A design method of finned heat dissipation system
By calculating the key parameters of the finned heat dissipation system and optimizing the fin area and circulation pump opening, the heat dissipation problem of the marine monitoring camera gimbal was solved, resulting in power savings and reduced system maintenance costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- 南通长三角智能感知研究院
- Filing Date
- 2022-10-09
- Publication Date
- 2026-05-29
AI Technical Summary
The heat dissipation of the pan-tilt unit of the marine surveillance camera is difficult. Traditional water cooling devices are bulky and consume a lot of power. The design of the finned tube size lacks a basis, resulting in wasted power and high maintenance costs.
By calculating the convective heat transfer coefficient between the liquid cooling plate and the refrigerant, the convective temperature difference, the thermal conductivity temperature difference, the convective heat transfer coefficient between the fins and the air, and the convective temperature difference between the fins, the fin area and the opening degree of the circulating pump can be quickly determined, the finned tube design can be optimized, and the opening degree of the circulating pump can be adjusted by adjusting the power of the chiller to save electricity.
It enables rapid design of finned tube dimensions, reduces power consumption, extends finned tube life, and lowers system operation and maintenance costs, making it suitable for offshore platforms where power supply is difficult.
Smart Images
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Abstract
Description
Technical Field
[0001] This invention relates to the field of heat dissipation system technology, and in particular to a design method for a finned heat dissipation system, which can quickly calculate the total fin area of the finned heat dissipation system and adjust the opening of the circulation pump by adjusting the power of the chiller. Background Technology
[0002] Marine surveillance camera pan-tilt units require explosion-proof and salt spray corrosion-resistant protection. The camera contains numerous heat sources; for example, to improve imaging accuracy, a chiller is typically needed to lower the camera lens temperature. Additionally, the control chips generate significant heat. These heat-generating components result in a large internal heat output for the camera. To meet explosion-proof and corrosion-resistant requirements, the entire camera must be housed in a sealed cylindrical enclosure, which cannot be welded, making heat dissipation extremely difficult. For such high heat flux density and unstable heat output, water cooling is generally employed. Traditional water cooling systems are bulky because they use chillers. While these chillers can lower the overall camera temperature, their large size makes them inconvenient to install and unsuitable for long-term operation. Therefore, traditional water cooling is unsuitable for marine surveillance camera pan-tilt units. Furthermore, improper cold-end design of the cooling system can lead to frost formation and moisture absorption, affecting normal camera operation. For marine platforms, power supply is challenging and maintenance costs are high, requiring careful consideration of system power consumption and component maintenance. Traditional liquid cooling methods using finned tubes for natural convection typically regulate the system's cooling capacity through pump flow. To ensure sufficient cooling, the system usually operates at a stable cooling power exceeding the maximum total heat output. However, for devices like marine surveillance camera pan-tilt units that operate intermittently with multiple heat sources, the total heat source power fluctuates significantly, and maintaining a consistently high cooling power output results in substantial energy waste. Furthermore, there is a lack of industry guidelines regarding finned tube fin size design, making it difficult to quickly design fin dimensions for specific projects.
[0003] In the field of platforms requiring explosion-proof and corrosion-resistant properties, there is an urgent need for a control method that controls the cyclic cooling capacity based on thermal power, as well as a method for rapidly designing finned tube dimensions. Summary of the Invention
[0004] The technical problem to be solved by the present invention is to provide a method for quickly calculating the fin area of a finned heat dissipation system and controlling the opening of the circulating pump of the finned heat dissipation system.
[0005] The design method of a finned heat dissipation system according to the present invention includes the following steps:
[0006] Step 1: The convective heat transfer coefficient h between the liquid cooling plate and the refrigerant. q Calculation: Where λ is the thermal conductivity of the refrigerant, d is the inner diameter of the finned tube, and Prq The Prandtl number for forced convection heat transfer within the liquid-cooled plate. ρ is the Reynolds number for internal forced convection heat transfer, ρ is the refrigerant density, u is the refrigerant velocity, μ is the refrigerant dynamic viscosity, and d is the inner diameter of the finned tube.
[0007] Step 2: Based on the convective heat transfer coefficient h between the liquid cooling plate and the refrigerant calculated in Step 1... q Calculate the convective temperature difference T1: Where Q is the heat output of the chiller, and S l This refers to the convective heat transfer area between the liquid cooling plate and the refrigerant.
