Converter valve tower heat dissipating capacity calculation method and computer equipment

Abstract

The invention belongs to the technical field of converter valves, and particularly relates to a converter valve tower heat dissipating capacity calculation method and computer equipment. The method comprises the following steps: acquiring emissivity and surface area of each material in a converter valve tower; performing weighted summation on the emissivity of all the materials according to the proportion of the surface area to obtain the average emissivity of the converter valve tower; and according to the average emissivity of the converter valve tower, calculating the radiation heat dissipating capacity of the converter valve tower. According to the method, the influence of different emissivity of different materials and different surface area ratios on the average emissivity is considered, the more accurate average emissivity of the converter valve tower can be obtained, and then the more accurate radiation heat dissipation amount of the converter valve tower can be calculated according to the average emissivity of the converter valve tower. Therefore, the calculation precision of the air heat dissipating capacity of the converter valve is improved, and reference is provided for design of the converter valve, a converter valve cooling system and a valve hall heating ventilation air conditioner.

Description

Technical Field

[0001] The present invention belongs to the technical field of converter valves, and particularly relates to a calculation method for the heat dissipation of a converter valve tower and a computer device. Background Art

[0002] As the core equipment of a high-voltage direct current (HVDC) transmission system, the normal operation of a converter valve is crucial for the stability and reliability of the entire system. During the operation of the converter valve, a large amount of heat is generated, and this heat needs to be dissipated through an effective heat dissipation method to ensure that the operating temperature of the converter valve is within the allowable range. The air heat dissipation of the converter valve tower, as one of the heat dissipation methods of the converter valve, has a direct impact on the design of the converter valve, the valve cooling system, and the HVAC of the valve hall. The air heat dissipation of the converter valve tower includes radiative heat dissipation and convective heat dissipation.

[0003] In the prior art, the calculation of radiative heat dissipation is usually carried out for objects made of a single material with regular shapes. However, a converter valve tower is often assembled from multiple materials, and the emissivities of different materials are different, so the radiative heat dissipations are also different. In the prior art, the emissivity of the entire converter valve cannot be accurately calculated, so the conventional thermodynamic calculation formula cannot be directly used to accurately calculate the radiative heat dissipation of the converter valve, resulting in a low calculation accuracy of the air heat dissipation of the converter valve and affecting the design of the converter valve, the converter valve cooling system, and the HVAC of the valve hall. Summary of the Invention

[0004] The purpose of the present invention is to provide a calculation method for the heat dissipation of a converter valve tower and a computer device, so as to solve the technical problem that the converter valve is composed of multiple materials with different emissivities, and the calculation accuracy of the overall emissivity is not high, resulting in inaccurate calculation of the radiative heat dissipation of the converter valve.

[0005] To solve the above technical problem, the present invention provides a calculation method for the heat dissipation of a converter valve tower, including the following steps:

[0006] Obtain the emissivities and surface areas of various materials in the converter valve tower; weight and sum the emissivities of all materials according to the proportion of their surface areas to obtain the average emissivity of the converter valve tower; calculate the radiative heat dissipation of the converter valve tower based on the average emissivity of the converter valve tower.

[0007] Further, the calculation method of the average temperature on the surface of the converter valve tower used in the process of calculating the radiative heat dissipation of the converter valve tower based on the average emissivity of the converter valve tower is as follows:

[0008]

[0009] In the formula, T is the average temperature on the surface of the converter valve tower, m1, m2,..., m nThe mass is divided into the mass of the first material, the second material, up to the nth material, where n is the total number of material types in the converter valve tower, T1, T2, …, T n The temperature is divided into the temperature of the first material, the second material, up to the nth material, c1, c2, …, c n The specific heat capacity is divided into the specific heat capacity of the first material, the second material, up to the nth material.

[0010] Furthermore, the following steps are also included:

[0011] Calculate the convective heat dissipation of the converter valve tower, and sum the radiative heat dissipation and the convective heat dissipation of the converter valve tower to obtain the air heat dissipation of the converter valve tower.

[0012] Furthermore, the natural convective heat transfer coefficient on the surface of the converter valve tower used when calculating the convective heat dissipation is obtained according to the relationship between the Nusselt number and the natural convective heat transfer coefficient.

[0013] Furthermore, the Nusselt number is obtained according to the correlation formula for natural convective heat transfer in a large space.

