A high-efficiency impinging jet heat exchange method using back pressure effect for energy saving and emission reduction

Abstract

The present application relates to a kind of high-efficiency impact jet heat exchange method for energy saving and emission reduction using back pressure effect, which is based on jet speed measuring experimental device, the jet speed measuring experimental device includes support, fan, PIV system and glass plate, comprising the following steps: S1, the establishment of physical model, the division of grid, the setting of boundary condition and the setting of working condition parameter, using computational fluid dynamics (CFD) solver to study the back pressure distribution in the flow field when the Reynolds number (Re) range is 3462-6125 and the normalized spacing H / D is 0.25, and the simulation data curve is obtained;The present application can save the physical space of cooling process when in use, greatly reduce the energy consumption cost and exhaust emission of electricity, and further greatly improve the heat exchange efficiency, therefore, the reasonable use of back pressure effect saves the production cost of enterprise, also improves productivity while achieving the effect of energy saving and emission reduction, avoids the problems of low heat exchange efficiency and low energy utilization rate of existing cooling process.

Description

Technical Field

[0001] This invention relates to a highly efficient impingement jet heat exchange method that utilizes back pressure effect to save energy and reduce emissions. Background Technology

[0002] For large-sized target plates requiring rapid cooling, such as flat glass and engine blades, the actual production process necessitates significant energy consumption from fans to achieve rapid cooling, severely depleting my country's limited energy resources. Therefore, addressing the problems of high energy consumption and low heat exchange efficiency in cooling processes is urgently needed. This invention addresses these problems by proposing a highly efficient impingement jet heat exchange method that utilizes back pressure effects for energy saving and emission reduction. Summary of the Invention

[0003] The technical problem to be solved by this invention is: in order to solve the problem that existing cooling processes have low heat exchange efficiency and low energy utilization, a high-efficiency impingement jet heat exchange method that utilizes back pressure effect to save energy and reduce emissions is provided.

[0004] The technical solution adopted by the present invention to solve its technical problem is: a high-efficiency impingement jet heat exchange method that utilizes back pressure effect for energy saving and emission reduction. The method is based on a jet velocity measurement experimental device, which includes a support, a fan, a PIV system and a glass plate.

[0005] The support is equipped with an air chamber that can move up and down. The air chamber and the glass plate are arranged opposite each other. The air chamber is connected to the fan through the upper and lower main air inlet pipes. The upper end of the air chamber is equipped with an air hole plate with air holes. An observation area is formed between the glass plate and the air hole plate. The distance from the air hole to the glass plate is H, and the diameter of the air hole is D. The left and right sides of the observation area are respectively formed by the feed inlet and the discharge outlet.

[0006] The PIV system is located outside the observation area and is used to align with the observation area to capture images of the observation area. It is characterized by the following steps:

[0007] S1. The physical model was established, the mesh was generated, the boundary conditions were set, and the operating parameters were set. A computational fluid dynamics (CFD) solver was used to study the back pressure distribution in the flow field when the Reynolds number (Re) ranged from 3462 to 6125 and the normalized spacing H / D was 0.25. The back pressure distribution cloud map of the flow field near the vent was obtained.

[0008] S2. The physical model was established, the mesh was generated, the boundary conditions were set, and the operating parameters were defined. A computational fluid dynamics (CFD) solver was used to study the axial velocity distribution at the outlet of the vent and the tangential velocity distribution near the wall of the glass plate near the vent when the Reynolds number (Re) ranged from 3462 to 6125 and the normalized spacing H / D was 0.25 to 1.25. Numerical simulation curves were obtained.

[0009] S3. Conduct experiments using a jet velocity measurement experimental device and obtain experimental results using particle image velocimetry (PIV), and verify step S2.

[0010] S4. Computational fluid dynamics (CFD) is used to simulate the quenching of the glass plate at high temperature to obtain simulation results, which are then verified with the experimental results in step S3.