[0008] Step 3, Calculation of thermal conductivity temperature difference T2: Where L is the thickness of the liquid cooling plate, S d λ is the heat conduction area of the liquid cooling plate. l Thermal conductivity of the liquid cooling plate;
[0009] Step 4, Calculation of the convective heat transfer coefficient hz between the fins and the air: h z =C(GrPr) z ) n Where C is 0.125, n is 1 / 3, Gr is the Grashof number for natural convection of the fins, g is the acceleration due to gravity, α is the volume change coefficient, l is the diameter of the finned tube, ν is the kinematic viscosity of the refrigerant, and Pr z Prandtl number for natural convection of the fins;
[0010] Step 5: Based on the fin-air convection heat transfer coefficient h calculated in Step 4... z Calculate the fin convection temperature difference T3: Among them, the fin area is S c ;
[0011] Step 6, fin area S c Determine: Based on the target temperature difference t ≥ T1 + T2 + T3, calculate the fin area S. c After determining the range, the fin area S is determined based on the actual situation. c ;
[0012] Step 7, at that time, the refrigerant flow rate u in the circuit i Calculation: Based on the fin area S determined in step six. c When calculating, the refrigerant flow rate u in the loop i ;
[0013] Step 8: Based on the refrigerant flow rate u in the loop calculated in step 7. i Calculate the opening degree k of the circulating pump: Where ρ is the refrigerant density, l is the diameter of the finned tube, and Q L The maximum mass flow rate provided to the circulating pump.
[0014] The above design method can quickly calculate the finned tube size, which facilitates the selection of finned tube models and greatly shortens the design and testing cycle. Furthermore, it can adjust the opening of the circulating pump by adjusting the power of the chiller, thereby minimizing power consumption while ensuring sufficient liquid cooling capacity. This makes the finned heat dissipation system suitable for offshore platforms where power supply is difficult, extends the life of the finned tube, and reduces system operation and maintenance costs.
[0015] Furthermore, in step one of the design method of the finned heat dissipation system of the present invention... Among them, c p λ is the specific heat capacity of the refrigerant, μ is the dynamic viscosity of the refrigerant, and λ is the thermal conductivity of the refrigerant.
[0016] Furthermore, in step four of the design method of the finned heat dissipation system of the present invention... Where g is the acceleration due to gravity, α is the volume change coefficient, l is the diameter of the finned tube, ν is the kinematic viscosity of the refrigerant, d is the inner diameter of the finned tube, and λ is the thermal conductivity of the refrigerant.
[0017] Furthermore, in the design method of the finned heat dissipation system of the present invention, α = 1.
[0018] Furthermore, step four of the design method for the finned heat dissipation system of the present invention... Among them, c pa For the specific heat capacity of air, μ a For aerodynamic viscosity, λ a The thermal conductivity of air.
[0019] Preferably, the liquid cooling plate used in the finned heat dissipation system design method of the present invention is made of any one of aluminum, aluminum alloy, copper, or copper alloy. These materials have high thermal conductivity, which can effectively reduce the overall thermal resistance of the system, thereby reducing the temperature loss of the refrigerant to the heat source.
[0020] Preferably, the refrigerant used in the design method of the finned heat dissipation system of the present invention is either perfluorotriethylamine or an aqueous solution of ethylene glycol. These liquids have high thermal conductivity, which can reduce the overall temperature difference in the liquid circuit and enhance heat transfer.
[0021] Compared with the prior art, the design method of the finned heat dissipation system of the present invention has the following advantages:
[0022] The design method of a finned heat dissipation system of the present invention includes (1) the convective heat transfer coefficient h between the liquid cooling plate and the refrigerant. q Calculation of (2) convective temperature difference T1, (3) thermal conductivity temperature difference T2, (4) convective heat transfer coefficient hz between fins and air, (5) convective temperature difference T3 between fins, (6) fin area Sc It is determined that (7) the refrigerant flow rate u in the circuit at that time i The calculation of (8) the opening degree k of the circulating pump, the design method provided by the present invention can quickly calculate the finned tube size, which is convenient for finned tube selection and greatly shortens the design and test cycle. The present invention can also adjust the opening degree of the circulating pump by the power of the chiller, thereby minimizing power consumption while ensuring sufficient liquid cooling capacity, making the system suitable for offshore platforms with power supply difficulties, extending the life of the finned tube, and reducing the system operation and maintenance costs. Detailed Implementation
[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.
