Device for measuring convective heat transfer coefficient on surface of transverse tube bundle

Abstract

The utility model discloses an experimental measurement device for a convective heat transfer coefficient on the surface of a transverse tube bundle. The experimental measurement device comprises a control box body, a heating power supply, a 16-channel temperature data acquisition card, a current sensor, a voltage digital display meter, a current digital display meter, an acrylic hollow circular tube, a bakelite hollow circular tube and the like. The overall dimension of the acrylic tube bundle is consistent with that of a to-be-tested test piece, and the control box integrates a power supply, a sensor, an acquisition card and a display meter. And the surface of the heating circular pipe is cooled by combining a wind tunnel. And a plurality of T-shaped thermocouples are arranged below the iron-chromium-aluminum sheets along the circumferential direction of the middle position of the tube bundle. And the signal acquisition card acquires the temperature of the sheet. And calculating the surface heat flux density through the electric power. And calculating a tube bundle surface convective heat transfer coefficient according to the heat flux density, the sheet temperature and the incoming flow temperature. The device is low in manufacturing cost, convenient to operate and short in thermal response time. And accurate measurement of the convective heat transfer coefficient of the circumferential surface can be realized.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of convection heat transfer coefficient determination, specifically a kind of device for the measurement of convection heat transfer coefficient of transverse sweeping tube bundle surface. BACKGROUND

[0002] Research and development of enhanced heat transfer technology are very important to the development of national economy. In order to design and manufacture heat exchanger with better heat transfer performance, the relevant theoretical formula and empirical relationship are particularly important. The traditional theoretical formula and empirical relationship have certain limitations due to the particularity of transverse sweeping tube bundle. And because of the complexity of transverse sweeping tube bundle flow field, its flow and heat transfer characteristics are difficult to analyze, so a set of device is needed to measure the convection heat transfer coefficient of transverse sweeping tube bundle surface. Through the public literature retrieval of prior art, it is found that the existing technology of transverse sweeping tube bundle heating experiment device has problems such as complex structure, uneven heating and so on. In order to study the flow and heat transfer characteristics of transverse sweeping tube bundle, the utility model designs a device for measuring the convection heat transfer coefficient of transverse sweeping tube bundle surface. SUMMARY

[0003] The utility model aims at the technical defects of prior art, and designs a transverse sweeping tube bundle surface convection heat transfer coefficient measuring device with low cost, simple processing, convenient operation and uniform heating.

[0004] The utility model can realize uniform heating along the circumference of tube bundle, and can directly collect data, with the characteristics of high precision, accurate measurement and flexible operation.

[0005] In order to achieve the above object, the utility model adopts the following technical scheme:

[0006] The device for measuring the convection heat transfer coefficient of transverse sweeping tube bundle surface includes control box, heating power supply, 16 channel temperature data acquisition card, current sensor, voltage digital display, current digital display, acrylic hollow pipe, bakelite hollow pipe, red copper electrode, iron-chromium-aluminum heating sheet, 15 T type thermocouples and wire.

[0007] The control box is used for placing heating power supply and 16 channel temperature data acquisition card and other structures.

[0008] The heating power supply is placed in the control box, and is used for supplying power to the iron-chromium-aluminum heating sheet.

[0009] The 16 channel temperature data acquisition card is placed in the control box, and is used for collecting temperature data of 15 T type thermocouples.

[0010] The current sensor is placed in the control box, and is used for measuring current.

[0011] The voltage digital display is placed in the control box, and is used for measuring voltage.

[0012] The current digital display is arranged in the control box and is used for displaying the current.

[0013] The shape parameters, size parameters and material parameters of the acrylic hollow circular tube are consistent with those of the inner circular tube of the pipe bundle experimental piece to be measured.

[0014] The bakelite hollow circular tube is used for arranging 15 T-shaped thermocouples and supporting the iron-chromium-aluminum heating sheet.

[0015] The iron-chromium-aluminum sheet is attached to the outer surface of the bakelite and is used for heating.

[0016] The 15 T-shaped thermocouples and the iron-chromium-aluminum sheet are attached and are arranged in the groove on the outer surface of the bakelite and are used for measuring the temperature of the sheet.

[0017] The red copper electrode is arranged at the two ends of the iron-chromium-aluminum heating sheet and is used for connecting the wires, a hole is arranged in the center of the red copper electrode, and fifteen holes are arranged in the circumferential direction and correspond to the 15 T-shaped thermocouples and are used for the passing of the wires.

[0018] The wires are used for connecting the 16-channel temperature data acquisition card and the 15 T-shaped thermocouples and connecting the power supply and the iron-chromium-aluminum heating sheet.

