Method for measuring heat transfer coefficient of solid pellets

Abstract

The invention relates to the technical field of convective heat transfer, and discloses a method for measuring the heat transfer coefficient of solid pellets, which comprises the following steps: step 1, filling half-tube water into a U-shaped differential pressure gauge PDIO1 in a measuring device, and adding quartz sand in a sand bed reaction until the upper surface of the quartz sand in a sand bed reactor is not in contact with a thermocouple TI01; step 2, turning on a total power supply and a control power supply of the measuring device, setting temperature control buttons of the heating temperatures TIC01, TIC02 and TIC03 of the tubular heating furnace, and setting three heating temperatures to about 500 DEG C; the moving distance of the ball screw is set through the industrial computer to control the moving track of the small ball, moving is more convenient, the position is more accurate, the ball screw is provided with the optoelectronic switch, the ball screw sliding block automatically stops when reaching the position of the optoelectronic switch, the ball screw sliding block can be prevented from moving excessively, and operation is safe.

Description

Technical Field

[0001] The invention relates to the technical field of convective heat transfer, in particular to a method for determining a heat transfer coefficient of a solid ball. Background Art

[0002] In engineering, we often encounter the process of transferring heat to the wall or from the wall to the fluid by macroscopic movement of the fluid. This process is generally called convective heat transfer (or convective heat transfer). Obviously, the physical properties of the fluid, the flow state of the fluid and the surrounding environment will affect the convective heat transfer. Understanding and measuring the convective heat transfer coefficient under various environments has important practical significance. Many existing experiments are conducted manually and the data are recorded by computer. The uncontrollable nature of human beings during recording makes the movement trajectory of the ball deviate greatly when the experiment is operated manually, resulting in inaccurate data and affecting the final time result.

[0003] The present invention provides an intelligent solid ball heat transfer coefficient measuring device, through which the method and principle of measuring the convective heat transfer coefficient and the Nusselt number can be learned, the characteristics of unsteady-state heat conduction and the physical meaning of the Biot number (Bi) can be learned, the operating characteristics of the fluidized bed and the fixed bed can be familiarized, and the cooling curve of the ball under natural convection, forced convection, fixed bed experiment and fluidized bed experiment can be measured. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In view of the shortcomings of the prior art, the present invention provides a method for measuring the heat transfer coefficient of a solid ball, which solves the problems of the moving trajectory of the ball in the prior art, inconvenient movement, inaccurate position and deviation.

[0006] (II) Technical solution

[0007] To achieve the above object, the present invention provides the following technical solution: a method for measuring the heat transfer coefficient of a solid ball, comprising the following steps:

[0008] Step 1: half of the U-shaped differential pressure gauge PDIO1 in the measuring device is filled with water, and quartz sand is added to the sand bed reaction. The amount of quartz sand added is based on the upper surface of the quartz sand in the sand bed reactor not contacting the thermocouple TI01;

[0009] Step 2: Turn on the main power and control power of the measuring device, set the temperature control buttons TIC01, TIC02, and TIC03 of the tubular heating furnace, and set the three heating temperatures to about 500°C;

[0010] Step 3: Place a small steel ball embedded with a thermocouple in a tubular heating furnace and observe the temperature of the small ball TI02. When the temperature of TI02 rises to about 480°C, the ball screw moves quickly to remove the steel ball and conduct experiments under different environmental conditions. The data of the temperature change of the small steel ball over time and the relationship between the cooling curve are recorded by a computer.

[0011] Step 4: The environmental conditions for the measurement device are: natural convection, forced convection, fixed bed and fluidized bed. The flow states are: laminar flow and turbulent flow;

[0012] Step 5: After the experiment, click the temperature control buttons TIC01, TIC02, and TIC03 of the tubular heating furnace to stop the heating of the tubular heating furnace, click the force control interface, exit the system, turn off the control power, and turn off the main power;

[0013] Step 6: When releasing the gravel from the gravel bed, loosen the fixing nut of the lower discharge valve of the rotating sand bed reactor, rotate the lower discharge valve of the sand bed reactor, and release the sand in the bed. During the sand release process, start the vortex air pump according to the opening status of the forced convection pipeline valve, blow down the sand in the bed, and finish the cleaning.