[0024] A design method for a finned heat dissipation system includes the following steps:
[0025] Step 1: The convective heat transfer coefficient h between the liquid cooling plate and the refrigerant. q Calculation: Where λ is the thermal conductivity of the refrigerant, and d is the inner diameter of the finned tube. c is the Prandtl number for forced convection heat transfer within the liquid-cooled plate. p λ is the specific heat capacity of the refrigerant, μ is the dynamic viscosity of the refrigerant, and λ is the thermal conductivity of the refrigerant. ρ is the Reynolds number for internal forced convection heat transfer, ρ is the refrigerant density, u is the refrigerant velocity, μ is the refrigerant dynamic viscosity, and d is the inner diameter of the finned tube.
[0026] Step 2: Based on the convective heat transfer coefficient h between the liquid cooling plate and the refrigerant calculated in Step 1... q Calculate the convective temperature difference T1: Where Q is the heat output of the chiller, and S l This refers to the convective heat transfer area between the liquid cooling plate and the refrigerant.
[0027] Step 3, Calculation of thermal conductivity temperature difference T2: Where L is the thickness of the liquid cooling plate, S d λ is the heat conduction area of the liquid cooling plate. l Thermal conductivity of the liquid cooling plate;
[0028] Step 4, Calculation of the convective heat transfer coefficient hz between the fins and the air: h z =C(GrPr) z ) n Where C takes the value 0.125 and n takes the value 1 / 3. Here, denoted as Grashof number (for natural convection), g is the acceleration due to gravity, α is the volume change coefficient, l is the diameter of the finned tube, ν is the kinematic viscosity of the refrigerant, d is the inner diameter of the finned tube, and λ is the thermal conductivity of the refrigerant. (where g is the acceleration due to gravity, α = 1 is the volume change coefficient, l is the diameter of the finned tube, and ν is the kinematic viscosity of the refrigerant.) For the Prandtl number of natural convection in the fins, c pa For the specific heat capacity of air, μ a For aerodynamic viscosity, λ a Thermal conductivity of air;
[0029] Step 5: Based on the fin-air convection heat transfer coefficient h calculated in Step 4... z Calculate the fin convection temperature difference T3: Among them, the fin area is S c ;
[0030] Step 6, fin area S c Determine: Based on the target temperature difference t ≥ T1 + T2 + T3, calculate the fin area. Determine the fin area S based on the actual situation. c When Q is calculated based on the maximum heat output of the chiller under actual operating conditions, let N be the number of fins, then the fin area S c The relationship between the finned tube diameter l and the diameter l is: Fins are usually standard parts. The selection of fin diameter is based on the specific requirements of the application. The formula can be used to calculate the number of fins required for the finned tube, thus allowing for the design of the finned tube specifications and dimensions. Using the above formula, the heat output Q of the refrigeration unit is taken as the maximum operating thermal power of the refrigeration unit, and the size of the liquid cooling plate is determined based on the actual heat source size. Substituting the refrigerant properties, the fin area S can be calculated. c This allows for the selection of finned tubes based on the actual height of the system during system design, while also saving materials and reducing overall system costs.
[0031] Step 7, at that time, the refrigerant flow rate u in the circuit i Calculation: Based on the fin area S determined in step six. c The refrigerant flow rate in the circuit during calculation
[0032] Step 8: Based on the refrigerant flow rate u in the loop calculated in step 7. i Calculate the opening degree k of the circulating pump: Where ρ is the refrigerant density, l is the diameter of the finned tube, and Q LThe maximum mass flow rate provided to the circulation pump. Since the heat generated by the chip in the camera is small and stable, while the heat generated by the refrigerator is large and varies significantly with the camera's power requirements, the refrigerator can output a real-time power signal. Based on the above formula, the opening of the circulation pump can be adjusted according to the change in the refrigerator's power. This allows the circulation pump opening to be controlled in real-time by the refrigerator's power, thereby saving energy, ensuring more stable temperature on the finned tubes, reducing thermal stress on the finned tubes, and extending their lifespan.
