tube heat exchanger is larger, and the strengthening effect is better.
Processing experimental data according to the experimental formula, and referring to the measurement data of the heat transfer coefficient of the reinforced pipe in the air-water vapor experiment in the table-1; table-2 air-steam experiment in the smooth tube heat transfer coefficient determination data, specific data fitting and comparative analysis see the attached diagram-3 air-steam system in the smooth tube lg (Nu/Pr ^0.4) -lg (Re) relationship diagram; FIG. 4 is a graph showing the relationship between the reinforcement tubes lg (Nu/Pr ^0.4) -lg (Re) in the air-steam system; FIG. 5 is a graph comparing Δ P-Nu for enhanced tubes and smooth tubes in an air-water vapor system.
TABLE-1 measurement data of heat transfer coefficient of smooth tube in air-water vapor experiment
TABLE-2 enhanced tube heat transfer coefficient determination data in air-water vapor experiment
The measurement data of the heat transfer coefficient of the smooth tube in the air-water vapor experiment are shown in the table-1; the measurement data of the heat transfer coefficient of the reinforced pipe in the air-water vapor experiment are shown in the table-2, and the calculated result shows that the reinforcement ratio Nu/Nu0Equal to 1.78, has remarkable strengthening effect.
Example 2 digital Heat transfer comprehensive experiment device (Water-saturated steam) teaching experiment strengthen description of experimental device performance (experimental device as figure 2)
The experimental method and the steps are as follows: and (I) switching on a power supply main brake, setting heating voltage, starting a switch of an electric heater of the steam self-generator 3, and starting heating. After the experiment begins for a period of time, the water vapor pressure reaches 0.1MPa, and a valve is opened to keep the pressureThe pressure is stable, the steam is filled into the heat exchange tube 12 of the smooth tube heat exchanger, the constant steam is discharged from the steam outlet, and the noncondensable liquid in the steam pipeline is discharged. And (3) turning on the water pump 1b, and introducing cold water into the tube side of the round smooth tube heat exchanger 10, so that the formation process of condensed water on the outer wall of the round smooth tube heat exchange tube 12 can be observed. After stabilizing for 10min, reading the flow rate V of the cold water by reading the turbine flowmeter 4; reading the cold water inlet temperature t1And outlet temperature t2(ii) a Three measured temperatures t of a second temperature sensor 8b at the pipe wall of the smooth pipe heat exchange pipe 12 at the cold water inlet endw11，tw12，tw13(ii) a Three measured temperatures t of a third temperature sensor 8c at the pipe wall of the cold water outlet end smooth pipe heat exchange pipe 12w21，tw22，tw23(ii) temperature; measuring temperature T at steam inlet end in smooth pipe external pressure-resistant glass sleeve 13 pipe1,. steam outlet end temperature T2measuring the pressure difference between two ends of the pressure-resistant glass sleeve 13 outside the smooth pipe, reading the pressure △ P of the differential pressure sensor 15, measuring and adjusting the flow rate V of cold water of the turbine flowmeter 4iAnd the temperature of the second temperature sensor 8b and the third temperature sensor 8c is repeatedly measured, and 6 sets of experiments are carried out. And thirdly, switching the branch, automatically filling the water vapor into the heat exchange tube 11 of the heat exchanger with the reinforced inner tube, and observing that the constant amount of the vapor is discharged from the vapor outlet, which marks that the experiment can be started. Measuring after the temperature is stabilized for 8min, and reading the flow velocity V of cold water by reading the turbine flowmeter 4; reading the cold water inlet temperature t1And cold water outlet temperature t2(ii) a Three measured temperatures t of the wall 8a of the first temperature sensor of the heat exchange tube 11 of the reinforced tube at the cold water inlet endw11，tw12，tw13(ii) a Three measured temperatures t of the fourth temperature sensor 8d on the wall of the heat exchange tube 11 of the cold water outlet reinforced tubew21，tw22，tw23(ii) temperature; measuring the temperature T at the steam inlet end in the pressure-resistant glass sleeve 10 outside the strengthening tube1Temperature T at the outlet of the steam2measuring the pressure difference between two ends of a pressure-resistant glass sleeve 10 outside the reinforced pipe, reading the pressure △ P of a differential pressure sensor 15, and reading the cold water flow velocity V by a rotary turbine flowmeter 4iAnd repeatedly measuring the average value of the temperatures of the first temperature sensor 8a and the fourth temperature sensor 8d to obtain 8 groups of air flow values. Throughout the experimentIn the course of the process, the heating voltage can be kept unchanged and can be properly regulated along with the change of the cold water flow. (the experimental step of the step (II) is repeated, (IV) 6 groups of experimental data are measured, (IV) after the experiment is finished, the steam self-generator (3) is closed, the water pump 1b is closed after 5min, the bypass valve is fully opened, the pipeline water and the non-condensable gas are completely discharged, (V) the experimental data are processed, the original data are uploaded to a server or a cloud platform, and the experimental data are analyzed and processed to generate an experimental report.