[0014] Preferably, the natural convection test in step 4: click on the natural convection experiment in the computer, then the natural convection experiment icon turns red, set the recording interval to 5S, input 0 at the air flow in the lower right corner, when the ball temperature TI02 rises to about 480°C, set the ball screw movement distance, remove the ball from the heating furnace, suspend the heated steel ball in the air, click to start recording data, and during the data recording process, minimize the atmospheric disturbance near the steel ball and record the cooling data of the ball.

[0015] Preferably, in the forced convection test in step 4: click on the forced convection test in the computer, cover the uppermost air outlet of the sand bed reactor with a chuck blind plate, and then clamp it with a clamp, adjust the vortex air pump bypass vent valve VA01 to the fully open state, open the VA05 and VA04 valves on the experimental device, close the VA02 and VA03 valves, then click on the vortex air pump, click to start, at this time the rotor flowmeter reading is about 13m3 / h, then adjust the vortex air pump bypass vent valve VA01 so that the rotor flowmeter reading is about 21m3 / h , then turn off the vortex air pump for standby use, then remove the chuck blind plate at the uppermost air outlet of the sand bed reactor, then click the forced convection experiment button, set the recording interval to 5S, and automatically stop recording data. You can also click the force control interface to stop recording, stop data recording in advance, and then click data save to save the data. Then click graph drawing to draw the curve. The curve graph can be saved in the form of a screenshot in the data EXCEL table, record the reading of the U-type differential pressure gauge at this time, which is the pressure drop of the bed, which is about 850pa, and the forced convection experiment is over.

[0016] Preferably, in the fixed bed experiment in step 4: after the forced convection experiment is completed, click the fixed bed experiment button, the fixed bed experiment button turns red, at this time the data recording interval and the air flow are the same as the forced convection experiment, the valve of the device is no longer adjusted, when the TI02 temperature rises to about 480°C, set the moving distance of the ball screw, quickly move the heated steel ball out, move it to the middle of the fixed bed sand bed quartz sand layer, so that the quartz sand layer completely buries the ball, and then clamp it with a clamp, and at the same time click the start recording button on the monitoring interface to start recording data. When the experiment is over, the data recording stops automatically, or you can click the force control interface to stop recording, stop data recording in advance, and then click data save to save the data, and then click graph drawing to draw the curve. The curve graph can be saved in the form of a screenshot in the data EXCEL table, and the reading of the U-type differential pressure gauge at this time is recorded, which is the pressure drop of the bed, which is about 900pa, and the fixed bed experiment is over.

[0017] Fluidized bed experiment and turbulence experiment in step 4: After the fixed bed experiment is completed, click the fluidized bed experiment button, the fluidized bed experiment button turns red, and the data recording interval and air flow are the same as those of the fixed bed experiment. Start recording data. When the experiment is over, the data recording stops automatically. You can also click the force control interface to stop recording, stop data recording in advance, and then click Save Data to save the data. Then click Graph Draw to draw a curve. The curve graph can be saved in the form of a screenshot in an EXCEL table. Record the reading of the U-type differential pressure gauge at this time, which is the pressure drop of the bed, which is about 350 Pa. The fluidized bed experiment is over.

[0018] Preferably, in the step 4, the fluidized bed experiment and the laminar flow experiment: after the fluidized bed experiment is completed, click the fluidized bed experiment button, the fluidized bed experiment button turns red, and the data recording interval is the same as the fixed bed experiment. The air flow rate is about 7m3 / h, and the ball screw movement distance is set. The cooled balls are taken out from the gravel bed reactor, and the uppermost air outlet of the gravel bed reactor is covered with a chuck blind plate, and then clamped with a clamp, and the vortex air pump bypass vent valve VA01 is adjusted to the fully open state, and the VA02 and VA03 valves on the experimental device are opened, and the VA04 and VA05 valves are closed. Then, the vortex air pump is clicked, and the start is started to record data. When the experiment is over, the data recording stops automatically. You can also click the force control interface to stop recording, stop data recording in advance, and then click data save to save the data. Then, click graph drawing to draw the curve. The curve graph can be saved in the form of a screenshot in the data EXCEL table, and the reading of the U-type differential pressure gauge at this time is recorded, which is the pressure drop of the bed, which is about 250pa. The fluidized bed experiment is over.