[0011] In some preferred embodiments, step S1 specifically includes the following steps:

[0012] S1.1 Establish a physical model of the impact jet. The lower part is the fluid domain, and the upper part is the solid domain with glass plate as the constituent material. Air impacts the glass plate vertically through the pores of the pore plate.

[0013] S1.2. Mesh the computational domain and refine the mesh for the fluid domain and the glass plate region;

[0014] S1.3 Set boundary conditions, including air being injected at different mass flow rates, inlet temperature set to 298K, turbulence intensity set to 5%, the inner wall of the fluid domain being adiabatic with no slippage, the flow outlet being designated as a pressure outlet, the pressure at the flow outlet being consistent with the ambient pressure, the lower surface of the glass plate being designated as a fluid-structure interaction boundary condition, and the rest being designated as convective heat transfer coefficient boundary conditions.

[0015] S1.4 Set the normalized spacing H / D to 0.25, and the Reynolds number (Re) to 3462, 5326 and 6125 respectively. Calculate the back pressure in the flow field and obtain the back pressure distribution cloud map near the vent.

[0016] In some preferred embodiments, step S2 specifically includes the following steps:

[0017] S2.1 Establish a physical model of the impact jet. The lower part is the fluid domain, and the upper part is the solid domain with glass plate as the constituent material. Air impacts the glass plate vertically through the pores of the pore plate.

[0018] S2.2. Mesh the computational domain and refine the mesh for the fluid domain and the glass plate region;

[0019] S2.3 Set boundary conditions, including air being injected at different mass flow rates, inlet temperature set to 298K, turbulence intensity set to 5%, the inner wall of the fluid domain being adiabatic with no slippage, the flow outlet being designated as a pressure outlet, the pressure at the flow outlet being consistent with the ambient pressure, the lower surface of the glass plate being designated as a fluid-structure interaction boundary condition, and the rest being designated as convective heat transfer coefficient boundary conditions.

[0020] S2.4 Set the normalized spacing H / D to 0.25-1.25, and the Reynolds number (Re) to 3462, 5326 and 6125 respectively. Calculate the axial velocity distribution at the vent outlet and the tangential velocity distribution near the glass plate wall near the vent, and obtain the numerical simulation curve.

[0021] In some preferred embodiments, the implementation steps of the jet velocity measurement experimental device in step S3 are as follows:

[0022] S3.1 Adjust the normalized spacing H / D to 0.25;

[0023] S3.2 Adjust the relative positions of the air chamber and the glass plate to form an observation area;

[0024] S3.3 Adjust the PIV system according to the observation area range to determine the optimal shooting position of the PIV digital camera and the laser sheet light of the PIV system. The laser sheet light is perpendicular to the vent plate and passes through the line connecting the center of the vent outlet.

[0025] S3.4. Turn on the fan and control the gas flow rate and tracer particle concentration;

[0026] S3.5 After the airflow pressure is uniform and the tracer particles are fully mixed, the jet region with a normalized spacing H / D = 0.25 is photographed, and the flow velocity data is calculated and obtained.

[0027] S3.6 Adjust the normalized spacing H / D to 0.5, 0.75, 1 and 1.25 respectively, and repeat steps S3.2-S3.5;

[0028] S3.7 Experimental results of normalized tangential velocity with normalized spacing H / D of 0.25-1.25 under Reynolds number (Re) of 3462-6125.

[0029] S3.8. Based on the experimental results, for jets at different Reynolds numbers (Re), the axial velocity at the outlet of the vent and the tangential velocity near the wall of the glass plate near the vent were extracted under different normalized spacing H / D, and the incident flow velocity V was used as the basis for these results. m Normalization processing;

[0030] S3.9 Extract the maximum tangential velocity Umax of the fluid under different Reynolds numbers (Re) and different normalized spacing H / D, obtain the relationship between the normalized maximum tangential velocity Umax / Vm and the normalized spacing H / D, and find that the normalized maximum tangential velocity curve near the wall of the glass plate has an inflection point of normalized spacing H / D = 0.4, and it is independent of the Reynolds number (Re);

[0031] S3.10 Extract the normalized axial velocity V at the pore outlet under different Reynolds numbers (Re) and different normalized spacing H / D.e / V m The experimental data curves in step S3 are compared with the numerical simulation curves in step S2, and the correctness of the numerical simulation model is verified.