The measurement data of the heat transfer coefficient of the smooth tube in the water-steam experiment are shown in the table-3; the heat transfer coefficient measurement data of the enhanced tube in the water-steam experiment is shown in the table-4, and the enhancement ratio is 1.18 according to the calculation result, so that the obvious enhancement effect is achieved. For data fitting and analytical comparison, see FIG. 6 for a plot of relationship of smooth tubes lg (Nu) -lg (Re) in the water-steam system; FIG. 7 is a graph showing the relationship between the reinforcement pipes lg (Nu) and lg (Re) in the water-steam system; FIG. 8 is a graph comparing Δ P-Nu for enhanced and smooth tubes in a water-steam system.
TABLE 3 measurement data of heat transfer coefficient of smooth tube in water-steam experiment
TABLE 4 enhanced tube heat transfer coefficient determination data in water-steam experiment
Example 3 the enhanced inner tube heat exchanger was replaced with an enhanced inner threaded tube for water-saturated steam experiment teaching experiments to enhance the performance of the experimental setup.
The experiment was carried out according to the same procedure as in example 2. And the first, second and fourth experimental steps are the same, and the branch is switched in the third experimental process, water vapor is filled into the reinforced internal threaded pipe to carry out the experiment, the original data is uploaded to a server or a cloud platform, and the experimental data is analyzed and processed to generate an experimental report. (experimental data and treatment protocol were the same as in example 2).
Claims (8)
1. The digital heat transfer comprehensive experimental device is characterized in that: the system consists of a steam system, a cold medium system, a heat exchange system and a data acquisition control system; wherein: the heat exchange system consists of a reinforced tube heat exchanger, a smooth tube heat exchanger, an air cooling fin heat exchanger (5) and a condensate tank (6): the reinforced tube heat exchanger consists of a reinforced tube observation sleeve (9), a reinforced tube external pressure-resistant glass sleeve (10) and a reinforced inner tube heat exchange tube (11); the smooth tube heat exchanger consists of a smooth tube heat exchange tube (12), a smooth tube external pressure-resistant glass sleeve (13) and a smooth tube observation sleeve (14); the reinforced pipe heat exchanger is parallel to the smooth pipe heat exchanger; the heat exchange tube (11) with the strengthened inner tube and the inner tube of the heat exchange tube (12) with the smooth tube are respectively connected with a cold medium system through pipelines; the outside of the heat exchange tube (11) of the strengthening inner tube is sleeved and connected with a pressure-resistant glass sleeve (10) outside the strengthening tube, and the pressure-resistant glass sleeve (10) outside the strengthening tube is sleeved and connected with an observation sleeve (9) of the strengthening tube; the outside of the smooth tube heat exchange tube (12) is sleeved with a smooth tube external pressure-resistant glass sleeve (13), and the outside of the smooth tube external pressure-resistant glass sleeve (13) is sleeved with a smooth tube observation sleeve (14); a steam pipeline of a self generator (3) of the steam system is respectively connected with a reinforced inner pipe heat exchange pipe (11) and a smooth pipe heat exchange pipe (12) in parallel; the tail parts of the shell sides of the heat exchange tubes (11) of the strengthening inner tube and the heat exchange tubes (12) of the smooth tube are connected with the air-cooled fin heat exchanger (5) and the condensate tank (6) through pipelines; the heat exchange tube (11) with the strengthened inner tube and the heat exchange tube (12) with the smooth tube are connected with an outdoor sewer through a pipeline at a tube pass emptying port; the cold medium system consists of material conveying equipment, a frequency converter (2) and a turbine flowmeter (4): wherein the material conveying equipment is connected with the turbine flowmeter (4) and an inner pipe of a reinforced inner pipe heat exchange pipe (11) of a reinforced pipe heat exchanger in a heat exchange system by a pipeline; the parallel connection is communicated with the inner pipe of a smooth pipe heat exchange pipe (12) of a smooth pipe heat exchanger in the heat exchange system; the data acquisition control system consists of a temperature sensor, a pressure sensor, a flowmeter sensor and a control panel; the inlet and outlet walls of the heat exchange tube (11) with the reinforced inner tube are respectively provided with a first temperature sensor (8a) and a fourth temperature sensor (8 d); the inlet and outlet walls of the smooth-tube heat exchange tube (12) are respectively provided with a second temperature sensor (8b) and a third temperature sensor (8 c); the inlet and outlet sections of the heat exchange tube (11) with the strengthened inner tube and the heat exchange tube (12) with the smooth tube are provided with a differential pressure sensor (15) and a pressure sensor (16); wherein the first temperature sensor 8a, the second temperature sensor 8b, the third temperature sensor 8c, the fourth temperature sensor 8d and the turbine flowmeter (4) are all connected with a control panel.