[0033] Preferably, the liquid cooling plate used in the finned heat dissipation system design method of the present invention is made of any one of aluminum, aluminum alloy, copper, or copper alloy. These materials have high thermal conductivity, which can effectively reduce the overall thermal resistance of the system, thereby reducing the temperature loss of the refrigerant to the heat source.
[0034] Preferably, the refrigerant used in the design method of the finned heat dissipation system of the present invention is either perfluorotriethylamine or an aqueous solution of ethylene glycol. These liquids have high thermal conductivity, which can reduce the overall temperature difference in the liquid circuit and enhance heat transfer.
[0035] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.
Claims
1. A design method for a finned heat dissipation system, characterized in that, Includes the following steps: Step 1: The convective heat transfer coefficient h between the liquid cooling plate and the refrigerant. q Calculation: Where λ is the thermal conductivity of the refrigerant, d is the inner diameter of the finned tube, and Pr q The Prandtl number for forced convection heat transfer within the liquid-cooled plate. ρ is the Reynolds number for internal forced convection heat transfer, ρ is the refrigerant density, u is the refrigerant velocity, μ is the refrigerant dynamic viscosity, and d is the inner diameter of the finned tube. Step 2: Based on the convective heat transfer coefficient h between the liquid cooling plate and the refrigerant calculated in Step 1... q Calculate the convective temperature difference T1: Where Q is the heat output of the refrigerator, and S l This refers to the convective heat transfer area between the liquid cooling plate and the refrigerant. Step 3, Calculation of thermal conductivity temperature difference T2: Where L is the thickness of the liquid cooling plate, and S d λ is the heat conduction area of the liquid cooling plate. l Thermal conductivity of the liquid cooling plate; Step 4, Calculation of the convective heat transfer coefficient hz between the fins and the air: Where C is 0.125, n is 1 / 3, Gr is the Grashof number for natural convection of the fins, g is the acceleration due to gravity, α is the volume change coefficient, l is the diameter of the finned tube, ν is the kinematic viscosity of the refrigerant, and Pr z Prandtl number for natural convection of the fins; Step 5: Based on the fin-air convection heat transfer coefficient h calculated in Step 4... z Calculate the fin convection temperature difference T3: The fin area is S. c ; Step 6, fin area S c Determine: Based on the target temperature difference t ≥ T1 + T2 + T3, calculate the fin area S. c After determining the range, the fin area S is determined based on the actual situation. c : When Q is calculated based on the maximum heat output of the chiller under actual operating conditions, let N be the number of fins, then the fin area S c The relationship between the finned tube diameter l and the diameter l is: Fins are usually standard parts. The selection of fin diameter is based on the specific requirements of the application. The formula can be used to calculate the number of fins required for a finned tube; Step 7, at that time, the refrigerant flow rate u in the circuit i Calculation: Based on the fin area S determined in step six. c When calculating, the refrigerant flow rate u in the loop i : ; Step 8: Based on the refrigerant flow rate u in the loop calculated in step 7. i Calculate the opening degree k of the circulating pump: Where ρ is the refrigerant density, l is the finned tube diameter, and Q L The maximum mass flow rate provided to the circulating pump.
2. The design method of a finned heat dissipation system according to claim 1, characterized in that, In step one , where c p λ is the specific heat capacity of the refrigerant, μ is the dynamic viscosity of the refrigerant, and λ is the thermal conductivity of the refrigerant.
3. The design method of a finned heat dissipation system according to claim 1, characterized in that, In step four Where g is the acceleration due to gravity, α is the volume change coefficient, l is the diameter of the finned tube, ν is the kinematic viscosity of the refrigerant, d is the inner diameter of the finned tube, and λ is the thermal conductivity of the refrigerant.
4. The design method of a finned heat dissipation system according to claim 3, characterized in that, The volume change coefficient α = 1.
5. The design method of a finned heat dissipation system according to claim 1, characterized in that, Step four , where c pa For the specific heat capacity of air, μ a For aerodynamic viscosity, λ a The thermal conductivity of air.
6. The design method of a finned heat dissipation system according to claim 1, characterized in that, The liquid cooling plate is made of any one of the following materials: aluminum, aluminum alloy, copper, or copper alloy.
7. The design method of a finned heat dissipation system according to claim 1, characterized in that, The refrigerant is selected from either perfluorotriethylamine or an aqueous solution of ethylene glycol.