[0032] In some preferred embodiments, the simulation step of quenching the glass plate at high temperature in step S4 is as follows:

[0033] S4.1 Establish a physical model of the impact jet. The lower part is the fluid domain, and the upper part is the solid domain with glass plate as the constituent material. Air impacts the glass plate vertically through the pores of the pore plate.

[0034] S4.2. Mesh the computational domain and refine the mesh for the fluid domain and the glass plate region;

[0035] S4.3 Set boundary conditions, including air being injected at different mass flow rates, inlet temperature set to 298K, turbulence intensity set to 5%, the inner wall of the fluid domain being adiabatic with no slippage, the flow outlet being designated as a pressure outlet, the pressure at the flow outlet being consistent with the ambient pressure, the lower surface of the glass plate being designated as a fluid-structure interaction boundary condition, and the rest being designated as convective heat transfer coefficient boundary conditions.

[0036] S4.4 The initial temperature of the glass plate is set to 953K. The normalized spacing H / D is set to 0.25, 0.5, 0.75, 1 and 1.25 respectively. The Reynolds number (Re) is 3462, 5326 and 6125. The tangential velocity of the fluid near the wall of the glass plate is calculated and the simulation results of the distribution of the normalized tangential velocity along the near wall are obtained.

[0037] S4.5. Verify the simulation results with the experimental results from step S3 to prove that the back pressure effect greatly reduces energy consumption and significantly shortens the cooling time.

[0038] The beneficial effects of this invention are as follows: When using the high-efficiency impingement jet heat exchange method that utilizes the back pressure effect for energy saving and emission reduction, this invention can save physical space in the cooling process, greatly reduce energy consumption costs such as electricity and exhaust emissions, and thus significantly improve heat exchange efficiency. Therefore, the rational use of the back pressure effect saves production costs for enterprises and achieves energy saving and emission reduction while improving productivity, avoiding the problems of low heat exchange efficiency and low energy utilization rate of existing cooling processes. Attached Figure Description

[0039] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0040] Figure 1 This invention compares the back pressure distribution in the flow field under the normalized spacing H / D of 0.25 and Reynolds number (Re) of 3462-6125.

[0041] Figure 2 This invention compares numerical simulation and experimental data on the radial distribution of the normalized axial velocity at the nozzle outlet under the conditions of a Reynolds number (Re) of 6125 and a normalized spacing H / D of 0.25-1.25.

[0042] Figure 3 The present invention is the distribution of normalized tangential velocity along the plate wall obtained experimentally under the condition that the normalized spacing H / D is 0.25-1.25 and the Reynolds number (Re) is 3462-6125.

[0043] Figure 4 This invention extracts the maximum tangential velocity of the fluid under different nozzle-plate spacings for jets at different Reynolds numbers (Re), and obtains the relationship between the normalized maximum tangential velocity of the fluid and the normalized spacing H / D.

[0044] Figure 5 The present invention is a simulation of the distribution of normalized tangential velocity along the plate wall under the condition that the normalized spacing H / D is 0.25-1.25 and the Reynolds number (Re) is 3462-6125.

[0045] Figure 6 This invention presents the curves showing the decrease in average temperature of the impact surface of a high-temperature glass plate with quenching time under different normalized spacing H / D. Detailed Implementation

[0046] The present invention will be further described in detail below with reference to the embodiments:

[0047] This invention is not limited to the specific embodiments listed below. Those skilled in the art can implement this invention using various other specific embodiments based on the content disclosed herein. Any modifications or alterations made to the design structure and concept of this invention fall within the protection scope of this invention. It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.