[0019] (III) Beneficial effects

[0020] Compared with the prior art, the present invention provides a method for measuring the heat transfer coefficient of a solid ball, which has the following beneficial effects:

[0021] 1. The method for determining the heat transfer coefficient of a solid ball uses an industrial computer to set the moving distance of the ball screw to control the moving trajectory of the ball. The movement is more convenient and the position is more accurate. A photoelectric switch is provided on the ball screw. When the ball screw slider reaches the photoelectric switch position, it stops automatically, which can prevent the ball screw slider from moving too far and ensure safe operation.

[0022] 2. The solid ball heat transfer coefficient determination method can transmit the experimental data of the device experimental process to the industrial computer for data recording and image drawing. The data can also be saved to the computer desktop, which is convenient for data processing.

[0023] 3. In the method for determining the heat transfer coefficient of solid pellets, a discharge handle is provided at the bottom of the gravel bed layer, which facilitates the discharge of gravel from the gravel bed layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of the method for measuring the heat transfer coefficient of solid pellets of the present invention. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] See also Figure 1 The present invention provides a new technical solution: a method for measuring the heat transfer coefficient of a solid ball. The device involved in the measuring method includes two photoelectric switches, a small steel ball, a VA05 valve, a VA03 valve, a VA02 valve, a VA04 valve and a VA01 valve. The two photoelectric switches control the ball screw D01 and the ball screw D02 respectively. The measuring device also includes a chuck blind plate, a vortex air pump, a silencer, a U-type differential pressure gauge and an industrial computer.

[0027] In nature and engineering, the mechanisms of heat transfer include conduction, convection and radiation. Several mechanisms may exist simultaneously during heat transfer, or a certain mechanism may be dominant. Different mechanisms correspond to different heat transfer methods or laws.

[0028] When there is a temperature difference in an object, heat will be transferred from the high temperature to the low temperature. The thermal conductivity of a substance is mainly a manifestation of the molecular transfer phenomenon.

[0029] Through the study of heat conduction, Fourier proposed:

[0030]

[0031] Where: The temperature gradient in the direction K / m ]

[0032] The above equation is called Fourier's law, which states that the heat flux is proportional to the temperature gradient. The negative sign indicates that the direction of heat conduction is opposite to the direction of the temperature gradient.

[0033] The thermal conductivity of metals is much greater than that of non-metals, ranging from 15 to 415 [ W / m ·K] range. The thermal conductivity of pure metals decreases with increasing temperature, while the opposite is true for alloys. However, the thermal conductivity of pure metals is usually higher than that of the alloys they are composed of. In this experiment, the selection of the ball material has an important influence on the experimental results.

[0034] Thermal convection is the process of heat transfer on the micro-cluster scale caused by the macroscopic movement of the fluid relative to the solid surface. In fact, it is inevitably accompanied by contact heat conduction between fluid micro-clusters and between fluid and the solid wall, so it is a comprehensive process of microscopic molecular heat conduction and macroscopic micro-cluster heat convection. The essence of thermal convection is the movement on the macroscopic scale. Different flow states (laminar flow and turbulent flow) have different heat transfer mechanisms.

[0035] Newton proposed the basic law of convective heat transfer - Newton's law of cooling:

[0036] Q=qA=αA(T W -T f ) (2)

[0037] α is not a physical constant. It depends on the physical, geometric and flow factors of the system and is usually determined by experiments. This experiment measures the convective heat transfer coefficient of the ball under different environments and flow conditions. Forced convection has better heat transfer effect than natural convection, and turbulent convection heat transfer coefficient is larger than laminar flow. This experiment tries to avoid errors in the experimental results caused by thermal radiation heat transfer.

