Enhanced heat exchange method for driving bubbles to flow

Abstract

The invention discloses an enhanced heat exchange method for driving bubbles to flow, which comprises the following steps: arranging a heat exchange device, injecting bubbles from the bottom through a storage unit in the heat exchange device, generating bubbles with a certain size and quantity by the heat exchange device, and pushing the bubbles to flow in the heat exchange device through a driving mechanism, bubbles are ensured to be uniformly distributed and effectively flow in a heat exchange medium, the rising momentum of the bubbles is used for driving liquid PCM to be mixed, the heat transfer performance is enhanced, the heat stratification phenomenon is reduced, the bubbles make contact with the surface of a heat exchange device in the flowing process, friction between fluid and the surface of the heat exchange device is increased, and therefore the heat exchange effect is enhanced. The rising momentum of the bubbles is used for driving the liquid PCM to be mixed, the heat transfer performance is enhanced, the heat stratification phenomenon is reduced, the contact area and frequency of the fluid and the surface of the heat exchanger are increased through flowing of the bubbles, and therefore the heat exchange efficiency is remarkably improved, the rising motion of the bubbles can drive the surrounding fluid to form convection, and the heat exchange effect is further enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal energy storage, and in particular to a method for enhancing heat exchange by driving bubble flow. Background Art

[0002] With the growth of global energy demand and the increase in carbon emissions, renewable energy has become the main direction to replace fossil energy. As we all know, the collection of most renewable energy is intermittent, so thermal energy storage technology has become a focus of attention. Among them, latent heat thermal energy storage has attracted much attention due to the high thermal energy density and stability of its phase change materials. However, the low thermal conductivity and thermal stratification phenomenon of phase change materials limit the performance of latent heat thermal energy storage, and its energy storage rate is significantly affected.

[0003] In Chinese Patent 202210068694.7, traditional heat exchange methods include natural convection, forced convection, heat conduction and radiation. These methods can meet the heat exchange requirements to a certain extent, but under certain conditions, when high viscosity fluids or small temperature differences are used for heat exchange, the efficiency is not ideal. Therefore, the present invention proposes an enhanced heat exchange method that drives bubble flow to solve the problems existing in the prior art. Summary of the Invention

[0004] In response to the above problems, the purpose of the present invention is to propose a method for enhancing heat exchange by driving bubble flow. This method uses the rising momentum of bubbles to drive liquid PCM mixing, enhances heat transfer performance and reduces thermal stratification. The flow of bubbles increases the contact area and frequency between the fluid and the heat exchanger surface, thereby significantly improving the heat exchange efficiency. The rising movement of bubbles also drives the surrounding fluid, forming convection, further enhancing the heat exchange effect.

[0005] To achieve the purpose of the present invention, the present invention is implemented through the following technical solutions: a method for enhancing heat exchange by driving bubble flow, comprising the following steps:

[0006] Step 1: Set up a heat exchange device and inject bubbles from the bottom through the storage unit inside the heat exchange device. The heat exchange device will generate bubbles of a certain size and quantity;

[0007] Step 2: Use the driving mechanism to push the bubbles to flow in the heat exchange device to ensure that the bubbles are evenly distributed in the heat exchange medium and flow effectively;

[0008] Step 3: Utilize the rising momentum of bubbles to drive liquid PCM mixing, thereby enhancing heat transfer performance and reducing thermal stratification;

[0009] Step 4: During the flow process, the bubbles come into contact with the surface of the heat exchanger, increasing the friction between the fluid and the surface of the heat exchanger, thereby enhancing the heat transfer effect. The rising bubbles drive the surrounding fluid, forming convection, further improving the heat transfer efficiency.

[0010] Step 5: A control unit is provided inside the heat exchange device to adjust the bubble generation and driving parameters according to actual conditions to achieve the best heat exchange effect.