[0048] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0049] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0050] A highly efficient impingement jet heat exchange method utilizing back pressure effect for energy saving and emission reduction is proposed. This method is based on a jet velocity measurement experimental device, which includes a support frame, a fan, a PIV system, and a glass plate.

[0051] The support frame is equipped with an air chamber that can move up and down. The air chamber and the glass plate are arranged opposite each other. The air chamber is connected to the fan through the upper and lower main air inlet pipes. The upper end of the air chamber is equipped with an air vent plate with air holes. An observation area is formed between the glass plate and the air vent plate. The distance from the air hole to the glass plate is H, and the diameter of the air hole is D. The left and right sides of the observation area are respectively formed by the feed inlet and the discharge outlet.

[0052] The PIV system is located outside the observation area and is used to align with the observation area to capture images of the observation area, including the following steps:

[0053] S1. The physical model was established, the mesh was generated, the boundary conditions were set, and the operating parameters were defined. A computational fluid dynamics (CFD) solver was used to study the back pressure distribution in the flow field when the Reynolds number (Re) ranged from 3462 to 6125 and the normalized spacing H / D was 0.25. The simulation data curves were obtained. The specific steps are as follows:

[0054] S1.1 Establish a physical model of the impact jet. The lower part is the fluid domain, and the upper part is the solid domain with glass as the constituent material. Air impacts the glass plate vertically through the pores of the pore plate.

[0055] S1.2. Mesh the computational domain and refine the mesh for the fluid domain and the glass plate region;

[0056] S1.3 Set boundary conditions, including air being injected at different mass flow rates, inlet temperature set to 298K, turbulence intensity set to 5%; the inner wall of the fluid domain is adiabatic and has no slippage; the flow outlet is specified as a pressure outlet, and the pressure at the flow outlet is consistent with the ambient pressure; the lower surface of the glass plate is specified as a fluid-structure interaction boundary condition, and the rest are specified as convective heat transfer coefficient boundary conditions.

[0057] S1.4 Set the normalized spacing H / D to 0.25, and the Reynolds number (Re) to 3462, 5326 and 6125 respectively. Calculate the back pressure in the flow field and obtain the back pressure distribution cloud map near the vent.

[0058] according to Figure 1 The results show that, under the same normalized spacing H / D of 0.25, the flow field generates significant back pressure, regardless of the Reynolds number (Re). As the Reynolds number (Re) increases, the flow field is more significantly affected by back pressure; that is, the higher the incident wind speed and the higher the Reynolds number (Re), the greater the back pressure.

[0059] S2. The physical model was established, the mesh was generated, boundary conditions were set, and operating parameters were defined. A computational fluid dynamics (CFD) solver was used to study the axial velocity distribution at the vent outlet and the tangential velocity distribution near the glass plate wall near the vent when the Reynolds number (Re) ranged from 3462 to 6125 and the normalized spacing H / D was 0.25 to 1.25. Numerical simulation curves were obtained. The specific operation steps are as follows:

[0060] S2.1 Establish a physical model of the impact jet. The lower part is the fluid domain, and the upper part is the solid domain with glass plate as the constituent material. Air impacts the glass plate vertically through the pores of the pore plate.

[0061] S2.2. Mesh the computational domain and refine the mesh for the fluid domain and the glass plate region;

[0062] S2.3 Set boundary conditions, including air being injected at different mass flow rates, inlet temperature set to 298K, turbulence intensity set to 5%, the inner wall of the fluid domain being adiabatic with no slippage, the flow outlet being designated as a pressure outlet, the pressure at the flow outlet being consistent with the ambient pressure, the lower surface of the glass plate being designated as a fluid-structure interaction boundary condition, and the rest being designated as convective heat transfer coefficient boundary conditions.

[0063] S2.4 Set the normalized spacing H / D to 0.25-1.25, and the Reynolds number (Re) to 3462, 5326 and 6125 respectively. Calculate the axial velocity distribution at the vent outlet and the tangential velocity distribution near the glass plate wall near the vent, and obtain the numerical simulation curve.