[0038] The sudden heating and cooling of an object is a non-steady heat conduction process. At this time, the temperature inside the heat-conducting object is a function of both the spatial position and time, T = f (x, y, z, t). When the object is heated or cooled by a heat-conducting medium, the heat conduction rate depends on both the internal thermal resistance of the object and the external convection thermal resistance between the object and the environment. For the sake of simplicity, many problems can be handled by ignoring one of the two. However, whether it can be simplified requires a criterion. Usually, the dimensionless Biot number (Bi) is defined, which is the ratio of the internal thermal resistance of the object to the external convection thermal resistance of the object for judgment.

[0039]

[0040] Where: δ = V / A - is the characteristic size, for a sphere it is R / 3

[0041] If the Bi number is very small, It shows that the internal thermal resistance is less than the external convection resistance. At this time, the internal thermal resistance can be ignored, and the temperature of the whole object can be simplified to be uniform, so that the temperature is only a function of time, that is, T = f(t). This method of simplifying the system to have uniform properties is called the lumped parameter method. Experiments show that as long as Bi < 0.1, the error of ignoring the internal thermal resistance for calculation is no more than 5%, which is usually allowed for engineering calculations.

[0042] A small steel ball with a diameter of ds and a temperature of T0 is placed at a constant temperature T f In the surrounding environment, if T0>T f , the instantaneous temperature T of the ball decreases as time t increases. According to the principle of thermal equilibrium, the change in the heat of the ball over time should be equal to the rate of heat dissipation to the surrounding environment through convection heat transfer.

[0043]

[0044] Initial conditions: t = 0, TT f =T0-T f

[0045] Integrating (5) we get:

[0046]

[0047] Defining the time constant From the analysis of formula (6), we can see that when the heat exchange between the object and the environment lasts for four times the time constant, that is, t = 4τ, we can get:

[0048]

[0049] Indicates excess temperature TT f The change has reached 98.2%, and the future change is only 1.8%. For engineering calculations, it can be approximated as a constant in the future.

[0050] For small balls Substituting into formula (6), we get:

[0051]

[0052] or

[0053] The cooling curve of the steel ball under different environments and flow conditions can be measured through experiments. The relationship between T and t can be recorded by a temperature recorder, and the corresponding values ​​of α and Nu can be calculated by equations (8) and (9).

[0054] For gases in the range of 20<Re<180000, i.e. at high Re numbers, the empirical formula for heat transfer around the sphere is:

[0055]

[0056] If heat is exchanged in a static fluid: Nu = 2.

[0057] The rotor flowmeter flow rate during the experiment is the gas flow rate under the conditions of 20℃ and 101325Pa. The gas flow rate needs to be corrected to the gas flow rate under the experimental temperature and pressure conditions:

[0058] P 标 =101325Pa (atmospheric pressure of gas under standard conditions)

[0059] T 标 =273.15+20K (temperature of gas under standard conditions)

[0060] ρ 0气 Density of air, at 20°C, 101325 Pa, ρ 0气 =1.205kg / m 3

[0061] ρ f Density of metal rotor, kg / m 3

[0062] V 0气 Indication of rotor flowmeter, m 3 / h

[0063] V B Actual air flow, m 3 / h

[0064] ρ 气 Density of air, kg / m 3 (Density of air after temperature and pressure correction)

[0065] P1=P 标 +PI01 Pa PI01—Intake pressure sensor reading (Pa)

[0066] t1=273.15+T f KT f — is the ambient temperature (℃)

[0067]

[0068] Gas rotor flowmeter correction formula:

[0069] Because f Much larger than ρ 气 ,so

[0070]

[0071] Steps:

[0072] Step 1: half a tube of water is filled into the U-type differential pressure gauge PDIO1 in the measuring device, and quartz sand is added to the sand bed reaction. The amount of quartz sand added is based on the upper surface of the quartz sand in the sand bed reactor not contacting the thermocouple TI01.

[0073] Step 2: Turn on the main power and control power of the measuring device, set the temperature control buttons TIC01, TIC02, and TIC03 of the tubular heating furnace, and set the three heating temperatures to about 500°C.