2. The digital heat transfer comprehensive experimental device according to claim 1, wherein the enhanced inner tube heat exchange tube (11) is any one of a finned tube, a threaded tube, a corrugated tube, or a circular straight tube with a helical coil inserted inside; the reinforced tube observation sleeve (9) and the smooth tube observation sleeve (14) are transparent PVC tubes, PP tubes and stainless steel sleeves.
3. The digital heat transfer comprehensive experimental facility as claimed in claim 1, characterized in that for an air-water vapor system, the material conveying equipment employs a fan (1 a); for the water-saturated steam system, the material conveying equipment adopts a pump device (1 b).
4. The method for conducting heat transfer teaching experiments by using the digital heat transfer comprehensive experiment device as claimed in claim 1 comprises the following specific steps: starting a power supply of a self generator (3) of a steam system, and heating to generate saturated water vapor; opening an inlet valve and an outlet valve of a heat exchange tube (12) of the smooth tube heat exchanger, starting cold medium conveying equipment, and adjusting a turbine flowmeter (4) to measure the temperature of a second temperature sensor (8b) and the temperature of a third temperature sensor (8c) under a certain flow; simultaneously measuring differential pressure data between the inlet and the outlet of a smooth tube heat exchanger tube (12); (III) heat exchange data measurement of the reinforced pipe: the branch is switched, water vapor is automatically filled into a heat exchange tube (11) of the enhanced tube heat exchanger, and a turbine flowmeter (4) is adjusted to measure the temperature of a first temperature sensor (8a) and the temperature of a fourth temperature sensor (8 d); simultaneously measuring the pressure difference data between the inlet and the outlet of the heat exchange tube (11) with the reinforced inner tube; after the experiment is finished, the steam self-generator (3) is closed, the cold medium conveying equipment is closed, the bypass valve is fully opened, and the water and the non-condensable gas in the pipeline are discharged; (V) processing experimental data: and uploading the original data to a server or a cloud platform, analyzing and processing the experimental data, and generating an experimental report.
5. The method according to claim 4, characterized in that the air-water vapor system is derived from the steam pressure range of the generator: 0 to 1.2 kPa; the measuring range of the measured air turbine flowmeter (4) is 0-30 m3H; uniformly taking 6 pieces of measured flow data; measuring the pressure drop range within the tube: 6 groups of data are measured within the range of 0-10 kPa.
6. The method according to claim 5, characterized in that the steam pressure range: 0 to 1.1 kPa; the measuring range of the measured air turbine flowmeter (4) is 10-20 m3H; the pressure drop range in the measuring tube is 1.4-5.5 kPa.
7. The method as claimed in claim 4, characterized in that the water-water vapor system is selected from the range of vapor pressures of the generator (3): 0 to 1.4 kPa; the measuring range of the turbine flowmeter (4) is 0-3 m3H; uniformly taking 6 pieces of measured flow data; the pressure drop measuring range of the round smooth tube heat exchanger (10) is 1-10 kPa; the pressure drop measuring range of the reinforced pipe (9) is 1-100 kPa.
8. The method as claimed in claim 7, characterized in that the water-water vapor system is selected from the range of vapor pressures of the generator (3): 0 to 1.2 kPa; the measuring range of the turbine flowmeter (4) is 0.4-1 m3H; the pressure drop measuring range of the round smooth tube heat exchanger (10) is 2.8-10 kPa; the pressure drop measuring range of the reinforced pipe (9) is 7.5-55 kPa.
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