[0014] Furthermore, the calculation method of the natural convective heat transfer coefficient on the surface of the converter valve tower used when calculating the convective heat dissipation is as follows:

[0015]

[0016] In the formula, h1 is the natural convective heat transfer coefficient on the surface of the converter valve tower, T is the average temperature on the surface of the converter valve tower, T a is the ambient temperature of the valve hall, λ is the thermal conductivity of air, ρ is the air density, C p is the specific heat capacity of air, g is the acceleration due to gravity, and ν is the kinematic viscosity of air.

[0017] Furthermore, the calculation method of the average temperature on the surface of the converter valve tower used when calculating the convective heat dissipation is as follows:

[0018]

[0019] In the formula, m1, m2, …, m n The mass is divided into the mass of the first material, the second material, up to the nth material, where n is the total number of material types in the converter valve tower, T1, T2, …, T n The temperature is divided into the temperature of the first material, the second material, up to the nth material, c1, c2, …, c n The specific heat capacity is divided into the specific heat capacity of the first material, the second material, up to the nth material.

[0020] The present invention is an improved invention, and its beneficial effects are as follows: The heat dissipation calculation method for the converter valve tower of the present invention proposes a method of obtaining the average emissivity of the converter valve by weighted summing the emissivities of various materials in the converter valve according to their surface area ratios, taking into account the influence of different material emissivities and different surface area ratios on the average emissivity, and can obtain a more accurate average emissivity of the converter valve tower. Then, based on the average emissivity of the converter valve tower, a more accurate radiative heat dissipation of the converter valve tower can be calculated, thereby improving the calculation accuracy of the air heat dissipation of the converter valve and providing a reference for the design of the converter valve, the converter valve cooling system, and the HVAC of the valve hall.

[0021] To solve the above technical problems, the present invention also provides a computer device, including a processor, and the processor implements the method steps as described in the heat dissipation calculation method for the converter valve tower of the present invention when executing a computer program.

[0022] The present invention is an improved invention, and its beneficial effects are the same as those of the heat dissipation calculation method for the converter valve tower of the present invention. Description of the Drawings

[0023] Figure 1 It is a flowchart of the heat dissipation calculation method for the converter valve tower in the method embodiment of the present invention. Detailed Embodiments

[0024] A heat dissipation calculation method and a computer device for a converter valve tower of the present invention propose a method of obtaining the average emissivity of the converter valve by weighted summing the emissivities of various materials in the converter valve according to their surface area ratios, taking into account the influence of different material emissivities and different surface area ratios on the average emissivity, and can obtain a more accurate average emissivity of the converter valve tower. Then, based on the average emissivity of the converter valve tower, a more accurate radiative heat dissipation of the converter valve tower can be calculated, thereby improving the calculation accuracy of the air heat dissipation of the converter valve and providing a reference for the design of the converter valve, the converter valve cooling system, and the HVAC of the valve hall.

[0025] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments.

[0026] Method Embodiment:

[0027] As Figure 1 shown, the heat dissipation calculation method for the converter valve tower of the present invention includes the following steps:

[0028] 1. Calculate the surface average temperature of the converter valve tower.

[0029] Due to the different materials that make up the converter valve and the different specific heat capacities of different materials, the method of directly averaging the temperatures of each material does not take into account the different characteristics of different materials, and the calculation results are not accurate enough. Therefore, the following method for calculating the average temperature of the converter valve tower surface is proposed in this embodiment:

[0030]

[0031] In the formula, T is the average temperature of the converter valve tower surface, m1, m2, …, m n are the masses of the first material, the second material to the nth material respectively, n is the total number of material types in the converter valve tower, T1, T2, …, T n are the temperatures of the first material, the second material to the nth material respectively, c1, c2, …, c n are the specific heat capacities of the first material, the second material to the nth material respectively.

[0032] Second, calculate the average emissivity of the converter valve tower.

[0033] Since the converter valve tower is composed of materials with different emissivities and cannot be directly calculated using conventional thermodynamic formulas, in this invention, the emissivities of different materials are weighted and summed according to the proportion of their surface areas to calculate the comprehensive emissivity (average emissivity) of the converter valve tower. The specific calculation formula is as follows:

[0034]

[0035] In the formula, ε is the surface emissivity of the converter valve tower; A1 is the surface area of material 1 on the converter valve tower surface, with the unit of m 2 ; ε1 is the emissivity of material 1 on the converter valve tower surface; A2 is the surface area of material 2 on the converter valve tower surface, with the unit of m 2 ; ε2 is the emissivity of material 3 on the converter valve tower surface; A n is the area of material n on the converter valve tower surface, with the unit of m 2 ; ε n is the emissivity of material n on the converter valve tower surface; A is the total surface area of the converter valve tower, with the unit of m 2 .