[0064] The numerical simulation steps are the same as step S1, except that the distance H / D between the pore and the plate is set to 0.25-1.25, and the Reynolds number (Re) is set to 3462-6125. The axial velocity at the pore outlet and the tangential velocity near the wall of the glass plate near the pore are calculated.

[0065] according to Figure 2 The left figure (CFD plot) shows that as the normalized spacing H / D decreases, the velocity at the stagnation point (x / D = 0) exhibits a dip, with a maximum value near the stagnation point boundary. Comparison shows that the velocity distribution at a normalized spacing H / D = 0.25 differs from other confined heights, with the velocity at the stagnation point decaying to a trough (approximately 0.65V) at the jet centerline. m The peak velocity at the vent outlet boundary (|x / D|=0.5) is approximately 1.4V. m This far exceeds the maximum value of other restricted heights (approximately 1.1V). m This is because the presence of the glass plate generates a significant back pressure within the flow field. This back pressure then acts on the fluid, affecting the velocity distribution at the jet outlet and causing a velocity surge at the orifice outlet boundary, thus creating the back pressure effect. Figure 1 and Figure 2 The back pressure distribution curve is basically consistent with the velocity distribution curve, which verifies the existence of the back pressure effect.

[0066] S3. Experiments were conducted using a jet velocimetry experimental setup and particle image velocimetry (PIV) to obtain experimental results, thus verifying step S2. The specific experimental steps for implementing this method are as follows:

[0067] S3.1 Adjust the normalized spacing H / D to 0.25;

[0068] S3.2 Adjust the relative position of the air chamber and the glass plate to form an observation area;

[0069] S3.3 Adjust the PIV system according to the observation area to determine the optimal shooting position of the PIV digital camera and the laser sheet light. The laser sheet light should be perpendicular to the vent plate and pass through the line connecting the centers of the vent outlets.

[0070] S3.4. Turn on the fan and control the gas flow and tracer particle concentration by adjusting the valve opening.

[0071] S3.5 After the airflow pressure is uniform and the tracer particles are fully mixed, the jet region with a normalized spacing H / D = 0.25 is photographed, and the flow velocity data is calculated and obtained.

[0072] S3.6 Adjust the normalized spacing H / D to 0.5, 0.75, 1, 1.25, and repeat steps S3.2-S3.5;

[0073] S3.7, Based on comparison Figure 3 Experimental results on normalized tangential velocities under Reynolds number (Re) conditions of 3462-6125 and H / D of 0.25-1.25 show that, regardless of the Reynolds number (Re), the maximum tangential velocity at the vent outlet boundary (|x / D|=0.5) always occurs at H / D=0.25. Therefore, this phenomenon can be concluded that it is only related to the restricted normalized spacing H / D; in other words, the back pressure effect is independent of the Reynolds number (Re).

[0074] S3.8. Based on the experimental results, for jets at different Reynolds numbers (Re), the axial velocity at the outlet of the vent and the tangential velocity near the wall of the glass plate near the vent were extracted under different normalized spacing H / D, such as... Figure 4 and the incident flow velocity V m Normalization processing;

[0075] S3.9. Within the entire dimensionless normalized spacing H / D range, there exists a definite value. The maximum tangential velocity of the fluid under different Reynolds numbers (Re) and different normalized spacing H / D is extracted. The relationship between the normalized maximum tangential velocity Umax / Vm and the normalized spacing H / D is obtained. It is also found that the normalized maximum tangential velocity curve Umax / Vm near the wall of the glass plate has an inflection point. The normalized spacing H / D = 0.4. This value is the turning point of the fluid velocity change and the quenching time change, and it is independent of the Reynolds number (Re).

[0076] S3.10. Based on the experimental results, for jets at different Reynolds numbers (Re), the normalized axial velocity V at the outlet of the vent was extracted under different normalized spacing H / D. e / V m Compare the experimental data curve in step S3 with the numerical simulation curve in step S2, such as... Figure 2 And verify the correctness of the numerical model.

