Method and system for regulating efficiency of mixed convection heat transfer in a non-uniformly heated channel
By adjusting the emissivity, geometry, and temperature characteristics of the inner wall of the non-uniform heating channel, the problem of heat transfer deterioration in mixed convection heat transfer within the non-uniform heating channel was solved, and the heat transfer efficiency was controlled and improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANGHAI JIAOTONG UNIV
- Filing Date
- 2022-12-27
- Publication Date
- 2026-07-03
AI Technical Summary
In existing technologies, mixed convection heat transfer in non-uniform heating channels suffers from heat transfer degradation, which cannot be effectively avoided.
By adjusting the emissivity, absorptivity, geometric properties, and temperature characteristics of the inner wall of the flow channel of the mixed convective fluid, the net radiative heat can be altered to regulate the mixed convective heat transfer efficiency, thereby maintaining, weakening, or eliminating heat transfer degradation.
It effectively controls the heat transfer deterioration phenomenon in mixed convection heat exchange, and maintains, weakens or eliminates heat transfer deterioration as needed, thereby improving heat exchange efficiency.
Smart Images
Figure CN115790251B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the technical field of mixed convection heat transfer, and more specifically, to a method and system for controlling the efficiency of mixed convection heat transfer in a non-uniform heating channel. Background Technology
[0002] A common phenomenon in uniformly heated channels is mixed convective heat transfer, where natural and forced convection coexist. Its characteristic is that when the natural and forced convection flows in the same direction, the near-wall velocity boundary layer of forced convection is accelerated by natural convection. However, due to mass conservation across the same flow cross-section, the velocity decreases at the channel center, resulting in laminarization of the turbulent flow. This leads to a decrease in turbulence intensity, and since heat transfer efficiency is positively correlated with turbulence intensity, therefore... Figure 1 As shown, for forced convection heat transfer, when natural convection is added to form mixed convection, the strengthening of natural convection will lead to a decrease in turbulence intensity, which will further lead to a decrease in the overall heat transfer efficiency until laminar flow is fully developed, at which point a relatively low heat transfer value will appear. After that, when natural convection gradually becomes dominant, the heat transfer efficiency will gradually recover and increase with the strengthening of natural convection, that is, a significant heat transfer deterioration zone will appear.
[0003] Chinese invention patent document CN107513915A discloses a method for intelligently and efficiently controlling the convective heat transfer of roadbed. The method includes the following steps: (1) laying ventilation pipes in the embankment and placing roadbed soil temperature sensors; (2) fixing a central rod to one or both ends of the ventilation pipe wall and fitting a rotating shaft sleeve onto the central rod; (3) fixing a damper to the rotating shaft sleeve; (4) simultaneously installing an intelligent logic controller and an air temperature sensor on the central rod; (5) installing a temperature sensor at the bottom of the ventilation pipe; (6) connecting the intelligent logic controller to the damper; and simultaneously connecting the intelligent logic controller to the air temperature sensor, the temperature sensor, and the roadbed soil temperature sensor respectively; (7) filling and compacting soil on the ventilation pipe and then laying horizontal insulation material, completing the subsequent engineering construction according to conventional technical requirements; (8) controlling the opening or closing of the damper and the degree of opening.
[0004] Regarding the existing technologies mentioned above, the inventors believe that for mixed convection heat transfer in non-uniform heating channels (non-uniformity can mean that the temperatures of each heating surface are different, with some being high and some low, the high-temperature surface being the heating surface, and the low-temperature surface being either the heating surface or the adiabatic surface), the published literature still considers it to basically follow the above-mentioned rules. However, due to the effect of the lower heating temperature surface, the aforementioned heat transfer deterioration zone experiences a lag, meaning that heat transfer deterioration still exists. This heat transfer deterioration phenomenon is a mechanistic characteristic of mixed convection and cannot be avoided. Summary of the Invention
[0005] In view of the deficiencies in the prior art, the purpose of this invention is to provide a method and system for regulating the efficiency of mixed convection heat transfer in a non-uniform heating channel.
[0006] A method for controlling the efficiency of mixed convection heat transfer in a non-uniform heating channel according to the present invention includes the following steps:
[0007] Steps for confirming regulatory targets: Confirm the regulatory targets;
[0008] Control steps: Adjust the mixing convection heat transfer efficiency in the non-uniform heating channel according to the confirmed control target.