[0036] Third, calculate the natural convection heat transfer coefficient on the converter valve tower surface.

[0037] In this embodiment, the calculation method of the natural convection heat transfer coefficient on the converter valve tower surface is as follows:

[0038]

[0039] In the formula, h1 is the natural convection heat transfer coefficient on the converter valve tower surface, T is the average temperature of the converter valve tower surface, T ais the ambient temperature of the valve hall, λ is the air thermal conductivity, ρ is the air density, C p is the specific heat capacity of air, g is the acceleration due to gravity, and ν is the kinematic viscosity of air.

[0040] In the present invention, the heat transfer between the converter valve tower and the air of the converter valve tower is equivalent to a turbulent heat dissipation model, and the values of constants and exponents are given, so as to obtain the natural convection heat transfer coefficient on the surface of the above-mentioned converter valve tower. By combining the natural convection heat transfer coefficient with the valve hall temperature and the average temperature of the valve tower surface, the convective heat dissipation of the converter valve tower can be obtained.

[0041] The convective heat transfer coefficient on the surface of the converter valve tower of the present invention is derived by the following method:

[0042] From the thermodynamic calculation formula, it can be obtained that:

[0043]

[0044] where h1 is the natural convection heat transfer coefficient on the surface of the converter valve tower, N u is the Nusselt number, λ is the air thermal conductivity, and l is the vertical height.

[0045] According to the experimental correlation formula of natural convection heat transfer in a large space, the calculation method of the Nusselt number is as follows.

[0046] N u = C(Gr·Pr) n

[0047] In the formula, Gr is the Grashof number, Pr is the Prandtl number, C is a constant, which takes the value of 0.11 in this embodiment, and n is an exponent, which takes the value of 1 / 3 in this embodiment.

[0048] The calculation method of the Grashof number is as follows:

[0049]

[0050] In the formula, g is the acceleration due to gravity, α v is the coefficient of cubical expansion, α v = 1 / T b where T b is the average temperature of the air at the hot and cold interfaces. Δt is the temperature difference between the surface temperature of the converter valve and the ambient temperature, Δt = T - T a and v is the kinematic viscosity of the ambient air.

[0051] The calculation method of the Prandtl number is as follows:

[0052]

[0053] In the formula, α is the thermal diffusivity, α = λ / (ρ·C p), where λ is the thermal conductivity of air, ρ is the density of air, and C p is the specific heat capacity of air.

[0054] According to the above calculation formula, the natural convective heat transfer coefficient h1 on the surface of the converter valve tower in this embodiment can be obtained.

[0055] IV. Calculate the radiative heat dissipation of the converter valve tower.

[0056] The calculation method of the radiative heat dissipation of the converter valve tower is as follows:

[0057] P1 = εAσ(T 4 - T a 4 )

[0058] In the formula, P1 is the radiative heat dissipation of the converter valve tower, ε is the average emissivity of the converter valve tower, A is the total surface area of the converter valve tower, σ is the Stefan-Boltzmann constant, and its value is 5.67×10 -8 W / (m·K 4 ); T is the average temperature on the surface of the converter valve tower, and T a is the ambient temperature of the converter valve hall.

[0059] V. Calculate the convective heat dissipation of the converter valve tower.

[0060] The calculation formula for the convective heat dissipation of the converter valve tower is:

[0061] P2 = h1A(T - T a )

[0062] In the formula, P2 is the convective heat dissipation of the converter valve tower, h1 is the natural convective heat transfer coefficient on the surface of the converter valve tower, A is the surface area of the converter valve tower, T is the average temperature of the converter valve tower, and T a is the average temperature (ambient temperature) of the converter valve hall.

[0063] VI. Calculate the total heat dissipation of the converter valve tower.

[0064] The total heat dissipation of the converter valve tower is equal to the sum of the radiative heat dissipation and the convective heat transfer.

[0065] P = P1 + P2

[0066] In the formula, P is the total heat dissipation of the converter valve tower (also known as the air heat dissipation), P1 is the radiative heat dissipation of the converter valve tower, and P2 is the convective heat dissipation of the converter valve tower.

[0067] Embodiment of computer equipment:

[0068] A computer device of the present invention includes a processor, and when the processor executes a computer program, it implements the method steps described in the method for calculating the heat dissipation of a converter valve tower in the method embodiment of the present invention. The specific process, principle, beneficial effects, etc. of this method have been described in detail in the method embodiment, and will not be elaborated in this embodiment.