[0077] S4. Computational fluid dynamics (CFD) is used to simulate the quenching of the glass plate at high temperature. The simulation results are then verified with the experimental results from step S3. The specific operation steps are as follows:

[0078] S4.1 Establish a physical model of the impact jet. The lower part is the fluid domain, and the upper part is the solid domain with glass as the constituent material. Air impacts the glass plate vertically through the pores of the pore plate.

[0079] S4.2. Mesh the computational domain and refine the mesh for the fluid domain and the glass plate region;

[0080] S4.3 Set boundary conditions, including air being injected at different mass flow rates, inlet temperature set to 298K, turbulence intensity set to 5%; the walls within the fluid domain are adiabatic with no slippage; the flow outlet is specified as a pressure outlet, with the pressure at the flow outlet being the same as the ambient pressure; the lower surface of the glass plate is specified as a fluid-structure interaction boundary condition, and the rest are specified as convective heat transfer coefficient boundary conditions.

[0081] S4.4 The initial temperature of the glass plate is set to 953K. The normalized spacing H / D is set to 0.25, 0.5, 0.75, 1, 1.25 in sequence. The Reynolds number (Re) is 3462, 5326, 6125. The tangential velocity of the fluid near the wall of the glass plate is calculated, and the simulation results of the distribution of the normalized tangential velocity along the near wall are obtained.

[0082] S4.5. Verify the simulation results with the experimental results from step S3 to prove that the back pressure effect greatly reduces energy consumption and significantly shortens the cooling time.

[0083] according to Figure 5 The results show that after the fluid is ejected from the vent and impacts the glass plate, the tangential velocity U remains zero at the stagnation point and increases radially, reaching a maximum near the vent outlet boundary (|x / D|=0.5) on the section adjacent to the boundary layer of the impact plate. Comparative results indicate that only the tangential velocity distribution at the normalized spacing H / D=0.25 differs from the tangential velocity distribution at other confined heights. Figure 5 As shown, when the normalized spacing H / D = 0.25, the tangential velocity has a maximum value near the vent outlet boundary (|x / D| = 0.5), which far exceeds the maximum value at the vent outlet boundary at other confined heights, reaching several times the vent incident velocity (approximately 1.0V). m -1.5V m The phenomenon described is only related to the restricted normalized spacing H / D, indicating that the back pressure effect is independent of the Reynolds number (Re).

[0084] comprehensive Figure 3 and Figure 5 The experimental results are consistent with the simulation results, and the experiment and simulation mutually verify each other.

[0085] comprehensive Figure 2 , Figure 3 and Figure 5The velocity of the fluid at the vent outlet boundary increases dramatically as the fluid flow space is compressed. This is the back pressure effect. When the dimensionless normalized spacing H / D < 0.4, the outflow velocity at the jet centerline decreases sharply under the back pressure effect. According to the law of conservation of mass, the outflow velocity at the vent outlet boundary increases dramatically, which leads to a sharp increase in the tangential velocity near the vent outlet boundary after impacting the glass plate surface. The value can increase to several times the airflow injection velocity, thereby greatly improving the heat transfer capacity of the impact surface.

[0086] according to Figure 6 The results show that the smaller the normalized spacing H / D, the steeper the decrease in the average temperature of the glass plate impact surface. In other words, the steeper the slope of the curve, the faster the cooling rate of the impact plate surface. This indicates that back pressure promotes the flow velocity in the flow field to exceed the actual inlet velocity, thereby enhancing the jet heat transfer capability. Figure 6 With a cooling time of 4 seconds, the surface temperature of the glass plate, which has the same initial temperature, is reduced to about 900K. When the normalized spacing H / D is 0.5, the required fluid Reynolds number (Re) is 6125. However, when the normalized spacing H / D is reduced to 0.25, the Reynolds number (Re) only needs to be 3462. That is, under the same working conditions and equipment conditions, the fluid mass is reduced by 43.5%. The same cooling effect can be achieved simply by reducing the spacing between the glass plate and the vent.