[0009] Preferably, in the step of confirming the control target, the control target includes maintaining heat transfer deterioration, reducing heat transfer deterioration, and eliminating heat transfer deterioration.
[0010] Preferably, in the control step, the net radiant heat from the high-temperature heated wall to the low-temperature wall within the flow channel of the mixed convective fluid is:
[0011]
[0012] Where σ represents the Boltzmann constant, BH represents the area of the high-temperature heated wall in the flow channel of the mixed convective fluid, H represents the length in the convective flow direction, B represents the wall width, T1 represents the wall temperature, and ε1 represents the wall emissivity; LH represents the area of the low-temperature wall in the flow channel of the mixed convective fluid, L represents the wall width, T2 represents the wall temperature, and ε2 represents the wall emissivity.
[0013] Preferably, in the step of confirming the control target, the control target is confirmed as maintaining heat transfer deterioration;
[0014] In the control step, the emissivity ε2 of the low-temperature wall surface is reduced; and / or the temperature difference T1-T2 between the high-temperature heated wall surface and the low-temperature wall surface is reduced; and / or the area ratio L / B is reduced.
[0015] This leads to a decrease in the net radiant heat from the high-temperature heated wall surface to the low-temperature wall surface. The total mixed convection heat transfer within the flow channel of the mixed convection fluid is dominated by the mixed convection heat transfer of the heating surface, resulting in a deterioration in heat transfer.
[0016] Preferably, in the step of confirming the control target, the control target is confirmed as reducing heat transfer deterioration;
[0017] In the control step, a preset emissivity ε2 and ε1 are selected; and / or, a preset appropriate temperature difference between the high-temperature heated wall surface and the low-temperature wall surface is selected; and / or, a preset area ratio L / B is selected.
[0018] By superimposing net radiative heat transfer or mixed convective heat transfer on the low-temperature wall surface with mixed convective heat transfer on the high-temperature wall surface, the deterioration of heat transfer is reduced.
[0019] Preferably, in the step of confirming the control target, the control target is confirmed as eliminating heat transfer deterioration;
[0020] In the control step, the emissivity ε2 and ε1 are increased; and / or, a preset temperature difference between the high-temperature heated wall and the low-temperature wall is selected; and / or, a preset area ratio L / B is selected.
[0021] By superimposing the mixing convection effect on the low-temperature wall surface with the mixing heat transfer effect on the high-temperature wall surface, the phenomenon of heat transfer deterioration is eliminated.
[0022] A system for regulating the efficiency of mixed convection heat transfer in a non-uniform heating channel according to the present invention includes the following modules:
[0023] Control target confirmation module: Confirms the control target;
[0024] Control module: Adjusts the mixing convection heat transfer efficiency within the non-uniform heating channel according to the confirmed control target.
[0025] Preferably, in the control target confirmation module, the control target includes maintaining heat transfer deterioration, reducing heat transfer deterioration, and eliminating heat transfer deterioration.
[0026] Preferably, in the control module, the net radiant heat from the high-temperature heated wall to the low-temperature wall within the flow channel of the mixed convective fluid is:
[0027]
[0028] Where σ represents the Boltzmann constant, BH represents the area of the high-temperature heated wall in the flow channel of the mixed convective fluid, H represents the length in the convective flow direction, B represents the wall width, T1 represents the wall temperature, and ε1 represents the wall emissivity; LH represents the area of the low-temperature wall in the flow channel of the mixed convective fluid, L represents the wall width, T2 represents the wall temperature, and ε2 represents the wall emissivity.
[0029] Preferably, in the control target confirmation module, the control target is confirmed as maintaining heat transfer deterioration;
[0030] In the control module, the emissivity ε2 of the low-temperature wall surface is reduced; and / or the temperature difference T1-T2 between the high-temperature heated wall surface and the low-temperature wall surface is reduced; and / or the area ratio L / B is reduced.
[0031] This leads to a decrease in the net radiant heat from the high-temperature heated wall surface to the low-temperature wall surface. The total mixed convection heat transfer within the flow channel of the mixed convection fluid is dominated by the mixed convection heat transfer of the heating surface, resulting in a deterioration in heat transfer.
[0032] Compared with the prior art, the present invention has the following beneficial effects:
[0033] 1. This invention modifies the heat transfer degradation phenomenon in mixed convection heat transfer, which is currently considered unavoidable, by changing the wall characteristics, such as radiation, geometry, and temperature, within the mixed convection heat transfer channel under non-uniform heating conditions.