[0011] A further improvement is that the heat exchange device in step one includes an air storage box, an air pump, a nozzle, a water seal layer, a heat exchanger, a phase change material, an insulation layer, an air layer and a hot air recovery pipe, an air pump is fixedly installed on one side of the air storage box, a nozzle is fixedly installed on the side above the air pump, a water seal layer is provided above the nozzle, a heat exchanger is fixedly installed above the water seal layer, multiple groups of phase change materials are fixedly provided inside the heat exchanger, an insulation layer is fixedly provided on the outside of the heat exchanger, an air layer is opened on the top of the heat exchanger, a hot air recovery pipe is fixedly installed on the top of the heat exchanger, and the other side of the hot air recovery pipe is interconnected with the air storage box.

[0012] A further improvement is that in step 2, the bubbles stir the PCM liquid through the upward momentum generated by the density difference, thereby improving the heat transfer efficiency. This device preferably uses 1-octanol as the PCM, which has a melting point of 56-58°C, a high phase change latent heat and transparency, and is suitable for visualization experiments and efficient heat storage.

[0013] Further improvements are: in step three, after the injection of bubbles, the thermal stratification phenomenon is completely eliminated; the average flow rate of the PCM is increased by 6.38 times, and the heat transfer coefficient is increased by 204%. The PCM is 1-octanol, which has high thermal energy density and good visual experimental characteristics.

[0014] A further improvement is that in step 4, the diameter of the bubbles sprayed from the nozzle is 2-3 mm, and the flow rate is 0.1-0.6 L / min.

[0015] A further improvement is that in step five, the charging time of the control unit is reduced by 40%, the heat storage efficiency is increased by 1.6 times, and the energy loss caused by bubble driving is less than 2% of the total input energy.

[0016] A further improvement is that the heat exchange device is mainly composed of an LHTES unit made of transparent polycarbonate, and the top and bottom are designed for the bubble outlet and injection port respectively.

[0017] A further improvement is that a temperature sensor is provided inside the heat exchange device, and the temperature sensor is distributed in the vertical direction of the PCM for real-time monitoring of temperature changes and heat distribution.

[0018] A further improvement is that a visualization device is provided outside the heat exchange device, and particle image velocimetry and image projection technology are used to analyze the influence of bubbles on the flow field and phase change interface of the PCM.

[0019] A further improvement is that the driving mechanism inside the heat exchange device is a mechanical vibrator, which can produce a fluid dynamic effect and drive the bubbles to be evenly distributed and effectively flow in the heat exchange medium.

[0020] The beneficial effects of the present invention are as follows: the present invention utilizes the mutual coordination among the air storage tank, air pump, nozzle, water seal layer, heat exchanger, phase change material, insulation layer, air layer and hot air recovery pipe, utilizes the rising momentum of bubbles to drive liquid PCM mixing, enhances heat transfer performance and reduces thermal stratification. The flow of bubbles increases the contact area and frequency between the fluid and the heat exchanger surface, thereby significantly improving the heat exchange efficiency. The rising movement of bubbles also drives the surrounding fluid to form convection, further enhancing the heat exchange effect. Due to the improvement in heat exchange efficiency, the system can achieve the same heat exchange effect with lower energy consumption, thereby reducing overall energy consumption. Through the precise control of the control unit, the bubble generation and flow parameters are adjusted according to actual needs to achieve intelligent management. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 Schematic diagram of the heat exchange device of the present invention;

[0023] Figure 2 It is a flow chart of the steps of the present invention.