[0019] Further, the heating power supply voltage DC 0-5V is adjustable, the maximum heating current is 40A, and the working voltage is AC 220V.

[0020] Further, the thermocouple measurement range is -100℃-500℃.

[0021] Further, the pipe bundle is provided with plugs at the two ends for fixing the pipe bundle and sealing the connecting part of the pipe bundle and the experimental piece, and fifteen holes are arranged at the middle position for placing the 15 T-shaped thermocouples.

[0022] Further, the 15 T-shaped thermocouples are evenly arranged in the circumferential direction, the interval is 24°, and the measurement is performed by rotating 30° each time. The measurement of the convective heat transfer coefficient at 60 points in the circumferential direction can be realized.

[0023] Further, the data signals of all the measuring devices are collected by the 16-channel temperature data acquisition card and are input to the computer.

[0024] Compared with the prior art, the utility model has the following advantages:

[0025] Compared to traditional transverse tube bundle surface convective heat transfer coefficient measuring devices, this invention uses acrylic as its primary material, resulting in simple processing and low cost. Furthermore, by moving the measuring device longitudinally, the experimenter can measure the circumferential distribution of the surface convective heat transfer coefficient at different longitudinal positions. The device is not a single unit, allowing for the replacement of individual components to extend its lifespan and reduce maintenance costs. The iron-chromium-aluminum heating element reduces circumferential heat conduction and thermal response time. The evenly distributed arrangement of 15 T-type thermocouples improves measurement efficiency. Attached Figure Description

[0026] Figure 1 A schematic diagram of the overall structure of the transverse tube bundle surface convective heat transfer coefficient measuring device of this invention is shown.

[0027] Figure 2 A cross-sectional view of the tube bundle center position of this utility model is shown.

[0028] 1-Control box; 2-Heating power supply; 3-16-channel temperature data acquisition card; 4-Current sensor; 5-Digital voltage display; 6-Digital current display; 7-Acrylic hollow tube; 8-Copper electrode; 9-Iron-chromium-aluminum heating sheet; 10-15 T-type thermocouples; 11-Bakeryl hollow tube. Detailed Implementation Plan

[0029] The present invention will be further described in detail with reference to the embodiments thereof:

[0030] like Figure 1 The apparatus shown for measuring the convective heat transfer coefficient across the surface of a tube bundle includes a control box 1; a heating power supply 2; a 16-channel temperature data acquisition card 3; a current sensor 4; a voltage digital display 5; a current digital display 6; an acrylic hollow tube 7; copper electrodes 8; iron-chromium-aluminum heating sheets 9; and 15 T-type thermocouples 10.

[0031] The control box 1 is used to house the heating power supply 2 and the 16-channel temperature data acquisition card 3, etc.

[0032] The heating power supply 2 is located in the control box 1 and is used to supply power to the iron-chromium-aluminum heating sheet 9. The voltage is adjustable from DC 0 to 5V, the maximum heating current is 40A, and the working voltage is AC 220V.

[0033] The 16-channel temperature data acquisition card 3 is placed in the control box 1 and is used to acquire temperature data from 15 T-type thermocouples 10. The measurement range is -100℃ to 500℃ and the accuracy is ±0.2%FS.

[0034] The current sensor 4 is placed in the control box 1 and is used to measure the current.

[0035] The voltage digital display meter 5 is arranged in the control box 1 and is used for measuring voltage.

[0036] The current digital display meter 6 is arranged in the control box 1 and is used for displaying current.

[0037] The acrylic tube bundle 7 is consistent with the shape parameter, size parameter and material parameter of the tube bundle in the experimental piece to be measured, and the two ends are provided with plugs for fixing the tube bundle 7 and sealing the connecting position of the tube bundle 7 and the experimental piece.

[0038] The iron-chromium-aluminum heating sheet 9 is square and is attached to the outside of the bakelite hollow circular tube 11 and is used for electric heating.

[0039] The 15 T-shaped thermocouples 10 and the iron-chromium-aluminum heating sheet 9 are attached and arranged in the groove on the surface of the bakelite hollow circular tube 11 and are used for measuring the temperature of the iron-chromium-aluminum heating sheet 9, and the 15 T-shaped thermocouples 10 are evenly arranged in the circumferential direction and are spaced apart by 24 degrees, and each rotation is 30 degrees during measurement, so that the measurement of the heat transfer coefficient at 60 points in the circumferential direction can be realized.

[0040] The red copper electrode 8 is arranged at the two ends of the iron-chromium-aluminum heating sheet 9 and is used for connecting wires, and a hole is arranged in the center of the red copper electrode 8 and fifteen holes are arranged in the circumferential direction and correspond to the 15 T-shaped thermocouples 10, and are used for the passing of wires.