[0074] Step 3: Place a small steel ball embedded with a thermocouple in a tubular heating furnace and observe the temperature of the ball TI02. When the temperature of TI02 rises to about 480°C (the heating speed is fastest when the ball is placed in the middle of the tubular heating furnace), the ball screw moves quickly to remove the steel ball and place it under different environmental conditions for experiments. The data on the temperature change of the small steel ball over time and the relationship between the cooling curve are recorded by a computer.

[0075] Step 4: The environmental conditions for the measurement device are: natural convection, forced convection, fixed bed and fluidized bed. The flow states are: laminar flow and turbulent flow.

[0076] Embodiment 1: Natural convection experiment: Click on the natural convection experiment in the computer, the icon of the natural convection experiment turns red, set the recording interval to 5S (reference value) (the upper limit of the experimental number is 500 groups, and the data exceeding 500 groups will no longer be recorded), the air flow rate in the lower right corner is input as 0, when the temperature of the ball TI02 rises to about 480°C, set the moving distance of the ball screw, remove the ball from the heating furnace, suspend the heated steel ball in the air, click to start recording data, and during the data recording process, minimize the atmospheric disturbance near the steel ball and record the cooling data of the ball;

[0077] When In((T0-Tf) / (T-Tf))≥4, that is, the change of T-Tf excess temperature has reached 98.2%, the force control automatically stops recording data. You can also click the force control interface to stop recording, stop data recording in advance, and then click data save to save the data, and then click graph drawing to draw the curve. The curve graph can be saved in the form of a screenshot in the data EXCEL table, and the natural convection test is over.

[0078] Embodiment 2: forced convection experiment: after the natural convection experiment is finished, the uppermost gas outlet of the sand bed reactor is covered with a chuck blind plate, and then clamped with a clamp, the bypass vent valve VA01 of the vortex air pump is adjusted to the fully open state of the valve, the VA05 and VA04 valves on the experimental device are opened, the VA02 and VA03 valves are closed, and then the vortex air pump is clicked and the start is clicked. At this time, the rotor flowmeter reading is about 13m3 / h, and then the bypass vent valve VA01 of the vortex air pump is adjusted so that the rotor flowmeter reading is about 21m3 / h (reference value), and then the vortex air pump is closed for standby use, and then the chuck blind plate of the uppermost gas outlet of the sand bed reactor is removed, and then the forced convection experiment button is clicked, and the recording interval is set to 5S (reference value) (the upper limit of the experimental sequence number is 500 groups, and the data exceeds 500 groups, and the subsequent data is no longer recorded), the air flow at the lower right corner is input as 21m3 / h, and when the TI02 temperature rises to about 480°C, the ball bearing is set Move the screw rod to a certain distance, quickly move the heated steel ball out, move it to the middle of the gravel bed reactor, and then clamp it with a clamp (when the ball is inserted downward into the gravel bed reactor, it must be inserted vertically and at a fast speed to prevent the ball from breaking the glass of the gravel bed reactor when inserted obliquely). Then click to start recording to record the cooling data and cooling curve of the ball temperature TI02 over time. When In((T0-Tf) / (T-Tf))≥4, that is, the change in T-Tf excess temperature has reached 98.2%, the data recording will stop automatically. You can also click the force control interface to stop recording and stop data recording in advance. Then click Save Data to save the data (after the data is saved, turn off the vortex air pump). Then click Graph Draw to draw the curve. The curve graph can be saved in the form of a screenshot in the data EXCEL table. Record the reading of the U-type differential pressure gauge at this time, which is the pressure drop of the bed, which is about 850pa (reference value). The forced convection experiment is over.