[0024] Figure identification: 1. Air storage box; 2. Air pump; 3. Nozzle; 4. Water seal layer; 5. Heat exchanger; 6. Phase change material; 7. Insulation layer; 8. Air layer; 9. Hot air recovery pipe. DETAILED DESCRIPTION

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0026] In the description of the present invention, it should be noted that, unless otherwise specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0027] In document 202210068694.7, two groups of buffer tanks are arranged in the high-temperature gas circuit to reduce the impact of transient pressure fluctuations of the gas booster pump on the circuit pressure and flow. Two groups of mass flow controllers with different ranges are arranged in parallel in the circuit to meet the precise flow measurement requirements from laminar flow to fully developed turbulence in the experimental section. The pressure and differential pressure measurement pressure-taking lines in the experimental section are arranged with insulating flanges to eliminate the influence of the electric heating effect on the gas pressure measurement, and at the same time enable the pressure transmitter to shield the electrical signal noise generated by the DC power supply. In this application, the existing heat exchange methods are often limited by the dynamic characteristics of the fluid and the physical design of the heat exchanger. It is difficult to achieve the optimal heat exchange effect under all working conditions. Energy consumption and environmental impact are also important factors that need to be considered. Bubble flow is considered to be a potential means of enhancing heat exchange in the field of heat exchange. The introduction of bubbles can increase the turbulence of the fluid, improve the heat transfer coefficient, and thus enhance the heat exchange effect.

[0028] according to Figure 1 、 Figure 2 As shown, this embodiment provides a method for enhancing heat exchange by driving bubble flow, comprising the following steps:

[0029] Step 1: Set up a heat exchange device and inject bubbles from the bottom through the storage unit inside the heat exchange device. The heat exchange device will generate bubbles of a certain size and quantity;

[0030] Step 2: Use the driving mechanism to push the bubbles to flow in the heat exchange device to ensure that the bubbles are evenly distributed in the heat exchange medium and flow effectively;

[0031] Step 3: Utilize the rising momentum of bubbles to drive liquid PCM mixing, thereby enhancing heat transfer performance and reducing thermal stratification;

[0032] Step 4: During the flow process, the bubbles come into contact with the surface of the heat exchanger, increasing the friction between the fluid and the surface of the heat exchanger, thereby enhancing the heat transfer effect. The rising bubbles drive the surrounding fluid, forming convection, further improving the heat transfer efficiency.

[0033] Step 5: A control unit is provided inside the heat exchange device to adjust the bubble generation and driving parameters according to actual conditions to achieve the best heat exchange effect.

[0034] The heat exchange device in step one includes an air storage box 1, an air pump 2, a nozzle 3, a water seal layer 4, a heat exchanger 5, a phase change material 6, an insulation layer 7, an air layer 8 and a hot air recovery pipe 9. The setting of the air storage box 1 provides a stable gas source to ensure that bubbles can be generated continuously. An air pump 2 is fixedly installed on one side of the air storage box 1. The air pump 2 is set to continuously and stably transport gas to ensure the continuous generation and flow of bubbles, thereby maintaining the efficient operation of the heat exchange system. A nozzle 3 is fixedly installed on one side above the air pump 2. The gas is sprayed out for use through the setting of the nozzle 3. A water seal layer 4 is set above the nozzle 3. The water seal layer 4 prevents the gas from escaping from the device, ensuring that the gas is effectively transported to the heat exchange medium, thereby generating bubbles. A heat exchanger 5 is fixedly installed above the water seal layer 4. The heat exchanger 5 provides a contact interface between the hot fluid and the cold fluid, so that heat can be transferred from the temperature A higher temperature fluid is transferred to a lower temperature fluid. Multiple groups of phase change materials 6 are fixedly installed inside the heat exchanger 5. The phase change material 6 absorbs heat during the melting process and releases heat during the solidification process, which helps to balance the heat load fluctuations and improve the thermal stability of the system. An insulation layer 7 is fixedly installed on the outside of the heat exchanger 5. The insulation layer 7 effectively slows down the conduction of heat from the inside of the heat exchanger to the external environment through the characteristics of its low thermal conductivity material, thereby reducing unnecessary heat loss. An air layer 8 is opened on the top of the heat exchanger 5. The setting of the air layer 8 effectively isolates the transfer of heat and reduces the heat exchange between the heat exchanger and the external environment. A hot air recovery pipe 9 is fixedly installed on the top of the heat exchanger 5. The other side of the hot air recovery pipe 9 is interconnected with the air storage box 1. The hot air is guided back to the air inlet of the heat exchange system through the hot air recovery pipe 9, so that this part of the heat energy will not be directly discharged into the environment, but will be reused.