[0034] 2. This invention can maintain, weaken, or even eliminate heat transfer deterioration as needed;
[0035] 3. By adjusting the temperature difference between the walls, this invention can adjust the offset of the heat transfer deterioration zone on different walls, so that the two deterioration zones are misaligned and superimposed, thereby significantly reducing the total deterioration zone. Attached Figure Description
[0036] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:
[0037] Figure 1 This is a schematic diagram illustrating the heat transfer deterioration that occurs when natural and forced convection are in the same direction under mixed convection.
[0038] Figure 2 A schematic diagram illustrating the retention and disappearance of the heat transfer deterioration zone under different control measures;
[0039] Figure 3 This is a schematic diagram of mixing convection under non-uniform heating conditions;
[0040] Figure 4 This is a schematic diagram showing the offset and superposition of heat transfer deterioration zones on different wall surfaces.
[0041] Figure label:
[0042] Higher temperature heating wall 1 mixed convection fluid 3
[0043] Lower temperature wall surface 2 Detailed Implementation
[0044] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.
[0045] This invention discloses a method for controlling the efficiency of mixed convection heat transfer in a non-uniform heating channel, such as... Figure 2 and Figure 3As shown, in a non-uniformly heated convection channel, there is a temperature difference between the heating surface at a higher temperature and the surface at a lower temperature (between the heating surface and the adiabatic surface). Even if the surface emissivity is the same, there will be net radiative heat transfer between the surfaces at different temperatures. That is, considering the radiative heat transfer between the surfaces in the channel, the high-temperature surface will still have a net radiative heat outflow to the low-temperature surface, while the low-temperature surface will have a net radiative heat inflow.
[0046] Higher and lower temperatures refer to the comparison of the wall temperatures within the convection channel, such as 70 degrees Celsius versus 30 degrees Celsius. These can be referred to as higher and lower temperatures respectively. High and low temperatures are relative concepts; wall temperatures can vary greatly in different application environments, ranging from tens to hundreds of degrees Celsius, yet this invention remains applicable. The focus of this invention is on the existence of varying temperatures on different walls within the same channel.
[0047] When a convective heat transfer fluid, such as air, flows through a channel, the air is almost transparent to thermal radiation, so the airflow can only carry away the heat in the channel through the convective heat transfer. Therefore, the net radiative heat flowing into the low-temperature surface must also be carried away by the air through mixed convection.
[0048] The total mixed convection heat transfer in the non-uniform heating channel is the superposition of the mixed convection heat transfer on the high-temperature heating wall and the mixed convection heat transfer on the low-temperature wall. The mixed convection heat transfer on the low-temperature wall, that is, the net radiative heat transfer from the high-temperature heating surface to the low-temperature heating surface (or the non-heated surface (insulating surface)), is controlled by the radiation characteristics such as the emissivity and absorptivity of the high-temperature and low-temperature heating surfaces, the surface geometry, and the surface temperature (as shown in Equation (1)).
[0049] This application proposes that the net radiative heat can be altered by changing the surface radiation characteristics of the convective heat transfer wall, such as the emissivity and absorptivity, through methods like changing the wall material or surface coating, or by adjusting the wall geometry and wall temperature, thereby ultimately changing the mixed convective heat transfer characteristics. Figure 2 As shown, this can weaken or even eliminate the heat transfer degradation phenomenon in mixed convection heat transfer.
[0050] In short, the present invention can change the wall characteristics, such as radiation, geometry, and temperature, in a mixed convection heat transfer channel under non-uniform heating conditions through the following specific steps, thereby controlling the heat transfer deterioration phenomenon that is currently considered unavoidable in mixed convection heat transfer, and can maintain, weaken, or even eliminate the heat transfer deterioration phenomenon as needed.
[0051] like Figure 3 As shown, for a mixed convective fluid, the higher-temperature heated wall in its flow channel has an area of BH, where H is the length in the convective flow direction, B is the wall width, and the wall temperature is the higher temperature T. 1，The wall emissivity is ε1; for the lower-temperature wall, the area is LH, where L is the wall width, the wall temperature is the lower temperature T2, and the wall emissivity is ε2; simplifying by assuming that the wall absorptivity and emissivity are the same, the net radiative heat from the higher-temperature heated wall to the lower-temperature wall can be expressed as follows:
[0052]
[0053] Where σ is the Boltzmann constant.