[0079] Example 3: Fixed bed experiment: After the forced convection experiment is completed, click the fixed bed experiment button, the fixed bed experiment button turns red, at this time the data recording interval and air flow are the same as the forced convection experiment, the valve of the device is no longer adjusted, when the TI02 temperature rises to about 480°C, set the ball screw movement distance, quickly move the heated steel ball out, move it to the middle of the fixed bed sand bed quartz sand layer, so that the quartz sand layer completely buries the ball, and then clamp it with a clamp, and click the monitoring interface to start recording button at the same time (when the ball is inserted downward into the sand bed reactor, it needs to be inserted vertically and quickly to prevent the ball from breaking the sand bed reactor glass when inserted obliquely). When starting to record data, the ball temperature should be kept at 4 Above 10℃, it is best to be consistent with the initial temperature recording data of forced convection data, record the cooling data and cooling curve of the small ball temperature TI02 over time, when In((T0-Tf) / (T-Tf))≥4, that is, the change of T-Tf excess temperature has reached 98.2%, automatically stop recording data, or click the force control interface to stop recording, stop data recording in advance, and then click data save to save the data (after the data is saved, turn off the vortex air pump), and then click graph to draw the curve. The curve graph can be saved in the form of a screenshot in the data EXCEL table, record the reading of the U-type differential pressure gauge at this time, which is the pressure drop of the bed, which is about 900pa (reference value), and the fixed bed experiment is over.

[0080] Embodiment 4: fluidized bed experiment (turbulence): after the fixed bed experiment is completed, click the fluidized bed experiment button, the fluidized bed experiment button turns red, at this time the data recording interval and air flow are the same as the fixed bed experiment, the cooled balls are taken out from the gravel bed reactor, the uppermost air outlet of the gravel bed reactor is covered with a chuck blind plate, and then clamped with a clamp, the vortex air pump bypass vent valve VA01 is adjusted to the fully open state, the VA02 and VA03 valves on the experimental device are opened, the VA04 and VA05 valves are closed, and then the vortex air pump is clicked, and the start is clicked. At this time, the rotor flowmeter reading is about 13m3 / h, and then the vortex air pump bypass vent valve VA01 is adjusted so that the rotor flowmeter reading is about 21m3 / h (reference value), and then the vortex air pump is closed for standby use. When the temperature of TI02 rises to about 480℃, set the moving distance of the ball screw, insert the heated ball until the bottom of the ball contacts the top of the quartz sand gravel bed, and then clamp it with a clamp. At the same time, click the start recording button on the monitoring interface (when the ball is inserted downward into the sand bed reactor, it must be inserted vertically and at a fast speed to prevent the ball from breaking the glass of the sand bed reactor when inserted obliquely). When starting to record data, the ball temperature must be kept above 410℃, and it is best to be consistent with the initial temperature recording data of other experimental data. Record the cooling data and cooling curve of the ball temperature TI02 over time. When In((T0-Tf) / (T-Tf))≥4, that is, the change of T-Tf excess temperature has reached 98.2%, the data recording will be automatically stopped. You can also click the force control interface to stop recording, stop data recording in advance, and then click Save Data to save the data (after the data is saved, turn off the vortex air pump), and then click Graph to draw the curve. The curve graph can be saved in the form of a screenshot in an EXCEL table. Record the reading of the U-type differential pressure gauge at this time, which is the pressure drop of the bed, which is about 350pa (reference value). The fluidized bed experiment (turbulence) is over.