[0035] In step 2, the bubbles stir the PCM liquid through the upward momentum generated by the density difference, thereby improving the heat transfer efficiency. This device preferably uses 1-octanol as the PCM, which has a melting point of 56-58°C, a high phase change latent heat and transparency, and is suitable for visualization experiments and efficient heat storage.

[0036] In step three, after the air bubbles were injected, the thermal stratification phenomenon was completely eliminated, the average flow rate of the PCM increased by 6.38 times, and the heat transfer coefficient increased by 204%.

[0037] In step 4, the bubble diameter ejected from the nozzle is 2-3 mm, and the flow rate is 0.1-0.6 L / min, wherein the PCM is 1-octanol, which has high thermal energy density and good visualization experimental characteristics.

[0038] In step five, the charging time of the control unit is reduced by 40%, the thermal storage efficiency is increased by 1.6 times, and the energy loss caused by bubble driving is less than 2% of the total input energy.

[0039] The heat exchange device is mainly composed of an LHTES unit made of transparent polycarbonate, with the top and bottom designed for bubble outlet and injection port respectively.

[0040] Temperature sensors are installed inside the heat exchanger and are distributed in the vertical direction of the PCM to monitor temperature changes and heat distribution in real time.

[0041] A visualization device is installed outside the heat exchanger, and particle image velocimetry and image projection technology are used to analyze the impact of bubbles on the flow field and phase change interface of PCM.

[0042] The driving mechanism inside the heat exchange device is a mechanical vibrator that can produce a fluid dynamic effect, driving the bubbles to be evenly distributed in the heat exchange medium and to flow effectively.

[0043] When the enhanced heat exchange method for driving bubble flow is used, a stable gas source is provided by the setting of the air storage tank 1 to ensure that bubbles can be continuously generated. The air is continuously and stably delivered by the setting of the air pump 3. The gas is ejected by the setting of the nozzle 3. The water seal layer 4 prevents the gas from escaping from the device, ensuring that the gas is effectively delivered to the heat exchange medium, thereby generating bubbles. The size and number of bubbles should be determined according to the design of the heat exchanger and the characteristics of the heat exchange medium. A mechanical vibrator is driven to drive the bubbles to flow in the heat exchanger, and the parameters of the driving mechanism are adjusted to optimize the flow path and speed of the bubbles. The heat exchanger 5 provides a flow path between the hot fluid and the cold fluid. The contact interface allows heat to be transferred from the fluid with higher temperature to the fluid with lower temperature. The phase-changing material 6 absorbs heat during the melting process and releases heat during the solidification process, helping to balance the heat load fluctuations and improve the thermal stability of the system. The insulation layer 7, through its low thermal conductivity material characteristics, effectively slows down the conduction of heat from the inside of the heat exchanger to the external environment, thereby reducing unnecessary heat loss. The setting of the air layer 8 effectively isolates the transfer of heat and reduces the heat exchange between the heat exchanger and the external environment. The hot air is guided back to the air inlet of the heat exchange system through the hot air recovery pipe 9, so that this part of the heat energy will not be directly discharged into the environment, but will be reused.