[0054] Figure 3 The diagram shows four walls, one labeled as the high-temperature heating surface and three as low-temperature surfaces. However, in actual applications, the distribution of high-temperature and low-temperature surfaces varies. For example, there may be two high-temperature surfaces and two low-temperature surfaces (they may be adjacent or opposite to each other); or three high-temperature surfaces and one low-temperature surface; or a circular pipe with a portion of its area being high-temperature and a portion being low-temperature; and there may also be multiple high-temperature surfaces with different higher temperatures T1 and T2, and multiple low-temperature surfaces with different lower temperatures T3 and T4.
[0055] The adjustment steps are as follows:
[0056] Analysis of the application of mixed convection revealed the following control objectives: 1.1 Maintaining heat transfer degradation; 1.2 Reducing heat transfer degradation; 1.3 Eliminating heat transfer degradation. For example, when using mixed convection to remove heat and ensure the wall temperature remains below safe limits, option 1.2 or 1.3 can be selected to suppress or eliminate heat transfer degradation, improve heat transfer efficiency, and ensure the wall temperature meets safety requirements. However, in the application environment of insulation surfaces, it is necessary to reduce the efficiency of wall surface mixed heat exchange to prevent excessive heat dissipation and increased energy consumption. In this case, option 1.1 can be selected to maintain the heat transfer degradation characteristics and meet insulation requirements.
[0057] For objective 1.1:
[0058] 2.1 The emissivity ε2 of the lower temperature wall surface can be adjusted (adjustment range 0-1);
[0059] 2.2 The temperature difference between the higher-temperature heated wall surface and the lower-temperature wall surface can be reduced. The adjustment range is >0. The specific value can be selected according to the application background.
[0060] 2.3 The area ratio L / B can be adjusted down, with an adjustment range > 0. The specific value can be selected based on the application background.
[0061] 2.4 Since the radiative heat transfer between walls is proportional to the emissivity, temperature difference, and area ratio L / B, reducing any one of these three factors or a combination of two or three factors to extremely low values will also drastically reduce the net radiative heat transfer between the aforementioned walls.
[0062] 2.5 At this time, the total mixed convection heat transfer in the channel is only dominated by the mixed convection heat transfer on the heating surface, and the heat transfer deterioration phenomenon is the same as that in the single-sided or uniformly heated channel. Figure 1 Phenomenon is the same.
[0063] For the control target 1.2:
[0064] 3.1 Select appropriate emissivities ε2 and ε1 (adjustment range: 0 - 1);
[0065] 3.2 Select an appropriate temperature difference between the higher-temperature heating wall and the lower-temperature wall, adjustment range > 0, and the specific value can be selected in combination with the application background;
[0066] 3.3 Select an appropriate area ratio L / B, adjustment range > 0, and the specific value can be selected in combination with the application background;
[0067] 3.4 Optionally adjust any one or a combination of two to three of the above to superimpose the net radiative heat transfer or the mixed convection heat transfer on the low-temperature wall with the mixed convection heat transfer on the high-temperature wall. Due to the existence of the wall temperature difference, when the heat transfer deterioration zones on the low-temperature and high-temperature walls are shown in the same figure, the two heat transfer deterioration zones will shift because the dimensionless Rayleigh number Ra in the abscissa is controlled by different wall temperatures T. Then, by adjusting the wall temperature difference, the shift amplitude can be adjusted. That is, for the heat transfer deterioration extreme point a corresponding to the higher-temperature heating wall, it appears at Ra(T1) Figure 4 / Re(T 0.33 ) f ) 0.8 Pr(T [[ID=2)6]] f ) 0.4 , where the dimensionless Reynolds number Re and Prandtl number Pr depend on the convective fluid temperature T f , since the corresponding low-temperature wall T2 < T1 at this time, it is necessary to wait for the natural convection to continue to strengthen until the heat transfer deterioration point b on the low-temperature wall is reached, so that Ra(T2) 0.33 / Re(T f ) 0.8 Pr(T f ) 0.4 | b = Ra(T1) 0.33 / Re(T f ) 0.8 Pr(T f ) 0.4 |a, it can be seen that the shift amplitude of the two heat transfer deterioration points can be calculated by the following formula: Ra(T1) 0.33 / Re(T f ) 0.8 Pr(T f ) 0.4 | b - Ra(T1) 0.33 / Re(T f ) 0.8 Pr(T f ) 0.4 |a. The corresponding lower-temperature wall surfaces cause the two deterioration zones to shift and overlap, thereby significantly reducing the total deterioration zone.