[0069] Among them, the processor can be a processing device such as a microprocessor MCU or a programmable logic device FPGA.

[0070] A method for calculating the heat dissipation of a converter valve tower and a computer device of the present invention add the products of the emissivity and surface area of all materials in the converter valve tower, and then divide by the total surface area of the converter valve tower to obtain the average heat dissipation rate of the converter valve tower, which can accurately reflect the surface radiation heat dissipation ability of the converter valve tower, thereby improving the calculation accuracy of the radiation heat dissipation of the converter valve tower. Combining with the convective heat dissipation of the converter valve tower, the accurate air heat dissipation of the converter valve tower can be obtained, providing guidance for the design of converter valves, converter valve cooling systems, and HVAC. Further, the calculation method of the average surface temperature of the converter valve tower of the present invention is improved, considering the mass and corresponding specific heat capacity of different materials, and the more accurate average temperature of the converter valve tower is calculated, further improving the calculation accuracy of the radiation heat dissipation and air heat dissipation of the converter valve tower. Further, the natural convection heat transfer coefficient is obtained according to the relationship between the Nusselt number and the natural convection heat transfer coefficient, and the large-space natural convection heat transfer experimental correlation is further used to calculate the Nusselt number, improving the accuracy of the natural convection heat transfer coefficient, thereby improving the calculation accuracy of the convective heat dissipation.

Claims

1. A method for calculating heat dissipation of a converter valve tower, characterized in that: The following steps are involved: The emissivity and surface area of ​​various materials in the converter valve tower are obtained; the average emissivity of the converter valve tower is obtained by weighted summing the emissivity of all materials according to the proportion of their surface areas; and the radiant heat dissipation of the converter valve tower is calculated based on the average emissivity of the converter valve tower.

2. The method for calculating heat dissipation of a converter valve tower according to claim 1, characterized in that: The calculation method of the average surface temperature of the converter valve tower used in calculating the radiation heat dissipation of the converter valve tower based on the average emissivity of the converter valve tower is as follows: Where T is the average temperature of the valve tower surface, m1, m2, ..., m n It is divided into the quality of the first material, the second material to the nth material, where n is the total number of material types in the converter valve tower, T1, T2, ..., T n Divided into the temperature of the first material, the second material to the nth material, c1, c2, ..., c n It is divided into the specific heat capacity of the first material, the second material to the nth material.

3. The method for calculating heat dissipation of a converter valve tower according to claim 1, characterized in that: The following steps are also included: The convective heat dissipation of the converter valve tower is calculated, and the radiation heat dissipation and the convective heat dissipation of the converter valve tower are summed to obtain the air heat dissipation of the converter valve tower.

4. The method for calculating heat dissipation of a converter valve tower according to claim 3, characterized in that: The natural convection heat transfer coefficient of the valve tower surface used in calculating the convection heat dissipation is obtained based on the relationship between the Nusselt number and the natural convection heat transfer coefficient.

5. The method for calculating heat dissipation of a converter valve tower according to claim 4, characterized in that: The Nusselt number is obtained based on the experimental correlation of natural convection heat transfer in large spaces.

6. The method for calculating heat dissipation of a converter valve tower according to claim 3, characterized in that: The natural convection heat transfer coefficient on the valve tower surface used in calculating convection heat dissipation is calculated as follows: Where h1 is the natural convection heat transfer coefficient on the valve tower surface, T is the average temperature on the valve tower surface, and T a is the ambient temperature of the valve hall, λ is the thermal conductivity of air, ρ is the air density, C p is the specific heat of air, g is the acceleration due to gravity, and ν is the kinematic viscosity of air.

7. The method for calculating heat dissipation of a converter valve tower according to claim 3, characterized in that: The average temperature of the valve tower surface used in calculating the convective heat dissipation is calculated as follows: Where m1, m2, …, m n It is divided into the quality of the first material, the second material to the nth material, where n is the total number of material types in the converter valve tower, T1, T2, ..., T n Divided into the temperature of the first material, the second material to the nth material, c1, c2, ..., c n It is divided into the specific heat capacity of the first material, the second material to the nth material.

8. A computer device comprising a processor, characterized in that: The processor implements the steps of the method for calculating the heat dissipation of a converter valve tower as described in any one of claims 1 to 7 when executing the computer program.

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