[0044] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for enhancing heat exchange by driving bubble flow, characterized in that: The following steps are involved: Step 1: Set up a heat exchange device and inject bubbles from the bottom through the storage unit inside the heat exchange device. The heat exchange device will generate bubbles of a certain size and quantity; Step 2: The driving mechanism inside the heat exchange device drives the bubbles to flow in the heat exchange device, ensuring that the bubbles are evenly distributed in the heat exchange medium and flow effectively; Step 3: When the bubbles flow, the upward momentum of the bubbles is used to drive the mixing of the liquid PCM, thereby enhancing the heat transfer performance and reducing the thermal stratification phenomenon; Step 4: During the flow process, the bubbles come into contact with the surface of the heat exchanger, increasing the friction between the fluid and the surface of the heat exchanger, thereby enhancing the heat transfer effect. The rising bubbles drive the surrounding fluid, forming convection, further improving the heat transfer efficiency. Step 5: A control unit is provided inside the heat exchange device to adjust the bubble generation and driving parameters according to actual conditions to achieve the best heat exchange effect.

2. The method for enhancing heat exchange by driving bubble flow according to claim 1, characterized in that: The heat exchange device in step 1 comprises an air storage box (1), an air pump (2), a nozzle (3), a water seal layer (4), a heat exchanger (5), a phase change material (6), a thermal insulation layer (7), an air layer (8) and a hot air recovery pipe (9), wherein the air pump (2) is fixedly mounted on one side of the air storage box (1), the nozzle (3) is fixedly mounted on one side above the air pump (2), a water seal layer (4) is arranged above the nozzle (3), a heat exchanger (5) is fixedly mounted above the water seal layer (4), a plurality of phase change materials (6) are fixedly arranged inside the heat exchanger (5), a thermal insulation layer (7) is fixedly mounted on the outside of the heat exchanger (5), an air layer (8) is opened on the top of the heat exchanger (5), a hot air recovery pipe (9) is fixedly mounted on the top of the heat exchanger (5), and the other side of the hot air recovery pipe (9) is communicated with the air storage box (1).

3. The method for enhancing heat exchange by driving bubble flow according to claim 1, characterized in that: In step 2, the bubbles stir the PCM liquid through the upward momentum generated by the density difference, thereby improving the heat transfer efficiency. This device uses 1-octanol as the PCM, which has a melting point of 56-58°C, a high phase change latent heat and transparency, and is suitable for visualization experiments and efficient heat storage.

4. The method for enhancing heat exchange by driving bubble flow according to claim 1, characterized in that: In step three, after the bubbles were injected, the thermal stratification phenomenon was completely eliminated, the average flow rate of the PCM increased by 6.38 times, and the heat transfer coefficient increased by 204%. The PCM had high thermal energy density and good visual experimental characteristics.

5. The method for enhancing heat exchange by driving bubble flow according to claim 1, characterized in that: In step 4, the diameter of the bubbles sprayed from the nozzle is 2-3 mm, and the flow rate is 0.1-0.6 L / min.

6. The method for enhancing heat exchange by driving bubble flow according to claim 1, characterized in that: In step five, the charging time of the control unit is reduced by 40%, the heat storage efficiency is increased by 1.6 times, and the energy loss caused by bubble driving is less than 2% of the total input energy.

7. The method for enhancing heat exchange by driving bubble flow according to claim 2, characterized in that: The heat exchange device is mainly composed of an LHTES unit made of transparent polycarbonate, and the top and bottom are designed for the bubble outlet and injection port respectively.

8. The method for enhancing heat exchange by driving bubble flow according to claim 1, characterized in that: The heat exchange device is provided with temperature sensors inside. The temperature sensors are distributed in the vertical direction of the PCM and are used to monitor temperature changes and heat distribution in real time.

9. The method for enhancing heat exchange by driving bubble flow according to claim 1, characterized in that: A visualization device is provided outside the heat exchange device, and particle image velocimetry and image projection technology are used to analyze the influence of bubbles on the flow field and phase change interface of the PCM.

10. The method for enhancing heat exchange by driving bubble flow according to claim 1, characterized in that: The driving mechanism inside the heat exchange device is a mechanical vibrator, which can produce a fluid dynamic effect and drive the bubbles to be evenly distributed and effectively flow in the heat exchange medium.

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