[0081] Example 5: Fluidized bed experiment (laminar flow optional): After the fluidized bed experiment (turbulent flow) is completed, click the fluidized bed experiment button, the fluidized bed experiment button turns red, and the data recording interval is the same as the fixed bed experiment. Input an air flow rate of about 7m3 / h (reference value), set the ball screw movement distance, take the cooled balls out of the gravel bed reactor, cover the uppermost air outlet of the gravel bed reactor with a chuck blind plate, and then clamp it with a clamp, adjust the vortex air pump bypass vent valve VA01 to the fully open state, open the VA02 and VA03 valves on the experimental device, close the VA04 and VA05 valves, then click the vortex air pump, click to start, at this time the rotor flowmeter reading is about 13m3 / h, then gradually and slowly close the valve VA02, so that the rotor flowmeter reading is about 7m3 / h (reference value), and then turn off the vortex air pump for standby use. When the temperature of TI02 rises to about 480℃, set the moving distance of the ball screw, quickly take out the heated steel ball, insert the heated ball until the bottom of the ball contacts the top of the quartz sand gravel, and then clamp it with a clamp. At the same time, click the start recording button on the monitoring interface (when the ball is inserted downward into the sand bed reactor, it must be inserted vertically and at a fast speed to prevent the ball from breaking the glass of the sand bed reactor when inserted obliquely). When starting to record data, the temperature of the ball should be kept above 410℃, and it is best to be consistent with the initial temperature recording data of other experimental data. Record the cooling data and cooling curve of the ball temperature TI02 over time. When In((T0-Tf) / (T-Tf))≥4, that is, the change of T-Tf excess temperature has reached 98.2%, the data recording will stop automatically. You can also click the force control interface to stop recording, stop data recording in advance, and then click data save to save the data (after the data is saved, turn off the vortex air pump), and then click graph drawing to draw the curve. The curve graph can be saved in the form of a screenshot in the data EXCEL table. Record the reading of the U-type differential pressure gauge at this time, which is the pressure drop of the bed, which is about 250pa (reference value). The fluidized bed experiment (laminar flow is optional) is over.

[0082] Step 5: When the experiment is over, click the temperature control buttons TIC01, TIC02, and TIC03 of the tubular heating furnace to stop heating the tubular heating furnace, click the force control interface, exit the system, turn off the control power, and turn off the main power.

[0083] Step 6: When releasing the gravel from the gravel bed, loosen the fixing nut of the lower discharge valve of the rotating sand bed reactor, rotate the lower discharge valve of the sand bed reactor, and release the sand in the bed. During the sand release process, start the vortex air pump according to the opening status of the forced convection pipeline valve, blow down the sand in the bed, and finish the cleaning.

[0084] Structure Description:

[0085] Chuck blind plate: The chuck blind plate is a mounting plate fastened by a clamp and has a certain degree of sealing.

[0086] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for measuring the heat transfer coefficient of a solid ball, characterized in that: The following steps are involved: Step 1: half of the U-shaped differential pressure gauge PDIO1 in the measuring device is filled with water, and quartz sand is added to the sand bed reaction. The amount of quartz sand added is based on the upper surface of the quartz sand in the sand bed reactor not contacting the thermocouple TI01; Step 2: Turn on the main power and control power of the measuring device, set the temperature control buttons TIC01, TIC02, and TIC03 of the tubular heating furnace, and set the three heating temperatures to about 500°C; Step 3: Place a small steel ball embedded with a thermocouple in a tubular heating furnace and observe the temperature of the small ball TI02. When the temperature of TI02 rises to about 480°C, the ball screw moves quickly to remove the steel ball and conduct experiments under different environmental conditions. The data of the temperature change of the small steel ball over time and the relationship between the cooling curve are recorded by a computer. Step 4: The environmental conditions for the measurement device are: natural convection, forced convection, fixed bed and fluidized bed. The flow states are: laminar flow and turbulent flow; Step 5: After the experiment, click the temperature control buttons TIC01, TIC02, and TIC03 of the tubular heating furnace to stop the heating of the tubular heating furnace, click the force control interface, exit the system, turn off the control power, and turn off the main power; Step 6: When releasing the gravel from the gravel bed, loosen the fixing nut of the lower discharge valve of the rotating sand bed reactor, rotate the lower discharge valve of the sand bed reactor, and release the sand in the bed. During the sand release process, start the vortex air pump according to the opening status of the forced convection pipeline valve, blow down the sand in the bed, and finish the cleaning.

2. A method for measuring heat transfer coefficient of a solid ball according to claim 1, characterized in that: The natural convection test in step 4: click on the natural convection experiment on the computer, the natural convection experiment icon turns red, set the recording interval to 5S, input 0 at the air flow in the lower right corner, when the ball temperature TI02 rises to about 480°C, set the ball screw movement distance, move the ball out of the heating furnace, suspend the heated steel ball in the air, click to start recording data, and during the data recording process, minimize the atmospheric disturbance near the steel ball and record the cooling data of the ball.