[0041] The bakelite hollow circular tube 11 is used for arranging the 15 T-shaped thermocouples 10 and supporting the iron-chromium-aluminum heating sheet 9.

[0042] The wires are used for connecting the 16-channel temperature data acquisition card 3 and the 15 T-shaped thermocouples 10 and connecting the heating power supply 2 and the iron-chromium-aluminum heating sheet 9.

[0043] The use and operation process of the utility model will be described as follows:

[0044] 1. The 15 T-shaped thermocouples 10 are evenly distributed in a circle in the tube bundle 7 to be measured, and the iron-chromium-aluminum heating sheet 9 is covered outside the 15 T-shaped thermocouples 10;

[0045] 2. The tube bundle 7 to be measured is installed to the measurement position of the experimental piece;

[0046] 3. The plugs are fixed to the two ends of the tube bundle 7 and the initial position is calibrated;

[0047] 4. The wires are used for connecting the control box 1 and the tube bundle 7;

[0048] 5. The heating power supply 2 is turned on, the appropriate current size is adjusted, the iron-chromium-aluminum heating sheet 9 starts to heat, the surface temperature of the tube bundle 7 and the flow temperature are measured after reaching the thermal equilibrium, the tube bundle 7 is rotated by 30 degrees, and the next measurement is repeated in the step 5;

[0049] 6. Calculate the electric power, i.e. the total thermal power, by heat balance, considering the heat flux density to be uniform, knowing the heat flow per point, the temperature difference (tube surface temperature and incoming flow temperature, as well as the heat exchange area), and calculate the surface heat exchange coefficient.

Claims

1. A device for measurement of heat transfer coefficient by cross flow over a tube bundle surface, characterized by, It comprises: a control box, a heating power supply, a 16-channel temperature data acquisition card, a current sensor, a voltage digital display meter, a current digital display meter, an acrylic hollow pipe, a bakelite hollow pipe, a red copper electrode, an iron-chromium-aluminum heating sheet, 15 T-type thermocouples, and wires; the control box is used for placing the heating power supply and the 16-channel temperature data acquisition card structure; the heating power supply is placed in the control box and used for supplying power to the iron-chromium-aluminum heating sheet; the 16-channel temperature data acquisition card is placed in the control box and used for collecting temperature data of the thermocouples; the current sensor is placed in the control box and used for measuring current; the voltage digital display meter is placed in the control box and used for measuring voltage; the current digital display meter is placed in the control box and used for displaying current; the acrylic pipe bundle is consistent with shape parameters, size parameters and material parameters of an inner pipe bundle of an experimental piece to be measured; the bakelite hollow pipe is used for arranging the 15 T-type thermocouples and supporting the iron-chromium-aluminum heating sheet; the iron-chromium-aluminum sheet is attached to an outer surface of the bakelite and used for heating; the 15 T-type thermocouples and the iron-chromium-aluminum sheet are attached and placed in a groove on the outer surface of the bakelite and used for measuring temperature of the sheet; the red copper electrode is placed at both ends of the iron-chromium-aluminum heating sheet and used for connecting the wires, a hole is arranged in the center of the red copper electrode, and fifteen holes are arranged in the circumferential direction and correspond to the 15 T-type thermocouples, for the passage of the wires; the wires are used for connecting the 16-channel temperature data acquisition card and the thermocouples and connecting the power supply and the iron-chromium-aluminum heating sheet.

2. A device for measuring the heat transfer coefficient of a cross flow over a tube bundle surface according to claim 1, characterized in that, The heating power supply voltage is adjustable from DC 0-5V, the maximum heating current is 40A, and the working voltage is AC 220V.

3. A device for measuring the heat transfer coefficient of a cross flow over a tube bundle surface according to claim 1, characterized in that, The thermocouple measurement range is -100℃-500℃, and the accuracy is ±0.2% FS.

4. A device for measuring the heat transfer coefficient of a cross flow over a tube bundle surface according to claim 1, characterized in that, The pipe bundle is provided with plugs at both ends for fixing the pipe bundle and sealing the connection of the pipe bundle and the experimental piece as a whole, and fifteen holes are arranged at the middle position for placing the 15 T-type thermocouples.

5. A device for measuring the heat transfer coefficient of a cross flow tube bundle surface according to claim 1, characterized in that, The 15 T-type thermocouples are evenly arranged in the circumferential direction, with an interval of 24°, and each rotation of 30° during measurement can realize measurement of the convective heat transfer coefficient at 60 points in the circumferential direction.

6. A device for measuring the heat transfer coefficient of a cross flow tube bundle surface according to claim 1, characterized in that, The 16-channel temperature data acquisition card constitutes a temperature data acquisition module, and data signals of all measurement devices are collected through the module and input to a computer.

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