[0087] This invention simulates the temperature change of the impact surface under different Reynolds number (Re) conditions, demonstrating that the positive effect of back pressure on jet impact heat transfer is independent of the Reynolds number (Re).

[0088] This invention saves physical space in the cooling process, significantly reduces energy consumption costs such as electricity and exhaust emissions, and thus greatly improves heat exchange efficiency. Therefore, the rational utilization of the back pressure effect saves production costs for enterprises and achieves energy conservation and emission reduction while improving productivity.

[0089] The above description, based on the preferred embodiments of the present invention, provides inspiration. Those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification but must be determined according to the claims.

Claims

1. A highly efficient impingement jet heat exchange method utilizing back pressure effect for energy saving and emission reduction, the method being based on a jet velocity measurement experimental device, the jet velocity measurement experimental device comprising a support, a fan, a PIV system, and a glass plate; The support is equipped with an air chamber that can move up and down. The air chamber and the glass plate are arranged opposite each other. The air chamber is connected to the fan through the upper and lower main air inlet pipes. The upper end of the air chamber is equipped with an air hole plate with air holes. An observation area is formed between the glass plate and the air hole plate. The distance from the air hole to the glass plate is H, and the diameter of the air hole is D. The left and right sides of the observation area are respectively formed by the feed inlet and the discharge outlet. The PIV system is located outside the observation area and is used to align with the observation area to capture images of the observation area. Its characteristic is... Includes the following steps: S1. The physical model was established, the mesh was generated, the boundary conditions were set, and the operating parameters were set. A computational fluid dynamics (CFD) solver was used to study the back pressure distribution in the flow field when the Reynolds number (Re) ranged from 3462 to 6125 and the normalized spacing H / D was 0.

25. The back pressure distribution cloud map of the flow field near the vent was obtained. S2. The physical model was established, the mesh was generated, the boundary conditions were set, and the operating parameters were defined. A computational fluid dynamics (CFD) solver was used to study the axial velocity distribution at the outlet of the vent and the tangential velocity distribution near the wall of the glass plate near the vent when the Reynolds number (Re) ranged from 3462 to 6125 and the normalized spacing H / D was 0.25 to 1.

25. Numerical simulation curves were obtained. S3. Experiments were conducted using a jet velocity measurement experimental device and the particle image velocimetry (PIV) method was used to obtain experimental results, which verified step S2 and further verified the back pressure effect. S4. Computational fluid dynamics (CFD) is used to simulate the quenching of the glass plate at high temperature. The simulation results are then verified with the experimental results from step S3. The implementation steps of the jet velocity measurement experimental device in step S3 are as follows: S3.1 Adjust the normalized spacing H / D; S3.2 Adjust the relative positions of the air chamber and the glass plate to form an observation area; S3.3 Adjust the PIV system according to the observation area range; S3.4 Control the gas flow rate and tracer particle concentration; S3.5 After the airflow pressure is uniform and the tracer particles are fully mixed, the jet region with the normalized spacing H / D is photographed, and the flow velocity data is calculated and obtained. S3.6 Adjust the normalized spacing H / D to different spacings, and repeat steps S3.2-S3.5; S3.7 Experimental results of normalized spacing H / D at different spacings under operating conditions within the Reynolds number (Re) range; S3.

8. Based on the experimental results, for jets at different Reynolds numbers (Re), the axial velocity at the outlet of the vent and the tangential velocity near the wall of the glass plate near the vent were extracted under different normalized spacing H / D, and the incident flow velocity V was used as the basis for these results. m Normalization processing; S3.9 Extract the maximum tangential velocity U of the fluid under different Reynolds numbers (Re) and different normalized spacing H / D. max The normalized maximum tangential velocity U of the fluid was obtained. max / V m The relationship between the normalized spacing H / D and the normalized maximum tangential velocity curve near the wall of the glass plate is obtained. There is an inflection point in the normalized spacing H / D, and it is independent of the Reynolds number (Re). S3.10 Extract the normalized axial velocity V at the pore outlet under different Reynolds numbers (Re) and different normalized spacing H / D. e / V m The experimental data curves in step S3 are compared with the numerical simulation curves in step S2, and the correctness of the numerical simulation model is verified.