[0068] Emissivity is the preferred adjustment item and can generally be adjusted; however, whether temperature difference and wall-to-wall ratio can be adjusted, and the range of adjustment, varies depending on the application.
[0069] Regarding regulation target 1.3:
[0070] 4.1 Maximize emissivity ε2 and ε1 (adjustable within the range of 0-1);
[0071] 4.2 An appropriate temperature difference between the higher-temperature heating wall and the lower-temperature wall can be selected, with an adjustment range > 0. The specific value can be selected based on the application background.
[0072] 4.3 An appropriate area ratio L / B can be selected, with an adjustment range > 0. The specific value can be selected based on the application background.
[0073] 4.4 Any one of the above three options or a combination of 2-3 options can be selected for adjustment so that the mixing convection effect on the low-temperature wall surface and the mixing heat transfer effect on the high-temperature wall surface are superimposed, thereby eliminating the deterioration phenomenon to the greatest extent.
[0074] The present invention also provides a system for regulating the mixed convection heat transfer efficiency in a non-uniform heating channel. The system for regulating the mixed convection heat transfer efficiency in a non-uniform heating channel can be implemented by executing the process steps of the method for regulating the mixed convection heat transfer efficiency in a non-uniform heating channel. That is, those skilled in the art can understand the method for regulating the mixed convection heat transfer efficiency in a non-uniform heating channel as a preferred embodiment of the system for regulating the mixed convection heat transfer efficiency in a non-uniform heating channel.
[0075] The control system includes the following modules:
[0076] Control Target Confirmation Module: Confirms the control targets. Control targets include maintaining heat transfer degradation, mitigating heat transfer degradation, and eliminating heat transfer degradation.
[0077] Control module: Adjusts the mixing convection heat transfer efficiency within the non-uniform heating channel according to the confirmed control target.
[0078] The net radiant heat from the higher-temperature heated wall to the lower-temperature wall within the flow channel of the mixed convective fluid is:
[0079]
[0080] Where σ represents the Boltzmann constant, BH represents the area of the higher-temperature heated wall in the flow channel of the mixed convective fluid, H represents the length in the convective flow direction, B represents the wall width, T1 represents the wall temperature, and ε1 represents the wall emissivity; LH represents the area of the lower-temperature wall in the flow channel of the mixed convective fluid, L represents the wall width, T2 represents the wall temperature, and ε2 represents the wall emissivity.
[0081] In the control target confirmation module, the control target is confirmed as maintaining heat transfer deterioration.
[0082] In the control module, the emissivity ε2 of the lower temperature wall surface is reduced; and / or the temperature difference T1-T2 between the higher temperature heated wall surface and the lower temperature wall surface is reduced; and / or the area ratio L / B is reduced; thereby reducing the net radiative heat from the higher temperature heated wall surface to the lower temperature wall surface, and the total mixed convection heat transfer in the flow channel of the mixed convection fluid is dominated by the mixed convection heat transfer of the heating surface, resulting in heat transfer deterioration.
[0083] Those skilled in the art will understand that, besides implementing the system and its various devices, modules, and units provided by this invention in the form of purely computer-readable program code, the same functions can be achieved entirely through logical programming of the method steps, making the system and its various devices, modules, and units of this invention function in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers. Therefore, the system and its various devices, modules, and units provided by this invention can be considered as a hardware component, and the devices, modules, and units included therein for implementing various functions can also be considered as structures within the hardware component; alternatively, the devices, modules, and units for implementing various functions can be considered as both software modules implementing the method and structures within the hardware component.
[0084] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.
Claims
1. A method for controlling the efficiency of mixed convection heat transfer in a non-uniform heating channel, characterized in that, Includes the following steps: Control target confirmation steps: Confirm the control target, which includes maintaining heat transfer degradation, reducing heat transfer degradation, and eliminating heat transfer degradation; Control steps: Based on the confirmed control target, control the net radiant heat of the convective heat transfer wall in the non-uniform heating channel, thereby changing the mixed convective heat transfer efficiency. By adjusting the wall temperature difference, the offset of the heat transfer deterioration zone on different wall surfaces is adjusted so that the two deterioration zones are misaligned and superimposed, thereby significantly reducing the total deterioration zone. In the aforementioned control step, the net radiant heat from the high-temperature heated wall to the low-temperature wall within the flow channel of the mixed convective fluid is: （1） in, BH represents the Boltzmann constant, and BH represents the area of the high-temperature heated wall within the flow channel of the mixed convective fluid. H Indicates the length in the direction of convective flow. B Indicates the width of the wall. T 1 represents the wall temperature. Indicates the wall emissivity; LH This represents the area of the low-temperature wall within the flow channel of the mixed convective fluid. L Indicates the wall width. T 2 indicates the wall temperature. This indicates the wall emissivity.