3. The method for measuring heat transfer coefficient of a solid ball according to claim 1, characterized in that: Forced convection test in step 4: click forced convection test in the computer, cover the uppermost air outlet of the sand bed reactor with a chuck blind plate, and then clamp it with a clamp, adjust the vortex air pump bypass vent valve VA01 to the fully open state, open the VA05 and VA04 valves on the experimental device, close the VA02 and VA03 valves, then click the vortex air pump, click to start, at this time the rotor flow meter reading is about 13m3 / h, then adjust the vortex air pump bypass vent valve VA01 so that the rotor flow meter reading is about 21m3 / h, and then Turn off the vortex air pump for standby use, then remove the chuck blind plate at the uppermost air outlet of the sand bed reactor, then click the forced convection experiment button, set the recording interval to 5S, and automatically stop recording data. You can also click the force control interface to stop recording, stop data recording in advance, and then click data save to save the data, and then click graph drawing to draw the curve. The curve graph can be saved in the form of a screenshot in an EXCEL table. Record the reading of the U-type differential pressure gauge at this time, which is the pressure drop of the bed, which is about 850pa. The forced convection experiment is over.

4. A method for measuring heat transfer coefficient of a solid ball according to claim 1, characterized in that: Fixed bed experiment in step 4: After the forced convection experiment is completed, click the fixed bed experiment button, the fixed bed experiment button turns red, at this time the data recording interval and air flow are the same as the forced convection experiment, the valve of the device is no longer adjusted, when the TI02 temperature rises to about 480°C, set the moving distance of the ball screw, quickly move the heated steel ball out, move it to the middle of the fixed bed sand bed quartz sand layer, so that the quartz sand layer completely buries the ball, and then clamp it with a clamp, and at the same time click the start recording button on the monitoring interface to start recording data. When the experiment is over, it automatically stops recording data, or you can click the force control interface to stop recording, stop data recording in advance, and then click data save to save the data, and then click graph drawing to draw the curve. The curve graph can be saved in the form of a screenshot in the data EXCEL table, record the reading of the U-type differential pressure gauge at this time, which is the pressure drop of the bed, which is about 900pa, and the fixed bed experiment is over.

5. The method for measuring heat transfer coefficient of a solid ball according to claim 1, characterized in that: Fluidized bed experiment and turbulence experiment in step 4: After the fixed bed experiment is completed, click the fluidized bed experiment button, the fluidized bed experiment button turns red, and the data recording interval and air flow are the same as those of the fixed bed experiment. Start recording data. When the experiment is over, the data recording stops automatically. You can also click the force control interface to stop recording, stop data recording in advance, and then click Save Data to save the data. Then click Graph Draw to draw a curve. The curve graph can be saved in the form of a screenshot in an EXCEL table. Record the reading of the U-type differential pressure gauge at this time, which is the pressure drop of the bed, which is about 350 Pa. The fluidized bed experiment is over.

6. A method for measuring heat transfer coefficient of a solid ball according to claim 1, characterized in that: Fluidized bed experiment and laminar flow experiment in step 4: after the fluidized bed experiment is completed, click the fluidized bed experiment button, the fluidized bed experiment button turns red, and the data recording interval is the same as that of the fixed bed experiment. Input an air flow rate of about 7m3 / h, set the moving distance of the ball screw, take the cooled balls out of the gravel bed reactor, cover the uppermost air outlet of the gravel bed reactor with a chuck blind plate, and then clamp it with a clamp, adjust the vortex air pump bypass vent valve VA01 to the fully open state, open the VA02 and VA03 valves on the experimental device, close the VA04 and VA05 valves, then click the vortex air pump, click start, and start recording data. When the experiment is over, it automatically stops recording data. You can also click the force control interface to stop recording and stop data recording in advance. Then click data save to save the data, and then click graph drawing to draw the curve. The curve graph can be saved in the form of a screenshot. In the data EXCEL table, record the reading of the U-type differential pressure gauge at this time, which is the pressure drop of the bed, which is about 250pa. The fluidized bed experiment is over.

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