2. The efficient impingement jet heat transfer method utilizing back pressure effect for energy saving and emission reduction as described in claim 1, characterized in that, The specific steps of step S1 are as follows: S1.1 Establish a physical model of the impact jet. The lower part is the fluid domain, and the upper part is the solid domain with glass plate as the constituent material. Air impacts the glass plate vertically through the pores of the pore plate. S1.

2. Mesh the computational domain and refine the mesh for the fluid domain and the glass plate region; S1.3 Set boundary conditions, including air being injected at different mass flow rates, inlet temperature set to 298K, turbulence intensity set to 5%, the inner wall of the fluid domain being adiabatic with no slippage, the flow outlet being designated as a pressure outlet, the pressure at the flow outlet being consistent with the ambient pressure, the lower surface of the glass plate being designated as a fluid-structure interaction boundary condition, and the rest being designated as convective heat transfer coefficient boundary conditions. S1.4 Set the normalized spacing H / D to 0.25, and the Reynolds number (Re) to 3462, 5326 and 6125 respectively. Calculate the back pressure in the flow field and obtain the back pressure distribution cloud map near the vent.

3. The efficient impingement jet heat transfer method utilizing back pressure effect for energy saving and emission reduction as described in claim 1, characterized in that, The specific steps of step S2 are as follows: S2.1 Establish a physical model of the impact jet. The lower part is the fluid domain, and the upper part is the solid domain with glass plate as the constituent material. Air impacts the glass plate vertically through the pores of the pore plate. S2.

2. Mesh the computational domain and refine the mesh for the fluid domain and the glass plate region; S2.3 Set boundary conditions, including air being injected at different mass flow rates, inlet temperature set to 298K, turbulence intensity set to 5%, the inner wall of the fluid domain being adiabatic with no slippage, the flow outlet being designated as a pressure outlet, the pressure at the flow outlet being consistent with the ambient pressure, the lower surface of the glass plate being designated as a fluid-structure interaction boundary condition, and the rest being designated as convective heat transfer coefficient boundary conditions. S2.4 Set the normalized spacing H / D to 0.25-1.25, and the Reynolds number (Re) to 3462, 5326 and 6125 respectively. Calculate the axial velocity distribution at the pore outlet and the tangential velocity distribution near the glass plate near the pore, and obtain the numerical simulation curve.

4. The efficient impingement jet heat transfer method utilizing back pressure effect for energy saving and emission reduction as described in claim 1, characterized in that, The simulation steps for quenching the glass plate at high temperature in step S4 are as follows: S4.1 Establish a physical model of the impact jet. The lower part is the fluid domain, and the upper part is the solid domain with glass plate as the constituent material. Air impacts the glass plate vertically through the pores of the pore plate. S4.

2. Mesh the computational domain and refine the mesh for the fluid domain and the glass plate region; S4.3 Set boundary conditions, including air being injected at different mass flow rates, inlet temperature set to 298K, turbulence intensity set to 5%, the inner wall of the fluid domain being adiabatic with no slippage, the flow outlet being designated as a pressure outlet, the pressure at the flow outlet being consistent with the ambient pressure, the lower surface of the glass plate being designated as a fluid-structure interaction boundary condition, and the rest being designated as convective heat transfer coefficient boundary conditions. S4.4 The initial temperature of the glass plate is set to 953K. The normalized spacing H / D is set to 0.25, 0.5, 0.75, 1 and 1.25 respectively. The Reynolds number (Re) is 3462, 5326 and 6125. The tangential velocity of the fluid near the wall of the glass plate is calculated and the simulation results of the distribution of normalized tangential velocity along the near wall are obtained. S4.

5. Verify the simulation results with the experimental results from step S3.

Images