2. The method for controlling the efficiency of mixed convection heat transfer in a non-uniform heating channel according to claim 1, characterized in that, In the step of confirming the control target, the control target is confirmed to be to maintain heat transfer deterioration; In the control step, the emissivity of the low-temperature wall is reduced. ; and / or, reduce the temperature difference between the high-temperature heated wall surface and the low-temperature wall surface. T 1- T 2; and / or, lower the area ratio L / B; This leads to a decrease in the net radiant heat from the high-temperature heated wall to the low-temperature wall. The total mixed convection heat transfer within the flow channel of the mixed convection fluid is dominated by the mixed convection heat transfer of the high-temperature heated surface, resulting in a deterioration in heat transfer.
3. The method for controlling the efficiency of mixed convection heat transfer in a non-uniform heating channel according to claim 1, characterized in that, In the step of confirming the control target, the control target is confirmed to be to reduce heat transfer deterioration; In the control step, a preset emissivity is selected. ; and / or, select a preset temperature difference between a high-temperature heated wall surface and a low-temperature wall surface of appropriate size; and / or, select a preset area ratio L / B; By superimposing net radiative heat transfer or mixed convective heat transfer on the low-temperature wall surface with mixed convective heat transfer on the high-temperature wall surface, the deterioration of heat transfer is reduced.
4. The method for controlling the efficiency of mixed convection heat transfer in a non-uniform heating channel according to claim 1, characterized in that, In the step of confirming the control target, the control target is confirmed to be the elimination of heat transfer deterioration; In the control step, the emissivity is increased. ; and / or, select a preset size for the temperature difference between the high-temperature heating wall and the heated surface wall; and / or, select a preset size for the area ratio L / B; By superimposing the mixing convection effect on the low-temperature wall surface with the mixing heat transfer effect on the high-temperature wall surface, the phenomenon of heat transfer deterioration is eliminated.
5. A system for regulating the efficiency of mixed convection heat transfer in a non-uniform heating channel, characterized in that, Includes the following modules: Control target confirmation module: confirms the control target, which includes maintaining heat transfer degradation, reducing heat transfer degradation, and eliminating heat transfer degradation; Control module: Based on the confirmed control target, it controls the net radiant heat of the convective heat transfer wall in the non-uniform heating channel, thereby changing the mixed convective heat transfer efficiency. By adjusting the wall temperature difference, the offset of the heat transfer deterioration zone on different wall surfaces is adjusted so that the two deterioration zones are misaligned and superimposed, thereby significantly reducing the total deterioration zone. In the control module, the net radiant heat from the high-temperature heated wall to the low-temperature wall within the flow channel of the mixed convective fluid is: （1） in, BH represents the Boltzmann constant, and BH represents the area of the high-temperature heated wall within the flow channel of the mixed convective fluid. H Indicates the length in the direction of convective flow. B Indicates the wall width. T 1 represents the wall temperature. Indicates the wall emissivity; LH This represents the area of the low-temperature wall within the flow channel of the mixed convective fluid. L Indicates the wall width. T 2 indicates the wall temperature. This indicates the wall emissivity.
6. The system for regulating the efficiency of mixed convection heat transfer in a non-uniform heating channel according to claim 5, characterized in that, In the control target confirmation module, the control target is confirmed to be to maintain heat transfer deterioration; In the control module, the emissivity of the low-temperature wall surface is reduced. ; and / or, reduce the temperature difference between the high-temperature heated wall surface and the low-temperature wall surface. T 1- T 2; and / or, lower the area ratio L / B; This leads to a decrease in the net radiant heat from the high-temperature heated wall surface to the low-temperature wall surface. The total mixed convection heat transfer within the flow channel of the mixed convection fluid is dominated by the mixed convection heat transfer of the heating surface, resulting in a deterioration in heat transfer.